Arunaksharan Narayanankutty

Polyphenols of virgin coconut oil prevent pro-oxidant mediated cell death

Abstract Virgin coconut oil (VCO), extracted from the fresh coconut kernel, is a food supplement enriched with medium chain saturated fatty acids and polyphenolic antioxidants. It is reported to have several health benefits including lipid lowering, antioxidant and anti-inflammatory activities. The pharmacological benefits of VCO have been attributed to its polyphenol content (VCOP), the mechanistic basis of which is less explored. Liquid chromatography/mass spectroscopy (LC/MS) analysis of VCOP documented the presence of gallic acid, ferulic acid (FA), quercetin, methyl catechin, dihydrokaempferol and myricetin glycoside. Pre-treatment of VCOP at different concentrations (25–100 μg/mL) significantly reduced the H2O2 and 2,2′-azobis (2-amidinopropane) dihydrochloride (AAPH) induced cell death in HCT-15 cells. Giving further insight to its mechanistic basis, oxidative stress induced alterations in glutathione (GSH) levels and activities of GR (Glutathione–Reductase), GPx (Glutathione–Peroxidase), GST (Glutathione-S-Transferase) and catalase (CAT) were restored to near-normal by VCOP, concomitantly reducing lipid peroxidation. The efficacy of VCOP was similar to that of Trolox and FA added in culture. The study thus suggests that VCOP protects cells from pro-oxidant insults by modulating cellular antioxidant status.

Virgin coconut oil reverses hepatic steatosis by restoring redox homeostasis and lipid metabolism in male Wistar rats

BACKGROUND Hepatosteatosis, a form of nonalcoholic fatty liver disease (NAFLD), is being increasingly recognized as a major health burden worldwide. Insulin resistance, dyslipidemia and imbalances in adipokine/cytokine interplay are reported to be involved in the onset and progression of this disease. Use of dietary nutraceuticals in prevention and treatment of NAFLD is emerging. Virgin coconut oil (VCO), a fermented product of fresh coconut kernel, has been shown to impede the development of hepatosteatosis in rats. This study analyzes the potential of VCO to reverse the already developed hepatosteatosis condition. RESULTS Hyperglycemia, reduced glucose tolerance, dyslipidemia, and hepatic macrovesicles in high-fructose-diet-fed rats (4 weeks) confirmed the development of hepatosteatosis. Natural reversion in these parameters was observed upon shifting to normal diet in untreated control animals. Administration of VCO, however, increased this natural reversion by improving high-density lipoprotein cholesterol level (53.5%) and reducing hepatic and serum triacylglycerols (78.0 and 51.7%). Increased hepatic glutathione level (P < 0.01), antioxidant enzyme activities (P < 0.05) and reduced lipid peroxidation were also noticed in these animals. These observations were in concordance with reduced liver enzyme activities (P < 0.01) and restoration of altered hepatic architecture. CONCLUSION The study indicates that VCO can be used as a nutraceutical against hepatosteatosis.

Vitamin E supplementation modulates the biological effects of omega-3 fatty acids in naturally aged rats.

Abstract Omega-3 fatty acids are well-known class of nutraceuticals with established health benefits. Recently, the oxidation products of these fatty acids are gaining attention, as they are likely to disturb body redox balance. Therefore, the efficacy of omega-3 fats under conditions of diminished antioxidant status, such as aging, is always a concern. Present study assessed the effects of omega-3 fats (DHA and EPA) together with or without vitamin-E in naturally aged rats. It was found that in omega-3 fats alone consumed rats the lipid profile was improved, while in omega-3 fat with vitamin-E-consumed group (OMVE), the hepato protective and antioxidant properties were pronounced, especially the redox status of brain tissue. It is possible that vitamin-E might have reduced the peroxidation of omega-3 fats, thereby allowing their synergistic effects. Hence, the use of vitamin-E along with omega-3 fat may be beneficial under aged conditions.

Epithelial Mesenchymal Transition in Cancer Progression: Prev entive Phytochemicals

BACKGROUND Epithelial-Mesenchymal Transition (EMT) is the conversion of epithelial cells into mesenchymal phenotype generally observed during embryogenesis and wound healing as well as in malignant transformation. Several signaling pathways and transcription factors associated with EMT have been explored. Dietary phytochemicals that are multi-targeted agents which interfere with these pathways, assume preventive potential against pathologic EMT. OBJECTIVE The present review aims to provide a detailed description of the nature and characteristics of EMT in physiological and pathophysiological conditions and the scope of phytochemicals in its prevention. METHOD Details regarding the initiation, progression as well as prevention of pathologic EMT and metastasis and recent patents on preventive phytochemicals were obtained from PubMed literatures and patent databases. RESULTS The phenotypic changes during EMT are regulated by transcription factors like Snail, Slug, Twist and Zeb, which are activated through diverse signaling pathways of TGF-β, NF-kB, Wnt and Notch. s phytocompounds that are potent enough to interfere with these signaling pathways, which in turn prevent pathological implications of EMT. Present review also discusses 28 recent patents on those phytocompounds. CONCLUSION EMT is a significant pharmacological target for developing preventive agents to combat pathological conditions like malignancy. Many of the phytochemicals cited in this review are being enrolled for different phases of clinical trials for their efficacy. In spite of the major limitations regarding bioavailability, sensitivity and tolerance of these compounds, their synthetic analogs, formulations and efficient drug delivery systems are also being attempted which will hopefully generate productive and promising results in near future.

Deep fried edible oils disturb hepatic redox equilibrium and heightens lipotoxicity and hepatosteatosis in male Wistar rats

Hepatosteatosis is a complex disorder, in which insulin resistance and associated dyslipidemic and inflammatory conditions are fundamental. Dietary habit, especially regular consumption of fat and sugar-rich diet, is an important risk factor. Coconut and mustard oils (CO and MO) are medium-chain saturated and monounsaturated fats that are common dietary ingredients among the Indian populations. Present study analyzed the effect of prolonged consumption of the fresh and thermally oxidized forms of these oils on glucose tolerance and hepatosteatosis in male Wistar rats. Thermally oxidized CO (TCO) and MO (TMO) possessed higher amount of lipid peroxidation products and elevated p-anisidine values than their fresh forms. Dietary administration of TCO and TMO along with fructose altered glucose tolerance and increased hyperglycemia in rats. Dyslipidemia was evident by elevated levels of triglycerides and reduced high density lipoprotein cholesterol (HDLc) levels in fructose and edible oil-fed group (p < 0.05). Additionally, hepatic antioxidant status was diminished and oxidative stress markers were elevated in TCO- and TMO-fed rats. Substantiating these, hike in liver function marker enzyme activities were also observed in these animals. Supporting this, histological analysis revealed higher incidence of microvesicles and hepatocellular ballooning. Results thus suggest that consumption of thermally oxidized fats may cause hepatic damage.

Coconut phytocompounds inhibits polyol pathway enzymes: Implication in prevention of microvascular diabetic complications

Coconut oil (CO), the primary choice of cooking purposes in the south Asian countries, is rich in medium chain saturated fatty acids, especially lauric acid (50-52%). The oil has high medicinal use in Ayurvedic system and known to contain polyphenolic antioxidants. Studies have reported that CO improves insulin sensitivity and shows hypoglycemic effect. However, there is no information regarding its effect on chronic diabetic complications including retinopathy and nephropathy is available. The secondary diabetic complications are mediated by the activation of polyol pathway, where aldose reductase (AR) plays crucial role. In this study, in silico analysis has been used to screen the effect of CO as well as its constituents, MCFAs and phenolic compounds, for targeting the molecules in polyol pathway. The study revealed that lauric acid (LA) interacts with AR and DPP-IV of polyol pathway and inhibits the activity of these enzymes. Validation studies using animal models confirmed the inhibition of AR and SDH in wistar rats. Further, the LA dose dependently reduced the expression of AR in HCT-15 cells. Together, the study suggests the possible role of CO, particularly LA in reducing secondary diabetic complications.

EGFR gene regulation in colorectal cancer cells by garlic phytocompounds with special emphasis on S-Allyl-L-Cysteine Sulfoxide

Colorectal cancer is one among the most common cancers in the world and a major cause of cancer related deaths. Similar to other cancers, colorectal carcinogenesis is often associated with over expression of genes related to cell growth and proliferation, especially Epidermal Growth Factor Receptor (EGFR). There is an increasing attention towards the plant derived compounds in prevention of colorectal carcinogenesis by downregulating EGFR. Among plants, garlic (Allium sativum L.) is emerging with anticancer properties by virtue of its organosulfur compounds. The present study was aimed to analyze the interaction ability of garlic compounds in the active region of EGFR gene by in silico molecular docking studies and in vitro validation. This was conducted using the Discovery studio software version 4.0. Among the tested compounds, s-allyl-l-cysteine-sulfoxide (SACS)/alliin showed higher affinity towards EGFR. Furthermore, wet lab analysis using cell viability test and EGFR expression analysis in colorectal cancer cells confirmed its efficacy as a potent anticancer agent.

Non-enzymatic conversion of primary oxidation products of Docosahexaenoic acid into less toxic acid molecules

Docosahexaenoic acid (DHA) is long chain omega-3 fatty acid with known health benefits and clinical significance. However, 4-hydroxy hexenal (HHE), an enzymatic oxidation product of DHA has recently been reported to have health-damaging effects. This conflict raises major concern on the long-term clinical use of these fatty acids. Even though the enzymatic and non-enzymatic conversion of HHE to nontoxic acid molecules is possible by the aldehyde detoxification systems, it has not yet studied. To address this, primary oxidation products of DHA in lipoxidase system were subjected to non-enzymatic conversion at physiological temperature over a period of 1 week. The reaction was monitored using HPLC, IR spectroscopy and biochemical assays (based on the loss of conjugated dienes, lipid peroxides aldehydes). Short term and long term cytotoxicity of the compounds generated at various time points were analyzed. IR and HPLC spectra revealed that the level of aldehydes in the primary oxidation products reduced over time, generating acids and acid derivatives within a week period. In short term and long term cytotoxicity analysis, initial decomposition products were found more toxic than the 1-week decomposition products. Further, when primary oxidation products were subjected to aldehyde dehydrogenase mediated oxidation, it generated products that are also less toxic. The study suggests the possible non-enzymatic conversion of primary oxidation products of DHA to less cytotoxic acid molecules. Exploration of the physiological roles of these acid molecules may explain the biological potential of omega-3 fatty acids.

Non-polar lipid carbonyls of thermally oxidized coconut oil induce hepatotoxicity mediated by redox imbalance

Thermal oxidation products of edible oils including aldehydes, peroxides and polymerized triglycerides formed during the cooking process are increasingly debated as contributory to chronic degenerative diseases. Depending on the oil used for cooking, the source of fatty acids and its oxidation products may vary and would have a differential influence on the physiological process. Coconut oil (CO) is a medium chain triglyceride-rich edible oil used in South India and other Asia Pacific countries for cooking purposes. The present study evaluated the biological effects of thermally oxidized coconut oil (TCO) as well as its non- polar hexane (TCOH) and polar methanol (TCO-M) sub-fractions in male Wistar rats. Results showed an increase in the thiobarbituric acid reactive substances (TBARs) and conjugated diene levels in TCO, which was extracted to TCOH fraction. The animals consumed TCO and its hexane and methanol fractions had a considerable increase in weight gain. However, serum and hepatic triglycerides were increased only in animals with TCO and TCOH administration. In these animals, the hepatic redox balance was disturbed, with a reduction in GSH and a concomitant increase in thiobarbituric acid reactive substances (TBARs). Increased incidence of microvesicles in hepatic histological observations also supported this assumption. Together, the study shows that TCO consumption is unhealthy, where the nonpolar compounds generated during thermal oxidation may be involved in the toxic insults.