Effects of hydrophilic compounds in purple rice husk on AFB1-induced mutagenesis

Vanillic acid protects mortality and toxicity induced by N-ethyl-N-nitrosourea in mice; in vivo model of chronic lymphocytic leukemia

Alkylating agents such as N-Ethyl-N-Nitrosourea (ENU) are ubiquitous within living cells and in the environment. This study designed to evaluate the chemopreventive activity of vanillic acid on ENU-induced toxicity and carcinogenesis in mice as an animal model of chronic lymphocytic leukemia (CLL). The female, Swiss albino mice were divided into three groups each with 7 mice, group I received normal saline, group II, mice received ENU at a dose of 80 mg/kg body weight i.p. to induce CLL on the 31th day of the study, and group III, the mice pretreated with vanillic acid at a dose of 20 mg/kg body weight/day, i.p. up to 30 days and received ENU. The animals were monitored for weight changes and mortality during 120 days, and then were sacrificed for isolation of lymphocytes, as target cells in CLL. Cellular parameters like reactive oxygen species (ROS) formation, malondialdehyde (MDA) production, depletion of glutathione (GSH), mitochondrial membrane potential (MMP) and lysosomal membrane integrity were studied. We found that pretreatment with vanillic acid significantly increased the survival of mice up to 57%, delay in death time (30%) and prevented weight changes after exposure to ENU. In addition, it was found that vanillic acid protected ROS formation, lipid peroxidation mitochondrial dysfunction, and lysosomal membrane destabilization in isolated lymphocytes. These data suggest that vanillic acid exhibited significant protection against ENU-induced toxicity and carcinogenicity, which might be related to the protection of the mitochondria and lysosomes and the reduction of ROS formation and oxidative stress.

Thai Rat-Tailed Radish Prevents Hepatocarcinogenesis in Rats by Blocking Mutagenicity, Inducing Hepatic Phase II Enzyme, and Decreasing Hepatic Pro-Inflammatory Cytokine Gene Expression

Raphanus sativus L. var. caudatus Alef (RS) is an indigenous Thai plant with nutritional and medicinal values such as anticancer activity, but only in vitro. The chemopreventive effects of RS were, therefore, investigated in the initial stage of hepatocarcinogenesis in rats. Diethylnitrosamine (DEN), a carcinogen, was intraperitoneally injected into rats to induce liver cancer. Along with the DEN injection, either aqueous (RS-H₂O) or dichloromethane (RS-DCM) extract was administered orally. Immunohistochemistry was used to detect glutathione S-transferase placental (GST-P) positive foci and apoptotic cells in rat livers as indicators of initial-stage carcinogenesis. The underlying mechanisms of chemoprevention were investigated with (a) antimutagenic activity, (b) hepatic phase II enzyme induction, and (c) hepatic pro-inflammatory cytokine gene expression. The results showed that RS-DCM was more potent than RS-H₂O in decreasing GST-P positive foci and apoptotic cells induced by DEN. The mechanisms of RS-DCM (phenolics and sulforaphene contents) against liver carcinogenesis (1) block the activity of carcinogens; (2) elevate phase II detoxifying enzymes; and (3) suppress the pro-inflammatory gene expression. RS-H₂O (phenolics contents), in contrast, only decreases pro-inflammatory gene expression. In conclusion, the RS extract consisting of phenolics and isothiocyanates exerted significant chemopreventive activity against DEN-induced liver carcinogenesis.

Valorization of Rice Husk (Oryza sativa L.) as a Source of In Vitro Antiglycative and Antioxidant Agents

Rice husk is a good source of polyphenols, but it has not been efficiently utilized in food applications yet. Therefore, the aim of this work is to investigate, by in vitro assays, the polyphenolic extract (RHE) capacity of this waste to counteract the protein glycation at different stages of the reaction, correlating this activity with the antiradical properties. A microwave-assisted extraction using hydro-alcoholic solvents was applied to recover husk polyphenols. Extraction parameters were optimized by the design of the experiment. The extract with the highest polyphenolic recovery was obtained at 500 W and 90 °C, using 1:35 g of dry material/mL solvent, 80% ethanol, and a 5 min extraction time. Results highlight the ability of RHE to inhibit the formation of fructosamine in the early stage of glycation with a dose-dependent activity. Furthermore, in the middle stage of the reaction, the highest RHE tested concentration (2.5 mg/mL) almost completely inhibit the monitored advanced glycation end products (AGEs), as well as showing a good trapping ability against α-dicarbonyl intermediates. A strong positive correlation with antioxidant activity is also found. The obtained results are supported by the presence of ten polyphenols detected by RP-HPLC-DAD-ESI-MSⁿ, mainly hydroxycinnamic acids and flavonoids, already reported in the literature as antiglycative and antioxidant agents.

Ameliorative Effect of Rice Husk Methanol Extract on Liver and Kidney Toxicities Induced by Subchronic Codeine Administration

Background and Objective. Rice husk remains a key by-product of rice milling generated in significant amount. Accumulated evidence indicates that rice husk contains numerous bioactive compounds; however, its application is limited. This study was designed to introduce an in vivo application of rice husk extract, against opioid-induced liver and kidney injuries. Codeine was considered a psychotic inducer in this study due to its global alarming misuse recently. The hepatorenal ameliorative proclivity of rice husk extract against codeine-induced toxicity on the liver and kidney in male albino Wistar rats was examined. To this effect, thirty-six (36) albino Wistar rats of weight 100-110 g were utilized and weight-matched animals placed in 6 groups of 6 rats each. After 30 days of the combined administration of codeine and the rice husk extract, the experimental animals were assayed for basic liver and renal markers such as AST, ALP, ALT, total protein, albumin, conjugated and total bilirubin, urea, creatinine, and electrolytes (sodium, potassium, chloride, and bicarbonate). Rice husks were collected from a local rice mill, and the extraction was done with methanol. Findings. Rice husk extract (RHE) significantly ameliorated the recorded hepatic damage. More so, the extract showed a significant action on the renal markers as well. A histopathology examination of the liver and kidney tissues revealed that RHE showed a hepatorenal ameliorative potential in a dose-dependent manner. Conclusion. Phytonutrient from RH possesses a healing ability against opioid-induced hepatorenal toxicity. Thus, RH is safe for human and may be adopted to obviate and manage codeine-induced hepatorenal damage or injury. Significance and Novelty. Data on the application of RHE as a phytonutrient to combat liver and kidney injuries were demonstrated. Future studies should evaluate its potential on other organs.

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

Purple rice has gained attention for its health promoting potential due to a high content of bioactive phytochemicals. The heat generated during cooking alters the quality and quantity of nutrients and phytochemicals in food. This study aimed to investigate the phytochemical profile and chemopreventive properties of cooked glutinous purple rice using cell-based assays and a rat model. Purple rice was cooked in a rice cooker and was then further extracted with solvents to obtain dichloromethane and methanol extracts. The methanol extracts of glutinous purple rice contained great amounts of phenolics, flavonoids, and anthocyanins. Protocatechuic acid (2.26–5.40 mg/g extract) and cyanidin 3-glucoside (34.3–65.7 mg/g extract) were the major phenolic acid and anthocyanin contents, respectively. After cooking, the content of anthocyanins, γ-oryzanols, and phytosterols decreased, while the amount of some phenolic acid and tocol contents increased. Methanol extracts of glutinous purple rice inhibited reactive oxygen species production about 60% in PMA-treated peripheral blood mononuclear cells, reduced nitric oxide formation in LPS-induced RAW 264.7 cells (26–39% inhibition), and exhibited antimutagenicity against several mutagens using the Ames test, but dichloromethane extracts presented only mild anti-inflammatory activities. Although methanol extracts induced mild mutagenicity (mutagenic index 2.0–2.5), they did not induce micronucleated hepatocyte formation and certain hepatic CYP450 isozyme activities in rats. However, the mutagenicity of the methanol extract significantly declined after cooking. In summary, the methanol extract of the cooked glutinous purple rice might be a promising cancer chemopreventive fraction, which was neither genotoxic nor posing adverse effects on phytochemical–drug interaction in rats.

Protective Role of Vanillic Acid against Diethylnitrosamine- and 1,2-Dimethylhydrazine-Induced Hepatocarcinogenesis in Rats

This study aimed to evaluate the cancer chemopreventive activity of vanillic acid (VA) in diethylnitrosamine- and 1,2-dimethylhydrazine-induced liver and colon carcinogenesis in rats. VA did not induce the formation of hepatic glutathione S-transferase placental form (GST-P) positive foci and colonic aberrant crypt foci, demonstrating no carcinogenic activity. VA (75 mg kg-1 body weight) could significantly reduce the number and areas of hepatic GST-P positive foci when administered before carcinogen injections, but no such effect was seen when it was administered after carcinogen injection. No protection was seen in the colon when VA was treated before or after carcinogen injection. Immunohistochemical studies demonstrated the decreased expression of proliferating cell nuclear antigen and the induction of apoptosis. Mechanistic studies showed that VA significantly induced the expression of GSTA-5 and Nrf-2 genes, which are associated with the detoxification system. Likewise, the antiproliferative effect was noticed by the reduction of Cyclin D1 expression. The apoptotic activity may be due to the upregulation of Caspase-3 and Bad levels and downregulation of the Bcl-2 level. These data suggest that VA exhibited significant protection against diethylnitrosamine- and 1,2-dimethylhydrazine-induced hepatocarcinogenesis, which might be related to the induction of the detoxifying enzyme, the reduction of proliferation and the induction of apoptosis.

Research progress on the protection and detoxification of phytochemicals against aflatoxin B1-Induced liver toxicity

Aflatoxin B₁ (AFB₁) is a potent hepatotoxic toxin, which can cause hepatitis, cirrhosis, and liver immunological damage. It has been involved in the etiology of human hepatocellular carcinoma. AFB₁ can cause oxidative stress in the body's metabolism process, and then cause cytotoxicity, such as apoptosis and DNA damage. Scientific research has discovered that phytochemicals can induce the detoxification pathway of AFB₁ through its biotransformation, thereby reducing the damage of AFB₁ to the human body. In clinical treatment, certain phytochemicals have been effectively used in the treatment of liver injury due to the advantages of multiple targets, multiple pathways, low toxicity and side effects. Therefore, the article summarizes the toxic mechanism of AFB₁-induced hepatoxicity, and the related research progress of phytochemicals for preventing and treating its cytotoxicity and genotoxicity. We also look forward to the existing problems and application prospects of phytochemicals in the pharmaceutical industry, in order to provide theoretical reference for the prevention and treatment of AFB₁ poisoning in future research work.

Inhibitory Effect of Thai Purple Rice Husk Extract on Chemically Induced Carcinogenesis in Rats

This study investigated the cancer chemopreventive effects of an acidic methanol extract of purple rice husk on chemically induced carcinogenesis in rats. This purple rice husk extract (PRHE) had high polyphenol contents. Vanillic acid was a major phenolic compound in PRHE. Three major anthocyanins found in PRHE were malvidin-3-glucoside, peonidin-3-glucoside and cyanidin-3-glucoside. PRHE was not toxic and clastogenic in rats. The LD50 of PRHE was greater than 2000 mg kg-1 body weight (BW). The oral administration of 300 or 1000 mg kg-1 BW of PRHE for 28 days significantly decreased the number of micronucleated hepatocytes in diethylnitrosamine-initiated rats. The inhibitory mechanisms were associated with the reduction of cytochrome P450 2E1 expression and induction of some detoxifying enzymes in the liver. In addition, treatment with 500 mg kg-1 BW of PRHE for eight weeks did not induce preneoplastic lesions in the liver and colon. It significantly inhibited hepatic glutathione-S-transferase positive foci formation induced by diethylnitrosamine and 1,2-dimethylhydrazine by suppression of hepatocyte proliferation and induction of apoptosis. In conclusion, PRHE did not present toxicity, clastogenicity or carcinogenicity in rats. It exhibited cancer chemopreventive properties against chemically induced early stages rat hepatocarcinogenesis. Anthocyanins and vanillic acid might be candidate anticarcinogenic compounds in purple rice husk.

Low-polar extract from seed of Cleistocalyx nervosum var. paniala modulates initiation and promotion stages of chemically-induced carcinogenesis in rats

BACKGROUND

Cleistocalyx nervosum var. paniala is a local fruit mainly cultivated in the north of Thailand. Our previous study has reported that the methanol extract of C. nervosum seed presented antimutagenicity in a Salmonella mutation assay. The present study focused on the effect of a low-polar extract of C. nervosum seed on the early stages of diethylnitrosamine (DEN)- and dimethylhydrazine (DMH)-induced carcinogenesis in rats.

METHODS

Dried C. nervosum seed powder was extracted using dichloromethane. To study its effect on the initiation stage of carcinogenesis of rats, they were fed with various doses of C. nervosum seed extract (CSE) for 21 days. DEN injection was used to initiate hepatocarcinogenesis and partial hepatectomy was performed to amplify mutated hepatocytes resulting in micronucleated hepatocyte formation. To study the role of CSE on the promotion stage, rats were injected with DEN and DMH to induce preneoplastic lesions and the numbers of glutathione S-transferase placental form (GST-P) positive foci in the liver and aberrant crypt foci (ACF) in the colon were measured. This was followed by CSE administration for 10 weeks. The inhibitory mechanisms of CSE on initiation and promotion stages, including xenobiotic metabolism, cell proliferation and apoptosis, were investigated.

RESULTS

The total phenolic content in CSE was 80.34 ± 2.29 mg gallic acid equivalents (GAE) per g of extract and 2,4'-dihydroxy-6'-methoxy-3',5'-dimethylchalcone was found to be a major flavonoid. The main terpenoids in CSE were β-selinene, α-selinene, γ-selinene and o-cymene while 24(Z)-methyl-25-homocholesterol was a major phytosterol. CSE significantly decreased the number of micronucleated hepatocytes in DEN-initiated rats and enhanced the activities of hepatic glutathione S-transferase and UDP-glucuronyltransferase. Furthermore, the formation of preneoplastic lesions in the liver and colon was statistically reduced by CSE. CSE also diminished cell proliferation in the liver and colon indicated by the number of PCNA positive cells. However, CSE did not alter the numbers of apoptotic hepatocytes and colonocytes in DEN- and DMH-initiated rats.

CONCLUSIONS

The dichloromethane extract of C. nervosum seed demonstrated chemopreventive effects on chemically-induced carcinogenesis in both initiation and promotion stages in rats. The inhibitory mechanism might be involved in the modulation of hepatic detoxifying enzymes and suppression of hepatocyte and colonocyte proliferation.

The phytochemical analysis and pharmacological potentials of husk and straw as paddy waste products

Rice serves as a staple food for one-half of the global population. However, rice production, particularly the rice milling process, results in a substantial amount of paddy waste products (e.g. bran, husk and straw) annually. Because the potentials of bran have been extensively explored in prior studies, the present review focuses exclusively on the phytochemical analysis and pharmacological potentials of husk and straw. This comprehensive review establishes a solid foundation for promoting husk and straw as medicinal substances given their promising pharmacological potentials as bioactive compound sources with therapeutic functions. © 2020 Society of Chemical Industry.

Inhibitory effect of purple rice husk extract on AFB1-induced micronucleus formation in rat liver through modulation of xenobiotic metabolizing enzymes

Background

Rice husk, a waste material produced during milling, contains numerous phytochemicals that may be sources of cancer chemopreventive agents. Various biological activities of white and colored rice husk have been reported. However, there are few comparative studies of the cancer chemopreventive effects of white and colored rice husk.

Methods

This study investigated the cancer chemopreventive activities of two different colors of rice husk using in vitro and in vivo models. A bacterial mutation assay using Salmonella typhimurium strains TA98 and TA100 was performed; enzyme induction activity in murine hepatoma cells was measured, and a liver micronucleus test was performed in male Wistar rats.

Results

The white rice husk (WRHE) and purple rice husk (PRHE) extracts were not mutagenic in Salmonella typhimurium TA98 or TA100 in the presence or absence of metabolic activation. However, the extracts exhibited antimutagenicity against aflatoxin B₁ (AFB₁) and 2-amino-3,4 dimethylimidazo[4,5-f]quinolone (MeIQ) in a Salmonella mutation assay. The extracts also induced anticarcinogenic enzyme activity in a murine Hepa1c1c7 hepatoma cell line. Interestingly, PRHE but not WRHE exhibited antigenotoxicity in the rat liver micronucleus test. PRHE significantly decreased the number of micronucleated hepatocytes in AFB₁-initiated rats. PRHE contained higher amounts of phenolic compounds and vitamin E than WRHE in both tocopherols and tocotrienols as well as polyphenol such as cyanidin-3-glucoside, protocatechuic acid and vanillic acid. Furthermore, PRHE increased CYP1A1 and 1A2 activities while decreasing CYP3A2 activity in the livers of AFB₁-treated rats. PRHE also enhanced various detoxifying enzyme activities, including glutathione S-transferase, NAD(P)H quinone oxidoreductase and heme oxygenase.

Conclusions

PRHE showed potent cancer chemopreventive activity in a rat liver micronucleus assay through modulation of phase I and II xenobiotic metabolizing enzymes involved in AFB₁ metabolism. Vitamin E and phenolic compounds may be candidate antimutagens in purple rice husk.

Electronic supplementary material

The online version of this article (10.1186/s12906-019-2647-9) contains supplementary material, which is available to authorized users.

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

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.