Study on the Chemical Constituents of Stigmata Maydis
Stigmata Maydis (SM) is the elongated stigmas of maize, a Poaceous grain. It has been used for the treatment of urinary and renal diseases, hypercholesterolemia and diabetes mellitus in traditional Chinese medicine. SM is rich in flavonoids and polysaccharides, and the two types of components from this material had been reported to demonstrate ABTS free radical-scavenging for reduction in advanced glycation end-products and anti-diabetic activity, respectively. However, the actual active components and composition for this material are still not clear. In this study, the dry materials of Stigmata Maydis were extracted by EtOH, concentration and liquid-liquid partitioned by Hex, EtOAc, BuOH and H2O in order to give the corresponding fractions. The extracts were fractionated into several fractions by chromatographic methods. The partial purified subfractions were further purified by various chromatographic methods to give 2, 10, 9 and two pure compounds from the Frs. 3 – 6 of the EtOAc-soluble extract (17.9 g), and 3 compounds from the Hex and n-BuOH extracts. The structure of the compounds were be elucidated as the structural types including steroids, flavonoids and nucleotide by the spectroscopic methods such as NMR, MS, UV and IR. The research outcome was beneficial for the finding of the anti-diabetic components from the title medicinal herb and other anti-diabetic herbs.