Leaf extract of Garcinia atroviridis promotes anti-heat stress and antioxidant effects in Caenorhabditis elegans

Introduction:Garcinia atroviridis has been used for traditional medicines, healthy foods and tea. The chemical compositions and biological activities of fruit, stem bark and root have been widely studied. However, the phytochemical components and the biological activities in Garcinia atroviridis leaves (GAL) are limited. This research aims to study the phytochemical components and the stress resistance effects of GAL in Caenorhabditis elegans (C. elegans).Methods: To investigate the chemical components and antioxidant activities of GAL extract, the ethanol extract was characterized by liquid chromatography-quadrupole time-of-flight mass spectrometry (LC-QTOF MS) analysis and C. elegans was used to evaluate the effects of GAL extracts on longevity and stress resistance.Results and discussion: The results revealed that the ethanol extract of GAL possesses free radical scavenging activities. Furthermore, GAL extract increased the lifespan of C. elegans by 6.02%, 15.26%, and 12.75% at concentrations of 25, 50, and 100 μg/mL, respectively. GAL extract exhibited improved stress resistance under conditions of heat and hydrogen peroxide-induced stress. The survival rates of GAL extract-treated worms were significantly higher than those of untreated worms, and GAL extract reduced reactive oxygen species (ROS) accumulation. Additionally, GAL extract treatment upregulated the expression of stress resistance-associated genes, including gst-4, sod-3, skn-1, and hsp16.2. GAL extract supplementation alleviated stress and enhanced longevity by inducing stress-related genes in C. elegans. The observed effects of GAL extracts may be attributed to the stimulation of oxidant enzymes mediated through DAF-16/FOXO and SKN-1/NRF2, as well as the enhancement of thermal defense in C. elegans. Collectively, this study provides the first evidence of the antioxidant activities of GAL and elucidates the underlying mechanisms of stress resistance

Antioxidant activity, anti-tyrosinase activity, molecular docking studies, and molecular dynamic simulation of active compounds found in nipa palm vinegar

Tyrosinase is a key enzyme in melanogenesis and its inhibitors have become increasingly because of their potential activity as hypopigmenting agents which have less side effects. Nipa palm vinegar is an aqueous product that is normally used as a food supplement. The aim of this study was to study the determination of antioxidant activity and tyrosinase inhibitory activities of aqueous extract of original nipa palm vinegar (AE O-NPV), nipa palm vinegar powder (NPV-P) and aqueous extract of nipa palm vinegar powder (AE NPV-P) were examined. Nipa palm vinegars were evaluated the phenolic and flavonoid content, and the active compounds which were submitted to molecular docking and molecular dynamic simulation, chemoinformatics, rule of five, skin absorption and toxicity. The highest phenolic and flavonoid contents in the AE O-NPV were 2.36 ± 0.23 mg gallic acid equivalents/g extract and 5.11 ± 0.59 mg quercetin equivalents/g, and the highest ABTS radical cation scavenging activity was also found. The AE O-NPV, NPV-P and AE NPV-P showed anti-mushroom tyrosinase activity. The HPLC analysis showed that there were vanillic acid and three flavonoids (catechin, rutin and quercetin). The molecular docking study revealed that the binding of the vanillic acid and three flavonoids occurred in the active site residues (histidine and other amino acids). Moreover, the number of hydrogen bond acceptors/donors, solubility, polar surface area and bioavailability score of the vanillic acid and three flavonoids were acceptable compared to Lipinski’s Rule of Five. The molecular dynamic simulation showed that vanillic acid interacts with HIS284 through π–π stacking hydrophobic interactions and forms a metal-acceptor interaction with the copper molecule at the tyrosinase active site. All compounds revealed good skin permeability and nontoxicity. Nipa palm vinegar could be a promising source of a new ingredient for tyrosinase inhibition for cosmetics or pharmaceutical products