Chemical Constituents And Their Bioactivity From Ganoderma Weberianum

Ganoderma weberianum（G.weberianum）belongs to the Ganoderma fungus of family Ganodermataceae.The species is distributed in Guangxi,Guizhou,Hainan,Yunnan and other places in China,and is used as a medicine or medicinal diet in the folk,which has the effect of enhancing activity.At present,there are few reports on the chemical composition and biological activity of wild G.weberianum fruiting bodies at home and abroad.In order to interpret the medicinal value of G.weberianum,the chemical constituents of the ethanol extract of G.weberianum were isolated,identified and evaluated for their biological activities.It is hoped to discover compounds with novel structures and significant biological activities,clarify the molecular basis of their pharmacodynamics and to develop their resources and use to provide theoretical reflections.In this paper,reversed-phase column chromatography,decompression silica gel column chromatography,Sephadex LH-20 and semi-pre HPLC were used to separate and purify the compounds.The structures of the compounds were det ermined by various spectroscopic techniques such as NMR and IR,as well as electron circular dichroism calculations.Thirty-four compounds were isolated fr om the ethanolic extract of the fruiting bodies of G.weberianum,which were identified as ganodeweberiols A-L（1-12）,3-O-acetyl lucidumol B（13）,ganoder iol B（14）,lanosta-7,9（11）-dien-3β-acetyloxy-24,25,26-trihydroxy（15）,3β-acetylo xylanosta-7,9（11）,24E-trien-26-oic acid（16）,27-nor-3β-hydroxylanosta-7,9（11）,23E-trien-25-one（17）,24-epi alismanol D（18）,3β,15α,26-trihydroxylanosta-7,9（11）,24E-triene（19）,5α-lanosta-7,9（11）,24E-triene-15α-26-dihydroxy-3-one（20）,3β-hy droxylup-20（29）-en-28-oic acid（betulinic acid）（21）,（24R）-6,9-epoxy-ergosta-7,22E-dien-3β-ol（22）,3β,5α,9α-trihydroxy-（24R）-ergosta-7,22E-dien-6-one（23）,3β,5α-dihydroxy-（24R）-ergosta-7,22E-dien-6-one（24）,（24R）-ergosta-8,22E-dien-3β,5α,6β,7α-tetraol（25）,5α,6α-epoxy-（24R）-ergosta-8（14）,22E-diene-3β,7α-diol（26）,（24R）-ergosta-7,22E-dien-3β,5α-diol-6,5-olide（27）,3β,5α,9α,14α-tetrahydroxy-（24R）-e rgosta-7,22E-dien-6-one（28）,（24R）-5α,8α-epidioxyergosta-6,22E-dien-3β-ol（29）,（24S）-ergosta-7,22E-dien-3β,5α,6β,9-tetraol（30）,（24S）-ergosta-7,22E-dien-3β,5α,6β-triol（31）,（1H-indol-3-yl）oxoacetamide（32）,3-hydroxy-2-methoxy-5,6-dimethyl benzoic acid（33）,and p-hydroxy benzoic acid methyl ester（34）.The above co mpounds were isolated from wild G.weberianum for the first time,among whi ch compounds 1-12 were new lanostane-type triterpenes.The antitumor activity,liver glucose inhibitory activity and anti-inflammatory activity of the compounds were detected by MTT method,theα-glucosidase inhibitory activity of the compounds was detected by p-NPG method,and the modified Ellman assay was used to detect the acetylcholinesterase inhibitory activity.The mechanisms of action of hypoglycemic activity were studied.Six compounds were found to have certain cytotoxic activity.Compounds 1 and 3 were cytotoxic to He La cell line with IC₅₀values of 31.6μM and 17.0μM,respectively.Compound 21showed cytotoxicity against the SGC-7901 cell line with an IC₅₀value of 45.6μM.Compound 28 was active against He La and SGC-7901 cell lines with IC₅₀values of6.8μM and 22.3μM,respectively.Compounds 3 and 6 significantly inhibited glucagon-induced hepatic glucose production in Hep G2 cells with EC₅₀values of 42.0and 85.9μM,respectively.Further studies on the mechanism of action showed that compounds 3 and 6 inhibited hepatic glucose production by inhibiting glucagon-induced c AMP accumulation.Compared with the positive control acarbose with IC₅₀value of 304.6μM,compounds 2,7,16,17 and 21 showed significantα-glucosidase inhibitory activity with IC₅₀values of 35.3μM-223.4Μm.Kinetic studies showed that the most potent compound 16 and 21 were a mixed-type inhibitor ofα-glucosidase.Furthermore,molecular docking simulations revealed the interaction of 16,17 and 21 withα-glucosidase.The results of structural-activity relationship analysis,enzyme kinetics and molecular docking model showed that triterpenoids containing carbonyl or carboxyl groups play an important role in enhancing the inhibitory activity ofα-glucosidase.Compound 8 showed moderate anti-inflammatory activity with IC₅₀value of 40.71μM（positive control quercetin:11.02μM）.All compounds showed very weak inhibitory activity against acetylcholinesterase.