2nd Edition of Agriculture, Forestry, and Horticulture World Conference 2026

Abstract

Yam (Dioscorea opposita L.) is a food with medicinal properties, widely popular for its anti-cancer, antioxidant, and anti-in ammatory effects, as well as its ability to lower blood sugar, blood pressure, and blood lipids while boosting immunity. However, yam undergo color changes during storage, such as browning. Additionally, the research team discovered that it also exhibits yellowing. Transcriptome and metabolome analyses of yellow yam extracts indicate that yellowing primarily results from the accumulation of multiple secondary metabolites. Phenylalanine undergoes enzymatic conversion to form coumestan-CoA, which is then processed by curcumin synthase into bis-demethoxycurcumin—the predominant component in yellow yam extracts. Coumaroyl-CoA enters the flavonoid metabolic pathway through multiple enzymatic reactions, yielding 19 flavonoids, including naringenin, hesperidin, and apigenin, that contribute to yellow yam formation. Transcriptional expression levels of key enzymes in glycolysis, the pentose phosphate pathway (PPP), and the tricarboxylic acid (TCA) cycle are upregulated, accumulating ATP and energy charges to supply energy for pigment synthesis. Furthermore, the PPP cycle can branch under enzymatic action to form β-carotene, which is converted into anthocyanins and other substances involved in yellow yam formation. Functional studies on yellow yam extract indicate that extracts at various concentrations (31.2 μg/mL–125 μg/mL) reduce the fluorescence intensity of the yolk sac in zebrafish embryos subjected to oxidative damage and enhance superoxide dismutase (SOD) activity. Further investigations revealed that this primarily occurs through regulating glutathione metabolism pathways, the MAPK signaling pathway, and pathways related to ascorbic acid and aldonic acid metabolism. This study elucidates the mechanism by which yellow yam extract boosts antioxidant, increases its added value, and provides a theoretical basis for its application.