Vol. 6, Issue 1, Part A (2024)

Diabetes mellitus, is a chronic metabolic disorder which has persisted for several decades as a major global public health concern. It is characterized by chronic hyperglycaemia associated with damage, dysfunction and failure of various organs leading to nephropathy, retinopathy, and peripheral neuropathy. This condition is indigenously managed with numerous readily available and affordable medicinal plants but with limited scientific evidence amongst which is Tapinanthus preussii. Therefore, this study investigated the anti-diabetic effect of graded dosages of Tapinanthus preussii crude aqueous leaf extract, on streptozotocin-induced diabetic male Wistar albino rats. A total of five normal and 25 streptozotocin induced diabetic rats were randomly assigned into six groups of five rats each: Groups 1, 2 and 3 served as normal, negative and positive controls that received water and 250 mg/kg body weight of chlorpropamide (A standard anti-diabetic drug) respectively while groups 4, 5 and 6 received 200, 350 and 500mg/kg body weight of the crude aqueous extract for 28 days. Blood samples were collected at 2,4,6 and 8 hours post administration for the short term study while for the long term study, at 7, 14, 21 and 28 days for the determination of blood glucose concentration. The maximum blood glucose reduction was 17.5% within 2 hours post-administration of 500mg/kg of the aqueous extract, compared to 12.78% for chlorpropamide and 0.38% for the positive negative diabetic control respectively. The 500mg/kg body weight aqueous extract again showed the highest reduction of 59.26% over a 28-day period, outperforming the 17.54% for chlorpropamide. The findings revealed that the extract displayed a stronger ability to lower blood sugar levels than the positive control. Hence, highlighting the dose and time-dependent nature of the anti-diabetic effects, with faster onset of activity observed at high dose of the extract. These findings suggest the potential of Tapinanthus preussii as a natural anti-diabetic agent, with promising results in lowering blood glucose levels in diabetic rats. The antidiabetic effects could be attributed to the phytochemicals like flavonoids, carotenoids, anthraquinones alkaloids, tannins, cyanogenic glycosides and saponins present in Tapinanthus preussii leaf extract.