Comparison of α-glucosyl hesperidin of citrus fruits and epigallocatechin gallate of green tea on the Loss of Rotavirus Infectivity in Cell Culture

Orange peel is the main by-product from orange juice industry. It is a known source of bioactive compounds, mostly phenolic compounds, and it has been widely studied for its healthy activities. Thus, this research focuses on the establishment of ultrasound-assisted extraction of phenolic compounds in orange peel using a sonotrode. For this purpose, a Box–Behnken design of 27 experiments was carried out with four independent factors—ratio ethanol/water (v/v), time (min), amplitude (%), and pulse (%). Quantitative analyses of phenolic compounds were performed and the antioxidant activity was measured by ABTS and DPPH methods. The validity of the experimental design was confirmed by ANOVA and the optimal sonotrode extraction conditions were obtained by response surface methodology (RSM). The extracts obtained in the established conditions were analyzed by High Performance Liquid Chromatography (HPLC) coupled to mass spectrometer detector and 74 polar compounds were identified. The highest phenolic content and antioxidant activity were obtained using 45/55 ethanol/water (v/v), 35 min, amplitude 90% (110 W), and pulse 100%. The established method allows an increment of phenolics recovery up to 60% higher than a conventional extraction. Moreover, the effect of drying on phenolic content was also evaluated.

Leptin resistance and co-existing insulin resistance is considered as hallmark of dietinduced obesity. Here, we investigated therapeutic potential of hesperidin to improve leptin and insulin resistance using high fat diet (HFD)-induced obese experimental animal model. We also performed in silico studies to validate therapeutic effectiveness of hesperidin by performing protein-ligand docking and molecular dynamics simulation studies. Group 1 was identified as control group receiving vehicle only. Group 2 was marked as non-treated group receiving 60% HFD. While, other groups were treated daily with orlistat (120 mg/kg/d), hesperidin (55 mg/kg/d), combination of hesperidin (55 mg/kg/d) + orlistat (120 mg/kg/d). Hesperidin alone (P<0.001) and particularly in combination with orlistat (P<0.001), resulted in controlling the levels of HFD-altered biomarkers including random and fasting state of glycemia, leptin and insulin resistance. Similarly, hesperidin also improved the serum and tissue levels of leptin, interleukin-6 and tumor necrosis factor-alpha more significantly (P<0.05) when compared with that of orlistat. These results were found to be in accordance with the results of histopathological examination of pancreas, liver and adipose tissues. In-silico studies also proved that hesperidin binds to leptin receptor with higher affinity as compared to that of orlistat and induces the favorable variations in geometrical conformation of leptin receptor to promote its association with leptin which may lead to the cascades of reactions culminating the lipolysis of fats that may ultimately lead to cure obesity. The results of this study may be a significant expectation among the forthcoming treatment strategies for leptin and insulin resistance.

Food polyphenols constitute a large family of substances with beneficial properties in a large group of communicable and non-communicable diseases. These compounds support and improve the body’s defences against oxidative stress and are helpful in the prevention of pathologies related to metabolic syndrome. Furthermore, they exhibit anti-inflammatory, antiviral, and antimicrobial properties. This chapter draws attention to certain nutritional components such as hesperidin and quercetin, which are emerging as good candidates for a complementary beneficial effect in the case of diseases caused by viruses, including COVID-19. These nutraceuticals have a complex mechanism of action, which involves both cellular defence against oxidative stress and the modulation of inflammation, which although normally is a defence, repair and activation mechanism of the immune system, it can elude its controls and become a systemic and destructive pathology (cytokine storm, respiratory distress syndrome). Furthermore, recent in silico simulation tests suggest that both hesperidin and quercetin may interfere with SARS-CoV-2 by binding to cell receptors and the proteolytic enzymes involved in its replication. In addition to the inhibitory effects on the virus at cellular level, the two flavonoids can have indirect effects in respiratory infectious diseases as they prevent or improve metabolic and vascular comorbidities that can complicate the clinical course. This brief review focuses on biochemical and pharmacological mechanisms of action of polyphenols in the context of the revaluation of dietary approaches to the prevention and treatment of infectious diseases caused by viruses, with a special application to COVID-19.