In vitro assessment of antioxidant, antimicrobial and phytochemical screening of crude methanolic extract of leaves of Murraya koenigii growing in Sri Lanka

Abstract

Curry leaves, commonly known as “karapincha” in Sinhala is a fascinating house plant grown in Asia and is native to Sri Lanka, Bangladesh and India. Among many different varieties of curry leaves available in Sri Lanka, Murraya koenigii is the most common belonging to family Rutaceae. Traditionally, M. koenigii has been well known to its health benefits and used in Ayurveda medicine practices in Sri Lanka. They are rich in nutrition owing to the presence of a variety of essential phytochemicals, minerals and trace minerals present in their leaves and seeds. Its antioxidant, antimicrobial and phytochemical screening activities were evaluated in the current study. The methanolic extract demonstrated a significant amount of antioxidant activity (IC50 =106.6 ± 4.2μg/ml) in 1,1-Diphenyl-2-picrylhydrazyl (DPPH) assays. Furthermore, the cold methanolic extract contains more or less amount of tannins, flavonoids, phenols and alkaloids. Saponins are absent in M. koenigii. Methanolic leaf extract of M. koenigii exhibited the highest inhibitory activity against Staphylococcus aureus compared to Escherichia coli and the zone of inhibition was 6.43 ± 0.06mm and 10.33 ± 0.21mm respectively. These findings revealed that the cold methanolic extract was found to have a good antioxidant activity as well as antimicrobial activities and contain many valuable phytochemicals. This study proves the medicinal values of the plant leaf extracts of M. koenigii that could be used as an excellent source of natural bioactive compounds in pharmacology.