THE EFFECT OF ADMINISTRATION OF AN EQUAL DOSE OF DIFFERENT CLASSES OF PHYTOCHEMICALS ON HEME OXYGENASE-1 GENE AND PROTEIN EXPRESSION IN MICE LIVER

Objective: Heme oxygenase-1 (HO-1) is enzyme that possesses antioxidant, anti-inflammatory, and cytoprotective functions. Induction of HO-1 occurs as an adaptive and beneficial response to various injurious stimuli such as oxidative stress. This study is aimed at monitoring the effects of administration of equal doses (50 mg/kg) of sulforaphane (SFN), curcumin, quercetin, indole-3-carbinol, and butylated hydroxyanisole (BHA) for 14 days on the levels of liver HO-1 gene and protein expression in mice. Method: A total of 48 adult male ICR white mice (25–30 g) were divided into eight groups: Normal control group (n=6), SFN-treated group (n=6), quercetin-treated group (n=6), curcumin-treated group (n=6), BHA-treated group (n=6), indole-3-carbinol treated group (n=6), vehicle 1 control group (n=6), and vehicle 2 control group (n=6). All chemicals were administered intraperitoneally at a dose of 50 mg/kg for 14 days. Vehicle 1 (dimethyl sulfoxide, TweenTM 20, and normal saline at a ratio of 0.05:0.1:0.85) was used to dissolve SFN, quercetin, and curcumin. Vehicle 2 (corn oil) was used to dissolve indole-3-carbinol and BHA. At day 15, the animals were sacrificed and their livers were isolated. From the liver, total RNA was extracted, reverse transcribed and subjected to quantitative real‐time polymerase chain reaction to detect HO-1 gene expression. Agarose gel electrophoresis was also performed to verify the specificity of the amplification. HO-1 protein expression was determined by Western blotting. Results: HO-1 gene expression showed significant increase of 4.6±0.3, 3.6±0.2, 3.6±0.4, 3.3±0.3, and 3.0±0.4-fold and HO-1 protein expression showed significant increase of 2.3±0.2, 2.2±0.2, 2.2±0.1, 1.8±0.1, and 1.7±0.2-fold following treatment with 50 mg/kg of SFN, indole-3-carbinol, BHA, curcumin, and quercetin, respectively, compared to controls (p<0.05). Conclusion: At a dose of 50 mg/kg, SFN administration for 14 days resulted in the highest induction of HO-1 gene and protein expression level in mice liver, and quercetin the lowest

Effect of Administration of an Equal Dose of Selected Dietary Chemicals on Nrf2 Nuclear Translocation in the Mouse Liver

Certain dietary chemicals influenced the expression of chemopreventive genes through the Nrf2-Keap1 pathway. However, the difference in Nrf2 activation potency of these chemicals is not well studied. This study is aimed at determining the difference in the potency of liver Nrf2 nuclear translocation induced by the administration of equal doses of selected dietary chemicals in mice. Male ICR white mice were administered 50 mg/kg of sulforaphane, quercetin, curcumin, butylated hydroxyanisole, and indole-3-carbinol for 14 days. On day 15, the animals were sacrificed, and their livers were isolated. Liver nuclear extracts were prepared, and Nrf2 nuclear translocation was detected through Western blotting. To determine the implication of the Nrf2 nuclear translocation on the expression levels of several Nrf2-regulated genes, liver RNA was extracted for qPCR assay. Equal doses of sulforaphane, quercetin, curcumin, butylated hydroxyanisole, and indole-3-carbinol significantly induced the nuclear translocation of Nrf2 with different intensities and subsequently increased the expression of Nrf2-regulated genes with an almost similar pattern as the Nrf2 nuclear translocation intensities (sulforaphane > butylated hydroxyanisole = indole-3-carbinol > curcumin > quercetin). In conclusion, sulforaphane is the most potent dietary chemical that induces the Nrf2 translocation into the nuclear fraction in the mouse liver

The effect of tocotrienol-rich fraction on the expression of glutathione S-transferase isoenzymes in mice liver

Glutathione S-transferase isoenzymes (GSTs) catalyze the conjugation reaction between glutathione and electrophilic compounds. GSTs are involved in the detoxification of toxic and carcinogenic compounds, thus protecting the body from toxic injuries. Tocotrienols are part of the vitamin E family and is believed to possess potent antioxidant activity. The objective of this study was to determine the effect of increasing doses of tocotrienol rich fraction (TRF) supplementation on liver GSTs gene and protein expression. A total of 30 male ICR white mice were divided into five groups (n=6 for each group) and given treatment for 14 days through oral supplementation. Groups were divided as follows: - three groups administered with TRF at doses of 200, 500 and 1000 mg/kg, respectively, a positive control group administered with 100 mg/kg butylated hydroxyanisole (BHA) and a control group administered with only the vehicle (corn oil). At day 15, the mice were sacrificed and their livers isolated. Total RNA was extracted from the liver and quantitative real-time polymerase chain reaction (qPCR) assays were performed to analyze GSTs gene expression. Total liver protein was also extracted and the protein expression of GSTs was determined by Western blotting. The results showed that TRF oral supplementation caused a significant dose-dependent increase in liver GST isoenzymes gene and protein expression, compared to controls. In conclusion, TRF oral supplementation for 14 days resulted in increased gene and protein expression of GST isoenzymes in mice liver dose-dependently, with the highest expression seen in mice treated with 1000 mg/kg TRF

Palm Oil Tocotrienols in Cancer Chemoprevention and Treatment

Cancer remains a worrying cause of fatality worldwide despite the advancement in medicine. Among the dietary phytonutrients, tocotrienols have been extensively studied for their bioactivity against cancer. Palm oil is a rich source of tocotrienols. The most common formulation of tocotrienols is the tocotrienol-rich fraction of palm oil (TRF). The anticancer activities of tocotrienols were once presumed due to their antioxidant and free radical scavenging properties. However, recent evidence suggested that tocotrienols are capable of demonstrating cancer-fighting properties through their influence in various signalling pathways. The selectivity of tocotrienols in killing cancer cells without affecting normal cells is indicative of their potential role in cancer treatment and prevention. Tocotrienols had proven to be particularly effective in the chemoprevention and treatment of breast, colorectal, pancreatic, prostate and liver cancers in many in vitro and in vivo animal experiments. However, the efficacy of tocotrienols in the management of human cancers are still questionable due to their poor bioavailability and lack of well-designed clinical trials. Nevertheless, due to their superb safety profiles, palm oil tocotrienols are still considered ideal candidates for future large scale clinical trials to prove their efficacy to treat or prevent cancers in humans