Antidiabetic, anthelmintic and antioxidation properties of novel and new phytocompounds isolated from the methanolic stem-bark of Vernonia amygdalina Delile (Asteraceae)

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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.