In vitro antioxidant, antibacterial, and cytotoxicity activities from Karanda (Carissa carandas L.) fruit extracts

Abstract

Background: Carissa carandas L. (Apocynaceae), commonly known as Karanda, is a widely used medicinal plant. In Thailand, Karanda fruits are favorite fruits especially at central region due to attractive shape and color with health promoting activities. Aims: The aims of the study were to evaluate its antibacterial and antioxidant activities. Furthermore, cytotoxicity of ripped Karanda fruit extracts was also evaluated with normal cells to claim for health safety. Materials and Methods: Total phenolic content (TPC) and antioxidant activity of dichloromethane (KD) and methanol (KM) extracts were performed by of Folin–Ciocalteu reagent; 2, 2-diphenyl-1-picrylhydrazyl radical, 2, 2-azinobis (3-ethylbenzothiazoline- 6-sulfonic acid) cation radical scavenging assays and oxygen radical absorbance capacity. Antibacterial tests against Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Acinetobacter baumanii, and Enterococcus faecalis were performed according to Clinical and Laboratory Standards Institute. Cytotoxicity of KD and KM were performed by resazurin microplate assay and used human dermal fibroblasts-neonatal (HDFn-neonatal) dermal fibroblast and Vero cells as normal cells. Results: KD and KM were contained TPC = 5.1 ± 0.5 and 19.4 ± 0.9 mg of gallic acid equivalent of extract, respectively. Antioxidant activities of KD and KM were 90-110 and 130-200 μmol Trolox equivalent antioxidant capacity, respectively. KD and KM were inhibited all tested bacteria at minimum inhibition concentration = 12.5-50 and 25-50 mg/ml, respectively. No any cytotoxic effect of KD and KM extracts to Vero cells and HDFn-neonatal dermal fibroblast. Conclusions: Ripped Karanda fruits were preferable antioxidant activities rather than unripe. Ripped Karanda fruits were also possessed antibacterial activity with no cytotoxicity to normal cells.