Effect of methanolic extract of Quercus infectoria bark on blood lipid profile, glycemia, inflammation, platelet aggregation, ulcer and bacterial activity. (c2005)

Abstract

Nowadays, the surge of consumption of herbal remedies has been stimulated by several factors, including notion that all herbal products are relatively safe and effective. The present investigation was undertaken to explore and shed light on possible medicinal effects of methanolic extract of oak tree (Quercus infectoria) bark upon blood lipid profile, glycemia, inflammation, platelet aggregation, ulcer and bacterial activity. After one month of chronic extract (0.5% w/v) intake via drinking water, only HDL-cholesterol levels were significantly increased, thus revealing a possible cardioprotective effect. No significant changes were observed in other lipid parameters studied. An increase in both serum glucose and insulin levels was observed in animals receiving the extract over the study period, which raise the possibility of development of insulin resistance syndrome. Liver enzymes activities: GOT, GPT and LDH, as well as urea and creatinine levels were assessed and the extract appeared not to have a negative impact on these parameters. The extract also exhibited an anti-inflammatory effect in cases of acute and chronic inflammation induced by carrageenan and formalin respectively. The 250mg/kg body weight dose showed the highest inhibitory activities in the two models used. The inhibition was even much greater than the reference drug diclofenac (10mg/kg body weight). In vitro studies showed a time-dependant stimulation of platelet aggregation when platelets were incubated in presence of 0.5mg/ml of the extract. Pre-treatment of fasted rats with two different doses of the extract (100 and 500 mg/kg body weight) showed a dose-dependant anti-ulcerogenic and gastroprotective effect against ethanolinduced gastric ulcer. The methanolic extract of Quercus infectoria bark was tested for its ability to inhibit 11 bacterial hospital isolates from different patients. The extract showed an antibacterial effect against four of the bacteria tested: Proteus mirabilis, Citrobacter braaki, and Staphylococcus aureus methicillin resistant and sensitive. These findings suggest that the methanolic extract of oak bark provides an inexpensive and powerful source of herbal supplement used to treat various conditions.