Syringic acid induces cancer cell death in the presence of Cu(Ⅱ)ions via pro-oxidant activity

Objective:To investigate the effects of syringic acid on HEK 293 and HepG2 cells in the absence and presence of exogenous Cu(Ⅱ)and Fe(Ⅱ)ions.Methods:The antiproliferative effects of syringic acid on HEK 293 and HepG2 cells in the absence and presence of exogenous Cu(Ⅱ)and Fe(Ⅱ)ions were examined by MTT assay.Additionally,colony-forming,reactive oxidative species(ROS)generation,apoptosis induction,autophagy,mitochondrial membrane potential,and mitochondrial mass were investigated.Results:At 24 and 72 h,no significant differences were observed in the viability of HepG2 cells between the control and syringic acid+Fe(Ⅱ)groups.However,exposure of HepG2 cells to syringic acid+Cu(Ⅱ)for 72 h reduced the cell viability significantly.Furthermore,ROS formation,induction of apoptosis,and autophagic vacuoles were significantly increased in HepG2 cells without marked changes in mitochondrial membrane potential and mitochondrial mass.Moreover,syringic acid+Cu(Ⅱ)reduced the plating efficiency and surviving fraction significantly.Conclusions:The combination of syringic acid with Cu(Ⅱ)was toxic to cancer cells and showed pro-oxidant activity.In addition,this combination induced autophagy in cancer cells with less cytotoxic effects on normal cells,which is a potential candidate for the development of novel therapeutics towards cancer.

Anti-Endotoxic Effects of Syringic Acid of Radix Isatidis

The anti-endotoxic effect of syringic acid (SA) isolated from Radix Isatidis (Banlangen, BLG) was studied. SA was extracted and isolated from BLG and diluted into 1 % solution. The content of SA-pretreated endotoxin (ET) was quantitatively determined using Limulus test. The ability of fever induction of ET pretreated with SA was measured using endotoxin-induced fever test in rabbits. The LPS-induced death in mice pretreated with and without SA was compared. Results showed that after pretreatment with SA, 83. 16 % of ET was destroyed, the ET-induced fever in rabbits relieved markedly and the LPS-induced death rate in mice dropped from 68 % to 20 %. It was concluded that SA isolated from BLG had anti-endotoxic effects.

HPLC-UV Analysis and Antioxidant Potential of Phenolic Compounds from Endemic Shrub of Arid Environment Tamarix pauciovulata J, Gay

This research presents complete phenolic compounds and biological activity of Tamarix pauciovulata J. Gay, an endemic Saharan species. The antioxidant assays revealed that crude extract showed strong DPPH scavenging activity （IC50 = 49.357 μg/mL） but in reducing power and hydrogen peroxide scavenging activity, butanolic and ethyl acetate fractions have a potent ferrous ion-chelating ability in particularly the butanolic fraction （63.18% reduced power at 50 μg/mL） and a powerful scavenging activity on hydrogen peroxide in particularly ethyl acetate fraction （IC50 = 0.205 μg/mL）. The phenolic compounds of Tamarix pauciovulata leaves were analyzed by HPLC-UV. The major phenolic of leaf extracts are syringic acid （1.07 g/100g）, quercetin （34.1 mg/100g）, kaempferol （5.77 mg/100g）, isorhamnetin （5 mg/100g）. Others phenols were identified such as isoquercetin, catechin, epicatechin and its derivatives. Results indicated that the leaves extracts from Tamarix pauciovulata have great capacities to prevent diseases caused by the overproduction of radicals and can become important source of dietary compounds with health protective potential.