Vitamin amino acids. Most vitamins are not single molecules, but groups of related molecules called vitamers. For example, vitamin E consists of four tocopherols and four tocotrienols. The thirteen vitamins required by human metabolism are: vitamin A (retinols and carotenoids), vitamin B (thiamine), vitamin B (riboflavin), vitamin B (niacin), vitamin B (pantothenic acid), vitamin B (pyridoxine), vitamin B (biotin), vitamin B (folic acid or folate), vitamin B (cobalamins), vitamin C (ascorbic acid), vitamin D (calciferols), vitamin E (tocopherols and tocotrienols), and vitamin K (quinones). Vitamins have diverse biochemical functions. Some forms of vitamin A function as regulators of cell and tissue
Procyanidin B2 has been shown to inhibit the formation of the advanced glycation end-products pentosidine, carboxymethyllysine (CML), and methylglyoxal (MGO). Procyanidin B2 Procyanidin B2 is a B type proanthocyanidin. Its structure is (−)-Epicatechin-(4β→8)-(−)-epicatechin. Procyanidin B2 can be found in "Cinchona pubescens" (Chinchona, in the rind, bark and cortex), in "Cinnamomum verum" (Ceylon cinnamon, in the rind, bark and cortex), in "Crataegus monogyna" (Common hawthorn, in the flower and blossom), in "Uncaria guianensis" (Cat's claw, in the root), in "Vitis vinifera" (Common grape vine, in the leaf), in "Litchi chinensis" (litchi, in the pericarp), in the apple, and in "Ecdysanthera utilis". Procyanidin B2