Department of Chemistry and Physics
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Item Activity of sterols isolated from the leaves of commiphora swynnertonii (Burtt) against some nosocomial infectious bacteria(The Journal of Phytopharmacology, 2022-09-04) Credo, David; Mabiki, Faith P.; Machumi, Francis; Chacha, Musa; Cornett, ClausCommiphora swynnertonii (Burtt) is traditionally used for medicinal purposes both in humans and animals in Tanzania. Previously, its leaves extract has been demonstrated antibacterial activity. However, there is limited information on identification of pure compounds responsible for its observed antibacterial activity. Therefore, this study was conducted to isolate and evaluate antibacterial activity of pure compounds isolated from its leaves extract. Colum chromatographic separation of its dichloromethane leaves extract afforded the isolation of two sterols namely, Cholest-7-en-3β-ol (1) and β-sitosterol (2). Their structures were deduced by using NMR data experimentally obtained and comparison with spectral data available in literatures. The sterols were evaluated for activity against four nosocomial infectious bacteria namely; Staphylococcus aureus, Enterococcus faecalis, Escherichia coli and Pseudomonas aeruginosa to determine Minimum Inhibitory Concentrations (MIC) by broth microdilution method. Cholest-7-en-3β-ol (1) demonstrated strong activity against S. aureus (MIC= 0.5 mg/ml) and weak activities (MIC >2mg/ml) against other bacteria. β-sitosterol (2) exhibited weak activities (MIC >2mg/ml) against all tested bacteria. Therefore, presence of antibacterial active compound(s) such as Cholest-7-en-3β-ol (1) among others in the leaves of C. swynnertonii can justify its earlier reported antibacterial activity and further confirms the claimed traditional uses of this plant in the treatment of bacterial infections.Item Antibacterial effects of single and combined crude extracts of synadenium glaucescens and commiphora swynnertonii(2022) Ochollah, G, Mary; Olsen, E, John; Mdegela, H, Robinson; Kusiluka, J.M, Lughano; Mabiki, P, Faith; Msengwa, S, ZaituniBackground: Synadenium glaucescens and Commiphora swynnertonii are among the reported plants used traditionally for treatment of bacterial infections. This study reports antibacterial effects of single and combined extracts from leaves, stem and root barks of Commiphora swynnertonii and Synadenium glaucescens. Materials and Methods: Plants were collected from Manyara and Njombe regions in Tanzania. Extraction was done using dichloromethane and methanol. The extracts were assessed for antibacterial activity against Gram-positive bacteria (Staphylococcus aureus and Enterococcus faecalis) and Gram-negative bacteria (Escherichia coli, Klebsiella pneumonia and Pseudomonas aeruginosa). Minimum Inhibitory Concentrations (MIC) was determined by broth microdilution, while Fractional Inhibitory Concentration (FIC) indices were calculated from MIC values of combined extracts to determine combination effects. Results: Strong antibacterial activities were demonstrated by all extracts of S. glaucescens (MIC 0.011-0.375mg/mL) against Gram-positive bacteria and methanol extracts of C. swynnertonii (MIC 0.047-0.375mg/mL). Synergistic effect was observed when combining methanol extracts of C. swynnertonii stem bark with S. glaucescens leaves against S. aureus (∑FIC 0.5), Other synergistic effects were observed against E. faecalis with dichloromethane extracts of C. swynnertonii stem bark and S. glaucescens stem bark (∑FIC 0.5), and C. swynnertonii root bark and S. glaucescens root bark (FIC index 0.3). For the remaining combinations, mainly additive effects were observed. Conclusion: Synergistic effects on bacteria were observed by combining different plant parts of S. glaucescens and C. swynnertonii suggesting that it could be beneficial to combine such extracts when used for antibacterial purposes.Item Assessing significance of community documented climate impacts and adaptation preferences and options in the lake victoria region, Tanzania(Ethiopian Journal of Environmental Studies & Management, 2017-02-13) Elisante, E.; Tungaraza, C.The study was conducted in Ukerewe Island in the Lake Victoria, Tanzania in order to ascertain the communities’ awareness on climate change impacts and adaptation/coping strategies. The methodology involved randomly selected 420 people mostly farmers and fishermen who were interviewed and involved in focus groups. It was observed that communities were aware of the changes in climatic parameters consequently impacting their livelihood. The most significant impacts were scarcity of water and poor crop production which received 100% support of the respondents. Other impacts included the change of water quality of the Lake Victoria (94.5%) and loss of biodiversity (35.7%). On the non-climatic factors, the major concern was on population growth (98.3%), loss of soil fertility (96%) and deforestation (84.8%). Of the suggested adaption options, provision of alternative food crops and fertility improvement to increase production were highly supported with highest total score of 48 on an arbitrary total assessment scale of maximum of 50. This was also observed on fish farming activities. The observations highlighted gender-based labour division imbalance where women and children were shown to shoulder the burden. It can be concluded that communities in the Lake Victoria region are affected by multiple impacts related to climate and also those not related to climate. Under various impacts communities set their own coping and adaptation strategies based on importance to livelihood. However, there is a need for proper guidance on how adaptation strategies are being executed.Item Assessment of sources and transformation of nitrate in groundwater on the slopes of Mount Meru, Tanzania(Springer, 2015-09-21) Elisante, Eliapenda; Muzuka, Alfred N. N.The stable isotope compositions of nitrogen-nitrate ( 15 N-NO 3 ) and oxygen-nitrate ( 18 O-NO 3 ), and concentration of nutrients (NO 3 - , NH 4 ? , NO 2 - , PO 43- ) for water samples collected from springs, shallow wells and boreholes during dry and wet seasons were used to inves- tigate sources and biogeochemical transformation of NO 3 - in groundwater along the slopes of Mount Meru. About 80 % of all water sources had nitrate concentration higher than background concentration of 10 mg/l during both seasons, while NH 4 ? and NO 2 - concentrations were very low probably due to nitrification. Concentrations of NO 3 - above 50 mg/l were observed in some water sources. Concentrations of PO 43- in all groundwater sources were very low during the two seasons owing to dilution and adsorption. The d 15 N-NO 3 - for boreholes waters averaged ?11.6 ± 2.1 and ?10.7 ± 2.1 % during dry and wet seasons, respectively. Similarly, the d 18 O-NO 3 - of bore- hole waters for the wet and dry seasons averaged ?5.2 ± 1.3 and ?4.6 ± 1.9 %, respectively. With regard to dug wells, the d 15 N-NO 3 - of well water averaged ?13.3 ± 2.5 and ?12.5 ± 2.3 % during dry and wet seasons, respectively, while the d 18 O-NO 3 - for the wet and dry seasons averaged ?7 ± 2.3 and ?6.4 ± 2.1 %, respectively. The d 15 N-NO 3 - , for springs averaged ?11.2 ± 2.2 % during dry season and ?11.7 ± 3.5 % during wet season whereas the d 18 O-NO 3 - for the wet and dry seasons averaged ?7.3 ± 3.6 and ?5.9 ± 2.6 %, respectively. The isotopic data suggested that the source of NO 3 - in the water sources are dominated by sewage and/or animal manure and to less extent, soil organic N. Few samples collected in close proximity of manure heaps and sanitary facilities had d 15 N values between 16 and 20 %suggesting occurrence of denitrification.Item Bacteriostatic and haemolytic activities of extracts and compounds of commiphora swynnertonii(Research Journal of Pharmacognosy, 2023) Msengwa, Zaituni; Credo, David; Mafuru, Magesa; Mwesongo, James; Mabiki, Faith Philemon; Mwang’onde, Beda John; Mtambo, Madundo Mkumbukwa; Kusiluka, Lughano Jeremy; Mdegela, Robinson Hammerthon; Olsen, John ElmerdahlBackground and objective: Commiphora swynnertonii (Pax) is used in traditional medicine to treat infectious diseases. Previous studies have reported antimicrobial activity of this plant; however, the activity of compounds that are present in extracts of this plant has not been thoroughly documented. Likewise, the primary mode of action (bactericidal or bacteriostatic) and the possible toxicity on red blood cells have not been reported. Methods: Extracts of leaves, whole root, root bark, root wood, whole stem, stem bark and stem wood, were produced using hexane, dichloromethane, methanol and water. Cold and hot extraction methods were employed. Antibacterial activity of extracts was tested against selected medically important Gram-positive and Gram-negative bacteria by growth inhibition, minimum inhibitory concentrations and time kill assays. Moreover, haemolytic activity against sheep red blood cells was determined in vitro. Results: The hexane extracts of whole root and root bark, methanol extracts of root wood, and dichloromethane extracts from the leaves of C. swynnertonii inhibited the growth of S. aureus. MIC values for the extracts and compounds, indicated moderate activity against Gram-positive bacteria (Staphylococcus aureus, Streptococci species and Enterococci species) while the activity against Gram-negative bacteria (Escherichia coli, Klebsiella species, Pseudomonas aeruginosa, Salmonella species, Shigella sonnei and Yersinia enterocolitica) was weak. Time kill profiles showed the extracts have bacteriostatic activity against S. aureus, and low haemolytic effect, except for extracts of whole root and leaves at the concentration of 1000 μg/mL. Conclusion: Extracts of C. swynnertonii showed bacteriostatic activity against Gram-positive bacteria with low toxicity on red blood cells.Item Comparison of two models in the estimation of nitrogen uptake rates using data from 15-N incubation experiments(nstitute of Oceanology PAS, 2005-08-16) Tungaraza, Clavery; Brion, Natacha; Baeyens, WillyThis paper compares two uptake rate models, Dugdale & Goering’s (D&G) model and Elskens’ model. The aim is to provide an insight into how estimates of uptake processes, i.e. regeneration and loss rates from both dissolved and particulate nitrogen pools, influence the total uptake rates when the two models are compared. The uptake rates of three nitrogenous nutrients (nitrate, ammonium and urea) from 15-N incubation experimental data were compared. The comparison indicated that the D&G model underestimated nitrate uptake rates by about 34%, implying a significant regeneration and loss rates of the nutrient. Elskens’ model further showed that the loss rates from the dissolved phase were about 40% and 25% for the ammonium and urea pools, respectively, indicating that the D&G model underestimated the experimental uptake rates of the nutrients. On average, nitrification made up about 30% of the total ammonium uptake flux, whereas the sinks from particulate nitrogen and dissolved nitrogen were estimated at 36% and 56%, respectively. The D&G model sometimes overestimated the f -ratio values to about 60% and higher as a result of ammonium and urea uptake rates underestimation. This paper also shows that detritus adsorption, bacterial uptake and cell lysis are equally important processes.Item Contamination and health risk assessment of heavy metals in selected highly edible fish species from lake Nyasa, Tanzania(Springer, 2023-04) Mwambene, Bupoki; Mwakalesi, Alinanuswe J.; Nehemia, Alex NahnsonHeavy metal contamination emanating from increased industrial and anthropogenic activities poses considerable environmen- tal risks to water resources, aquatic biodiversity, and human health. These metals are major sources of various unfavorable environmental changes and human health hazards. This research investigated the potential contamination level and health risk assessment of heavy metals (Fe, Zn, Ni, Cu and Cr) in five highly edible fishes (O. microlepis, C. gariepinus, O.niloticus, R. moorii,B. meridionalis) from Lake Nyasa. The results indicated that gills contained higher amounts of heavy metals compared to muscles. The levels of Fe and Zn were higher in the gills of C. gariepinus and O.niloticus than O. microlepis, R. moorii, and B. meridionalis. Similarly, amounts of Cu and Cr were higher in the gills of C. gariepinus and O. microlepis. The general trend of heavy metal concentrations accumulated in selected fish species was Fe > Zn > Ni > Cu > Cr. The amounts of heavy metals found in the fish samples were within acceptable limits set by FAO and WHO. Furthermore, the risk assessments indicated that the current exposure levels are unlikely to cause serious health risks. However, the progressive monitoring of levels of heavy metals in various aquatic organisms from Lake Nyasa is important for the continued protection of human health against hazardous health effects.Item Corrosion inhibition of Amino Pentadecylphenols (APPs) derived from Cashew Nut shell liquid on mild steel in Acidic medium(Scientific Research Publishing Inc., 2016-08) Philip, Joseph Yoeza Naimani; Buchweshaija, Joseph; Mwakalesi, Alinanuswe J.In this study, corrosion inhibiting properties of amino pentadecylphenols (APPs) derived from Cashew Nut Shell Liquid (CNSL) on mild steel in aerated 0.10 M HCl at 303 K were studied using Electrochemical Impedance Spectroscopy (EIS) and potentiodynamic polarization measurements. Both methods indicated the potential of a mixture of amino pentadecyphenols to serve as a corro- sion inhibitor in mild steel in 0.10 M HCl. Corrosion inhibition efficiencies were observed to in- crease with increase in the inhibitor concentration, with maximum corrosion inhibition of about 98% at inhibitor concentration of 600 ppm. The adsorption of the inhibitor on mild steel surface was found to obey Temkin adsorption isotherm, signifying physical adsorption of the inhibitor molecules on mild steel surface.Item Corrosion inhibition of mild steel in sulphuric acid solution with tetradenia riparia leaves aqueous extract: kinetics and thermodynamics(ResearchGate, 2022-01-23) Mwakalesi, Alinanuswe J.One of the most successful ways for maximizing profit and lowering costs is to use mild steel over other corrosion-resistant alloys. As a result, mild steel is the most commonly used metallic material in many industries, and its corrosion resistance has received a lot of attention. The mild steel corrosion inhibition using compounds derived from plants is the most practicable and preferable technique because of their linked low cost and green chemistry credentials. This study reports on the kinetics and thermodynamics of mild steel corrosion inhibition in sulphuric acid media utilizing Tetradenia riparia leaves aqueous extract as a potential green inhibitor. The investigations were carried out using the gasometric technique. The findings indicated that the corrosion inhibition efficiency (IE) increased with increasing inhibitor concentration with an optimal value of 90.6% at 500-ppm. The increase in temperature 298 to 338 K lowered the corrosion inhibition efficiency by only 4%. The adsorption kinetics of the extract on the mild steel fit into Langmuir, Temkin, EL-awady, and Freundlich models, but the Langmuir was the best. The results of this investigation show that adsorption of the extracted chemicals on mild steel in a sulphuric acid solution is feasible and most likely involves a combination of physical and chemical adsorption.Item Dependence of air quality on meteorological parameters in Dar es Salaam, Tanzania(Tanzania Journal of Natural and Applied Sciences, 2010) Mkoma, Stelyus L.; Kimambo, Offoro N.; Mabiki, Faith P.; Tungaraza, Clavery T.The influence of meteorology on air quality in Dar es Salaam was investigated. Precipitation, temperature, relative humidity and wind speed were measured during wet and dry seasons of 2005 and 2006 period and their relationship with reported mass of particles of aerodynamic diameter smaller than 10 μm (PM10) for the site was assessed. Results indicate that the highest median concentrations for the PM10 mass (58 μg/m 3 ) was observed during the 2005 dry season and the lowest median (40 μg/m 3 ) during the 2006 wet season. It is interpreted that reasons for the higher levels of the PM10 mass in the dry season are due to temperature inversions, soil dust dispersal and absence of rain wash-down. The observed PM10 levels are also affected by the variations in sources strengths and in meteorological conditions such as mixing height, precipitation, relative humidity, wind speed and direction as supported by air mass trajectories.Item Development and validation of lc-ms/ms method for determination of non-opioid analgesics in adulterated herbal medicines(Sokoine university of agriculture, 2022) Mpanyakavili, Anna LucasBackground: Herbal medicines are increasingly used worldwide despite the increased concern of their adulteration with conventional drugs. Non-opioid analgesics are among of the conventional drugs reported to be used in adulteration of anti-pain herbal medicines. This rise a need for developing reliable analytical method for determination of adulterated conventional drugs in herbal medicines for quality control. This study aimed at developing a high throughput Liquid Chromatography coupled with Tandem Mass Spectrometry for determination of non-opioid analgesics (acetaminophen, caffeine, acetylsalicylic acid, diclofenac, and ibuprofen) in herbal medicines in one run. The study also aimed at optimizing a sample preparation technique to enhance detection of the adulterants in herbal medicine obtained from the Tanzania market. Methodology: Solid Phase Extraction (SPE) and Ultrasonic Assisted Extraction (UAE) methods were compared in respect of recoveries, extraction time, complexity, matrix effects, and expenses for sample preparation. Waters OASIS Hydrophilic-lipophilic balance (HLB) 200 mg 6 mL, a C 18 sorbent was used in Solid Phase Extraction method optimization. The optimized parameters were effects of filters on sample filtration, sample loading pH, selection of suitable solvents for conditioning, washing, and elution. Ultrasonic bath and centrifuge were used for optimization of ultrasonic assisted extraction method parameters including effectives of organic solvent in extraction, extraction solvent content, and sample to extraction solvent volume ratio. Both methods were evaluated by calculating their matrix effects, absolute recoveries, and percentage recovery for sub- steps. The effective sample preparation method was used in development and validation of an advanced hyphenated method using an Agilent Technologies 1100 series Liquid Chromatography coupled with Waters Tandem Mass spectrometry (LC-MS/MS) with electrospray ionization. The LC-MS/MS method was validated for its selectivity, sensitivity, linearity, accuracy, precision, recovery, matrix effects, and stability. It was then used to analyse 132 samples collected from the markets of four regions in Tanzania. Results and Discussion: The Ultrasonic Assisted Extraction method showed to be efficient to Solid Phase Extraction method for extraction of selected non-opioid analgesics. This was clearly evidenced by high recoveries, minimum extraction time, good peak shape, its simplicity in procedures, and use of less expensive consumables. The absolute recoveries for Ultrasonic Assisted Extraction were at acceptable range (> 60%) ranging from 60 % to 107 % while for Solid Phase Extraction method showed poor recovery except for diclofenac and ibuprofen having 83% and 67%, respectively. The matrix effect expressed as signal suppression/enhancement ranged from 70% - 122% for Ultrasonic Assisted Extraction method and 3% to 124% for Solid Phase Extraction method. From the results the Ultrasonic Assisted Extraction method was chosen for sample extraction for analysis of Herbal Samples. The developed LC-MS/MS method was linear with coefficient of determination of R 2 ≥ 0.9931. The Limit of Detection (LOD) and Limit of Quantification (LOQ) for selected non-opioid analgesics were within the range of 0 – 3.7 μg/mL. The intra-precision of the LC-MS/MS method was expressed as Relative Standard deviation and was less than 9.5% with varying matrix effect among analytes. Twenty one percent (21%) of 132 collected herbal medicines were adulterated with caffeine and acetylsalicylic acid. 1,029.22 μg/mL was one of the highest concentration of caffeine detected in one of the analysed herbal medicines. Conclusion and recommendation: This is the first study in Tanzania to report an analytical method for analysis of five (5) non opioid analgesics in herbal medicines in Tanzania. The developed LC-MS/MS method is suitable for the identification and quantification of 5 non opioid analgesics explored adulterants. The method can be adopted by the regulatory authorities for routine analysis of herbal medicines for monitoring its quality and safety. Further studies are recommended for Ultrasonic Assisted Extraction method using additional internal standards. Key words: Herbal medicines, Adulteration, Analgesics, Solid Phase extraction, Ultrasonic assisted extraction, LC-MS/MS. Usuli wa tatizo: Ongezeko la matumizi ya dawa zitokanazo na mimea-dawa linazidi kukua ulimwenguni licha ya wasiwasi uliopo wa kuathiriwa kwa dawa hizo kwa kuchanganywa na dawa za kisasa. Dawa za kutuliza maumivu za kisasa ni miongoni mwa dawa zinazoripotiwa kuongezwa katika dawa zitokanazo na mimea dawa za kupunguza maumivu na hivyo kushusha ubora wake. Hivyo, kuna uhitaji mkubwa wa kuunda njia ya kisayansi yenye kuaminika kwa ajili ya uchambuzi na utambuzi wa dawa zitokanazo na mimea dawa zilizochanganywa na dawa za kisasa ili kudhibiti ubora na kuongeza usalama kwa watumiaji. Utafiti huu ulilenga kutengeneza njia ya kisayansi ya uchambuzi inayotumia teknolojia ya LC-MS/MS ili kubaini aina na kiasi cha dawa za kisasa za kutuliza maumivu (asetaminopheni, kafeini, aspirini, diclofenaki, na ibuprofeni) zilizomo ndani ya dawa zitokanazo na mimea dawa. Utafiti huu pia ulilenga kuboresha mbinu ya utayarishaji wa sampuli ili kuboresha ugunduzi wa dawa za kisasa ndani ya dawa zitokanazo na mimea dawa zinazopatikana katika soko la Tanzania. Methodolojia: Utafiti ulilinganisha njia mbili, Solid Phase Extraction (SPE ) na Ultrasonic Assisted Extraction (UAE), kwa kuzingatia uhuishaji, muda ambao ulitumika kuchukua kiziduo, athari za dutu za ziada, na gharama za uandaaji wa sampuli. Teknolojia ya Waters OASIS Hydrophilic-lipophilic balance (HLB) 200 mg 6 mL, sobanti C18 ilitumika katika mchakato wa kuchambua dutu lengwa. Vigezo stahiki vilipatikana kutokana na athari zilizojitokeza katika uandaaji wa sampuli. Pia teknolojia ya ultrasonic assisted extraction ilitumika kuweka sawa mchakato wa kikemikali wa kuchambua dutu lengwa kutoka kwenye sampuli. Njia zote mbili zilitathiminiwa kwa kukokotoa athari zilizojitokeza, kiasi cha dutu zilizopatikana katika mchakato, na kiasi cha dutu kilichopatikana katika hatua zilizofuata. Njia bora ya kuandaa sampuli stahiki ilitumika katika kutengeneza na kuthibitisha njia yenye ufanisi wa kuchambua dutu lengwa. Kukamilisha zoezi hili, teknolojia ya Agilent Technologies 1100 series Liquid Chromatography na ile ya Waters Tandem Mass spectrometry (LC-MS/MS) yenye electrospray ionization vilitumika. Njia ya LC-MS/MS ilihakikiwa uwezo wake katika kubaini dutu husika, usahihi, utoshelevu, na umadhubuti. Aidha, njia hii ilitumika kuchambua sampuli 132 zilizokusanywa kutoka kwenye masoko ya mikoa minne nchini Tanzania. Matokeo na mjadala: Njia ya UAE ilionyesha kuwa na ufanisi katika kuandaa sampuli ya dawa za kupunguza maumivu zilizochaguliwa kwa ajili ya utafiti. Hii ilithibitishwa na uwezo mkubwa katika kuhuisha, kutumia muda mchache, kutoa taswira nyoofu, urahisi katika kutumia pamoja na utumiaji wa malighafi za gharama ndogo. Uhuishaji halisi wa UAE ulikuwa katika kiwango kinachokubalika, yani, kuanzia 60 % hadi 107 %, wakati njia ya SPE ilionesha uhuishaji dhaifu isipokuwa kwa diclofenac (83%) na ibuprofen (67%). Athari za ziada zilizooneshwa kama alama zilizodhibitiwa (fiche) zilianzia 70% - 122% kwa njia ya UAE na 3% hadi 124% kwa njia ya SPE. Kutokana na matokeo, UAE ilichaguliwa kwa ajili ya kuandaa sampuli zitokanazo na mimea dawa kwa ajili ya uchambuzi. Njia ya LC-MS/MS ililandana na kizigeu-tambuzi, R 2 ≥ 0.9931, upeo wa kubaini pamoja na upeo wa kiasi kwa dawa za kuzuia maumivu zilizotafitiwa zilikuwa kati ya 0 – 3.7 μg/mL. Utashelevu wa ndani wa njia ya LC-MS/MS ilijidhihirisha kama achano sanifu-wiano ambalo lilikuwa 9.5% iliyokuwa na athari za ziada mbalimbali katika dutu zilizochambuliwa. Asilimia ishirini na moja (21%) ya dawa 132 za asili zilikuwa zimechanganywa na kafeini na aspirini. Kiasi cha juu cha kafeini kilichogunduliwa katika dawa zilizochunguzwa ni 1,029.22 μg/mL. Hitimisho na mapendekezo: Huu ni utafiti wa kwanza nchini Tanzania uliotumia njia changanuzi kuchunguza uwepo wa dawa tano za kisasa ndani ya dawa zitokanazo na mimea dawa za kutuliza maumivu. Njia iliyobuniwa ya LC-MS/MS ilifaa katika kutambua na kupima dawa tano za kupunguza maumivu zilizotumika kama viharibifu. Hivyo, njia hii inaweza kutumiwa na mamlaka za udhibiti wa ubora na usalama wa dawa za asili. Inapendekezwa kuwa tafiti zaidi zifanyike kutengeneza njia zingine za LC-MS/MS kwa dawa zingine ili kudhibiti ubora wake. Maneno muhimu: Dawa za mimea-dawa, kuchanganywa, dawa za kutuliza maumivu, uziduzi, LC-MS/MS.Item Development and validation of LC-MS/MS method for determination of non-opioid analgesics in adulterated herbal medicines(Sokoine University of Agriculture, 2022-11) Mpanyakavili, Anna LucasBackground: Herbal medicines are increasingly used worldwide despite the increased concern of their adulteration with conventional drugs. Non-opioid analgesics are among of the conventional drugs reported to be used in adulteration of anti-pain herbal medicines. This rise a need for developing reliable analytical method for determination of adulterated conventional drugs in herbal medicines for quality control. This study aimed at developing a high throughput Liquid Chromatography coupled with Tandem Mass Spectrometry for determination of non-opioid analgesics (acetaminophen, caffeine, acetylsalicylic acid, diclofenac, and ibuprofen) in herbal medicines in one run. The study also aimed at optimizing a sample preparation technique to enhance detection of the adulterants in herbal medicine obtained from the Tanzania market. Methodology: Solid Phase Extraction (SPE) and Ultrasonic Assisted Extraction (UAE) methods were compared in respect of recoveries, extraction time, complexity, matrix effects, and expenses for sample preparation. Waters OASIS Hydrophilic-lipophilic balance (HLB) 200 mg 6 mL, a C 18 sorbent was used in Solid Phase Extraction method optimization. The optimized parameters were effects of filters on sample filtration, sample loading pH, selection of suitable solvents for conditioning, washing, and elution. Ultrasonic bath and centrifuge were used for optimization of ultrasonic assisted extraction method parameters including effectives of organic solvent in extraction, extraction solvent content, and sample to extraction solvent volume ratio. Both methods were evaluated by calculating their matrix effects, absolute recoveries, and percentage recovery for sub- steps. The effective sample preparation method was used in development and validation of an advanced hyphenated method using an Agilent Technologies 1100 series Liquid Chromatography coupled with Waters Tandem Mass spectrometry (LC-MS/MS) with electrospray ionization. The LC-MS/MS method was validated for its selectivity, sensitivity, linearity, accuracy, precision, recovery, matrix effects, and stability. It was then used to analyse 132 samples collected from the markets of four regions in Tanzania. Results and Discussion: The Ultrasonic Assisted Extraction method showed to be efficient to Solid Phase Extraction method for extraction of selected non-opioid analgesics. This was clearly evidenced by high recoveries, minimum extraction time, good peak shape, its simplicity in procedures, and use of less expensive consumables. The absolute recoveries for Ultrasonic Assisted Extraction were at acceptable range (> 60%) ranging from 60 % to 107 % while for Solid Phase Extraction method showed poor recovery except for diclofenac and ibuprofen having 83% and 67%, respectively. The matrix effect expressed as signal suppression/enhancement ranged from 70% - 122% for Ultrasonic Assisted Extraction method and 3% to 124% for Solid Phase Extraction method. From the results the Ultrasonic Assisted Extraction method was chosen for sample extraction for analysis of Herbal Samples. The developed LC-MS/MS method was linear with coefficient of determination of R 2 ≥ 0.9931. The Limit of Detection (LOD) and Limit of Quantification (LOQ) for selected non-opioid analgesics were within the range of 0 – 3.7 μg/mL. The intra-precision of the LC-MS/MS method was expressed as Relative Standard deviation and was less than 9.5% with varying matrix effect among analytes. Twenty one percent (21%) of 132 collected herbal medicines were adulterated with caffeine and acetylsalicylic acid. 1,029.22 μg/mL was one of the highest concentration of caffeine detected in one of the analysed herbal medicines. Conclusion and recommendation: This is the first study in Tanzania to report an analytical method for analysis of five (5) non opioid analgesics in herbal medicines in Tanzania. The developed LC-MS/MS method is suitable for the identification and quantification of 5 non opioid analgesics explored adulterants. The method can be adopted by the regulatory authorities for routine analysis of herbal medicines for monitoring its quality and safety. Further studies are recommended for Ultrasonic Assisted Extraction method using additional internal standards.Item Ecotoxicity of mercury contaminated sediment collected from Mabubi river (Geita district, Tanzania) to the early life stages Of African catfish (clarias gariepinus)(Elsevier, 2009) Chibunda, R.T; Pereka, A. E; Phiri, E.C.J; Tungaraza, C.The quality of Hg contaminated sediments in artisanal gold mining areas of Tanzania have to date only been assessed through bulk chemical analysis. However, measurement of contaminant levels alone has a limited ability to predict adverse effects on living resources. In this study we investigated the possible effects of Hg contaminated sediments from the river Mabubi which drains the artisanal gold mine on the hatching success, larval survival and growth of the African catfish (Clarias gariepinus). The tested species is a resident fish whose demersal behaviour keeps it in frequent contact with the sediment. Sediments collected downstream of the mine decreased survival and impaired growth of Clarias gariepinus but did not affect its hatching success. These effects were observed up to six kilometres downstream of the mining activity. The calculated 5 d- LC 50 value (larval survival) was 1.75 μg/g Hg dw (95% CL of 0.72 – 2.53), the 5d-NOEC for hatching was >2.3 μg/g Hg dw and that for larval survival and growth was 0.23 μg/g Hg dw. In conclusion, chemistry and ecotoxicity results from this study suggest that sediments collected downstream of the mine adversely affect catfish and probably other fauna and as such present a considerable local environmental risk.Item Effect of changes in business environments on traded medicinal plants products in Tanzania: an explorative study(Heliyon, 2022) Mpelangwa, Eziacka Mathew; Makindara, Jeremia Ramos; Sorensen, Olav Jull; Bengesi, Kenneth Michael Kitundu; Mabiki, Faith PhilemonIn Tanzania, a complex rural to urban supply network for the medicinal plants' products trade has developed over time driven by changes in business environments at the macro level notably in the policy and regulatory frameworks and the micro level resulting from traders’ reactions and responses to those changes and pandemics. These changes in business environments and responses of traders have shaped the current trade practices. However, the response of traders to changes in business environments and the evolutionary paths over time are not well documented. Therefore, this paper aimed to synchronize changes in business environment over time and empirically determine how the trade has evolved concerning the responses of the medicinal plants' traders in Tanzania. The study applied economic evolution theory to describe the interactions of changes in business en- vironments and responses of traders to demarcate the evolutionary stages. Primary data were collected from traders, regulators, and researchers through ten focus group discussions and sixteen in-depth interviews from five regions of Tanzania. The results indicated that the traders of medicinal plant products responded by improving product appearance and modernizing both practices and business premises. The study findings have identified four evolutionary stages of trade in medicinal plant products in Tanzania: The first stage was the colonial era (1882–1961), the second is the government supremacy era (1961–1984), the third is the emergence of the private sector era (1985–2004), and the fourth is the market and regulation integration era (started in 2005). Moreover, because of the partial implementation of the regulatory framework, the fifth stage of trade evolution is also ex- pected. This stage is expected to be demarcated when the regulatory framework and market forces work together. Therefore, the study recommends that proper enforcement measures be put in place to ensure desired results whenever there are changes in business environments in traditional medicines practice. This is due to the expectation of the fifth stage whereby one of its characteristics is stiff competition among traders and which will require robust business models to survive in business.Item Effective corrosion inhibition of mild steel in an acidic environment using an aqueous extract of Macadamia Nut Green Peel biowaste(MDPI, 2022-12) Mwakalesi, Alinanuswe J.; Nyangi, MagoriImproving the corrosion resistance of mild steel in an acidic aqueous environment is an important industrial consideration due to the use of acids for descaling and cleaning. The application of corrosion inhibitors is one of the most effective and economical means of protecting metals against corrosion. Plant-derived compounds have recently gained attention due to their low cost, non-toxic, and environmentally friendly properties. Biowastes are recognized as a potential cheap source of green corrosion inhibitors, and their use can help to lower the costs associated with corrosion inhibitors. Green peel biowaste (GPBW) generated from macadamia nut processing is typically dumped into the environment, posing a disposal concern. The use of the waste as a potential source of organic compounds with green chemistry attributes for mild steel corrosion inhibition in an acidic solution was proposed in this study. The gasometric and optical methods were used to carry out the investigations. Results showed that mild steel corrosion rates decreased as extract concentrations increased. As a result, mild steel corrosion inhibition increased with increasing inhibitor concentration and reached a peak value of 81% at 0.5 g/L extract concentration. The optical images showed that the inhibitor molecules adsorbed on the metal surface to form a protective film that isolated the mild steel from the corrosive solution. The adsorption of inhibitor molecules on the mild steel surface followed the Langmuir adsorption isotherm, indicating the formation of a monolayer film with a homogeneous distribution of adsorbed molecules. A Gibbs free energy (G◦ ads) of 24 kJ/mol indicated the inhibition process was mainly characterized by physical adsorption. The results of this study suggest that aqueous GPBW extract could serve as an inexpensive, non-toxic, and renewable corrosion inhibitor of mild steel in acidic solutions.Item Elemental composition and sources of atmospheric particulate matter in Dar es salaam, Tanzania(Ethiopian Journal of Environmental Studies and Management, 2010) Mkoma, S. L; Tungaraza, C; Maenhaut, W; Raes, NAn intensive aerosol field campaign was carried out from 16 August to 16 September 2005 (dry season) at a kerbside in Dar es Salaam, Tanzania. A Gent PM 10 stacked filter unit sampler with coarse and fine Nuclepore polycarbonate filters, providing fine (0.4 μm) and coarse (8 μm) size fractions, was deployed. A total of 64 parallel collections were made. All samples were analysed for the PM mass by weighing. A further analysis was performed for 25 elements by particle-induced x-ray emission spectrometry. The PM 10 mass, as derived from the 3 stacked filter unit samples, was, on average, 58 μg/m . The concentrations of the heavy metals were lower than those for the elements of crustal origin. Nevertheless, some typical anthropogenic metals, such as Zn and Pb, exhibited much higher median PM 10 levels, suggesting strong local sources for these elements in Dar es Salaam. The results also showed very strong day/night differences for the crustal elements (Al, Si, Ca, Ti and Fe). Most elements exhibit strong correlations in the coarse size fraction and somewhat weaker ones in the fine size fraction suggesting that they may originate predominantly from the same source. Principal component analysis with VARIMAX rotation was applied to the data set. Five and four components were identified for the fine and coarse fractions and explained 86.5% and 90.8% of the variance in the data set respectively.Item Epifriedelanol is the key Compound to antibacterial Effects of extracts of synadenium glaucescens (pax) against Medically important bacteria(Frontiers, 2023) Msengwa, Zaituni; Rwegoshora, Frank; David, Credo; Mwesongo, James; Mafuru, Magesa; Mabiki, Faith P; Mwang’onde, Beda J; Mtambo, Madundo M; Kusiluka, Lughano J. M; Mdegela, Robinson H; Olsen, John EIntroduction: Synadenium glaucescens has been used for the treatment of bacterial infections in many parts of the world. We investigated the antibacterial and cytotoxicity activities of secondary metabolites of this plant. Methods: Hexane, dichloromethane, methanol, and water were used as extraction solvents. The extract of the root bark was fractionated with ethyl acetate and methanol. The isolation of compounds from root barks, leaves and stem wood extracts were carried out using column chromatography. Antibacterial activities were characterized based on growth curves, killing curves and MIC determinations. Haemolytic effect towards sheep red blood cells (RBCs) was analysed with spectrophotometer at the wavelength of 540nm. Results and Discussion: Extracts from whole root and root bark showed strong activity against Staphylococcus aureus, and Streptococci and Enterococci species, and moderate to weak activity against Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Salmonella species, Shigella sonnei and Yersinia enterocolitica. Staphylococcus aureus was the most susceptible, and E. coli and Klebsiella pneumonia were the least susceptible ones. Likewise, extracts, fractions, sub-fractions and epifriedelanol demonstrated bacteriostatic activity against S. aureus. The haemolytic activity of the extracts, fractions, sub-fractions and epifriedelanol was significantly low compared to the positive control, hydrogen peroxide. But extract from leaves showed high haemolytic effects at the concentrations of 500 mg/mL and 1000 mg/mL. Thus, extracts of S. glaucescens have antibacterial activity against several Gram-positive bacteria including Methicillin Resistant S. aureus with low haemolytic activity. At high concentrations, the extracts from leaves have toxicity risk. More studies for the active compounds are required for biological testing.Item Exploiting Ion–Dipole and Ion‑Exchange interactions for the removal of Aminopyridines from aqueous environments using Polymer inclusion membranes(Springer, 2023-07-12) Mwakalesi, Alinanuswe J.; Potter, Ian D.Aminopyridines, such as 4-amino-2-chloropyridine (ACP), are not only starting materials for many useful chemicals but also decomposition by-products that are extremely stable in an aqueous environment. Aliquat 336 has proved useful as a car- rier in polymer inclusion membranes (PIMs) for the extraction and transport of small organic anions through ion-exchange processes. However, less attention has been paid to the use of the carrier for the extraction of neutral or cationic organic compounds like aminopyridines. The current study focuses on using PIMs containing Aliquat 336 to target ACP using ion–dipole interactions. The investigations were performed using both experimental methods and computational model- ling. The findings indicated that ACP was transported through a combination of both passive and facilitated diffusion in the rate-determining steps. Significant facilitated transport occurred when PIMs contained 10 wt% or more Aliquat 336. The transport of ACP was fundamentally driven by pH but also benefited from a chloride gradient that resulted in the concurrent transport of orthophosphate. An optimal membrane composition delivered a reasonable flux of 413 (± 9) × 10–8 mol m−2 s−1 and good transport efficiency of 98% for ACP. Our findings provide more incentive for the continued development of PIM chemistry to target troublesome organic pollutants and recover useful chemicals from water sources.Item Green synthesis of silver nanoparticles using aqueous extract of vachellia xanthophloea and their potential use for antibacterial and sensing of mercury ions(Springer, 2023-07-06) Mwakalesi, Alinanuswe J.The use of silver nanoparticles (Ag-NPs) in different fields such as agriculture, medicine, and environment has recently increased. As a result, studies on their synthesis and applications have gained attention. In the present study, the synthesis of Ag-NPs using cheap, renewable, and environmentally friendly phytochemicals extracted from Vachellia xanthophloea leaves is reported. Additionally, potential uses of the nanoparticles against gram-positive (Staphylococcus aureus) and gram-negative (Escherichia coli) bacteria and for sensing of mercury ions from aqueous solutions were investigated. The findings showed that the formation of nanoparticles was associated with a color change from green to brown with a UV–Vis maximal absorbance peak at 420 nm due to surface plasmon resonance on Ag-NPs. The synthesized Ag-NPs showed effec- tive antibacterial effects against both gram-positive (Staphylococcus aureus) and gram-negative (Escherichia coli) bacteria. The antibacterial effectiveness as indicated by the minimum inhibitory concentration (MIC) was higher for Staphylococcus aureus (0.04 mg/mL) compared to E. coli (0.33 mg/mL). Similarly, the minimum bactericidal concentration (MBC) values were 0.04 and 0.66 mg/mL for S. aureus and E. coli, respectively. The nanoparticles were also sensitive to metal ions ( Hg2+, Ba2+, Mg2+, Zn2+, Cu2+, Ni2+, Co2+, and Fe2+) and showed a remarkable selectivity to mercury. The potential use of the nanoparticles for sensing of mercury ions from real water samples of ground and tap waters produced satisfactory results. The limit of detection (LOD) and limit of quantification (LQD) for sensing of Hg2+ were determined to be 22.2 µM and 73.9 µM, respectively. The findings from the current study indicate that Ag-NPs prepared using Vachellia xanthophloea leaves aqueous extract could serve as effective an antibacterial agent and a sensor of mercury ions for aqueous samples.Item Higher order perturbation analysis of plasma and gravitational waves(Universiteit Antwerpen, 2004) Karugila, Geoffrey KamahangaPlateau [1] initiated experimentally and theoretically the stability of a liquid cylinder with surface tension. Lord Rayleigh [2] improved this work and developed the linearized theory for sound waves (although the calculation of sound velocity goes back to Newton and Laplace) and for the Plateau experiments which was then applied to all kinds of fields: gravitation [3. 4, 5], plasma [6], (magneto)hydrodynamics [7, 8, 9], energy principles [10]. The linear theory flourished tremendously in the past century to a large extent due to the goal of fusion. Soon the need for nonlinear theories was manifest e.g. Callebaut [11, 12]. We therefore see in the previous decades a lot of work on nonlinear theory of plasma waves and instabilities being done. These yield either exact solutions or approximate ones. Often exact solutions are obtained after that the equations have been approximated. We may mention the papers with the exact solutions by Malfliet et al. [13, 14, 15], Hereman et al. [16, 17, 18], Verheest et al. [19, 20, 21] on solitary waves and those of Khater et al. on Backlund transformations and Painleve analysis [22, 23, 24, 25]. Amiranashvili et al. [26] gave some exact solutions for standing waves in bounded plasmas without using the solitary wave theory but with some boundary conditions. Callebaut and Tsintsadze [27, 28] e.g., neglecting some higher order terms, dealt with the nonlinear bunching of Alfven waves and the filamentation and modulation of weakly ionized magnetized plasmas. In fact, except for the approaches leading to solitary wave solutions, the nonlinear methods usually yield approximations and usually one has barely an idea how long these are valid in the behavior of the plasma. The approach used in this thesis exploits the Fourier analysis for nonlinear systems. It is rather different from the approaches just mentioned as it allows some insight in the convergence. Moreover, it gives useful results for the many cases where one can not find a closed form for the solitary waves. Indeed the solitary waves are an exceptional and rare case, comparable with a polynomial (as is clear e.g. from Malfliet’s work, see references cited) while the general solution is an infinite series. The polynomial may use a function (e.g. tanh) instead of the (combined) variable itself. Similarly the series may use any function although the customary ones are exponentials and (co)sines. Infinite Fourier series may in principle be considered as an exact solution, but in practice it often is an approximation, which, however, allows clear insight on its validity. The set of (partial differential) equations (e.g. equations (2.1) - (2.4)), together with some initial and/or boundary conditions, defines a set of func tions (which are, of course, interrelated). From the Fourier theory it is known that if a periodic function is continuous from — oo to +oo and has a deriva tive which is piecewise monotonous and continuous, then the function may be developed in a Fourier series which is absolutely and uniformly convergent in any interval. In the thesis we deal with the single variable x (= co t + k • r), which is the combination of the four independent variables i.e. the angular frequency ( cj = 2 tt z /, v = frequency), the time (Z), the wave vector (fc) and space (r). Thus the conditions have to be satisfied for the function(s) of this combined variable. In particular the function should be periodic in co t and in k r. However, an exponential growth is easily accommodated just like the periodic situations as was the case in a hydrodynamical problem [12]. Hence under rather general conditions it is possible to expand the functions defined by the set of equations. When will this breakdown? E.g. when the series diverges, i.e., physically speaking, when instability leading to dis- rupture develops meaning that a (large) amount of energy has been made available (either injected externally or freed by the system itself from e.g. its potential energy or, more generally, from its free energy). The convergence of the series puts conditions on the linear theory, mainly on its amplitude. In fact a linearized theory can never determine its own limitations: that has to be done by the nonlinear analysis. In the previous works [12] it turned out that some experimental situa tions, in particular the oscillations and instabilities of a liquid jet, could be explained very well by this method. Moreover some cases appeared where the nonlinear theory showed that the linear theory was good even up to de struction of the configuration, while for wavelengths much larger than the diameter of the jet the nonlinear terms became dominant. Another breakdown of the method may occur e.g. when the function(s) is (are) not periodic. However, in the linear perturbation theory one works usually with a periodic perturbation and this generates naturally higher order terms which are periodic too as is obvious e.g. in our present work and in the works of Callebaut [12, 29, 30]. For a non-periodic solution one has to take a wholly different start in the linear theory, e.g. by using a series in t and/or re, ?/, 2, or some adequate combination of those, or if nevertheless a periodic or exponential start is used as first order term, to adapt profoundly the nonlinear terms. Such nonlinear approaches have been elaborated in various ways in the literature see e.g. the cited references of Malfliet et al.; Hereman et al.; Verheest et al.; Khater et al.; Callebaut and Tsintsadze.
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