Comparative Study of Phytochemical Constituents and Antimicrobial Activities of Acalypha wilkesiana and Acalypha godseffiana Extracts

Abstract

Aim: The aim of the investigation was to evaluate and compare the phytoconstituents and antimicrobial activities of leaf extracts of two species of Acalypha (A. wilkesiana and                      A. godseffiana). Methodology: The methods employed include manual pulverization of the air-dried leaves and solvent (ethanol) percolation for 72 hrs. The crude extracts were kept in sterile Mc Cartney bottles and stored in the refrigerator 4±2°C. Thereafter, they were screened for phytochemical components. Moreover, they were investigated for antimicrobial activities against Bacillus subtilis, Escherichia coli, Enterococcus faecalis, Klebsiella pneumoniae, Streptococcus pneumoniae, Staphylococcus aureus, Aspergillus flavus, Candida albicans, and Cryptococcus neoformans. Results: From the results obtained during the study, flavonoid, saponin, phobatanin, tannin and alkaloid were found in both A. wilkesiana and A. godseffiana, steroid was found only in                          A. wilkesiana while terpenoid and anthraquinones were not detected in the two species. The quantitative screening showed that A. wilkesiana extract possess more of flavonoid (7.32 µg/g), tannin (4.21 µg/g), alkaloid (4.19 µg/g) and steroids (1.18 µg/g) compared to the extract of A. godseffiana, whereas, saponin (5.23 µg/g) and phobatanin (4.32 µg/g) were found to be present in higher quantities in A. godseffiana than the extract of A. wilkesiana. The antimicrobial activity assay revealed that at the highest concentration used (50 mg/ml) the zones of inhibition ranged from 9.00±0.00b mm against A. fumigatus to 16.00±0.00d mm against S. aureus. Moreover, there was a significant difference between the susceptibility of Gram positive bacteria and Gram negative bacteria. The extract of A. godseffiana was more active against the selected pathogens compared to the extract from A. wilkesiana. Conclusion: The results obtained suggest that both species of Acalypha possess comparable phytochemicals however, A. godseffiana was more potent as antimicrobial agent than A. wilkesiana this support their folkloric use as remedy for several disease conditions and new antimicrobial agents may be developed from them.