Investigation of phytochemicals and antioxidant activity of Plectranthus bourneae Gamble - an endemic plant species of western ghats of Tamil Nadu, India

The present investigation focuses on phytochemical screening and biological activities of Plectranthus bourneae, a medicinal plant species. Various solvents or ethanolic extract of leaf was used to investigate the phytochemicals by qualitative and quantitative methods, GC-MS, FTIR, and antioxidant activities. Qualitative phytochemical analysis of leaf extracts showed the presence of alkaloids, carbohydrates, saponins, glycosides, phytosterols, resins, phenols, tannins, diterpenes, flavonoids, proteins and amino acids. The highest concentrations of total phenolic content (50.10 ± 1.84 mg GAE/g) and tannins (83.03 µg/ml) was observed in ethanolic extracts. GC-MS results revealed the presence of various phytocompounds which are greatly known for their biological activities. The results of FTIR spectra confirmed the presence of different functional groups with peaks at 3347.74 cm− 1 (alcohols, phenols) and 2924.23 cm− 1 (alkanes). The free radical scavenging activity of the ethanolic leaf extract was found to be high in DPPH (441.27 µg/ml) and hydroxyl radicals (22.4–74.4% at the concentration of 1000 µg/ml) scavenging assays. © 2022, The Author(s) under exclusive licence to Society for Plant Research.