The phenolic content, antioxidant and cytotoxic activities of Origanum sipyleum from Turkey

Abstract

Origanum sipyleum is a medicinal plant species belonging to the genusOriganum and traditionally vegetative parts of this plant have been used asmedicinal tea or food additives. The current study has been designed to examinethe antioxidant, cytotoxic activities and total phenolic, flavonoid and tannincontents as well as the chemical composition of the ethanol extract of O.sipyleum. The antioxidant capacity of O. sipyleum was determined using sixcomplementary methods, ?-carotene/linoleic acid and phosphomolybdenum testsystems, radical scavenging (ABTS and DPPH), metal chelating and reducingpower assays. The phenolics were identified using HPLC. A brine shrimp(Artemia salina L.) lethality test was used for determining cytotoxic activity. Theethanol extract exhibited high DPPH free radical scavenging (DPPH, IC50:102.75µg/mL), ABTS radical scavenging (ABTS, IC50:88.64 µg/mL), metal chelating(20.68 %) and reducing power capacity (0.51 mg/mL). The antioxidant activitiesof the O. sipyleum with ?-carotene/Linoleic acid and phosphomolybdenum werecalculated as 85.59 % and 62.95 µg/mg respectively. The phenolic contents ofthe ethanol extract were evaluated using HPLC and determined major phenolics:caffeic acid, epicatechin and 2,5 dihydroxybenzoic. Furthermore, to gether withcytotoxic activity (LC50, 327.414 µg/mL) O. sipyleum is also rich in totalphenolic, flavonoid and tannin contents were 203.57 ± 4.62 mgGAE/g, 46.98 ±0.34 mgQE/g and 34.55 ± 0.56 mgCE/g respectively. These results could provideaddition information for the potential use of this medicinal plant as a foodingredient and as a natural antioxidant in the diet, as well as for thepharmaceutical industry.