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Sokoine University of Agriculture  Institutional Repository (SUA IR). This repository was built and is maintained by the university library  (Sokoine National Agricultural Library-SNAL) , in order to collect, preserve and disseminate scholarly output generated by University research community (staff and students) members.

This repository hosts a variety of openly accessible materials including: scholarly articles and books, theses and dissertations, conference proceedings and technical reports. For assistance about depositing your research output in the repository click here. SUA IR Policy  click here or any queries contact us at snal@sua.ac.tz.

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Recent Submissions

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Analytical methods for screening and determination of conventional drugs adulterated in herbal products
(Sokoine University of Agriculture, 2023-05) Mwankuna Christopher Johnson
Herbal products are popular worldwide. Their popularity is threatened by untrustworthy manufacturers who add conventional drugs. The addition of conventional drugs increases the risk of developing antimicrobial resistance and herb-drug interactions. To safeguard the users and enhance the safety of herbal products, analytical methods for screening and determining conventional drugs adulterated in herbal products are required. Therefore, this study was carried out to develop analytical methods and apply them in screening and determination of antibiotic, antimalarial, pain killer and erectile dysfunction adulterants in herbal products. Thin layer chromatography methods for screening twelve conventional drugs in herbal products were developed and applied. The analytes were extracted from herbal products using a solvent mixture of acetonitrile:methanol:acetic acid:water (4:4:1:1, v/v). The mobile phase consisting of dichloromethane:ethyl acetate:methanol (75:15:10, v/v) separated well trimethoprim, sildenafil, paracetamol and sulfamethoxazole. Pyrimethamine, metronidazole and sulfadoxine were well separated by dichloromethane:ethyl acetate:methanol (77.5:12.5:10, v/v). In addition, acetyl salicylic acid, ibuprofen, diclofenac, quinine and lumefantrine were well separated by ethyl acetate:methanol:30% ammonia (75:22.5:2.5, v/v). Chromatographic separations were highly reproducible and more than 10 samples were analysed in one run. The developed methods were used to screen 229 herbal products. Consequently, 24.0% of the samples contained one adulterant while 21.4% contained at least two adulterants. A high performance liquid chromatography–tandem mass spectrometry method was developed and used for screening and determining six conventional antibiotics (amoxicillin, ampicillin, metronidazole, trimethoprim, sulfamethoxazole, and ciprofloxacin) in herbal products. The developed method had linear (r2 ≥ 0.996) calibration curves over the range of 0.005–2.5 μg mL–1 for all compounds except metronidazole, whose range was 0.005–1 μg mL–1. The limit of detection ranged from 0.012 to 0.046 μg mL–1 while the limit of quantification ranged from 0.066 to 0.153 μg mL–1. Accuracy, expressed as recovery of spiked herbal products ranged from 45% to 114%. The precision expressed as relative standard deviation at two concentration levels ranged from 1.6% to 15.9%. The matrix effect, expressed as matrix factor ranged from 0.79 to 0.92. The developed method was used to analyse 78 herbal products purchased from Njombe, Morogoro, Manyara, Arusha, Mwanza and Dar es Salaam in Tanzania. Metronidazole was detected in eight samples with the highest concentration of 1.38 μg g–1. Another high performance liquid chromatography–tandem mass spectrometry method was developed and used to screen and determine eleven conventional antimalarials (chloroquine, quinine, sulfadoxine, pyrimethamine, mefloquine, lumefantrine, amodiaquine, artemisinin, dihydroartemisinin, artesunate and artemether) in herbal products. The developed method had linear (r2 ≥ 0.991) calibration curves over the range of 0.001–0.3 μg mL–1 for all compounds. The limit of detection ranged from 0.002 to 0.02 g mL–1 while the limit of quantification ranged from 0.006 to 0.08 g mL–1. Accuracy, expressed as recovery of spiked herbal products ranged from 52% to 128%. The precision, expressed as percent relative standard deviation at two concentration levels, ranged from 1.0% to 13.8%. The matrix effect, expressed as the matrix factor ranged from 0.77 to 0.97. The developed method was used to analyse 50 herbal product samples from Njombe, Morogoro, Manyara, Arusha, Mwanza and Dar es Salaam in Tanzania. Ten of the herbal products were found to contain amodiaquine, sulfadoxine, pyrimethamine, mefloquine, dihydroartemisinin, artemether and lumefantrine. The developed thin layer chromatography and high performance liquid chromatography–tandem mass spectrometry methods are considered valuable tools for a better understanding of the adulteration of herbal products by addition of conventional drugs. The thin layer chromatography methods can be used for preliminary screening of herbal products prior to confirmation by other techniques such as high performance liquid chromatography–tandem mass spectrometry. On the other hand, confirmation and quantification of the selected antibiotic and antimalarial adulterants in herbal products can be achieved using the developed high performance liquid chromatography–tandem mass spectrometry methods.
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Optimization of HPLC–MS/MS method for determination of antimalarial adulterants in herbal products
(SPRINGER, 2023-01-12) Mwankuna Christopher J.; Kiros Feven; Mariki Eliapenda E.; Mabiki Faith P.; Malebo Hamisi M.; Mdegela Robinson H.; Styrishave Bjarne
The use of herbal products is booming all over the world because of being believed as safer than conventional drugs and free of side effects. However, there are untrustworthy manufacturers who adulterate herbal products by adding conventional drugs which might eventually lead to microbial resistance and herb-to-drug interactions. There is a need to develop methods for detecting adulterants in herbal products. A high performance liquid chromatography-tandem mass spectrometry (HPLC– MS/MS) method for simultaneous identification and determination of conventional antimalarials (chloroquine, quinine, sulfadoxine, pyrimethamine, mefloquine, lumefantrine, amodiaquine, artemisinin, dihydroartemisinin, artesunate and artemether) in herbal products was developed. Stable isotopically labelled compounds (artemether-d3, quindine-d3, and sulfadoxine-d3) were used as internal standards (ISs) for quantitative analysis. Extraction of analytes was performed using methanol: water: formic acid (90:10:0.1, v/v) and chromatographic separation was done in a gradient mode using mobile phase A: Ultrapure water containing 0.1% formic acid and 1 mM ammonium formate and mobile phase B: Acetonitrile/ methanol (50:50) containing 0.1% formic acid and 1 mM ammonium formate. The calibration curves were linear (r2 ≥ 0.991) over the range of 0.001–0.3 μg ­mL−1 for all compounds. The limit of detection (LOD) ranged from 0.002 to 0.02 μg ­mL−1 while the limit of quantification (LOQ) ranged from 0.006 to 0.08 μg ­mL−1. Accuracy, expressed as recovery of spiked herbal products ranged from 52 to 128%. The precision, expressed as percent relative standard deviation (%RSD) at two concentration levels, ranged from 1.0 to 13.8%. The matrix effect expressed as the matrix factor (MF) ranged from 0.77 to 0.97. The developed method was used to identify and quantify conventional antimalarials in herbal product samples from Tanzania. Ten out of 50 herbal products were found to contain amodiaquine, sulfadoxine, pyrimethamine, mefloquine, dihydroartemisinin, artemether and lumefantrine. The developed method is considered a valuable tool for getting a better understanding of the adulteration of conventional antimalarials in herbal products.
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A HPLC-MS/MS method for screening of selected antibiotic adulterants in herbal drugs
(The Royal Society of Chemistry, 2022) Mwankuna Christopher Johnson; Uwamaliya Grâce Ange; Mariki Eliapenda Elisante; Mabiki Faith; Malebo Hamisi M.; Mdegela Robinson; Styrishaveb Bjarne
The use of herbal products adulterated with conventional drugs increases the risk of developing microbial resistance and causes herb-to-drug interaction, leading to severe clinical consequences. The complex nature of herbal products has been a challenge for the unambiguous identification of adulterants. The improved analytical selectivity and sensitivity of hyphenated techniques such as high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) enable the confirmatory screening of adulterants in herbal products. Simultaneous screening of adulterants is necessary and efficient because it has been established that more than one chemical adulterant may be present in one herbal product. An HPLC-MS/MS method for the simultaneous detection and quantification of amoxicillin, ampicillin, metronidazole, ciprofloxacin, sulfamethoxazole, and trimethoprim in powdered herbal drugs was developed. Deuterated metronidazole-d3, trimethoprim-d3, ciprofloxacin-d8, and sulfamethoxazole-d4 were used as internal standards (ISs). For each analyte, two transitions were monitored using protonated molecules as precursor ions. The extraction of analytes from herbal products was performed using a simple methanol : water : formic acid (90 : 10 : 0.05, v/v) extraction solvent. Chromatographic separation was done in a gradient of 0.01% formic acid in methanol and 0.01% formic acid in MilliQ water. The calibration curves were linear (r2 $ 0.996) over the range of 0.005–2.5 mg mL 1 for all compounds except metronidazole, whose range was 0.005–1 mg mL 1. The limit of detection (LOD) ranged from 0.012 to 0.046 mg mL 1, while the limit of quantification (LOQ) ranged from 0.066 to 0.153 mg mL 1. The accuracy, expressed as the recovery of spiked herbal products, ranged from 45% to 114%. The precision, expressed as relative standard deviation (RSD) at two concentration levels, ranged from 1.6% to 15.9%. The matrix effect expressed as the matrix factor (MF) ranged from 0.79 to 0.92. The developed method was applied to powder herbal products purchased in Tanzania. Amoxicillin, ampicillin, trimethoprim, sulfamethoxazole, and ciprofloxacin were not detected in all samples. Metronidazole was detected in eight samples with the highest concentration of 1.38 mg g 1. The developed method is suitable for the detection of all the studied antibiotic adulterants in herbal products. Quantification can be performed for all the compounds except ciprofloxacin due to its lower recovery.
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Effects of food insecurity among pastoralist families in the changing climate of Iringa rural District, Tanzania
(Sokoine University of Agriculture, 2014) Mdachi, Mary
Dietary intake measures are useful for assessing nutritional status of an individual. Dietary intake depends on the availability of healthy foods, as well as on resources available to an individual, allowing them to purchase or access foods. This study was carried out in 20 villages in Iringa Rural District, between July and September 2013 to assess effects of food insecurity among pastoralist women and their infants. Interviews were used to gather information on food insecurity and food frequency in pastoralist households. Anthropometric measurements and haemoglobin (Hb) concentrations of the participants were also collected. A total of 200 women and 30 infants were included in the study. The results indicated that majority (75.8%) of women’s diet was of plant origin. Approximately 75% of women had food shortages, defined as having at least one meal per day composed of limited food groups and quantities. All children were given meals mainly composed of carbohydrates (40%) once a day with no consistent pattern of types of foods or feeding times. Data on the nutritional status of children indicated that 6.6% of the Barbaig children experienced wasting while 10% of the Sukuma children were stunted. For women, 28% were underweight, while 7% were obese. Haemoglobin data indicate that 87.5% of children were anaemic while 42% of women were anaemic. It is concluded that most women and children had food insecurity and poor nutritional status which partly would be caused by climate change. It is recommended that nutritional education programs should be introduced in health facilities and in schools so as to improve the knowledge on nutrition. Also education should be given to the heads of households on how to utilize livestock in improving their livelihood/income and strategies to climate change adaptations.
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Gender-based coping strategies against food insecurity in Dodoma rural District, Tanzania
(Sokoine University of Agriculture, 2001) Mwagile, Merina Yared
Drought, dependence on rainfall, poor storage and poor agricultural practices have been identified as the main contributing factors to food insecurity in the country. On the other hand, the Tanzania Government has made several policy declarations including carrying out a number of campaigns and mobilisation programs with the objective of attaining food security for the country. Dodoma region has been a victim of famine for many years. For example, at the end of 18th century the caravan trade increased food requirements for the thousands of travellers. This made the area face frequent famines which were mainly due to the successive lowering of the production potential including acceleration of soil erosion caused by deforestation and over mexploitation of agricultural land due to marginal land cultivated without conservation measures. From the few studies that have assessed food security in Tanzania, the proportion of households in rural areas that suffer from food insufficiency, is very high being as high as 77%. However, less has been done in studying the role of gender in developing coping strategies against food insecurity. This study was conducted to assess the role played by men and women in developing coping strategies against food insecurity. More specifically, the study intended first, to identify the types of food insecurity in the area and their causes, second, to identify the coping strategies developed by men and women and third, to identify and assess the socio-economic factors that influence the choice of the key coping strategies. The study has focused on selected villages in Dodoma Rural District. The study was carried out in two phases. Phase one of the study involved reconnaissance survey together with Participatory Rural Appraisal (PRA) techniques. Other tools used were participant observation and checklists. The second phase was mainly based on questionnaire survey. Questionnaire survey was done in Mzula, Mvumi Makulu and Ndebwe villages with a sample size of 120 households. Data collected by using PRA techniques in phase one were analysed with the help of the communities and the results were communicated back to them for verification. Data collected in phase two were analysed by using both quantitative and qualitative methods. The Statistical Package for Social Sciences (SPSS) was the main tool used for analysing quantitative data whereas descriptive statistics, cross tabulation and logistic regression were done. Content and Structural-Functional Analyses were used for qualitative data. The study revealed the presence of chronic food insecurity in Dodoma Rural District, which was mainly caused by drought and pests. In order to cope with food shortage, the study revealed a number of coping strategies employed by men and women in Dodoma Rural District. These included: collection of wild foods; doing casual labour, that is, selling labour in other peoples’ farms; doing off- farm activities; food borrowing; crop diversification; migration to other areas and receiving remittances from relatives who stay in urban areas. Women were using most of the identified coping strategies. Three coping strategies were mostly used in the study area. These included: collecting wild foods, which was reported by 57 percent of women and 41 percent of men; doing casual labour which was reported by 51 percent of women and 34 percent of men, and doing off-farm activities reported by 39 percent of the women and 29 percent of the men. The study further revealed that the choice of these key coping strategies have been influenced by some socio­ economic factors namely farm size, education level, age, amount of food stored and dependency ratio. Respondents who were having small farms of below 5ha tended to look for casual labour, that is, selling their labour to other people’s farms. Heads of during the period of the study. Others who have not been mentioned have been very helpful. To ever)' one I say, thank you very much, you have been wonderful. household who had formal education did not participate much on off-farm activities compared to those without formal education. It was also revealed that the higher the age of the head of household, the more was the tendency to participate in those key coping strategies. Having stored less amount of food to fulfil the minimum requirements of the household made the household members to participate more in those coping strategies. Having lower dependency ratio was another factor which influences people to participate in those coping strategies. The study concludes by pointing out that participation of women in coping with food shortage and their role in ensuring food security as discussed in this study provides the evidence that many differences between women and men are socially constructed and can be changed. Opportunities to training on food processing especially on how to preserve food to be used in time of food shortages can be a powerful incentive for women to ensure food security in their households. It is recommended that deliberate efforts to assist households that depend on rain fed production to diversify their sources of livelihood be taken. Diversification of sources of livelihood can be achieved through promotion of other sources of income generation. Promotion of off-farm activities coupled with policies designed to provide good rural markets for households that depend on food purchases are crucial. The study further recommends that training schemes targeting the rural poor households especially women on food processing be given due consideration in policy formulation. It is emphasised that those training should focus more on processing of wild foods