Summary: | Plectranthus amboinicus (Lour.) Spreng (Lamiaceae) is traditionally used in folk medicine to treat countless illnesses. This study aimed to determine the phytochemicals analysis including, phytochemical screening, total phenolic and flavonoid contents as well as DPPH radical scavenging activity of P. amboinicus leaf extracts. The extraction of phytochemicals was performed using sequential maceration method using n-hexane, ethyl acetate and methanol. Phytochemical screening was conducted using standard chemical tests, while total phenolic and flavonoid contents were performed using Folin-Ciocalteu and aluminum chloride colorimetric methods, respectively. All extracts were subjected to 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical assay. Preliminary phytochemical analysis revealed that the leaves of P. amboinicus consisted of flavonoids, phenols, terpenoids, glycosides and tannins, but showed negative results for alkaloids and saponins tests. The greatest phenolic content was observed in the ethyl acetate extract (73.31 ± 0.97 mg GAE/g), while the lowest value was reported in the nhexane extract (24.63 ± 0.84 mg GAE/g). The ethyl acetate extract also composed of the highest flavonoid content (95.72 ± 0.80 mg QE/g), while the methanol extract had the lowest flavonoid content (9.84 ± 0.69 mg QE/g). Among the extracts, the methanol extract demonstrated better DPPH radical scavenging activity with an IC50 of 878.37 μg/mL. © 2023 Malaysian Society for Biochemistry and Molecular Biology. All rights reserved.
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