Antioxidant and anti-aging effects of quercetin 3-O-rhamnoside isolated from Houttuynia cordata Thunb extract on Caenorhabditis elegans

Abstract

Humans inevitably generate reactive oxygen species (ROS) during respiration, leading to oxidative stress, which antioxidants counteract. However, aging and lifestyle factors increase ROS levels, contributing to disease. This study evaluated the antioxidant and anti-aging effects of Houttuynia cordata extract and fractions using Caenorhabditis elegans. The most active ethyl acetate (EA) fraction was isolated via open column chromatography and identified as quercetin 3-O-rhamnoside (quercitrin) through NMR and LC-MS/MS analysis. Antioxidant enzyme activities (SOD, catalase, SOD-3) and intracellular ROS inhibition were assessed, alongside stress resistance under oxidative and thermal conditions. Additionally, quercitrin's effects on aging were examined by measuring SIR2.1 and DAF-2 expression in the insulin signaling pathway (IIS) and analyzing its concentration-dependent regulation of DAF-16 using GFP transgenic worms. Quercitrin modulated aging related proteins, enhanced antioxidant enzyme activity, inhibited ROS accumulation, extended lifespan, and improved resistance to thermal stress. These findings highlight quercitrin's strong antioxidant and anti-aging properties.

Keywords: Anti-aging; Antioxidant; Caenorhabditis elegans; Houttuynia cordata Thunb; Quercetin 3-O-rhamnoside (Quercitrin); ROS; Western blot.