LIGUSTRUM VULGARE L.: IN VITRO FREE RADICAL SCAVENGING ACTIVITY AND PRO-OXIDANT PROPERTIES IN HUMAN COLON CANCER CELL LINES

Ligustrum vulgare L. is a semi-evergreen woody branched bush from the family Oleaceae, widespread and frequently used in traditional medicine and pharmacy for treating different diseases. The aim of this study was to determine phenolic and flavonoid contents in L. vulgare leaf and fruit methanolic extracts, its free radical scavenging potential and in vitro effects on pro-oxidant/antioxidant status of human colon cancer cells (HCT-116 and SW480). The total phenolic content and DPPH free radical scavenging activity, concentration of superoxide anion radical (O-2(.-)), nitrites and reduced glutathione (GSH) in HCT-116 and SW480 cells were determined spectrophotometricaly. Inducible nitric oxide synthase (iNOS) protein expression was determined by imunoflorescence. Higher concentration of phenolic compounds and flavonoids was observed in leaf in comparison to fruit extracts. Both leaf and fruit extracts had considerably high ability for free radical scavenging by DPPH. The obtained results indicated that L. vulgare extracts increased O-2(.)-and GSH concentrations, inhibited iNOS protein expression and nitrites production in HCT-116 and SW480 cells. All the investigated parameters indicate the presence of oxidative stress in treated cells and pro-oxidative effect of L. vulgare extracts on colon cancer cells, which is associated with cytotoxic and apoptotic ability of L. vulgare.