DOI: https://doi.org/10.55373/mjchem.v28i1.1

Keywords: Plukenetia volubilis L., secondary metabolites, antioxidant properties, young and mature leaf

Abstract

Plukenetia volubilis L. (Sacha Inchi), is a high-value medicinal plant originating from the Amazon region. The leaves of P. volubilis are abundant in secondary metabolites, suggesting promising pharmaceutical potential. Despite the presence of secondary metabolites in P. volubilis leaves, detailed studies on their specific composition based on their level of maturity and biological relevance remain limited. This study analysed the secondary metabolites in young and mature leaves with hexane, ethanol, and dichloromethane extraction, followed by Total Phenolic Content (TPC), Total Flavonoid Content (TFC), and Total Tannin Content (TTC). Meanwhile, the antioxidant properties were assessed using 2,2-Diphenyl-1-Picrylhydrazyl (DPPH) radical scavenging and Ferric Reducing Antioxidant Power (FRAP) assays. Mature leaves yielded a higher crude extract (23.04%) than young leaves (22.09%). The highest TPC (24.08±2.38 mg GAE/g) was found in ethanol mature leaves extract and the lowest was found in hexane young leaves extract (13.74±0.62 mg GAE/g). The highest TFC value (61.48±0.08 mg QE/g) was found in dichloromethane young leaves extract while the lowest TFC value (24.25±0.52 mg QE/g) was found in hexane mature leaves extract. Besides, TTC was shown the highest in dichloromethane young leaves extract (220.13±0.21 mg/TAE g) and the lowest TTC showed in dichloromethane mature leaves extract (0.08±2.23 mg/TAE g). In the FRAP assay, the ethanol mature leaves extract showed the highest antioxidant activity (13.16±1.80 umol (Fe (II)/g sample), while the ethanol young leaves extract had the lowest antioxidant activity (6.31±0.92 umol (Fe (II)/g sample). In the DPPH assay, the highest antioxidant activity was shown by hexane mature leaves extract with the IC₅₀ value of 0.47 mg/mL. Meanwhile, dichloromethane young leaves extract showed the lowest antioxidant activity with an IC₅₀ value of 7.85 mg/mL. Dichloromethane mature leaves extract had the highest secondary metabolite content, according to the comparative analysis of all results. These findings demonstrate a statistically significant influence of leaf maturity and solvent polarity on the extraction efficiency and antioxidant activity of P. volubilis leaves (p < 0.05), indicating their potential as a valuable natural source of antioxidants.