Environmental Influences on Marker Compound Accumulation in the Roots of <i>Reynoutria multiflora</i> Cultivated in Korea

Reynoutria multiflora (Thunb.) Moldenke is a perennial medicinal plant widely used in East Asia for its bioactive root compounds, including 2,3,5,4′-tetrahydroxy stilbene-2-O-β-D-glucoside (THSG), emodin, and physcion. Although numerous studies have explored its bioactive compounds and therapeutic potential, the influence of field-based environmental factors on compound accumulation remains poorly understood. This study aimed to assess the relationship between soil and meteorological variables and the concentrations of marker compounds in R. multiflora roots obtained from four cultivation sites in southern Korea. A total of 43 root samples were analyzed using a validated UHPLC-MS/MS method, and corresponding environmental data including 13 soil physicochemical properties and 10 meteorological parameters with altitude were monitored and statistically evaluated. The results showed that meteorological factors, particularly temperature and altitude, had stronger correlations with compound accumulation than soil factors. emodin content was positively correlated with annual average and maximum temperatures, while THSG showed a negatively response to temperature, depending on the thermal variables with altitude. Among soil characteristics, only cation exchange capacity (CEC) showed a significant negative correlation with emodin, suggesting that stable nutrient conditions may suppress stress-induced secondary metabolite production. These findings highlight the ecological sensitivity of secondary metabolite biosynthesis in R. multiflora and provide valuable insights for developing site specific cultivation strategies to enhance the quality and consistency of this medicinal crop under domestic conditions.