Analysis of chlorogenic acids in beverages prepared from Chinese health foods and investigation, in vitro, of effects on glucose absorption in cultured Caco-2 cells

The effects of aqueous extracts of Kuding tea (Ilex latifolia Thunb.) and the large-leaf form of Camellia sinensis var. sinensis), chrysanthemum (Dendranthema morifolium Ramat), honeysuckle flower (Lonicera japonica Thunb.), and purple sweet potato (Ipomoea batatas) stem on glucose absorption were investigated using Caco-2 cells. Glucose absorption by Caco-2 cells was significantly inhibited by aqueous extract of Kuding tea, chrysanthemum and purple sweet potato stem under both Na+-dependent conditions and Na+-free conditions indicating effects on SGLT1 and GLUT transporters. Analysis of the (poly)phenols in these aqueous extracts suggested that dicaffeoylquinic acids and flavanols may be particularly important in producing these effects. Kuding tea extract was the most effective, suggesting that this merits evaluation in a clinical study.