GC-MS Analysis, Antimicrobial and Antioxidant Activities of Extracts of the Aerial Parts of Conyza sumatrensis

Abstract

Phytochemical analyses as well as antimicrobial and antioxidant activities of the extracts of C. sumatrensis aerial parts were investigated in this study.

METHODS: The aerial parts of C. sumatrensis were air dried, weighed and exhaustively extracted with hexane, ethyl acetate and methanol successively. The crude extracts were screened for metabolites.  These extracts of the plant were evaluated for antimicrobial and antioxidant activities using agar  diffusion and DPPH method respectively. The extracts were also analysed using Gas chromatography – Mass spectrometry, and the chromatogram coupled with mass spectra of the compounds were matched with a standard library.

RESULTS: Preliminary phytochemical investigation of  rude n-hexane, ethyl acetate and methanol extracts of the aerial parts of Conyza sumatrensis revealed the presence of anthraquinones, flavonoids, terpenoids, phenolics, tannin, glycosides and carbohydrate. All the crude  extracts gave a clear zone of inhibition against the growth of the test bacteria (Staphylococcus aureus, Escherichia coli, Bacillus subtilis, Pseudomona aeruginosa, Salmonella typhi, Klebsiellae pneumonae) at moderate to high  concentrations, as well as test fungi (Candida albicans, Aspergillus niger, penicillium notatum and  Rhizopus stolonifer) at high concentration. Methanolic extract exhibited significant radical scavenging  property with IC₅₀ of 17.08 μg/mL while n-hexane and ethyl acetate extracts showed no significant antioxidant activity. GC-MS of N-hexane extract showed a total number of eleven chemical constituents with α-Farnesene and spathulenol being the most abundance compounds constituting 20.27 and 22.28% of the extract respectively. Ethyl acetate extract revealed thirteen  compounds with two most abundant compounds, cis-β-farnesene (16.64 %) and cis-pinane (21.09 %). While  methanolic extract affords seventeen compounds with Ephytol being the most abundant compound  (19.36 %). © JASEM

Keywords: Antimicrobial activity, Antioxidant, GC-MS analysis, Phytochemicals, Conyza sumatrensis