Safety of oligonol, a highly bioavailable lychee-derived polyphenolic antioxidant, on liver, kidney and heart function in rats

Litchi (Litchi chinensis Sonn.): a comprehensive review of phytochemistry, medicinal properties, and product development

Since ancient times, litchi has been well recognized as a functional food for the management of various ailments. Many bioactives, including flavanoids, anthocyanins, phenolics, sesquiterpenes, triterpenes, and lignans, have been identified from litchi with a myriad of biological properties both in vitro and in vivo. In spite of the extensive research progress, systemic reviews regarding the bioactives of litchi are rather scarce. Therefore, it is crucial to comprehensively analyze the pharmacological activities and the structure-activity relationships of the abundant bioactives of litchi. Besides, more and more studies have focused on litchi preservation and development of its by-products, which is significant for enhancing the economic value of litchi. Based on the analysis of published articles and patents, this review aims to reveal the development trends of litchi in the healthcare field by providing a systematic summary of the pharmacological activities of its extracts, its phytochemical composition, and the nutritional and potential health benefits of litchi seed, pulp and pericarp with structure-activity relationship analysis. In addition, its by-products also exhibited promising development potential in the field of material science and environmental protection. Furthermore, this study also provides an overview of the strategies of the postharvest storage and processing of litchi.

Harnessing polyphenol power by targeting eNOS for vascular diseases

Vascular diseases arise due to vascular endothelium dysfunction in response to several pro-inflammatory stimuli and invading pathogens. Thickening of the vessel wall, formation of atherosclerotic plaques consisting of proliferating smooth muscle cells, macrophages and lymphocytes are the major consequences of impaired endothelium resulting in atherosclerosis, hypercholesterolemia, hypertension, type 2 diabetes mellitus, chronic renal failure and many others. Decreased nitric oxide (NO) bioavailability was found to be associated with anomalous endothelial function because of either its reduced production level by endothelial NO synthase (eNOS) which synthesize this potent endogenous vasodilator from L-arginine or its enhanced breakdown due to severe oxidative stress and eNOS uncoupling. Polyphenols are a group of bioactive compounds having more than 7000 chemical entities present in different cereals, fruits and vegetables. These natural compounds possess many OH groups which are largely responsible for their strong antioxidative, anti-inflammatory antithrombotic and anti-hypersensitive properties. Several flavonoid-derived polyphenols like flavones, isoflavones, flavanones, flavonols and anthocyanidins and non-flavonoid polyphenols like tannins, curcumins and resveratrol have attracted scientific interest for their beneficial effects in preventing endothelial dysfunction. This article will focus on in vitro as well as in vivo and clinical studies evidences of the polyphenols with eNOS modulating activity against vascular disease condition while their molecular mechanism will also be discussed.

Effects of a Standardized Oligomerized-Polyphenol from Litchi chinensis Fruit Extract and Mixed Plant Extract Supplementation on Peripheral Circulation and Cold Sensitivity

Certain individuals tend to suffer from a cold sensation-particularly in the lower extremities-despite most people not suffering from the same sensation. In Japan, this phenomenon is called "hie-sho" and reduces quality of life for several people, particularly women. A previous study has shown that a standardized oligomerized-polyphenol from Litchi chinensis fruit extract (OPLFE) reportedly causes a significant increase in body surface temperature. The present study aimed to investigate whether supplementation with OPLFE affected peripheral circulation and cold sensitivity. This randomized, double-blind, placebo-controlled trial was performed including 25 participants (age, 45.0±10.4 y; 3 males and 22 females) who were assigned to consume OPLFE, mixed plant extract with OPLFE, or placebo capsules for 14 d. Participants were instructed to relax for 60 min in a temperature-controlled room prior to obtaining measurements. Changes in skin temperature and peripheral blood flow of the middle finger were assessed immediately before and 1, 5, 10, 20, and 30 min after immersion in cold water (10ºC). Participants' height, weight, skin temperature, and blood flow in peripheral tissue were measured; furthermore, their "hie-sho" was measured using the Visual Analog Scale (VAS). Skin temperature and blood flow in peripheral tissue increased in the OPLFE and mixed plant extract with OPLFE groups on day 14 compared with those on day 1. In addition, cold sensitivity in these two groups significantly improved between day 1 and day 14. These findings suggest that OPLFE improves "hie-sho" by increasing peripheral blood flow and skin temperature.

Interventions of natural and synthetic agents in inflammatory bowel disease, modulation of nitric oxide pathways

Inflammatory bowel disease (IBD) refers to a group of disorders characterized by chronic inflammation of the gastrointestinal (GI) tract. The elevated levels of nitric oxide (NO) in serum and affected tissues; mainly synthesized by the inducible nitric oxide synthase (iNOS) enzyme; can exacerbate GI inflammation and is one of the major biomarkers of GI inflammation. Various natural and synthetic agents are able to ameliorate GI inflammation and decrease iNOS expression to the extent comparable with some IBD drugs. Thereby, the purpose of this study was to gather a list of natural or synthetic mediators capable of modulating IBD through the NO pathway. Electronic databases including Google Scholar and PubMed were searched from 1980 to May 2018. We found that polyphenols and particularly flavonoids are able to markedly attenuate NO production and iNOS expression through the nuclear factor κB (NF-κB) and JAK/STAT signaling pathways. Prebiotics and probiotics can also alter the GI microbiota and reduce NO expression in IBD models through a broad array of mechanisms. A number of synthetic molecules have been found to suppress NO expression either dependent on the NF-κB signaling pathway (i.e., dexamethasone, pioglitazone, tropisetron) or independent from this pathway (i.e., nicotine, prednisolone, celecoxib, β-adrenoceptor antagonists). Co-administration of natural and synthetic agents can affect the tissue level of NO and may improve IBD symptoms mainly by modulating the Toll like receptor-4 and NF-κB signaling pathways.

Nutrient components, health benefits, and safety of litchi (Litchi chinensis Sonn.): A review

Litchi (Litchi chinensis Sonn.) is a tropical to subtropical fruit that is widely cultivated in more than 20 countries worldwide. It is normally consumed as fresh or processed and has become one of the most popular fruits because it has a delicious flavor, attractive color, and high nutritive value. Whole litchi fruits have been used not only as a food source but also for medicinal purposes. As a traditional Chinese medicine, litchi has been used for centuries to treat stomach ulcers, diabetes, cough, diarrhea, and dyspepsia, as well as to kill intestinal worms. Both in vitro and in vivo studies have indicated that whole litchi fruits exhibit antioxidant, hypoglycemic, hepatoprotective, hypolipidemic, and antiobesity activities and show anticancer, antiatherosclerotic, hypotensive, neuroprotective, and immunomodulatory activities. The health benefits of litchi have been attributed to its wide range of nutritional components, among which polysaccharides and polyphenols have been proven to possess various beneficial properties. The diversity and composition of litchi polysaccharides and polyphenols have vital influences on their biological activities. In addition, consuming fresh litchi and its products could lead to some adverse reactions for some people such as pruritus, urticaria, swelling of the lips, swelling of the throat, dyspnea, or diarrhea. These safety problems are probably caused by the soluble protein in litchi that could cause anaphylactic and inflammatory reactions. To achieve reasonable applications of litchi in the food, medical and cosmetics industries, this review focuses on recent findings related to the nutrient components, health benefits, and safety of litchi.

Supplementation with Oligonol, Prevents Weight Gain and Improves Lipid Profile in Overweight and Obese Saudi Females

Background:

Obesity is a global health problem, increasing susceptibility to Type 2 Diabetes (T2DM) and Cardiovascular Disease (CVD). Varieties of products have been proposed for treatment with varying degrees of success. Recent studies, suggested Oligonol; an optimized phenolic product mixture from Lychee Fruit Polyphenols (LFP); as such treatment in Japanese population.

Objectives:

We aimed to investigate the effect of oligonol on weight, insulin resistance by (HOMA-IR), lipids profile, leptin, Adiponectin, and resistin in healthy overweight and obese Saudi females.

Subjects and Methods:

60 Saudi healthy overweight and obese females were enrolled in a double blind case/control study to take either Oligonol or placebo for 12 weeks without dietary or lifestyle re-strictions. Weight, height, Waist Circumference (WC), hip circumference (HC), and blood pressure were measured, and fasting blood samples of participants were taken before, and at the end of study. Total cholesterol, HDL-cholesterol, triglycerides, glucose, insulin, leptin, adiponectin, and resistin were meas-ured. LDL- cholesterol, HOMA-IR were calculated by equation.

Results:

47 subjects completed the study, 25 in placebo group, and 22 in Oligonol group. No ill effects were noted in any participant. Oligonol reduced means of serum triglycerides (P=0.008), and resistin (P=0.045) significantly. In addition, no weight gain was noted in oligonol group, unlike placebo group which exhibited significant increase in mean weight (P= 0.036), WC (P=0.027), HC (P= 0.047), and leptin (P <0.001).

Conclusion:

Oligonol could be suggested as future hypolipidemic and weight controlling agent for overweight and obese Saudi females.

Inhibition of Adipogenesis by Oligonol through Akt-mTOR Inhibition in 3T3-L1 Adipocytes

Polyphenols have recently become an important focus of study in obesity research. Oligonol is an oligomerized polyphenol, typically comprised of catechin-type polyphenols from a variety of fruits, which has been found to exhibit better bioavailability and bioreactivity than natural polyphenol compounds. Here, we demonstrated that Oligonol inhibits 3T3-L1 adipocyte differentiation by reducing adipogenic gene expression. During adipogenesis, Oligonol downregulated the mRNA levels of peroxisome proliferator-activated receptor γ (PPARγ), CCAAT/enhancer binding proteins α (C/EBPα), and δ (C/EBPδ) in a dose-dependent manner and the expression of genes involved in lipid biosynthesis. The antiadipogenic effect of Oligonol appears to originate from its ability to inhibit the Akt and mammalian target of rapamycin (mTOR) signaling pathway by diminishing the phosphorylation of ribosomal protein S6 kinase (p70S6K), a downstream target of mTOR and forkhead box protein O1 (Foxo1). These results suggest that Oligonol may be a potent regulator of obesity by repressing major adipogenic genes through inhibition of the Akt signaling pathway, which induces the inhibition of lipid accumulation, ultimately inhibiting adipogenesis.