ABSTRACT
The study was to characterize the polyphenolic composition, antioxidant properties, and hepatoprotective effects of a polyphenols-enriched extract (HMTP) from Huangshan Maofeng green tea. HPLC analysis showed that three predominantly polyphenolic compounds present in HMTP were epigallocatechin (271.2 µg/mg extract), rutin (239.3 µg/mg) and epicatechin (89.3 µg/mg). HMTP was shown to exhibit strong scavenging activities against DPPH, O2(-), and OH, and ferric-reducing antioxidant power in vitro. Administration of HMTP at 200, 400 and 800 mg/kg bw in mice prior to CCl4 injury significantly decreased the CCl4-induced elevation of serum ALT, AST and ALP activities, and prevented an increase in hepatic MDA levels (p<0.05). Mice with HMTP pretreatment displayed a better profile of hepatosomatic index and the improved GSH-Px and SOD activities in the liver, relative to CCl4-intoxicated mice. Liver pathological observation also confirmed the protection on CCl4-caused histological alteration, suggesting that HMTP has potential to be explored as valuable hepatoprotective function food.
Subject(s)
Chemical and Drug Induced Liver Injury/prevention & control , Plant Extracts/pharmacology , Polyphenols/pharmacology , Tea/chemistry , Animals , Antioxidants/chemistry , Antioxidants/pharmacology , Body Weight/drug effects , Carbon Tetrachloride/toxicity , Catechin/analogs & derivatives , Catechin/chemistry , Catechin/pharmacology , Chromatography, High Pressure Liquid , Mice , Organ Size/drug effects , Plant Extracts/chemistry , Rutin/chemistry , Rutin/pharmacologyABSTRACT
Oxidative stress is one of the major factors in the pathogenesis of liver disease. Quercetin is a plant-based antioxidant traditionally used as a treatment for hepatic injury, but its poor solubility affects its bioavailability. We here report the regulative effects on hepatoprotection and absorption in mice of quercetin sulfation to form quercetin-5',8-disulfonate (QS), a novel synthetic compound. Oral administration of both QS and the parent quercetin at 100, 200 and 500 mg/kg·bw prior to acute CCl4 oxidative damage in mice, effectively attenuated serum alanine aminotransferase (ALT), aspartate aminotransferase (AST) and lactate dehydrogenase (LDH) activities and hepatic malondialdehyde (MDA) levels (p<0.05), and suppressed the CCl4-induced depletion of glutathione peroxidase (GSH-Px) and total superoxide dismutase (T-SOD). Selective 5',8-sulfation of quercetin increased the hepatoprotective effect, and its relative absorption relative to quercetin (p<0.05) as indicated by an improved 24-hour urinary excretion and a decreased fecal excretion determined by HPLC. These results and histopathological observations collectively demonstrate that quercetin sulfation increases its hepatoprotective effects and absorption in mice, and QS has potential as a chemopreventive and chemotherapeutic agent for liver diseases.
