Purpose: To evaluate the
in vitro cytotoxic, antioxidant and antimicrobial activities of
Clinacanthus nutans
extracts and semi-fractions.
Method: The plant was subjected to cold solvent extraction to produce petroleum ether, ethyl acetate
and methanol crude extracts, followed by isolation using bioassay-guided fractionation. The crude
extracts (0.2 to 10.0 mg/ml) were tested against HeLa and K-562 cell lines using 3-(4,5-dimethylthiazol-
2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and antioxidant activity using 1, 1-diphenyl-2-
picrylhydrazyl (DPPH) assay. Furthermore, fractions isolated from ethyl acetate leaf extract (0.02 to
10.0 mg/ml) were tested against
Bacillus cereus
(ATCC11778),
Escherichia coli
(ATCC25922),
Salmonella enterica
Typhimurium (ATCC14028) and
Candida albicans
(ATCC10231) using minimum
inhibitory concentration (MIC) and minimum bactericidal or fungicidal (MBC/MFC) assays.
Results: Petroleum ether extracts demonstrated the strongest cytotoxic activity against HeLa and K-
562 cells with IC50 of 18.0 and 20.0 μg/mL, respectively. Petroleum ether extracts also displayed the
highest radical scavenging activity of 82.00 ± 0.02 %, compared with ascorbic acid and α-tocopherol
corresponding values of 88.7 ± 0.0 and 86.6 ± 0.0 %, respectively. In MIC assay, all the crude extracts
and fractions showed inhibition against all tested microorganisms. Fraction 7 displayed the lowest MIC
and MBC/MFC values against
B. cereus and
C. albicans at 1.39 mg/ml, respectively. Ampicillin and
amphotericin B displayed MIC value of 1.3 mg/ml.
Conclusion: The bioactive compounds from
C. nutans are potential cytotoxic, antimicrobial and
antioxidant agents.
