Protective Effects of Defatted Sticky Rice Bran Extracts on the Early Stages of Hepatocarcinogenesis in Rats

Abstract

Use of natural products is one strategy to lessen cancer incidence. Rice bran, especially from colored rice, contains high antioxidant activity. Cancer chemopreventive effects of hydrophilic purple rice bran extract (PRBE) and white rice bran extract (WRBE) on carcinogen-induced preneoplastic lesion formation in livers of rats were investigated. A 15-week administration of PRBE and WRBE did not induce hepatic glutathione S-transferase placental form (GST-P) positive foci formation as the biomarker of rat hepatocarcinogenesis. PRBE and WRBE at 500 mg/kg body weight significantly decreased number and size of GST-P positive foci in diethylnitrosamine (DEN)-initiated rats. The number of proliferating nuclear antigen positive hepatocytes were also reduced in preneoplastic lesions in both PRBE and WRBE fed DEN-treated rats. Notably, the inhibitory effect on GST-P positive foci formation induced by DEN during the initiation stage was found only in rats treated by PRBE for five weeks. Furthermore, PRBE attenuated the expression of proinflammatory cytokines involving genes including TNF-α, iNOS, and NF-κB. PBRE contained a higher number of anthocyanins and other phenolic compounds and vitamin E. PRBE might protect DEN-induced hepatocarcinogenesis in rats via attenuation of cellular inflammation and cell proliferation. Anthocyanins and other phenolic compounds, as well as vitamin E, might play a role in cancer chemopreventive activity in rice bran extract.

Anthocyanins: Promising Natural Products with Diverse Pharmacological Activities

“…Anthocyanins extracted from purple rice bran can inhibit the expression of the inflammatory enzyme iNOS and the proinflammatory cytokines TNF-α and NF-κB, and ultimately reduce preneoplastic cell proliferation in mice with diethylnitrosamine (DEN)-induced early hepatocarcinogenesis, thus protecting against DEN-induced hepatocarcinogenesis [105]. Liao et al, found that 150 mg•kg −1 anthocyanins extracted from mulberries reduce the incidence of liver cancer induced by N-nitrosodiethylamine by half.…”

Comparative Studies on the Hepatoprotective Effect of White and Coloured Rice Bran Oil against Acetaminophen-Induced Oxidative Stress in Mice through Antioxidant- and Xenobiotic-Metabolizing Systems

“…Coloured rice bran extract showed greater antiproliferative activity than brown rice bran extract against MCF-7 and MDA-MB-231 breast cancer cell lines [ 32 ]. In addition, defatted sticky purple rice bran extract could inhibit preneoplastic lesion formation of carcinogen-induced hepatocarcinogenesis in rats with five weeks of treatment compared with white rice bran extract by attenuation of inflammation and cell proliferation [ 33 ]. Even though rice bran has been reported, studies comparing RBOs are few.…”

Assessment of Systemic Toxicity, Genotoxicity, and Early Phase Hepatocarcinogenicity of Iron (III)-Tannic Acid Nanoparticles in Rats

“…Liver portions were fixed in 10% buffered formalin and then embedded in paraffin for histopathological assessment of the formation of GST-P positive foci as a preneoplastic lesion in the livers, proliferating cell nuclear antigen (PCNA)-positive cells as cell proliferation markers and apoptotic cells by terminal deoxynucleotidyl transferase (TdT) dUTP nick end labelling (TUNEL) assay. These procedures were performed according to the method previously described [ 17 ].…”