The aim of this study is to determine the total phenolic content and primary antioxidant activity of methanolic and ethanolic extracts of four aromatic plants’ leaves namely knotweed (Polygonum minus), curry (Murraya koenigii), kaffir lime (Citrus hysrix) and fragrant screwpine (Pandanus odurus). Total phenolic content (TPC) assay using Folin-Ciocalteu method was used to assess the presence and level of phenolic compounds in each sample. The present study showed that both methanolic and ethanolic extracts of P. minus had the highest TPC and followed by M. koenigii, C. hystrix and P. odorus. Primary antioxidant activity in terms of free radical scavenging activities of both methanolic and ethanolic extracts was then measured by 2, 2, diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging activity assay. The lowest EC50 values based on the DPPH. radical scavenging activity were shown by P. minus extracts as compared to the other samples. For both ethanolic and methanolic extracts, the correlations between TPC and EC50 based on the DPPH. radical scavenging activity assay were negative and weak. Relatively, the present results suggest that of the four aromaticplants, P. minus and M. koenigii have shown potential as sources of natural antioxidants.
This work aimed to assess the antioxidant and antimicrobial properties of Oxalis corymbosa extracts. Biochemical analyses were conducted on various plant parts, utilizing enzymatic and non-enzymatic assays. Parameters such as total soluble protein, chlorophyll, and carotenoid contents were also evaluated to elucidate the role of bioactive chemical compounds. The antimicrobial screening of extracts was performed against the bacterial and fungal strains Escherichia coli, Staphylococcus aureus, and Candida albicans, respectively. Results indicated that chlorophyll a, chlorophyll b, total chlorophyll, carotenoid content, anthocyanin content, catalase, peroxidase, and superoxide dismutase were most abundant in the O. corymbosa leaves. Moreover, total ascorbate peroxidase content, total phenolic content, and total flavonoid content were found to be higher in the roots compared to other parts. High-performance liquid chromatography analysis identified chlorogenic acid as the major component, followed by gallic acid, caffeic acid, quercetin, and salicylic acid. Regarding antibacterial potential, each extract exhibited significant activity, with methanolic and ethyl acetate extracts demonstrating the maximum inhibition zone against S. aureus and E. coli, respectively. These findings highlight the substantial antioxidant and antibacterial potential of different parts of O. corymbosa, suggesting their promising applications as ingredients in various nutraceutical products.