Abstract

• In the present work, locally grown M. koenigii leaves were selected to investigate the chemical constituents and some bioactivities. The main aim of this research was to study the chemical constituents of essential oil and some biological activities such as antioxidant, antimicrobial, and antiproliferative activities of leaves. The preliminary phytochemical tests indicated that various types of compounds, such as alkaloids, α-amino acids, carbohydrates, cyanogenic glycosides, glycosides, organic acids, phenolic compounds, reducing sugars, saponins, steroids, and terpenoids were present in the selected leaves samples, except for flavonoids, tannins, and starch. The essential oil (2.44%) was extracted from the leaves of M. koenigii by steam distillation method. The total phenolic content was found to be 2.73 ± 0.004 µg GAE/mg in the ethanol extract and 2.56 ± 0.003 µg GAE/mg in the watery extract by the Folin-Ciocalteu assay. The antioxidant activity of an ethanol extract (IC50 = 34.84 µg/mL) was found to be more effective than watery extracts (IC50 = 42.92 µg/mL) by the DPPH assay. The antimicrobial activity of the leaves was screened by using the agar well diffusion method. The PE, EtOAc, and EtOH extracts showed antimicrobial activity against all tested microorganisms (16 to 18 mm). In vitro antiproliferative activity of ethanol and watery extracts was tested on five cancer cell lines by the CCK-8 assay. The ethanol extract inhibited the growth of MCF7 (IC50 1 µg/mL), A549 (IC50 1 µg/mL), Kato III (IC50 15.3 µg/mL), GSU (IC50 1 µg/mL), and Hela (human cervical cancer) (IC50 1 µg/mL). The watery extract, was tested against MCF7 (IC50 > 100 µg/mL), A549 (IC50 62.1 µg/mL), Kato III (IC50 > 100 µg/mL), GSU (IC50 9.6 µg/mL) and Hela (IC50 > 100 µg/mL). GC-MS analysis of essential oil from M. koenigii leaves showed the presence of pxylene, α-methyl styrene, azulene, 3-carene, methyl hexadecanoate, 9,12- octadecadienoate, 9- octadecadienoate, methyl stearate and methyl eicosanoate respectively.