The purpose of this paper is to study the structure‐activity correlation of four medicinal plants – Ocimum basilicum L., Piper betle L., Grewia asiatica L., Lantana camara L. in crude methanolic extract. These plants have been used in Ayurvedic preparation as alternative medicine. The contents of phenolic compounds (flavonoids, anthocyanin) and antioxidant capacities were evaluated.
Folin‐Ciocalteu method was used for the analysis of the phenolic compounds. Total flavonoids were also evaluated. DPPH, ABTS+, FRAP and H2O2 assays were used to evaluate antioxidant activity. Most of the assays were determined spectrometrically.
O. basilicum L. had the highest of total phenolics content (305.11 mg GAE/g), highest content of anthocyanins (15.427 mg/Kg) and total flavonoids (9.692 QE mg/g). The DPPH, ABTS+, FRAP and H2O2 assay indicated that these plants possessed considerable antioxidant activities.
The results also showed that O. basilicum and L. camara from red colored cultivars possessed high contents of phenolic compounds. FRAP assay showed AOA in the following sequence – Lantana camara>Ocimum basilicum>Piper betle>Grewia asiatica. Since L. camara showed highest antioxidant capacity thus it can be a potential resource for commercial antioxidant.
