A new flavan named 4α; 5-dimethoxy-8-formyl-7-hydroxy-6-methylflavan （1） was isolated from Sinacalia tangutica. Its structure was determined using spectroscopic methods and X-ray diffraction experiments.
A new flavan-3-ol glucoside, (-)-afzelechin-7-O-β-D-glucopyranoside (1), has been isolated from the stem of Daphniphyllum oldhami. The structure of the new compound was elucidated on the basis of detailed spectroscop...A new flavan-3-ol glucoside, (-)-afzelechin-7-O-β-D-glucopyranoside (1), has been isolated from the stem of Daphniphyllum oldhami. The structure of the new compound was elucidated on the basis of detailed spectroscopie analysis and comparison with related compounds.展开更多
Two new compounds 7-hydroxy-5-O-（β-D-glucopyranoside） flavan （1） and （Z）-4＇,6＇-dihydroxy-2＇-O-（β-D-glucopyranoside） chalcone （2）, along with eight known compounds, were isolated from the stem bark of Dr...Two new compounds 7-hydroxy-5-O-（β-D-glucopyranoside） flavan （1） and （Z）-4＇,6＇-dihydroxy-2＇-O-（β-D-glucopyranoside） chalcone （2）, along with eight known compounds, were isolated from the stem bark of Drypetes parvifolia （Euphorbiaceae）. Their structures were established on the basis of spectroscopic analysis and chemical evidence.展开更多
Objective Flavans are a set of naturally occurring flavonoids possessing a 2-phenylchroman nucleus,which are widely distributed in the plant kingdom.A number of flavan compounds exhibit antitumor activities.In our pre...Objective Flavans are a set of naturally occurring flavonoids possessing a 2-phenylchroman nucleus,which are widely distributed in the plant kingdom.A number of flavan compounds exhibit antitumor activities.In our previous report,a straightforward synthetic procedure for 2(±)-7,8,3',4',5'-pentamethoxyflavan(PMF)was developed.To be more important,PMF showed growth inhibitory effect on various human tumor cell lines,especially against HL60 cells.In the present study,we aim to investigate the molecular mechanisms of action of PMF in HL60 cells.This is the first report of the molecular mechanisms on anti-tumor effect of flavan compounds.Methods Trypan blue exclusion experiment was used for cell growth inhibition assay.Cell apoptosis,cell cycle distribution and the mitochondrial membrane potential(MMP)were assessed by flowcytometric analysis after AO/EB,PI and Rh123 flurescence staining,respectively.Cell cycle-and apoptosis-related proteins were detected using western blotting analysis.Results PMF(1-30 μM)inhibited the growth of HL60 cells in a time-and concentration-dependent manner.Antiproliferative effect of PMF on HL60 cells was associated with G2/M cell cycle arrest,which was mediated by regulating the expression of p21,Cdc25C and cyclin A proteins and inhibiting the phosphorylation of Cdc2 at Thr161.The prolonged PMF treatment also induced apoptosis of HL60 cells,which was characterized by DNA fragmentation,cleavage of poly(ADP-ribose)polymerase,caspase-3,caspase-8 and caspase-9,changes of Bcl-2 and Bax expression and a decrease in the mitochondrial membrane potential(MMP).Furthermore,caspase-3 inhibitor,not caspase-8 inhibitor and caspase-9 inhibitor,completely blocked PMF-caused apoptosis.Conclusions PMF inhibited the growth of HL60 cells via induction of G2/M arrest and apoptosis.Blockade of cell cycle was associated with the downregulation of Cdc2 complex activity.Both death receptor and mitochondrial apoptotic pathways explained PMF-caused apoptosis.展开更多
A convenient cyclization method for the flavans synthesis is described. BF3 was used for the first time as an efficient catalyst to effect the cyclization of 1,3-diarylpropan-1-ols.
Objective To study the chemical constituents of Pronephrium triphyllum.Methods The chemical constituents in the plant were isolated and purified with silica gel and Sephadex LH-20.Their structures were identified by a...Objective To study the chemical constituents of Pronephrium triphyllum.Methods The chemical constituents in the plant were isolated and purified with silica gel and Sephadex LH-20.Their structures were identified by analyses of spectral data and physicochemical properties.Results Six compounds were isolated and identified as shelincaoide A(1),n-butyl-β-D-fructopyranoside(2),triphyllin A(3),6,7-di-hydroxycoumarin(4),daucosterol(5),and β-sitosterol(6),respectively.Conclusion Compound 1 is found to be a new compound.Compounds 2 and 4 are firstly isolated from the plants in Pronephrium Presl.and all compounds except 3 are obtained from the species for the first time.展开更多
An efficient and feasible synthetic approach was developed for the synthesis of an array of new flavane derivafives from the substituted benzaldehyde with the reduction of chalcones and subsequent cyclization as the k...An efficient and feasible synthetic approach was developed for the synthesis of an array of new flavane derivafives from the substituted benzaldehyde with the reduction of chalcones and subsequent cyclization as the key steps. The purity and structure of the products were confirmed by the elemental analysis and a combination of its IR, ^1H and ^13C NMR, and mass spectra. These synthetic compounds were tested for xanthine oxidase （XO） inhibitions and antifungal actions against Candida albicans, Cryptococcus neoformans, Aspergillus sp. and Trichophyton rubrum. 7-Hydrazinocarbonylmethoxy-4＇-methoxyflavane （9） was found to be the most XO inhibitory with IC50=76.4 μmol/L, and the most potent antifungal compound was 4＇-hydrazinocarbonylmethoxyflavane （12） with minimal inhibition concentration MIC=8 μg/mL against Trichophyton rubrum.展开更多
Aim To investigate the chemical constituents from the twigs and leaves of Pithecellobium clypearia Benth and their immunomodulatory effects. Methods The constituents were separated and purified by various chromatograp...Aim To investigate the chemical constituents from the twigs and leaves of Pithecellobium clypearia Benth and their immunomodulatory effects. Methods The constituents were separated and purified by various chromatographic methods and their structures were identified on the basis of spectral analysis. The immufiomodulatory effects of all the compounds were examined by a Con A-induced T lymphocytes proliferation assay. Results Eight compounds were isolated and identified as （-）- epigallocatechin （1）, （-）-5, 7, 3′, 4′, 5′-pentahydroxyflavan （2）, （-）-epigallocatechin-7-gallate （3）, （-）-5, 3′, 4′, 5′-tetrahydroxyfiavan- 7-gallate （4）, quercitin-3-O-α-L-rhamnpyranoside （5）, myricitin-3-O-α-L-rhamnpyranoside （6）, gallic acid （7）, and ethyl gallate （8）, respectively. Conclusion Compounds 3 and 8 were isolated from this genus for the first time, and compound 1 was isolated from this species for the first time. Compound 3 exhibited a strong inhibition on the T lymphocytes proliferation induced by Con A with an IC50 of 4.4 μmol·L^-1.展开更多
Stomach and colorectal cancers are common cancers and leading causes of cancer deaths.Because the alimentary tract can interact directly with dietary components,stomach and colorectal cancer may be closely related to ...Stomach and colorectal cancers are common cancers and leading causes of cancer deaths.Because the alimentary tract can interact directly with dietary components,stomach and colorectal cancer may be closely related to dietary intake.We systematically searched published literature written in English via PubMed by searching for terms related to stomach and colorectal cancer risk and dietary flavonoids up to June 30,2012.Twenty-three studies out of 209 identified articles were finally selected for the analysis.Log point effect estimates and the corresponding standard errors were calculated using covariate-adjusted point effect estimates and 95%CIs from the selected studies.Total dietary flavonoid intake was not associated with a reduced risk of colorectal or stomach cancer [odds ratio(OR)(95%CI) = 1.00(0.90-1.11) and 1.07(0.70-1.61),respectively].Among flavonoid subclasses,the intake of flavonols,flavan-3-ols,anthocyanidins,and proanthocyanidins showed a significant inverse association with colorectal cancer risk [OR(95%CI) = 0.71(0.63-0.81),0.88(0.79-0.97),0.68(0.56-0.82),and 0.72(0.61-0.85),respectively].A significant association was found only between flavonols and stomach cancer risk based on a limited number of selected studies [OR(95%CI) = 0.68(0.46-0.99)].In the summary estimates from casecontrol studies,all flavonoid subclasses except flavones and flavanones were inversely associated with colorectal cancer risk,whereas neither total flavonoids nor any subclasses of flavonoids were associated with colorectal cancer risk in the summary estimates based on the cohort studies.The significant association between flavonoid subclasses and cancer risk might be closely related to bias derived from the case-control design.There was no clear evidence that dietary flavonoids are associated with reduced risk of stomach and colorectal cancer.展开更多
文摘A new flavan named 4α; 5-dimethoxy-8-formyl-7-hydroxy-6-methylflavan （1） was isolated from Sinacalia tangutica. Its structure was determined using spectroscopic methods and X-ray diffraction experiments.
文摘A new flavan-3-ol glucoside, (-)-afzelechin-7-O-β-D-glucopyranoside (1), has been isolated from the stem of Daphniphyllum oldhami. The structure of the new compound was elucidated on the basis of detailed spectroscopie analysis and comparison with related compounds.
基金One of the authors(J.Wandji)is grateful for grant(No.F/2624-3F)from the International Foundation for Science(Sweden)the sponsorship of the"UniversitéParis Descartes,France"during his multiple research visits in Paris.
文摘Two new compounds 7-hydroxy-5-O-（β-D-glucopyranoside） flavan （1） and （Z）-4＇,6＇-dihydroxy-2＇-O-（β-D-glucopyranoside） chalcone （2）, along with eight known compounds, were isolated from the stem bark of Drypetes parvifolia （Euphorbiaceae）. Their structures were established on the basis of spectroscopic analysis and chemical evidence.
文摘Objective Flavans are a set of naturally occurring flavonoids possessing a 2-phenylchroman nucleus,which are widely distributed in the plant kingdom.A number of flavan compounds exhibit antitumor activities.In our previous report,a straightforward synthetic procedure for 2(±)-7,8,3',4',5'-pentamethoxyflavan(PMF)was developed.To be more important,PMF showed growth inhibitory effect on various human tumor cell lines,especially against HL60 cells.In the present study,we aim to investigate the molecular mechanisms of action of PMF in HL60 cells.This is the first report of the molecular mechanisms on anti-tumor effect of flavan compounds.Methods Trypan blue exclusion experiment was used for cell growth inhibition assay.Cell apoptosis,cell cycle distribution and the mitochondrial membrane potential(MMP)were assessed by flowcytometric analysis after AO/EB,PI and Rh123 flurescence staining,respectively.Cell cycle-and apoptosis-related proteins were detected using western blotting analysis.Results PMF(1-30 μM)inhibited the growth of HL60 cells in a time-and concentration-dependent manner.Antiproliferative effect of PMF on HL60 cells was associated with G2/M cell cycle arrest,which was mediated by regulating the expression of p21,Cdc25C and cyclin A proteins and inhibiting the phosphorylation of Cdc2 at Thr161.The prolonged PMF treatment also induced apoptosis of HL60 cells,which was characterized by DNA fragmentation,cleavage of poly(ADP-ribose)polymerase,caspase-3,caspase-8 and caspase-9,changes of Bcl-2 and Bax expression and a decrease in the mitochondrial membrane potential(MMP).Furthermore,caspase-3 inhibitor,not caspase-8 inhibitor and caspase-9 inhibitor,completely blocked PMF-caused apoptosis.Conclusions PMF inhibited the growth of HL60 cells via induction of G2/M arrest and apoptosis.Blockade of cell cycle was associated with the downregulation of Cdc2 complex activity.Both death receptor and mitochondrial apoptotic pathways explained PMF-caused apoptosis.
文摘A convenient cyclization method for the flavans synthesis is described. BF3 was used for the first time as an efficient catalyst to effect the cyclization of 1,3-diarylpropan-1-ols.
基金Science and Technology Project of Zhongshan,China (20071A036)
文摘Objective To study the chemical constituents of Pronephrium triphyllum.Methods The chemical constituents in the plant were isolated and purified with silica gel and Sephadex LH-20.Their structures were identified by analyses of spectral data and physicochemical properties.Results Six compounds were isolated and identified as shelincaoide A(1),n-butyl-β-D-fructopyranoside(2),triphyllin A(3),6,7-di-hydroxycoumarin(4),daucosterol(5),and β-sitosterol(6),respectively.Conclusion Compound 1 is found to be a new compound.Compounds 2 and 4 are firstly isolated from the plants in Pronephrium Presl.and all compounds except 3 are obtained from the species for the first time.
基金Project supported by the Key Project of the Ministry of Education of China （No. 03013）, the National Natural Science Foundation of China （No. 20372010） and Trans-century Training Program Foundation for the Talents, Ministry of Education of China and Chinese Academy of Medical Sciences.
文摘An efficient and feasible synthetic approach was developed for the synthesis of an array of new flavane derivafives from the substituted benzaldehyde with the reduction of chalcones and subsequent cyclization as the key steps. The purity and structure of the products were confirmed by the elemental analysis and a combination of its IR, ^1H and ^13C NMR, and mass spectra. These synthetic compounds were tested for xanthine oxidase （XO） inhibitions and antifungal actions against Candida albicans, Cryptococcus neoformans, Aspergillus sp. and Trichophyton rubrum. 7-Hydrazinocarbonylmethoxy-4＇-methoxyflavane （9） was found to be the most XO inhibitory with IC50=76.4 μmol/L, and the most potent antifungal compound was 4＇-hydrazinocarbonylmethoxyflavane （12） with minimal inhibition concentration MIC=8 μg/mL against Trichophyton rubrum.
文摘Aim To investigate the chemical constituents from the twigs and leaves of Pithecellobium clypearia Benth and their immunomodulatory effects. Methods The constituents were separated and purified by various chromatographic methods and their structures were identified on the basis of spectral analysis. The immufiomodulatory effects of all the compounds were examined by a Con A-induced T lymphocytes proliferation assay. Results Eight compounds were isolated and identified as （-）- epigallocatechin （1）, （-）-5, 7, 3′, 4′, 5′-pentahydroxyflavan （2）, （-）-epigallocatechin-7-gallate （3）, （-）-5, 3′, 4′, 5′-tetrahydroxyfiavan- 7-gallate （4）, quercitin-3-O-α-L-rhamnpyranoside （5）, myricitin-3-O-α-L-rhamnpyranoside （6）, gallic acid （7）, and ethyl gallate （8）, respectively. Conclusion Compounds 3 and 8 were isolated from this genus for the first time, and compound 1 was isolated from this species for the first time. Compound 3 exhibited a strong inhibition on the T lymphocytes proliferation induced by Con A with an IC50 of 4.4 μmol·L^-1.
文摘Stomach and colorectal cancers are common cancers and leading causes of cancer deaths.Because the alimentary tract can interact directly with dietary components,stomach and colorectal cancer may be closely related to dietary intake.We systematically searched published literature written in English via PubMed by searching for terms related to stomach and colorectal cancer risk and dietary flavonoids up to June 30,2012.Twenty-three studies out of 209 identified articles were finally selected for the analysis.Log point effect estimates and the corresponding standard errors were calculated using covariate-adjusted point effect estimates and 95%CIs from the selected studies.Total dietary flavonoid intake was not associated with a reduced risk of colorectal or stomach cancer [odds ratio(OR)(95%CI) = 1.00(0.90-1.11) and 1.07(0.70-1.61),respectively].Among flavonoid subclasses,the intake of flavonols,flavan-3-ols,anthocyanidins,and proanthocyanidins showed a significant inverse association with colorectal cancer risk [OR(95%CI) = 0.71(0.63-0.81),0.88(0.79-0.97),0.68(0.56-0.82),and 0.72(0.61-0.85),respectively].A significant association was found only between flavonols and stomach cancer risk based on a limited number of selected studies [OR(95%CI) = 0.68(0.46-0.99)].In the summary estimates from casecontrol studies,all flavonoid subclasses except flavones and flavanones were inversely associated with colorectal cancer risk,whereas neither total flavonoids nor any subclasses of flavonoids were associated with colorectal cancer risk in the summary estimates based on the cohort studies.The significant association between flavonoid subclasses and cancer risk might be closely related to bias derived from the case-control design.There was no clear evidence that dietary flavonoids are associated with reduced risk of stomach and colorectal cancer.
