Mori Ramulus (Chin.Ph.)-the Dried Twigs of Morus alba L./Part 1: Discovery of Two Novel Coumarin Glycosides from the Anti-Hyperuricemic Ethanol Extract.

In Traditional Chinese Medicine (TCM), Mori ramulus (Chin.Ph.)-the dried twigs of Morus alba L.-is extensively used as an antirheumatic agent and also finds additional use in asthma therapy. As a pathological high xanthine oxidase (XO, EC 1.1.3.22) activity is strongly correlated to hyperuricemy and gout, standard anti-hyperuremic therapy typically involves XO inhibitors like allopurinol, which often cause adverse effects by inhibiting other enzymes involved in purine metabolism. Mori ramulus may therefore be a promissing source for the development of new antirheumatic therapeutics with less side effects. Coumarins, one of the dominant groups of bioactive constituents of M. alba , have been demonstrated to possess anti-inflammatory, antiplatelet aggregation, antitumor, and acetylcholinesterase (AChE) inhibitory activities. The combination of HPLC (DAD) and Q-TOF technique could give excellent separating and good structural characterization abilities which make it suitable to analyze complex multi-herbal extracts in TCM. The aim of this study was to develop a HPLC (DAD)/ESI-Q-TOF-MS/MS method for the identification and profiling of pharmacologically active coumarin glycosides in Mori ramulus refined extracts for used in TCM. This HPLC (DAD)/ESI-Q-TOF-MS/MS method provided a rapid and accurate method for identification of coumarin glycosides-including new natural products described here for the first time-in the crude extract of M. alba L. In the course of this project, two novel natural products moriramulosid A (umbelliferone-6-β-d-apiofuranosyl-(1→6)-β-d-glucopyranoside) and moriramulosid B (6-[[6- O -(6-deoxy-α-l-mannopyranosyl)-β-d-glucopyranosyl]oxy]-2 H -1-benzopyran-1-one) were newly discovered and the known natural product Scopolin was identified in M. alba L. for the first time.