New diterpenoid glucosides from Siegesbeckia pubescens

Plants of the genus Siegesbeckia are annual herbs widely distributed in tropical and temperate zones and they are used as a traditional medicine to treat rheumatic arthritis, hypertension, malaria, neurasthenia and snake-bite in China. In previous papers, we reported on five new ent-kaurane and ent-pimarane diterpenoids, siegesbeckioside, siegesbeckiol and siegesbeckic acid1, orientalin A and B, and eight know compounds2,3. The present paper describes the isolation and structural elucidation …     

A New Perylenequinone from Hypomyces sp.

Some metabolites of fungi and plants containing perylenequinones have been used as folk medicine for the treatment of many diseases1,2. A filamentous fungus, Ascomy-cetes Hypocreaceae Hypomyces (Fr.) Tul. sp., was found from the northwestern mountains of Yunnan Province, and cultured successfully in the laboratory. A new perylenequinone, named hypomycin A (1), was isolated from its mycelia. In this paper the structure elucidation of 1 was described. Figure 1 The structure of compound 1 Fig…     

7,3′-二甲氧基-4′,5′-次乙二氧基黄烷酮的合成

以香草醛和问苯二酚为原料,经7步反应合成了新的苯并二氧六环新木脂素黄酮类似物7,3′-二甲氧基-4′,5′-次乙二氧基黄烷酮,总收率16．1％,其结构经^1H NMR,IR和MS证实。     

A New Sesquiterpenoid from Magnolia delavayi

A new sesquiterpenoid was obstained from the leaves of Magnolia delavayi. Its structure was determined as 8β-acetoxy-10α-ethyloxy-guaia-4α, 11-diol on the basis of spectral evidence.     

A New Taxoid from Leaves and Branches of Taxus chinensis

A new taxoid, 2-deacetyl-2α, 14β-dihydroxybaccatin Ⅳ (1), was isolated from the leaves and branches of Taxus chinensis together with the known compound baccatin Ⅳ (2). The structure of the new compound was elucidated by spectroscopic techniques. The detailed ^13C NMR assignments of baccatin Ⅳ are reported for the first time.     

A Novel Sesquiterpene Isolated from Stereum sp. 8954

The basidiomycete Stereum sp. 8954 was collected in Xishuangbanna, Yunnan Province, and the mycelium of Stereum sp. 8954 was separated from fruit body and deposited in Laboratory for Conservation and Utilization of Bio-resources, Yunnan University. After fermentation, a novel sesquiterpene was isolated from the culture of the strain. The present paper deals with the structural elucidation of the new compound. Experimental Stereum sp. 8954 was fermented with PDA medium (10 L) at 26 oC fo…     

THE GLOBAL BIOSTRATIGRAPHICAL CORRELATION OF THE MEISHUCUNIAN STAGE AND THE PRECAMBRIAN-CAMBRIAN BOUNDARY

The Meishucunian Stage is rich in fossils and is characterized by their distinct evolutionsequence, so based on the established zonation of small shelly fossils, the sequence of tracefossils and the stratotype point (China "B", the dividing point between Units 6 and 7 or be-tween fossil zones Ⅰ and Ⅱ), the Meishucun section is more widely applicable to both region-al and intercontinental correlations. In this respect, the stage is well suited for both thecarbonate and the clastic-rock sedimentary regions. The Meishucunian small shelly fossil assem-blages are correlated with those found in Siberia of U.S.S.R., Mongolia, Central England,South Australia and Northwestern Canada. The Meishucunian trace fossil sequence can alsobe broadly correlated with that in the Russian Platform of U.S.S.R., Northwest Europe,Great Britain, Spain, Australia, the Western United States and Southeastern Canada.     

A Styrylpyrone Dimer from the Bark of Goniothalamus leiocarpus

A dimer of styrylpyrone derivative, leiocarpin E(1), was isolated from the bark of Goniothalamus leiocarpus. Its structures was elucidated by means of spectral and chemical methods. The cytotoxicity of leiocarpin E against HL-60 cells was tested.     

Two New Dammarane Glycosides from the Acid Hydrolysis Product of Panax Notoginseng

In our continuing research works on Panax notoginseng (Burk.) F. H. Chen, a famous traditional Chinese herb medicine1, two new dammarane glycosides named notoginsenosides T1 (1) and T2 (2) were isolated from the mild acid hydrolysis products of the root saponins. We report herein the structure elucidation of these two novel glycosides.Notoginsenosides T1(1) was obtained as white solid, [(] = +14.49 (0.50, MeOH). Its negative mode HR-FAB-MS spectrum showing the quasimolecular ion peak a…     

A New Ceramide from the Basidiomycetes Armillaria mellea

As one part of our study on the bioactive metabolites of the higher fungi in Yunnan Province, the chemical constituents of Armillaria mellea (Tricholomataceae) collected at Zhong Dian in Yunnan Province have been investigated. The present report deals with the structural elucidation of a new ceramide 1, named armillaramide, isolated from the AcOEt extract of the fruiting bodies of this fungus.Figure 1 The structure of armillaramide 1Compound 1, white amorphous powder, mp 113(117(C, [(] + …