Determination of Flavonoids, Phenolic and Total Antioxidant Content from the Leaves, Stems and Roots of Betel Plants

Betel (Piper betle L.) is one of the medicinal plants widely used in traditional medicine for its therapeutic properties. This study aimed to determine the levels of total flavonoids, phenolics, and antioxidants in the leaves, stems, and roots of four betel species, namely Piper betle L., Piper ornatum N.E. Br., Peperomia pellucida (L.) Kunth, and Piper aduncum L. The TFC was measured using the aluminum chloride (AlCl₃) colorimetric method, while total phenolic content was determined using the Folin–Ciocalteu method. The antioxidant activity was assessed by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) and Modified Phenanthroline Method (MPM). The results showed that the highest TFC was found in Peperomia pellucida (L.) Kunth leaves (79.27 ± 1.37 mg QE/g DW), whereas the highest total phenolic content was observed in Piper betle L. stems (23.97 ± 0.04 mg GAE/g DW). The strongest antioxidant activity was also observed in Peperomia pellucida (L.) Kunth leaves (23.93 ± 0.36 mg AAE/g DW). Correlation analysis revealed a very strong relationship between total flavonoids and antioxidant activity in leaves (r = 0.9892), and a strong correlation between total phenolics and antioxidant activity in roots (r = 0.9745). These findings suggest that the antioxidant potential of betel species is closely related to their secondary metabolite composition, particularly flavonoids and phenolic compounds.