Abstract

• This research aims to evaluate the phytochemical tests, antioxidant, antimicrobial and cytotoxic activities from the leaves of Calotropis gigantea (L.) W.P. Aiton. The total phenol contents of watery extract (47.56 ± 0.1 mg GAE/g) and ethanol extract (64.18 ± 0.7 mg GAE/g) of the sample were tested by using Folin-Ciocalteu method. The total flavonoid contents of watery extract (33.49 ± 0.3 mg QE/g) and ethanol extract (35.47 ± 0.1 mg QE/g) of the sample were determined by aluminum chloride method. In addition, the tannin content (2.1 %) was determined by using titration method. From EDXRF investigation, C. gigantean sample contains high concentrations of organic compounds together with trace amounts of some elements. The antioxidant activity was done on the watery extract (IC50 = 42.37 μg/mL) and ethanol extract (IC50 = 33.67 μg/mL) by using DPPH assay. Then, antimicrobial activities of ethanol and watery extracts of the samples were investigated by agar well diffusion method using pathogenic microorganisms such as Escherichia coli, Saccharomyces cerevisiae, Candida albicans, Agrobacterium tumefaciens and Salmonella typhi against test microorganisms (13 - 15 mm inhibition zone diameters). Moreover, cytotoxicity of the ethanol extract (LD50 value of 1.76 µg/mL) was higher than watery extract (LD50 value of 8.57 µg/mL) of sample, determined by using brine shrimp lethality bioassay. According to these experimental results, the leaf of C. gigantean is safe and suitable to treat various diseases including cancer and aging.