Studies On The Chemical Constituents From Dioscorea Bulbifera L. And Artocarpus Hypargyreus Hance

This paper consists of three chapters. The first chapter introduces the chemical constituents of Dioscorea bulbifera L., the second chapter introduces the biologically active constituents of Artocarpus hypargyreus Hance, and the last chapter is a review on the progress in the chemistry and biological activities of Dioscorea bulbifera L.The dried rhizomes of Dioscorea bulbifera L. are used as traditional Chinese medicine ’Huangyaozi’ for the treatment of pharyngitis, neoplasm, haematemesis, pertussis and asthma, and also can be used clinically against goiter, thyroid cancer, esophagus cancer, gastric cancer and diabetes. The modern pharmacological study showed that the crude extract from the rhizomes of D. bulbifera had antitumor, antibiosis, anti-inflammatory, and anti-goiter effects. Some diterpenoids and flavonoids have been isolated form D. bulbifera. But the bioactive constituents need to be expolored.Further separation of the EtOAc-soluble fraction from an ethanol extract of the rhizomes of D. bulbifera afforded fourteen compounds, including six diterpene lactones, diosbulbin B (Ⅰ-4), diosbulbin D (Ⅰ-2), diosbulbin E (Ⅰ-1), diosbulbin F (Ⅰ-3), diosbulbin G (Ⅰ-5), and diosbulbin L (Ⅰ-6), four phenanthrenes, 2,3,5,7-phenanthrenetetraol (Ⅰ-7),9,10-dihydro-2,3,5,7-phenanthrenetetraol (Ⅰ-8), 5,7-dimethoxy-2,6-phenanthrenediol (Ⅰ-9), and ochrone A (Ⅰ-10), and four other compounds, myricetin (Ⅰ-11), quercetin (Ⅰ-12), isolariciresino (Ⅰ-13) and saikochromone A (Ⅰ-14).CompoundsⅠ-7 is a new phenanthrene, while compoundsⅠ-9,Ⅰ-10,Ⅰ-13 andⅠ-14 were isolated from this species for the first time.Artocarpus hypargyreus Hance belongs to the family of Moraceae, which is used as the traditional folk medicine for the treatment of rheumatism, cephalalgia, stomachache, and hypogalactia. So far, there are limited data on the chemical constituents of A. hypargyreus. Our preliminary study suggested that the extract of A. hypargyreus partitioned by CHCl3 had significant inhibitory effect on pancrelipase. Futher isolation and biological evaluation have been done. Meanwhile, the EtOAc-soluble fraction showed inhibitory effect on tyrosinase with IC50 of 0.35±0.01μg/ml.Tyrosinase, a polyphenol oxidase, is a key enzyme of melanin’s synthesis. Tyrosinase inhibitors can be used to prevent and treat pigmentation, melasma, and melanoma. Thus, further separation of this extract afforded ten compounds, artohypaflavone (Ⅱ-1), brosimone H (Ⅱ-2), artonin A (Ⅱ-3), artocarpin (Ⅱ-4), artopetelin B (Ⅱ-5), (-)-epiafzelechin (Ⅱ-6), oxyresveratrol (Ⅱ-7), (+)-afzelechin (Ⅱ-8), (+)-catechin (Ⅱ-9), and (+)-afzelechin-3-O-α-L-rhamnopyranoside (11-10).CompoundsⅡ-1 is a new isoprenylated flavone, while compoundsⅡ-2,Ⅱ-4-Ⅱ-6,Ⅱ-8 were isolated from this species for the first time. CompoundsⅡ-2-Ⅱ-10 were screened for inhibitory effect on tyrosinase. CompoundsⅡ-6 andⅡ-7 showed significant inhibitory effect on tyrosinase with IC50 of 13.50±0.96μM and 0.47±0.02μM.