Phytochemical Screening and Antioxidant Activities of the Seedling Extracts from Inca Peanut Plukenetia volubilis

Background: Plukenetia volubilis L., Inca peanut is an oleaginous plant, widely cultivated as commercially in South East Asia, especially in Thailand. The oil from the seed plant is a greatest interesting a natural source. Objectives: The aims of this study were investigated phytochemical screening, to evaluated the total flavonoids and phenolic compound contents as well as antioxidant activities of seedling extract from P. volubilis. Methods: The dried P. volubilis seedlings of 21 days growing period were extracted by using different solvent including aqueous (ASS), 50% ethanolic (HESS), and 95% ethanolic (ESS) extracts. The phytochemical screenings were determined on total phenolic compound (TPC) and flavonoid (TFC) contents. The antioxidation were tested by using 2,2-diphenyl-1-picrylhydrazy radical scavenging (DPPH), 2,2 -azinobis-(3-ethylbenzothiazoline-6-sulphonate) (ABTS⁺) assay, and ferric reducing antioxidant power (FRAP). Results: The results found that the ESS were significantly highest amount on total phenolic compound (23.0809±0.8632 mgGE/gExt ) and flavonoid (466.3839±1.5580 mgQE/gExt) contents. In this study, ascorbic acid (IC₅₀ =0.016±0.0003 mg/mL) and Trolox (IC₅₀ =0.044±0.0008 mg/mL) as standard substances were showed more potent than all of the extracts from P. volubilis seedlings. Surprisingly, the ESS has more potent on free radical scavenging higher than different solvents; DPPH=0.007± 0.001 (IC₅₀=mg/mL), ABTS= 1.4065± 0.0505 (IC₅₀=mg/mL),and FRAP= 74.4960± 2.6067 (mg=TE/gExt). Conclusion: the plant seedling extracts composed with high amount of flavonoids and phenolic compound contents possess valuable to antioxidant activities. The seedling extracts from the plant could apply to supplementary food, cosmetic, pharmaceutical, and horticultural industries. Next study, chemical compositions, the major active compound(s), and biological activities will be clarified.