Total phenolic content, total flavonoid content and antioxidant activity of ethanolic extract of Rafflesia kerri Meijer, Lojing Highlands, Peninsular Malaysia

Abstract

Rafflesia kerri Meijer belongs to genus Rafflesia, recognized as the biggest flower in the world. This species found distributed in tropical rainforest of Thailand and Peninsular Malaysia. The flower believed to have medicinal values and used as traditional herbs by aborigine ethnic group and locals. Herein, this study was conducted to evaluate the total phenolic content (TPC), total flavonoid content (TFC) and antioxidant activity of the flower by using several antioxidant assays, which includes 2,2-diphenyl-1-picrylhydrazyl radicals (DPPH) and ferric reducing antioxidant power (FRAP). The extract of female ethanolic extract exhibited highest antioxidant activity in all of the assays (FRAP = 4642.844 ± 10.777 mM/mg) and median inhibition concentration (IC50 = 49.850 ± 2.179). The same extract showed the presence of phenolic and flavonoid content with respective value of (Gallic acid equivalent, GAE) of 1634.731 ± 20.465 mg/100g and Quercetin equivalent (QE = 817.000 ± 69.282 mg/g) respectively with significantly differences (p < 0.05) compared to male ethanolic extract. Thus, the flower is highly valuable not only for ecotourism industry but also has potent medicinal value for human health improvement.