|其他摘要||Higher fungi continue to offer an unique and renewable resource for the discovery of potential new drugs and biological entities because of the chemical and biological diversity of their secondary metabolites. Yunnan Province, as one of the hotspots for biodiversity, is a rich region for higher fungi. On the other hand, many higher fungi can be fermented, and a single strain often has the potential to produce more various compounds in different cultivation conditions (one strain-many compounds, OSMAC). As an important part of our works on searching for secondary metabolites with unique chemical and biological diversity from higher fungi in Yunnan Province, the chemical constituents of twelve higher fungi were studied. Those fungi included Daldinia concentrica, Phaeolus schweinitzii, Rhizopogon luteolus, Astraeus hygrometricus, Bondarzewia berkeleyi, Xylaria longipes, Hebeloma westraliense, Hebeloma.versipelle, Lactarius pubescens, Russula decolorans, Tylopilus ballouii, and Inonotus radiatus. 106 compounds have been obtained by chromatographic methods, among which, 72 different compounds were elucidated on the basis of spectroscopic data including 12 new ones.
Chapter 1: Chemical investigation of D. concentrica and X. longipes
Twenty compounds were isolated and identified from the culture broth of D. concentrica by OSMAC approach. Among them, six were new ones, including four botrydial sesquiterpenoids (1-4) and two concentricolide derivates (11-12). Those botrydial sesquiterpenoids were obtained for the first time from the genus Daldinia, and compound 4 was a rare nor-sesquiterpenoid aldehyde. Five known compounds were also isolated from the culture broth of X. longipes.
Chapter 2: Chemical investigation of H. versipelle and H. westraliense
A new cytotoxic lanostane triterpenoid, 24(E)-3β-hydroxylanosta-8,24-dien-26- al-21-oic acid (1), together with eleven known compounds, were obtained from the fruiting bodies of H. versipelle. The compound 1 moderately inhibited the growth of four tumor cell lines (IC50 10-25.0 μg/ml). Six known compounds were also isolated from the culture broth of H. westraliense, and volemolide (15), a norsterol, has been found in the Cortinariaceae for the first time.
Chapter 3: Chemical investigation of L. pubescens and R. decolorans
Phytochemical study of the fruiting bodies of L. pubescens has resulted in the isolation of six compounds, including a new marasmane sesquiterpenoid. From the fruiting bodies of R. decolorans, nine known compounds were isolated and identified.
Chapter 4: Chemical investigation of P. schweinitzii, B. berkeleyi and I. radiatus
Mushroom belonging to Polyporaceae were rich in secondary metabolites, which with a variety of biological activities. During our phytochemical study of three species of Polyporaceae, eighteen compounds, including two new ones, were gained and identified by spectroscopic analysis. Among them, eight compounds have been obtained and elucidated from liquid culture of P. schweinitzii and B. berkeleyi, respectively. (3R)-5- hydroxymellein-α-D-glucopyranoside (5) was a new one from P. schweinitzii, and compound 9 was a new dihydrobenzofuran cyclopentenone from B. berkeleyi, and five known compounds were also obtained from the fruit bodies of I. radiatu.
Chapter 5: Chemical investigation of A. hygrometricus
The culture broth of A. hygrometricus has afforded a new naturally occurring polyhydroxylated steryl ester (1) and seven other known compounds.
Chapter 6: Chemical investigation of R. luteolus
A new cyclopentenone (7) has been found in the culture broth of R. luteolus, along with seven known compounds, and their structures were assigned by means of spectroscopic methods.
Chapter 7: Chemical investigation of T. ballouii
In this work, twelve known compounds were obtained from the fruit bodies of T. ballouii.
Chapter 8: Screening for antifungal activities of sixty higher fungi
Ethanol extracts of sixty higher fungi collected in Yunnan Province were subjected to screening for antifungal activity, using the poison food technique against several plant pathogenic fungi. Of the extracts tested, those of A. dispansus and D. concentrica exhibited considerable activities, and it was found that the extract of A. dispansus almost completely inhibited mycelial growth of S. sclerotiorum and F. graminearum S. Grifolin, the active compound, was isolated from the fruiting bodies of A. dispansus by bioassay-guided fractionation, and its antifungal activities were evaluated in vitro against nine plant pathogenic fungi and in vivo against E. graminis. In vitro, grifolin inhibited mycelial growth of S. sclerotiorum and F. graminearum with inhibition of 86.4 and 80.9% at 304.9 μm, respectively, and completely inhibited spore germination of F. graminearum, G. fructigenum and P. oryzae at 38.1 μm. In vivo, the curative effect of grifolin against E. graminis was 65.5% at 304.9 μm after 8 days.
Chapter 9: OSMAC-an efficient approach to exploit the secondary metabolites diversity of microorganism
This chapter summarized the concept and foundation of OSMAC, and several examples using this method were also presented.|