Ilex (Aquifoliaceae) species are distributed widely in the People's Republic of China, and some are used extensively in folk medicine. For example, I. rotunda is an antipyretic and antidote and used for the treatment of the common cold, tonsillitis, and stomach and intestinal ulcers. I. pubescens is used for the treatment of coronary disease, myocardial infarction, dysentery, and erysipelas. I. cornuta and I. latifolia are used for the treatment of headache, toothache, bloodshot eyes, and tinnitus. Many reports indicate that saponins are the major constituents of Ilex species.1-5) The occurrence of flavonoids, 6) xanthines, 7) aldehydes, 8) hemiterpene glycosides, 9,10) triterpenes and alkanes, 11) anthocyanins, 12) pentyl esters, hexyl esters, and other lipophilic compounds 13) were reported. Several biological activities were related to the compounds isolated from Ilex species, including hypocholesterolemic 14) and antioxidant 15,16) activities. In a continuation of our study on the constituents of the medicinal plants of the Aquifoliaceae family. 17,18) We investigated the water-soulble fraction of Ilex oblonga. This plant is a well-known endemic herb to treat gumboil, eczema, rheumatism, scald and bruise in Guangxi province of China. 19) No previous phytochemical investigation on I. oblonga has been reported. In this paper, we describe the isolation and structure elucidation of ten triterpenoid saponins designated as oblonganoside A (1) (7) 22) from the leaves of I. oblonga.
Results and DiscussionThe leaves of I. oblonga were extracted with MeOH under reflux. The MeOH extract was subjected to Diaion HP-20 column chromatography to give H 2 O, MeOH, and acetoneeluted fractions. The MeOH eluted fraction was subjected to ordinary and reversed phase silica gel column chromatography and finally HPLC to furnish triterpenoid saponons 1-10.Compound 1 was obtained as a white powder and exhib- Ministry of Education, Fujian Agriculture and Forestry University; Fuzhou, Fujian, 350002, P. R. China: and b Department of Bio-engineering & Technology, Huaqiao University; Quanzhou, Fujian, 362011, P. R. China. Received November 3, 2006; accepted December 21, 2006 Six new triterpenoid saponins of the ursane types were isolated from the MeOH extract of the leaves of Ilex oblonga. They were oblonganoside A (1), oblonganoside B (2), oblonganoside C (6), oblonganoside D (8), oblonganoside E (9), and oblonganoside F (10), together with three known triterpenoid saponins. The structures of these compounds were elucidated on the basis of spectroscopic analysis, and compound 1 showed appreciable inhibitory activity against TMV replication with EC 50 value 0.074 mM.