Antimicrobial, antioxidant, and GC-MS analysis of hexane extract of the leaves of Solanum erianthum

Solanum erianthum is used in ethnomedicine for the treatment of various diseases. In the study, the hexane extract of the plant was screened for antimicrobial and antioxidant activities. Dried leaves samples were extracted with hexane. The extract was screened for activity against Staphylococcus aureus, Escherichia coli, Bacillus subtilis, Pseudomonas aeruginosa, Salmonella typhi, Klebisidlae pneumonae, Candida albicans, Aspergillus niger, Penicillium notatum and Rhizopus stolonifer at concentrations ranging between 6.25 mg/ml and 200 mg/ml using the agar diffusion method. The extract was screened for antioxidant activities using the DPPH free radical scavenging assay at concentrations between 0.0625 mg/ml and 1 mg/ml. All results were compared with those of the standard drugs. GC-MS analysis of the extract was thereafter carried out. Activities generally increased with the concentration in the antimicrobial assay. The highest zone of inhibition (28 mm) was obtained against S. aureus at 200 mg/ml. The extract, however, did not show a zone of inhibition as high as that of the standard drug (gentamycin and tioconazole) against any of the test organisms. IC₅₀ value of 0.729 was obtained in the DPPH assay which is higher than the IC₅₀ value (of 0.017) got for the standard Ascorbic acid. Some of the major compounds observed in extract include 1-octadecene (23.59 %), 9,12-Octadecadienoic acid (Z,Z) (14.01 %) and hexadecanoic acid ethyl ester (8.06 %). These compounds could have contributed to the bioactivities demonstrated by the extracts.