Antihyperlipidemic effects of mature coconut water and its role in regulating lipid metabolism in alloxan-induced experimental diabetes

Anti-cataract effects of coconut water in vivo and in vitro

OBJECTIVE

To determine the anti-cataract effects of coconut water (CW) in vivo and in vitro, and to explore the potential pathogenic mechanism.

METHODS

In this study, 48 male Sprague-Dawley rats were randomly divided into 4 groups: control (CO), diabetic (DM), diabetic treated with CW (DM + CW), and diabetic treated with Glibenclamide (DM + Gli). Except for the CO group, in the other three groups, intraperitoneal injection of STZ (60 mg/kg) was conducted to establish diabetic models. The experiment was conducted for 20 weeks. The slit-lamp examination was undertaken during the period of experiment (20 weeks), and then, all rats were sacrificed. The levels of superoxide dismutase (SOD), malondialdehyde (MDA), and glutathione peroxidase (GSH-Px) in the left lens were measured by using biochemical assays. The right lens was used for pathological analysis. The rat lens epithelial cells (LECs) were cultured in vitro and the subcultured cell were divided into four groups, namely the normal glucose group (5 mmol /L glucose, Group I), the high glucose group (40 mmol/L glucose, Group II), high glucose +5% CW group (Group III), and high glucose +10% CW group (Group IV). LECs were cultured under the conditions as described above for 48 h. Cell proliferation and the morphological changes were observed with interted phase contrast microscope.The level of cell apoptosis was determined by flow cytometry. the level of SOD, MDA and GSH-Px were also detected.

RESULTS

The lens opacity index decreased in diabetic rats, and LECs apoptosis ratio also decreased in high glucose environments that received CW. Under treatment with CW, reduced MDA level and elevated activities of SOD and GSH-Px were detected, both in vivo and in vitro experiments. The increased severity of cataract and LECs apoptosis were noted in diabetic rats that received normal water, while CW markedly mitigated the enhanced cataract severity and the reduction of LECs induced by diabetes mellitus.

CONCLUSION

CW is a functional food that can protect the lens from diabetic cataract. The possible underlying mechanism may be partly explained via the decreased oxidative stress in lens. However, further research needs to be conducted to indicate the pathogenic mechanism of anti-diabetic effects of CW.

The Effect of Coconut Water on Adipocyte Differentiation and Lipid Accumulation in 3T3-L1 Cells

Coconut water is reported to have lipid-lowering effects in animal studies. However, there is lack of published reports regarding its effect on adipocytes. This study observed the effect of coconut water on adipocyte differentiation and lipid accumulation in 3T3-L1 cells. The sample used in this study was mature coconut water from tall variety. Based on a preliminary study, the sample was heat-treated and added with certain amino acids as precursors for Maillard reaction to improve its original flavor. As a comparison, aromatic coconut water was used since it is highly preferred as a fresh beverage. Six samples were supplemented to 3T3-L1 cells, which were then analyzed for cell proliferation, lipid accumulation, triglyceride content, and gene expression. Arginine and vitamin C contents of the samples were also determined. The data were analyzed with ANOVA and followed by Tukey's test. Results showed that aromatic coconut water could slightly suppress lipid accumulation, while mature coconut water had a significantly lower percentage of accumulation compared to the control sample (p<0.05). Canned and fresh samples had no significant difference in terms of lipid-lowering activity (p>0.05). Similarly, the addition of lysine and proline in canned samples did not significantly affect the cells' differentiation. There was no significant effect on expressions of C/EBP-α and PPARγ, indicating the possibility of other pathways involved in hypolipidemic effect of coconut water. This study showed that coconut water might have potential to inhibit adipogenesis in 3T3-L1 cells due to its bioactive compounds.

Effects of Coconut Water on Retina in Diabetic Rats

Coconut water (CW) is a natural aseptic nutritious beverage, containing several biologically active compounds. This study aimed to determine the antiretinopathy effects of CW on diabetic Sprague Dawley (SD) rats using streptozotocin (STZ) and explore its potential mechanism. After allowing the rats to acclimatize for 7 days, 48 healthy adult male SD rats were selected and randomly divided into 4 groups, involving control (Ctrl), diabetic rats (DM), diabetic rats treated with CW (DM-CW), and diabetic rats treated with glibenclamide (DM-Gli). The diabetic models were established by an intraperitoneal injection of STZ (60 mg/kg). The Ctrl group was injected with an equal volume of sodium citrate solution. The experiment was totally conducted during 20 weeks, and then, all rats were sacrificed. The serum levels of superoxide dismutase (SOD), malondialdehyde (MDA), and glutathione peroxidase (GSH-Px) were measured; additionally, the activities of interleukin-6 (IL-6) and intercellular adhesion molecule-1 (ICAM-1) in the retina were investigated using biochemical assays. Hematoxylin and eosin (H&E) staining was performed to observe pathological changes of retinal tissues. In presence of treatment with CW, serum level of MDA was decreased, while serum levels of SOD and GSH-Px were increased; besides, the activities of IL-6 and ICAM-1 in the retina were reduced compared with the DM group. The antiretinopathy feature of CW was confirmed by the increased number of neurons in the ganglion cell layer (GCL), total retina thickness (TRT), and thickness of the retinal nuclear layer (RNL) in diabetic rats. CW can be protective against diabetic retinopathy (DR), and its effects are comparable to Gli. The possible underlying mechanism may be partly explained by decreasing oxidative stress and anti-inflammatory activities in the retina. However, further research should be conducted to reveal the exact mechanism.

Dietary coconut water vinegar for improvement of obesity-associated inflammation in high-fat-diet-treated mice

Obesity has become a serious health problem worldwide. Various types of healthy food, including vinegar, have been proposed to manage obesity. However, different types of vinegar may have different bioactivities. This study was performed to evaluate the anti-obesity and anti-inflammatory effects of coconut water vinegar on high-fat-diet (HFD)-induced obese mice. Changes in the gut microbiota of the mice were also evaluated. To induce obesity, C57/BL mice were continuously fed an HFD for 33 weeks. Coconut water vinegar (0.08 and 2 ml/kg body weight) was fed to the obese mice from early in week 24 to the end of week 33. Changes in the body weight, fat-pad weight, serum lipid profile, expression of adipogenesis-related genes and adipokines in the fat pad, expression of inflammatory-related genes, and nitric oxide levels in the livers of the untreated and coconut water vinegar-treated mice were evaluated. Faecal samples from the untreated and coconut water vinegar-treated mice (2 ml/kg body weight) were subjected to 16S metagenomic analysis to compare their gut microbiota. The oral intake of coconut water vinegar significantly (p < 0.05) reduced the body weight, fat-pad weight, and serum lipid profile of the HFD-induced obese mice in a dose-dependent manner. We also observed up-regulation of adiponectin and down-regulation of sterol regulatory element-binding protein-1, retinol-binding protein-4, and resistin expression. The coconut water vinegar also reduced HFD-induced inflammation by down-regulating nuclear factor-κB and inducible nitric oxide synthase expression, which consequently reduced the nitric oxide level in the liver. Alterations in the gut microbiota due to an increase in the populations of the Bacteroides and Akkermansia genera by the coconut water vinegar may have helped to overcome the obesity and inflammation caused by the HFD. These results provide valuable insights into coconut water vinegar as a potential food ingredient with anti-obesity and anti-inflammatory effects.

An Overview of Phytoconstituents, Biotechnological Applications, and Nutritive Aspects of Coconut (Cocos nucifera)

Cocos nucifera is one of the highest nutritional and medicinal value plants with various fractions of proteins which play a major role in several biological applications such as anti-microbial, anti-inflammatory, anti-diabetic, anti-neoplastic, anti-parasitic, insecticidal, and leishmanicidal activities. This review is focused on several biotechnological, biomedical aspects of various solvent extracts collected from different parts of coconut and the phytochemical constituents which are present in it. The results obtained from this source will facilitate most of the researchers to focus their work toward the process of diagnosing diseases in future.

Cocos nucifera (L.) (Arecaceae): A phytochemical and pharmacological review

Cocos nucifera (L.) (Arecaceae) is commonly called the “coconut tree” and is the most naturally widespread fruit plant on Earth. Throughout history, humans have used medicinal plants therapeutically, and minerals, plants, and animals have traditionally been the main sources of drugs. The constituents of C. nucifera have some biological effects, such as antihelminthic, anti-inflammatory, antinociceptive, antioxidant, antifungal, antimicrobial, and antitumor activities. Our objective in the present study was to review the phytochemical profile, pharmacological activities, and toxicology of C. nucifera to guide future preclinical and clinical studies using this plant. This systematic review consisted of searches performed using scientific databases such as Scopus, Science Direct, PubMed, SciVerse, and Scientific Electronic Library Online. Some uses of the plant were partially confirmed by previous studies demonstrating analgesic, antiarthritic, antibacterial, antipyretic, antihelminthic, antidiarrheal, and hypoglycemic activities. In addition, other properties such as antihypertensive, anti-inflammatory, antimicrobial, antioxidant, cardioprotective, antiseizure, cytotoxicity, hepatoprotective, vasodilation, nephroprotective, and anti-osteoporosis effects were also reported. Because each part of C. nucifera has different constituents, the pharmacological effects of the plant vary according to the part of the plant evaluated.