Antioxidant Activity and Lipoxygenase Inhibitory Effect of <i>Caralluma arabica</i> and Related Polyphenolic Constituents

Abstract

Phytochemicals have been of great interest as a source of natural antioxidants used for health promotion, food preservation, food flavoring and cosmetics. In this research, alcoholic extract from Caralluma arabica and different solvent fractions were evaluated for their antioxidant, anti-inflammatory and anti-cancer properties as well as their polyphenolic compositions. The total antioxidant property was estimated by the ferric reducing antioxidant power (FRAP), 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2, 2-azino-bis(3-ethylbenzothiazoline-6-sulfonate) (ABTS+) and β -carotene bleaching tests. Among the ethanol extract and three fractions, the ethyl acetate fraction showed the highest phenolic content (33.1 mg gallic acid/g) and the best antioxidant activity. The ascorbic acid equivalent antioxidant capacities of the ethyl acetate fraction were 143.64, 381.3, 112.6 μmol/g in FRAP, ABTS and DPPH assays, respectively. This study verified that the ethanol extract and ethyl acetate fraction from Caralluma arabica have strong antioxidant activity that was correlated with their high level of phenolic content. Furthermore, the same extract showed appreciable anti-inflammatory via Lipoxygenase inhibitory activity (LOX), the IC 50 values ranged from 11.2 - 30.77 μg/mL. Moreover, Ethyl acetate fraction showed the strongest cytotoxic effect (IC 50 = 87.55 μg/mL) against MCF-7 breast cancer cell line. These findings suggest that Caralluma arabica may be considered as an interesting source of antioxidants for nutraceutical industries.