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Oxytetracycline is used to treat various diseases in cattle. However, its use may be associated with unacceptable residue levels in food. Oxytetracycline residues in tissues from indigenous cattle were determined in a cross-sectional study conducted in the Kilosa district, Tanzania, between November 2012 and April 2013. A total of 60 tissue samples, including muscle, liver and kidney, were collected from slaughterhouses and butchers and analysed for oxytetracycline using high-performance liquid chromatography. Oxytetracycline residues were found in 71.1% of the samples, of which 68.3% were above acceptable regulatory levels. The mean concentration of oxytetracycline across tissues was 3401.1 µg/kg ± 879.3 µg/kg; concentrations in muscle, liver and kidney were 2604.1 µg/kg ± 703.7 µg/kg, 3434.4 µg/kg ± 606.4 µg/kg and 3533.1 µg/kg ± 803.6 µg/kg, respectively. High levels of oxytetracycline residue in meat from indigenous cattle may pose a health threat to consumers in Kilosa. The findings possibly reflect a general lack of implementation of recommended withdrawal periods, ignorance about drug use and lack of extension services. Strict regulation of the use of antimicrobial drugs in the livestock industry and associated testing of animal-derived food sources prior to marketing are required.

Background/Aim:Some of the antifungal drugs used in the current treatments regime are responding to antimicrobial resistance. In rural areas of Southern Tanzania, indigenous people use antifungal drugs alone or together with medicinal plants to curb the effects of antibiotic resistance. This study documented ethnobotanical information of medicinal plants used for managing fungal infections in the Southern Highlands of Tanzania and further assess their safety.Materials and Methods:Ethnobotanical survey was conducted in Makete and Mufindi districts between July 2014 and December 2015 using semi-structured questionnaires followed by two focus group discussions to verify respondents’ information. Cytotoxicity study was conducted on extracts of collected plants using brine shrimp lethality test and analyzed by MS Excel 2013 program.Results:During this survey about 46 plant species belonging to 28 families of angiosperms were reported to be traditionally useful in managing fungal and other health conditions. Among these, Terminalia sericea, Aloe nutii, Aloe lateritia, Zanthoxylum chalybeum, Zanthoxylum deremense, and Kigelia africana were frequently mentioned to be used for managing fungal infections. The preparation of these herbals was mostly by boiling plant parts especially the leaves and roots. Cytotoxicity study revealed that most of the plants tested were nontoxic with LC50 > 100 which implies that most compounds from these plants are safe for therapeutic use. The dichloromethane extract of Croton macrostachyus recorded the highest with LC50 value 12.94 µg/ml. The ethnobotanical survey correlated well with documented literature from elsewhere about the bioactivity of most plants.Conclusions:The ethnobotanical survey has revealed that traditional healers are rich of knowledge to build on for therapeutic studies. Most of the plants are safe for use; and thus can be considered for further studies on drug discovery.

Optimization of extraction conditions and phytochemical screening of the root bark of Synadenium glaucescens were carried out in a stepwise manner in order to obtain the highest yields and the constituents of the extracts. Sequential extraction using Soxhlet method was performed using dichloromethane, hexane and petroleum ether, respectively, each followed by ethanol. Extraction conditions included: running time of 2 to 6 hours, temperature at 25 o C to 95 o C and particle size ranging from 0.4mm to >3mm diameter. Phytochemical screening was done using derivatisation techniques, gas chromatography-mass spectrometry and high performance liquid chromatography. Extraction with dichloromethane followed by ethanol resulted in a higher yield by 25%, within 4 hrs of extraction, particle size of 1mm, at temperatures of 30 o C for dichloromethane and 75 o C for ethanol. Fatty acid analysis indicated absence of free fatty acids in both Dichloromethane and ethanolic extracts. Silylation and Thin Layer Chromatography indicated the presence of non hindered and hindered functionality and the presence of triterpenoids in the dichloromethane extract. Phytochemical screening of the dichloromethane extracts indicated that it is composed of two main triterpenoids that best matched with Lanosterol (42%) and Cycloartenol (31%). Other minor compounds identified through chromatographic analysis were phytol, ergostadiol, hentriacontane, sitastirol aceate, lupeol and hopenone. The ethanolic extracts indicated the presence of polyphenolic compounds.

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