Polyphenol content, antioxidant capacity, and composition in different varieties of sweet potato (Ipomoea batatas L.) leaves during growth stages

Sweet potato ( Ipomoea batatas L.) leaves are rich in polyphenols and consumed as leaf vegetable in world. The content and composition of polyphenols are diversity at different harvesting period. This study investigated the changes of total polyphenols content (TPC), antioxidant capacity, and polyphenol fractions content of sixteen varieties of SPLs during growth stage. The results showed significant diversity in the concentrations of active compounds in different genotypes and growth stages. TPC ranged from 27.45 to 243.82 mg CAE/g DW among the varieties over various growth stages, with G3 and E1 varieties exhibiting relatively high TPC and antioxidant capacity. Twelve polyphenol fractions were identified in SPLs. Correlation analysis demonstrated a significant positive relationship between antioxidant capacity and the content of monosubstituted caffeoylquinic acids (3-caffeoylquinic acid, 5-caffeoylquinic acid, 4-caffeoylquinic acid) and disubstituted caffeoylquinic acids (3,4-di-O-caffeoylquinic acid, 3,5-di-O-caffeoylquinic acid, 4,5-di-O-caffeoylquinic acid). Principal component analysis highlighted the superior performance of the E1 variety in terms of polyphenol content and antioxidant capacity.