Abstract

The bitter leaf plant (Vernonia amygdalina Del.) is a native shrub tree species popular in Nigeria for its nutritional and therapeutic properties. This study aimed to determine the antioxidant activities of V. amygdalina varieties collected from Southern Nigeria by comparing the antioxidant activities of V. amygdalina varieties collected from different parts of Southern Nigeria. A total of forty (40) varieties of V. amygdalina were sampled from different parts of Southern Nigeria. In vitro antioxidant assays of V. amygdalina methanolic extract include: flavonoid and phenolic contents antioxidant activities. V. amygdalina variety from Oshimili south (Delta State) had significantly higher flavonoid content while Ethiope East (Delta), had significantly lowest flavoniod content when compared with V. amygdalina varieties of the other Southern States. V. amygdalina from Anochia North (Delta) and Ikpoba Okha (Edo) had significantly higher phenolic content while Yala (Cross Rivers) had significantly lowest phenolic content when compared with the other Southern States. Positive correlation (r² = 0.1011) was observed between phenolic and flavonoid contents of V. amygdalina varieties in the different States of Southern Nigeria. In conclusion, the findings of this study revealed that V. amygdalina has a high amount of natural flavonoid and phenolic content antioxidant activities when compared to analytical grade ascorbic acid and varying amounts of flavonoid and phenolic content antioxidant activities among the varieties collected from different parts of Southern Nigeria.