Characterizing Ethnomedicinal Tetrastigma hemsleyanum Diels et Gilg Grown Under Different Cultivation Methods Using Stable Isotopes and Elemental Analyses

Tetrastigma hemsleyanum Diels et Gilg is a high-value edible and medicinal homologous plant, routinely grown under conventional field or greenhouse production systems across Asia. However, mislabeling of conventional products as the rarer (and more expensive) wild version may occur for financial gain. In this study, stable isotopes (δ13C, δ15N, δ2H, and δ18O) and metal contents (Cr, Cu, Ni, As, Cd, Pb) were used to characterize plant tissues (tuber root, stem, leaf) and corresponding soils originating from simulated-wild-cultivated (WC) and greenhouse-cultivated (GC) pot trials using the same soil. Carbon and nitrogen isotopes served as key indicators for distinguishing GC and WC products. Specifically, δ13C values of GC plant tissues were 1.4 to 2.4‰ more positive than those of WC plant tissues (p < 0.05), and δ15N values in GC tissues were 2.7 to 4.6‰ more positive than δ15N in WC tissues (p < 0.01). Lower δ15N values observed in WC products indicate slower nitrogen turnover compared with GC products. Soil metal concentrations had significant differences between the two cultivation systems, but only limited effects on metal bioconcentration factors (BCFs) and translocation factors (TFs) in T. hemsleyanum tissues. Pb and Cd concentrations in root tissues had large differences between cultivation systems, and carbon dynamics in GC plants were more negatively affected by Pb levels in soils. These findings provide the first investigation of T. hemsleyanum grown under different cultivation practices and establish a scientific basis for distinguishing other wild or simulated-wild labeled food and medicinal plant products from conventionally grown products in future studies.