Antimicrobial and Cytotoxic Activities and GC-MS Analysis of Phytocomponents of Methanolic Extract of Curculigo pilosa (Schum and Thonn) Engl. (Hypoxidaceae) Rhizomes

Abstract

Objectives: To investigate the antimicrobial and cytotoxic activities of crude methanol extract of Curculigo pilosa (Schum and Thonn) Engl. (Hypoxidaceae) rhizomes and its solvent soluble fractions and to analyze the most active fraction by Gas Chromatography Mass Spectrometry (GC-MS) technique. Place and Duration of Study: Department of Chemistry and Department of Microbiology, School of Natural and Applied Sciences, Federal University of Technology, Minna, Nigeria in June, 2012. Methodology: Shade air-dried powder of Curculigo pilosa rhizomes was extracted with methanol by Soxhlet extraction. Crude methanol extract of Curculigo pilosa root (CCPM) and the solvent soluble fractions namely: n-hexane (CPH), chloroform (CPC), ethylacetate (CPE), n-butanol (CPB) and residue (CPM) were obtained. Phytochemical constituents of the most active fraction (methanol residue) of Curculigo pilosarhizomes were determined using GC-MS technique. Results: The antimicrobial activity of some solvent fractions tested except n-hexane fraction appears to be promising with Minimum Inhibitory Concentration (MIC) ranging from 0.09–6.25 mg/mL. However, ethyl acetate and n-butanol fractions showed antibacterial activity against highest number of bacterial strains. The results revealed that methanolic residue was more potent than derived fractions. Cytotoxicity assay results indicated weak cytotoxic activity of the crude C. pilosa methanol root extract as displayed by its LC50(764.07μg/mL). The qualitative phytochemical evaluation indicates the presence of chemical constituents such as flavonoids, terpenoid, saponins, tannins, alkaloids, cardiac glycosides, steroid and anthraquinone. The quantitative analysis of its metabolites depicts alkaloids (12.80±0.49), saponins (54.49±0.33), flavonoids (44.88±0.36), tannins (69.49±0.65), phenols (50.40±0.34), oxalates (10.95±0.63), cyanides (44.87±0.70) and phytate (15.00±0.05). The major phytocomponents identified by GC-MS analysis in the combined fractions of C. pilosa methanolic residue indicated that there were different types of high and low molecular weight compounds. In particular, it revealed the presence of 3-eicosyne (8.98%), pentadecanoic acid (2.41%) hexadecanoic acid (31.18%), octadecanoic acid (1.52%) 9-octadecenoic acid (24.42%), linoleic acid ethyl ester(3.93%), androstan-3-one (5.90%), 1-phenanthrenenmethanol (5.78%), 1,2-benzenedicarboxylic acid (4.59%), hexanedioc acid (13.38%), 8,11-octadecadienoic acid (9.02%), nonadecane (3.52%), ethanol-2, 2-oxybis (20.75%), propane-1-(1-methylethoxy) (8.05%) and 2, 6,10-dodecatriene-1-ol (5.14%). Conclusion: In this study, some of the phytocompounds identified are biologically important and may have contributed to the observed antimicrobial activity, hence their therapeutic significance which may support the ethnomedicinal uses of C. pilosa in the treatment of venereal diseases in humans.