Diabetes mellitus is a chronic metabolic disorder which has greatly led to an increase in morbidity and mortality globally. Although Xerophyta spekei is widely used for the management of diabetes among the Embu and Mbeere communities in Kenya, it has never been empirically evaluated for its hypoglycemic activity. This study was carried out to verify the hypoglycemic activity of dichloromethane (DCM) extract of Xerophyta spekei as well as its antioxidant activity using various in vitro techniques. Phytochemicals associated with its antioxidant activity were identified through GC-MS. Data were subjected to descriptive statistics and expressed as mean ± standard error of the mean (X̄ ± SEM). Comparison between various variables was performed by using unpaired Student’s t-test and one-way analysis of variance (ANOVA), followed by Tukey’s post-hoc test. The confidence interval was set at 95%. The obtained results were presented in tables and graphs. Results showed that there was no difference in α-amylase inhibition activity between the plant extract and the standard (IC50 525.9 ± 12.34 and 475.1 ± 9.115, respectively; $p>0.05$). Besides, the glucose adsorption activity of the extract increased with an increase in glucose concentration (from 5.89 to 32.64 mg/dl at 5 mmol and 30 mmol of glucose, respectively; $p<0.05$). The extract also limited the diffusion of glucose more than the negative control (7.49 and 17.63 mg/dl, respectively; $p<0.05$). It also enhanced glucose uptake by yeast cells. In addition, the studied plant extract showed notable antioxidant activities. The therapeutic effects exhibited by this plant in managing diabetes mellitus and other ailments could be due to its antioxidant as well as its hypoglycemic activity. The study recommends the evaluation of X. spekei for in vivo hypoglycemic and antioxidant activities. Besides, the isolation of bioactive phytochemicals from the plant may lead to the development of new hypoglycaemic agents.

Background: The medicinal plant Xerophyta spekei is used among Embu and Mbeere communities to manage diabetes mellitus. However, its efficacy has never been evaluated in vivo. The purpose of this study was to investigate its quantitative phytochemical and antidiabetic potential. Extraction was done using Dichloromethane (DCM). Quantitative phytochemical analysis was conducted using GC-MS. To evaluate antidiabetic activity, groups of mice which included normal control, diabetic control, positive control, and extract-administered groups (50, 100, 150, and 200 mg/kg body weight) were used. Alloxan monohydrate was used to induce diabetes. Blood glucose of the mice was determined hourly for the first six hours, and once after 12 and 24 h on the first day. Thereafter, the blood glucose in mice was determined once a week for three weeks. During the experimental period of three weeks, body weights were determined. After 21 days, lipid profiles, kidney and liver function tests as well as ex vivo antioxidant assays were carried out. Results: The phytochemicals classes identified included flavonoids, phenolic compounds, phytosterols, terpenoids, fatty acids, tocopherols and alkaloids. Stigmasterol had the highest concentration (12.99 ± 2.56 mg/g). The extract decreased blood glucose dose-dependently, with 200 mg/kg bw dose resulting in the highest % mean change (40.10 ± 0.95). The extract gradually decreased blood glucose during 21 days of treatment. It attenuated loss of body weight and aberrant biochemical parameters including liver and renal function tests as well as lipid profiles in diabetic mice. Furthermore, it reduced levels of malondialdehyde and enhanced enzymatic antioxidant activities in diabetic mice. Conclusions: The study confirms that DCM extract X. spekei contains phytochemicals with antioxidant and antidiabetic properties. The findings authenticate the folkloric use of X. spekei in managing diabetes mellitus. The medicinal plant also serves as a potential source for developing antidiabetic agents.