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

Abstract

Rice bran oil (RBO) comprises various nutrients and phytochemicals which exhibit several health benefits. There are no studies regarding the functional effects of different colours of RBO. This study was aimed to compare the constituents and antioxidant activities of white rice bran oil (WRBO) and coloured rice bran oil (CRBO). Each RBO showed similar free fatty acid profiles. However, greater amounts of vitamin E, phytosterols, carotenoids, and chlorophylls were found in CRBO, which had lower γ-oryzanol content than WRBO. Oxidative stress was induced in male mice by an overdose of acetaminophen (APAP) at 300 mg/kg body weight. The mice were then fed with RBO at the equivalent dose to 100 mg/kg body weight of γ-oryzanol three hours later and sacrificed six hours after APAP treatment. The administration of 100 mg γ-oryzanol equivalent in CRBO ameliorated APAP-induced hepatotoxicity in mice more strongly than 100 mg γ-oryzanol equivalent in WRBO, as evidenced by the significant reduction of serum ALT, hepatocellular necrosis, and hepatic lipid peroxidation. CRBO could improve xenobiotic-metabolizing and antioxidant enzyme activities, including glutathione S -transferase, superoxide dismutase, glutathione peroxidase, and glutathione reductase, and also increase mRNA expression of various antioxidant-responsive genes. Vitamin E, phytosterols, carotenoids, and chlorophyll might be the protective compounds in CRBO that alleviate APAP-induced hepatotoxicity through the interruption of APAP metabolism and the activation of antioxidant systems at both transcriptional and enzymatic levels. These findings might provide a protective role of CRBO on oxidative stress associated with several degenerative diseases.

Phytochemical Profile and Chemopreventive Properties of Cooked Glutinous Purple Rice Extracts Using Cell-Based Assays and Rat Model

“…Phenolic acid, anthocyanin, and γ-oryzanol content was determined by using reverse phase HPLC, as has been described in our previous studies [ 17 , 18 ]. Ten microliters of each extract were injected into a reverse phase C18 column (4.6 mm × 250 mm, 5 μm) for determination of phenolic acids and anthocyanins using Zorbax Eclipse Plus C18 (Agilent Technologies, Santa Clara, CA, USA) and to measure the γ-oryzanol content using Inertsil ODS-3 (GL Sciences Inc., Tokyo, Japan).…”

“…Phytosterols and tocols were determined according to Phannasorn et al (2021) [ 18 ]. For phytosterol measurements, five microliters of the samples were injected into a Kinetex PFP column (4.6 × 250 mm, 5 μm, Phenomenex, Inc., Torrance, CA, USA), and an Agilent HPLC 1100 was connected to a diode array detector (Model G1315 A; Agilent Technologies, Santa Clara, CA, USA).…”

“…Xenobiotic metabolizing enzyme activities were determined in the microsome of livers by ultracentrifugation [ 18 ]. The amount of microsomal protein was determined using the Lowry method.…”

Enriched Riceberry Bran Oil Exerts Chemopreventive Properties through Anti-Inflammation and Alteration of Gut Microbiota in Carcinogen-Induced Liver and Colon Carcinogenesis in Rats

“…RBBO was supplied by Kurk Rice Mill (Chiang Rai, Thailand). The extraction process and major chemical constituents have been described in our previously published report [ 26 ]. Briefly, RBBO was extracted via the cold pressing method obtaining crude oil and was further purified by press filtration, and various phytochemicals were immediately analyzed by gas chromatography–mass spectrometry, high-performance liquid chromatography, and spectrophotometry.…”

“…The main fatty acids of RBBO used in this study were composed of 42.61% oleic acid and 30.76% linoleic acid. One gram of RBBO contained 56.74 mg of γ-oryzanol, 6.01 mg of phytosterols, and 1.46 mg of total vitamin E with γ-tocotrienol as a major tocol [ 26 ].…”