Fig. 1 in Discovery of a stable vitamin C glycoside in crab apples (Malus sylvestris)

Fig. 1. Structures of AA (1) and the only known naturally occurring derivatives in plants, 2-O-β-D-glucopyranosyl L-ascorbic acid (2) and 6-O-β-D-glucopyranosyl L-ascorbic acid (3). Synthetic 2-O-α-D-glucopyranosyl L-ascorbic acid (4) is commonly used in cosmetic products.