Prunus the skin than in the flesh. They also contain moderate levels of carotenoids and ascorbic acid. Peaches and nectarines are orange and yellow in color which can be attributed to the carotenoids present. Ascorbic acid is important in hydroxylation reactions, such as collagen synthesis and de novo synthesis of bone and cartilage, and wound healing. Ascorbic acid is also a precursor of Vitamin C, which is essential for repairing tissues and absorbing iron. Various "Prunus" species are winter hosts of the Damson-hop aphid, "Phorodon humuli", which is destructive to hops "Humulus lupulus" just at the time of their maturity, so
Vitamin time it was shown that not all vitamins are amines, the word was already ubiquitous. In 1920, Jack Cecil Drummond proposed that the final "e" be dropped to deemphasize the "amine" reference, after researchers began to suspect that not all "vitamines" (in particular, vitamin A) have an amine component. In 1930, Paul Karrer elucidated the correct structure for beta-carotene, the main precursor of vitamin A, and identified other carotenoids. Karrer and Norman Haworth confirmed Albert Szent-Györgyi's discovery of ascorbic acid and made significant contributions to the chemistry of flavins, which led to the identification of lactoflavin. For their investigations on