Abstract

ANTIMYCOBACTERIAL AND ANTIOXIDANT ACTIVITIES OF THE LEAVES OF ACALYPHA FIMBRIATA (SCHUMACH & THONN) AND GC-MS ANALYSIS OF ITS BIOACTIVE HEXANE FRACTION

*Morufu Adisa Ademoye, Labunmi Lajide and Bodunde Joseph Owolabi

ABSTRACT

The antimycobacterial effect of hexane and ethylacetate fractions from ethanol leave extract of Acalypha fimbriata on H37Rv and local isolates of Mycobacterium tuberculosis (Mtb) strains were investigated using proportion and nitrate reduction methods. The antioxidant activity of the plant was assessed by investigating DPPH scavenging, NO scavenging, Reduction Potential and Iron (II) chelation ability. The chemical profile of the active hexane fraction was examined using GC-MS analysis. The two fractions inhibited the growth of the Mtb strains used with the ethylacetate fraction showing of MIC of 0.5 mg/ml lower than the hexane fraction of MIC 2.5 mg/ml. The antioxidant result showed the plant IC50 DPPH scavenging activity of 3.907 mg/ml lower than the standard ascorbic value of 9.400 mg/ml. Again, the A. fimbriata Reduction Potential IC50 value is 11.003 μg/ml compared to the 324.259 μg/ml of the ascorbic acid. However, the standard ascorbic acid NO scavenging activity IC50 value of 324.259 μg/ml is lower than 426.284 μg/ml of A. fimbriata. The iron (II) chelation response of the leaves of the plant was dose dependent with the compound ethylenediaminetetraacetic acid (EDTA) used as the standard. The GC-MS analysis of the active hexane fraction showed the presence of sixteen compounds which include hexadecanoic acid ethyl ester (19.41%), phytol (17.04%), hexadecanoic acid methyl ester (15.68%), ethyl 9,12,15-Octadecatrienoate (13.27%) and squalene (1.24%). The strong antioxidant potentials of the extract of the leaves of the plant coupled with the bioactive chemical compounds present in the active hexane fraction would have inevitably contributed to the antimycobacterial activity of the plant. There is still need for further research work to determine the bioactive constituents that could be responsible for the antimycobacterium activity of the ethylacetate fraction.

Keywords: Mycobacterium tuberculosis, Acalypha fimbriata, Antioxidant, GC-MS.