Search

The use of plants for the treatment of diseases in Africa is attracting more attention. This use of plants calls for more researches towards the validation of the healing claims by herbalist and the users of these herbs. Vernonia amygdalina Delile (Asteraceae) is one of the widely used plants in Nigeria by herbalists for the treatment of different diseases. In our previous studies on the methanolic stem-bark extract of this plant, we isolated novel and new compounds after scientifically validating the antidiabetic and anthelmintic effect of the methanolic stem-bark extract. In this present study, we aimed at identifying which of the isolated compounds is or are responsible for the antidiabetic and anthelmintic properties of the methanolic stem-bark extract of the plant. We also evaluated the antioxidation effects of the isolates. The antidiabetic effects of the isolated compounds were carried out in-vivo using streptozotocin-induced diabetes rats, while the anthelmintic effect was done in-vitro with Eisenia foetida, an adult worm. The antioxidation properties were evaluated using 2,2-diphenyl-1-picrylhydrazyl, nitric oxide and hydrogen peroxide radical scavenging protocols. The results obtained showed that out of the five compounds tested, only 6β,10β,14β-Trimethylheptadecan-15α-olyl-15-O-β-D-glucopyranosyl-1,5β-olide showed a significant reduction in the blood glucose in the course of treatment compared to standard metformin, while only glucuronolactone showed anthelmintic effect with total paralysis and death times of 153.7±1.21, 84.9±1.24 and 53.4±0.08, in comparison to 17.3±0.08, 10.5±0.06 and 8.3±0.06 for the standard (albendazole) at 30, 50 and 70 mg, respectively. The isolates also produced different percentages of 2,2-diphenyl-1-picrylhydrazyl, nitric oxide and hydrogen peroxide radicals scavenging abilities. From the results obtained in these studies only 6β,10β,14β-Trimethylheptadecan-15α-olyl-15-O-β-D-glucopyranosyl-1,5β-olide has antidiabetic property out of the five isolated compounds, while only glucuronolactone has anthelmintic property. All the isolated compounds showed mild antioxidation effect. Further researches are needed to identify the mechanism through which the two compounds exerted antidiabetic and anthelmintic effects.

Ethnomedicinal surveys have documented the traditional use of Carallia brachiata (Lour.) Merill (Rhizophoraceae) leaves in the management of diabetes mellitus in the Northeastern region of India. This study screens the hydro-alcoholic extract (HAE) of C. brachiata leaves for antioxidant and antidiabetic activities. The HAE was prepared using ethanol:water (7:3) by cold maceration method. The antidiabetic activity of HAE was evaluated in vivo in streptozotocin-induced diabetic rats at the doses of 250 or 500 mg/kg body weight for 21 days. The extract was also evaluated for in vitro and in vivo antioxidant activity. Results revealed that HAE of C. brachiata leaves possesses good hypoglycemic activity in diabetic rats. The hypoglycemic activity of HAE was found significant as compared to normal rats. Results of antioxidant activity were found statistically significant compared to standard drugs, quercetin and gallic acid. Results indicated a possible role of the HAE of C. brachiata leaves as herbal antioxidants in the prevention and/or treatment of oxidative stress-induced diabetes. Results suggested that antioxidant plant phenolics/flavonoids might be responsible for the antidiabetic efficacy of HAE. Further research can be undertaken on the HAE of C. brachiata leaves for exploration of biochemical mechanisms of antidiabetic action with the isolation of bioactive flavonoids having antidiabetic potential. [ABSTRACT FROM AUTHOR]