Evaluation of Antioxidant activities, Anthocyanins, Total Phenolic Content, Vitamin C Content and Cytotoxicity of Carissa carandas Linn.

Abstract

Carissa carandas, commonly known in Thai as 'nham-daeng', has a long history in alternative medicine in Thailand. Ethanolic extracts of fresh leaves, unripe fruits and fully-ripe fruits were investigated for their antioxidant activity, total phenolic content, total anthocyanins, anthocyanin identification, vitamin C content and cytotoxicity. Results showed that the leaf extract exhibited the high- est antioxidant activity, FRAP value and total phenolic content. The antioxidant activities of leaf, unripe and fully-ripe fruit extracts were 65.24±0.69, 0.85±0.03 and 2.42±0.41 mg AAE/g, respectively. Total phenolic contents were 24.91±0.22, 1.29±0.16 and 4.67±0.41 mg GAE/g and total anthocyanins were 0, 0.33±0.04 and 54.80±6.07 mg/l, respectively. The fully-ripe fruit extract, which showed low antioxidant activity and total phenolic contents, exhibited the highest total anthocyanins and cyanidin-3-galactoside levels. The unripe fruit extract showed the highest content of vitamin C (300.75±57 mg/100g). The major anthocyanin of all samples was cyanidin-3-galactoside. At a concentration of 200 µg/ml, treatment with the leaf extract caused the greatest reduction in HepG2 viability among the three extracts. These results indicated that the amounts of total phe- nolics and antioxidant activity could be correlated with cytotoxicity on HepG2 cells for the leaf sample.