PHYTOCHEMICAL, GC-MS AND ANTIMICROBIAL ACTIVITY OF THE METHANOL AND N-HEXANE EXTRACT OF THE LEAF OF HEVEA BRASILIENSIS (EUPHORBIACEAE)
Abstract
Background: Medicinal plants have formed the basis of traditional medicine for centuries. The search for antimicrobial agents from plant sources is crucial in the face of increasing antibiotic resistance. Hevea brasiliensis (Euphorbiaceae), the natural rubber tree, has documented ethnomedicinal uses but remains underexplored for its antimicrobial potential.
Aim: This study evaluated the phytochemical composition, gas chromatography-mass spectrometry (GC-MS) chemical profile, and antimicrobial activity of methanol and n-hexane leaf extracts of Hevea brasiliensis.
Methods: The dried powdered leaves were extracted successively with n-hexane and methanol using cold maceration. Phytochemical screening was performed using standard qualitative tests. GC-MS analysis was conducted on the n-hexane extract. Antimicrobial activity was assessed against eight microorganisms (Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, Bacillus subtilis, Serratia rubidae, Salmonella typhi, Candida albicans, Aspergillus niger) using the agar well diffusion method to determine minimum inhibitory concentrations (MIC).
Results: Phytochemical screening revealed the presence of alkaloids, carbohydrates, glycosides, tannins, flavonoids, proteins, and amino acids in both extracts, while saponins and proteins were absent in the n-hexane extract. GC-MS analysis of the n-hexane extract identified 13 chemical constituents, with oleic acid (27.53% area), pentadecanoic acid, 14-methyl ester (15.20%), and octadecanoic acid (12.75%) as the most abundant. The extracts exhibited antimicrobial activity with MIC values ranging from 0.2 mg/mL (against Bacillus subtilis and Aspergillus niger) to 0.9 mg/mL (against Pseudomonas aeruginosa and Serratia rubidae). The vehicle control (50% DMSO) showed no inhibition.
Conclusion: The leaf extracts of Hevea brasiliensis contain bioactive phytochemicals that demonstrate significant antimicrobial activity against both bacterial and fungal strains. The GC-MS analysis revealed the presence of known antimicrobial fatty acids. These findings support the traditional use of the plant and suggest its potential as a source of novel antimicrobial agents.
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