Background: Diabetes mellitus (DM) poses immense challenge to the health of people worldwide. Current therapies are limited by cost and adverse effects. Solanum nigrum, a complex of many species in the family Solanaceae has been recorded to be used by many communities in the management of DM. The aim of this study was to evaluate the phytochemical, antidiabetic efficacy and safety of two species, namely; Solanum villosum and S. nigrum var sarrachoides using streptozotocin-induced diabetic mice model.Methods: Qualitative assessment for phytochemical constituents was carried out. Acute toxicity was conducted based on ‘Organisation of Economic Cooperation and Development’ 2001 guidelines. Diabetes was induced by injection of streptozotocin at a dose of 200 mg/kg body weight intraperitoneal after the mice fasted for 8 hours. Aqueous extracts were administered orally using an oral gavage at doses of 150, and 300 mg/kg body weight for each plant daily and monitored weekly for 28 days.Results: Both plants contain vital phytochemicals. Flavonoids, alkaloids, tannins, saponins, phenols, and glycosides were present in both plants. However, phytosterols and coumarins were absent in S. villosum. Additionally, both plants did not show toxicity. Both plants showed efficacy with S. nigrum var sarrachoides being more potent at both doses.Conclusions: The study validates the use of these plants by herbalists and recommends further studies on them with the aim of elucidating the active compounds that can be used as novel therapies for diabetes. Additionally, the study recommends the evaluation of other species in this complex for antidiabetic properties.

Background: Cadmium (Cd) is a common pollutant and potential neuro-toxicant to humans. The main treatment for heavy metal toxicity is chelation therapy which is however replete with grave side effects. This study was designed to determine the neuroprotective effects of extracts of the tea beverage on experimentally induced cadmium toxicity in the brain of rats. Cadmiumas CdCl2 was administered subcutaneously while tea was given orally.Methods: Healthy Wister rats were used to study the effects of co-administration of Cd and tea extracts on the brain. Cadmium was injected subcutaneously while tea was administered orally to the rats. Brain tissue from euthanized rats was assayed for Zinc Fingers and Homeoboxes Protein 1 (ZHX1), reduced glutathione (GSH), and lipid peroxidation markers Thiobarbituric Acid Reactive Substances (TBARS). Neurohistochemical and histopathological studies were also carried out on the brain tissues of the rats.Results: Cadmium significantly induced neuronal damage exhibited by a significant (p < 0.05) decrease in ZHX1 in the brain tissue, significant (p <0.05) increase in TBARS, as well as significant (p < 0.05) increase in GSH implying an impaired antioxidant defense system. Co-administration of Cd with black or green tea extracts resulted in a significant decrease in lipid peroxidation as well as maintenance of GSH and ZHX1. The neurohistochemical and histopathological studies in the brain of the rats indicated that the tea extracts significantly reduced CdCl2 toxicity and preserved the normal histological architecture of the brain tissues.Conclusion: This paper reports for the first time the efficacy of tea extracts in protecting rats from cadmium induced toxicity and disturbances of antioxidant defense system in the brain.Key words: Tea; flavonoids; Cadmium; neurotoxicity; Chelating agents.

Background: Tea is a beverage that is most widely consumed worldwide. Studies have shown that oral consumption of tea has health benefits however, there is paucity of data in Kenya detailing the biochemical effects of tea in the liver and elucidation of its mechanism of action.Methods: The polyphenol composition and antioxidant capacity of tea were determined by HPLC and the Folins Ciocalteu spectrophotometric methods. Metal levels were determined using flame Atomic Absorption Spectrometer (AAS). Aqueous black and green tea extracts were administered to the rats at dosages of 400mg/kg b.w.t. The effect of tea on total blood proteins, Albumin, ZHX1, TBARS, AST, ALP and ALT were determined by spectrophotometric methods. The body weight of each rat was also determined at one week interval.Results: Total Polyphenols (TP), Total Catechins (TC) and Antioxidant Activity (AA) between the black and green teas were significantly (P<0.05) different. Green tea had the highest levels of TP (19.70-26.12%), TC (8.51%-17.60%) and AA (86.65%-94.50%). Tea did not have a significant (P>0.05) effect on TP, ALB, ALT, AST, ALP, MDA and ZHX1 in the test animals compared with the controls. This data indicates that green tea is rich in catechins while black tea being rich in Theaflavins (TFs) and Thearubigins (TRs). Both tea products possess essential and non-essential metals well within the maximum permissible concentrations.Conclusions: Findings from this study indicate both green and black tea aqueous extracts have polyphenols and high antioxidant activity. Administration of the aqueous tea extracts have no toxicological effect on the liver.