Airborne microplastics: Consequences to human health?

Reactive oxygen species (ROS) and cancer: Role of antioxidative nutraceuticals

Resveratrol (3,5,4′-trihydroxy-trans-stilbene) belongs to polyphenols’ stilbenoids group, possessing two phenol rings linked to each other by an ethylene bridge. This natural polyphenol has been detected in more than 70 plant species, especially in grapes’ skin and seeds, and was found in discrete amounts in red wines and various human foods. It is a phytoalexin that acts against pathogens, including bacteria and fungi. As a natural food ingredient, numerous studies have demonstrated that resveratrol possesses a very high antioxidant potential. Resveratrol also exhibit antitumor activity, and is considered a potential candidate for prevention and treatment of several types of cancer. Indeed, resveratrol anticancer properties have been confirmed by many in vitro and in vivo studies, which shows that resveratrol is able to inhibit all carcinogenesis stages (e.g., initiation, promotion and progression). Even more, other bioactive effects, namely as anti-inflammatory, anticarcinogenic, cardioprotective, vasorelaxant, phytoestrogenic and neuroprotective have also been reported. Nonetheless, resveratrol application is still being a major challenge for pharmaceutical industry, due to its poor solubility and bioavailability, as well as adverse effects. In this sense, this review summarized current data on resveratrol pharmacological effects.

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Resveratrol: A Double-Edged Sword in Health Benefits

Oxidative stress is a component of many diseases, including atherosclerosis, chronic obstructive pulmonary disease, Alzheimer disease and cancer. Although numerous small molecules evaluated as antioxidants have exhibited therapeutic potential in preclinical studies, clinical trial results have been disappointing. A greater understanding of the mechanisms through which antioxidants act and where and when they are effective may provide a rational approach that leads to greater pharmacological success. Here, we review the relationships between oxidative stress, redox signalling and disease, the mechanisms through which oxidative stress can contribute to pathology, how antioxidant defences work, what limits their effectiveness and how antioxidant defences can be increased through physiological signalling, dietary components and potential pharmaceutical intervention.

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Targeting oxidative stress in disease: promise and limitations of antioxidant therapy.

Assessment of microplastics in freshwater systems: A review.

Virgin microplastics cause toxicity and modulate the impacts of phenanthrene on biomarker responses in African catfish (Clarias gariepinus).

Abundance and characteristics of microplastics in commercial marine fish from Malaysia

Resveratrol is a potent polyphenolic compound that is being extensively studied in the amelioration of viral infections both in vitro and in vivo. Its antioxidant effect is mainly elicited through inhibition of important gene pathways like the NF-κβ pathway, while its antiviral effects are associated with inhibitions of viral replication, protein synthesis, gene expression, and nucleic acid synthesis. Although the beneficial roles of resveratrol in several viral diseases have been well documented, a few adverse effects have been reported as well. This review highlights the antiviral mechanisms of resveratrol in human and animal viral infections and how some of these effects are associated with the antioxidant properties of the compound.

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Antiviral Activity of Resveratrol against Human and Animal Viruses

Colorectal cancer (CRC) is the third most common malignancy in males and the second most common cancer worldwide. Chronic colonic inflammation is a known risk factor for CRC. Cocoa contains many polyphenolic compounds that have beneficial effects in humans. The objective of this study is to explore the antioxidant properties of cocoa in the mouse model of azoxymethane (AOM)/dextran sulfate sodium (DSS)-induced colitis-associated cancer, focusing on the activation of Nrf2 signaling. Mice were treated with AOM/DSS and randomized to receive either a control diet or a 5 and 10% cocoa diet during the study period. On day 62 of the experiment, the entire colon was processed for biochemical and histopathological examination and further evaluations. Increased levels of malondialdehyde (MDA) were observed in AOM/DSS-induced mice; however, subsequent administration of cocoa decreased the MDA. Enzymatic and nonenzymatic antioxidants, such as superoxide dismutase, catalase, glutathione peroxidase and glutathione reductase, were decreased in the AOM/DSS mice. Cocoa treatment increases the activities/levels of enzymatic and nonenzymatic antioxidants. Inflammatory mediators, such as inducible nitric oxide synthase (iNOS) and cyclooxygenase (COX)-2, were elevated during AOM/DSS-induction, and treatment with 5 and 10% cocoa effectively decreases the expression of iNOS and COX-2. The NF-E2-related factor 2 and its downstream targets, such as NQO1 and UDP-GT, were increased by cocoa treatment. The results of our study suggest that cocoa may merit further clinical investigation as a chemopreventive agent that helps prevent CAC.

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Dietary cocoa protects against colitis-associated cancer by activating the Nrf2/Keap1 pathway.

Rhaphidophora decursiva (Roxb.) Schott is commonly used to treat colon cancer among Chinese community in Malaysia. This study aims to evaluate histopathologic changes in liver and kidney tissues after treated with R. decursiva extract in male Sprague Dawley rats. The rats were divided into 4 groups consisting of 6 rats per group for each acute, subacute and subchronic toxicity evaluations, with a total of 72 rats. All control groups received distilled water (vehicle). For subacute toxicity, the 3 treatment groups received a daily oral dose of the plant extract at 70, 140 or 210 mg/kg for 28 days. As no lethality was observed in subacute toxicity study, similar doses were used for the 3 treatment groups in 90-day subchronic toxicity. Histological examination of liver revealed some abnormal but not significant morphology characteristics. For acute toxicity, liver tissues in group treated with 2100 and 3500 mg/ kg extracts showed presence of activated kupffer cells, sinusoidal dilatation and cytoplasmic vacuolation, same as group treated with 140 and 210 mg/kg extracts for both subacute and subchronic toxicity. However, group treated with 140 mg/kg extract in subchronic toxicity just showed the presence of cytoplasmic vacuolation. Similarly, no significant abnormal histopathological changes were observed in kidneys tissue for all toxicity studies. The presence of granular cast were noticed in group treated with 2100 and 3500 mg/kg extracts for acute toxicity, however, cellular and protein cast only occurred in group treated with 3500 mg/kg extracts. For subacute and subchronic toxicity, granular cast can be observed in group treated with 210 mg/kg extract. Also, cellular can be seen in group treated with 210 mg/kg extract for subacute toxicity. In conclusion, the treatment of R. decursiva extracts did not show any significant toxicological changes as observed by histopathological examination in the kidney and liver tissues for all toxicity studies.

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Hazilawati Hamzah

Papers

Virgin microplastics cause toxicity and modulate the impacts of phenanthrene on biomarker responses in African catfish (Clarias gariepinus).

Abundance and characteristics of microplastics in commercial marine fish from Malaysia

Antiviral Activity of Resveratrol against Human and Animal Viruses

Dietary cocoa protects against colitis-associated cancer by activating the Nrf2/Keap1 pathway.

Histopathologic Changes in Liver and Kidney Tissues from Male Sprague Dawley Rats Treated with Rhaphidophora Decursiva (Roxb.) Schott Extract