In Vitro Screening of Cytotoxic, Antimicrobial and Antioxidant Activities of Clinacanthus nutans (Acanthaceae) leaf extracts

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 to10.0 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 ìg/mL, respectively. Petroleum ether extracts also displayed the highest radical scavenging activity of 82.00 ± 0.02 %, compared with ascorbic acid and á-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.Keywords: Clinacanthus nutans, Cytotoxic, Antioxidant, Antimicrobia

Cytotoxic Effect and Antioxidant Activity of Bioassay-guided Fractions from Solanum nigrum Extracts

Purpose: To evaluate the cytotoxic effect and antioxidant activity of bioassay-guided fractions from Malaysian species of Solanum nigrum.Methods: Methanol leaf and ethanol fruit extracts of Solanum nigrum were subjected to bioassay-guided fractionation using column chromatography. The semi-purified fractions were investigated for their in vitro cytotoxic effect against various cancer cell lines using 3-(4, 5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2H-tetrazolium bromide (MTT) assay, and for antioxidant activity using 2, 2-diphenyl-1- picryhydrazyl (DPPH) assay.Results: From bioassay-guided fractionation, 13 and 17 fractions were obtained from the methanol leaf and ethanol fruit extracts, respectively. In MTT assay, fractions 1, 2 and 4 from methanol extract showed the highest cytotoxic effect against the cancer cells with IC50 of 13.0 μg/mL at 48 h incubation. For the ethanol extract, fractions 14 and 15 showed the highest cytotoxic effect with IC50 of 12.0 μg/mL against K-562 cells, while fractions 13, 14 and 17 showed IC50 of 13.0 μg/mL against HeLa cells. Doxorubicin hydrochloride and vinblastine sulfate inhibited the cancer cells with IC50 range of 1.3 to 17.0 μg/mL. The highest radical scavenging activity was exhibited by fraction 2 from methanol extract with ED50 value of 0.10 mg/ml, while fraction 15 from ethanol extract showed ED50 of 0.79 mg/mL. Ascorbic acid and α-tocopherol exhibited radical scavenging activity of 95.0 ± 0.01 % (ED50 = 0.05 mg/mL) and 93.0 ± 0.01 % (ED50 = 0.10 mg/mL), respectively.Conclusion: Solanum nigrum leaves and fruits are potential sources of cytotoxic and antioxidant agents.Keywords: Solanum nigrum, Cytotoxic Activity, Anti-oxidant Activity, Bioassay-guided Fractionation, Doxorubicin, Vinblastin