Two folate-derived analogues from an aqueous decoction of Uncaria rhynchophylla
Yue Wang, Qing-Lan Guo, Ruo-Fei Li, Cheng-Bo Xu, Cheng-Gen Zhu, Jian-Gong Shi
Chinese Journal of Natural Medicines
Two new folate-derived analogues, named uncarophyllofolic acids A (1) and B (2), respectively, were isolated from the Uncaria rhynchophylla hook bearing stem (Gouteng in Chinese). The distinct stereochemical structures of 1 and 2 were determined by spectroscopic data analysis in combination with acidic hydrolysis and Marfey's derivatization, along with comparison of their specific rotation and Cotton effect (CE) data with those of the biogenetically related known derivatives as well as theoretical calculations of electronic circular dichroism (ECD) spectra. A plausible biosynthetic pathway of 1 and 2, associating to folate metabolism and the previously reported orychophragines A–C from Orychophragmus violaceus, is discussed.
Circular dichroism, Stereochemistry, Absorption, Quantitation, Natural products, Medicinal