Butein imparts free radical scavenging, anti-oxidative and pro-apoptotic properties in the flower extracts of Butea monosperma

The flower of Butea monosperma (Lam.) (Fabaceae) has been used in traditional Indian medicine in the treatment of many ailments including liver disorders. To understand the pharmacological basis of its beneficial effects, the extracts of dried flowers in water, methanol, butanol, ethyl acetate and acetone were evaluated for free radical scavenging and pro-apoptotic activities in cell cultures (human hepatoma Huh-7 cell line and immortalized AML-12 mouse hepatocytes). Butrin and butein -the active constituents of flower extracts- were used as reference molecules. The levels of cell injury markers like lactate dehydrogenase, glutathione and lipid peroxidation and primary antioxidant enzymes glutathione S-transferase and catalase were also measured. The aqueous and butanolic extracts exhibited better 2,2-diphenyl-1-picrylhydrazyl scavenging and cytotoxic activities in hepatoma cells than in immortalized hepatocytes. Interestingly, butein inhibited 2,2-diphenyl-1-picrylhydrazyl radical better than butrin. The aqueous and butanolic extracts were further investigated for hepatoprotection against carbon tertrachloride-induced biochemical changes and cell death. Both extracts, just as butrin and butein, significantly reversed the cellular glutathione levels and lipid peroxidation, and glutathione-S-transferase activity. Lactate dehydrogenase leakage and cell death were also prevented. However, only butein revived the catalase activity. Thus, the butein content of Butea monosperma flower extracts is important for free radical scavenging activity, apoptotic cell death and protection against oxidative injury in hepatic cells.

Chemoprevention by Butea monosperma of hepatic carcinogenesis and oxidative damage in male wistar rats.

In this communication, we document chemopreventive effects of Butea monosperma extract on hepatic carcinogenesis and on tumor promoter induced markers and oxidative stress in male Wistar rats. Treatment of male Wistar rats for five consecutive days with 2-AAF i.p. induced significant hepatic toxicity, oxidative stress and hyperproliferation. Pretreatment of B.monosperma extract (100 and 200 mg/kg body weight) prevented oxidative stress by restoring the levels of antioxidant enzymes and also prevented toxicity at both doses. The promotion parameters induced (ornithine decarboxylase activity and DNA synthesis) by 2-AAF administration in diet with partial hepatectomy (PH) were also significantly suppressed dose dependently by B. monosperma. Thereafter, we proceeded with studies on rat liver carcinogenesis. After fourteen days of DEN treatment, dietary administration of 2-AAF with PH resulted in a 100% incidence of tumors in the animals. However, B.monosperma caused reduction in the number of tumors/ rat and percentage of tumor bearing rats at the end of the study, as confirmed histologically. Thus, our data suggest that B.monosperma extract is a potent chemopreventive agent which suppresses 2-AAF-induced hepatic carcinogenesis and oxidative damage in Wistar rats. The protective activity of the plant might be due to the two major constituents (butrin and isobutrin).