This study was conducted to investigate the chemical constituents of Piper wallichii(Miq.) Hand.-Mazz. and evaluate their biological activity. Compounds were isolated by various column chromatographic methods, and the...This study was conducted to investigate the chemical constituents of Piper wallichii(Miq.) Hand.-Mazz. and evaluate their biological activity. Compounds were isolated by various column chromatographic methods, and their structures were elucidated on the basis of physical characteristics and spectral data. The 1, 1-diphenyl-2-picrylhydrazyl(DPPH)-scavenging activity and acetylcholinesterase(AChE)-inhibitory activity of the compounds were evaluated. Five compounds were obtained and identified as 8-C-β-D-glucopyranosylkaempferol-3-O-β-D-glucopyranoside(1), 1, 2-dihydro-6,8-dimethoxy-7-hydroxy-1-(3, 5-dimethoxy-4-hydroxyphenyl)-N1, N2-bis-[2-(4-hydroxyphenyl)ethyl]-2, 3-naphthalene dicarboxamide(2), goniothalactam(3), aristololactam A IIIa(4) and piperlonguminine(5). Compound 1 was a new flavonol C-glycoside, 2 was a rare lignanamide, which was isolated from the family Piperaceae for the first time, and compound 3 was isolated from this plant for the first time. Among them, 2 showed potent DPPH-scavenging activity, with IC50 of 31.38 ± 0.97 μmol·L-1; Compounds 2, 3, and 4 showed AChE inhibitory activity at 100 μmol·L-1, with inhibition rates of 28.57% ± 1.47%, 18.48% ± 2.41% and 17.4% ± 3.03%, respectively.展开更多
A new isoprenylated flavonol, named broussonol A (1) was isolated from the leaves of Broussonetia kazinoki Sieb. The structure of broussonol A was characterized by chemical and spectral methods.
A new flavonol glycoside, isorhamnetin-3-O-b-D-xyloside, was isolated from the extract of leaves and twigs of Alchornea davidii (Euphorbiaceae). Its structure was established on the basis of the spectral analysis and ...A new flavonol glycoside, isorhamnetin-3-O-b-D-xyloside, was isolated from the extract of leaves and twigs of Alchornea davidii (Euphorbiaceae). Its structure was established on the basis of the spectral analysis and chemical degradation. Antimicrobial assay showed that it moderately inhibited the growth of test bacteria (Staphylococcus aureus, Bacillus subtilis and Pseudomonas fluorescens) and fungi (Candida albicans, Aspergillus niger and Trichophyton rubrum) with MICs at 50 g/mL.展开更多
A new flavonol glycoside, named neosmitilbin was isolated form the rhizome of Smilax glabra. Its structure and absolute configuration were elucidated on the basis of spectroscopic studies.
Three new flavonol glycosides were isolated from the leaves of Helicia nilagirica Beed.. The structures were elucidated as kaempferol-3-O-b-D-xylopyranosyl-(16)-b-D-glyco- pyranosyl-(12)-a-L-rhamnopyranoside, querce...Three new flavonol glycosides were isolated from the leaves of Helicia nilagirica Beed.. The structures were elucidated as kaempferol-3-O-b-D-xylopyranosyl-(16)-b-D-glyco- pyranosyl-(12)-a-L-rhamnopyranoside, quercetin-3-O-b-D-xylopyranosyl-(16)-b-D-glycopy- ranosyl-(12)-[-b-D-xylopyranosyl-(14)]-a-L-rhamnopyranoside, and quercetin-3-O-b-D- xylopyranosyl-(16)-b-D-glycopyranosyl-(12)-a-L-rhamnopyranoside, named as Helicianeoside A、B and C, respectively.展开更多
The cell cycle checkpoint system play a pivotal role in the cellular DNA damage response, and the discovery of checkpoint inhibitors is expected to sensitize current cancer therapies. Checkpoint signaling cascades are...The cell cycle checkpoint system play a pivotal role in the cellular DNA damage response, and the discovery of checkpoint inhibitors is expected to sensitize current cancer therapies. Checkpoint signaling cascades are critically modulated by ATM (ataxia telangiectasia-mutated) and its related molecules. Generally, ATM primarily responds to ionizing irradiation-induced DNA double-strand breaks. Heavy ions from an accelerated carbon ion beam have been used to cure cancer because they are more effective than ionizing irradiation such as X-ray and γ-radiation in terms of biological damage. In a previous study, we demonstrated that a persimmon leaf flavonol (PLF) promoted the cytotoxic effect of chemotherapeutic agents on cancer cells through inhibition of checkpoint activities, especially in the ATM dependent pathway. The present study investigated whether PLF inhibits checkpoint activity during the DNA damage response induced by heavy ion irradiation. Treatment with PLF significantly increased the cytotoxicity of heavy ion irradiation in A549 adenocarcinoma cells. The phosphorylation of checkpoint proteins such as p53, SMC1, and Chk1 was increased by heavy ions. PLF reduced the phosphorylation of checkpoint proteins. Pre-treatment with PLF significantly prevented the decrease of mitotic cells in heavy ion-exposed cells. We further evaluated tumor volume in SCID mice inoculated with human lung adenocarcinoma A549 cells. The combination treatment of PLF and heavy ion resulted in a decrease of tumor volume compared with controls, although PLF itself did not exhibit any effect. These results indicate that PLF inhibits tumor growth through modulation of the DNA damage response. PLF may be useful for clinical application in combination with heavy ion radiotherapy.展开更多
Two new diacetylated flavonol glycosides, kampferol-3-O--3? 6?diacetylglucopyrano- side and quercetin-3-O--3? 6?diacetylglucopyranoside were isolated from knoxia corymbosa. Their structures were elucidated by spectro...Two new diacetylated flavonol glycosides, kampferol-3-O--3? 6?diacetylglucopyrano- side and quercetin-3-O--3? 6?diacetylglucopyranoside were isolated from knoxia corymbosa. Their structures were elucidated by spectroscopic evidents.展开更多
Two new flavonol glycosides, tamarixetin 3-O-β-D-xylopyranosyl-（1-2）-α-L-ribopyranoside （1） and tamarixetin 3-O-α-L-ribopyranoside （2） were isolated from the leaves of Bridelia tomentosa. Their structures wer...Two new flavonol glycosides, tamarixetin 3-O-β-D-xylopyranosyl-（1-2）-α-L-ribopyranoside （1） and tamarixetin 3-O-α-L-ribopyranoside （2） were isolated from the leaves of Bridelia tomentosa. Their structures were elucidated by 1D and 2D NMR analysis, as well as MS and IR spectra.展开更多
A new prenylated flavonol, maackiaflavonol, was isolated from the ethanol extract of the roots of Maackia tenuifolia. Its structure was elucidated as 7-hydrox-8-prenylflavonol by means of spectroscopic analysis (UV, I...A new prenylated flavonol, maackiaflavonol, was isolated from the ethanol extract of the roots of Maackia tenuifolia. Its structure was elucidated as 7-hydrox-8-prenylflavonol by means of spectroscopic analysis (UV, IR, MS, NMR and 1H-1H COSY) and confirmed by total synthesis.展开更多
A new benzofuranolignan austrafuran A （1） and a new flavonol derivative 5,7,2′,4′-tetrahydroxy-3-methoxyflavone （2） were isolated from the stem of Morus australis. Their structures were determined on the basis o...A new benzofuranolignan austrafuran A （1） and a new flavonol derivative 5,7,2′,4′-tetrahydroxy-3-methoxyflavone （2） were isolated from the stem of Morus australis. Their structures were determined on the basis of spectroscopic evidences.展开更多
Flavonols were extracted from Acanthopanax Senticosus Harms by Soxhlet extraction（SE）,atmospheric pressure microwave-assisted extraction（AMAE） and pressurized microwave-assisted extraction（PMAE）.The influences o...Flavonols were extracted from Acanthopanax Senticosus Harms by Soxhlet extraction（SE）,atmospheric pressure microwave-assisted extraction（AMAE） and pressurized microwave-assisted extraction（PMAE）.The influences of experimental conditions,such as concentration of ethanol in the eluent,microwave irradiation time,etc.on the extraction yield were studied.Four flavonols（hyperin,rutin,quercitrin and quercetin） in the extracts were determined quantitatively by HPLC method.The experimental results demonstrate the advantages of PMAE and AMAE over those of conventional SE,that is the extraction time is dramatically reduced,and the yields of flavonols are effective improved.Although the yield of flavonols is higher and the extraction time is shorter by PMAE than those of AMAE,flavonols are easy to be decomposed over a certain time.展开更多
A new flavonol oligosaccharide, quercetin-3-O-[b-D-xylopyranosyl-(12)- a-L-rhamnopyranosyl-(16)]-b-D-glucopyranoside-3-O-b-D-glucopyranoside, named aescuflavoside was isolated from Aesculus chinensis. Its structure w...A new flavonol oligosaccharide, quercetin-3-O-[b-D-xylopyranosyl-(12)- a-L-rhamnopyranosyl-(16)]-b-D-glucopyranoside-3-O-b-D-glucopyranoside, named aescuflavoside was isolated from Aesculus chinensis. Its structure was elucidated by spectra FAB-MS, 1D NMR and 2D NMR including 1H NMR, 13C NMR, HMQC and HMBC techniques.展开更多
The enthalpies of bond dissociations of the hydroxyl groups, the energy of the highest occupied molecular orbitals and the corresponding radicals spin densities of all possible ten isomeric mono-hydroxyl flavones are ...The enthalpies of bond dissociations of the hydroxyl groups, the energy of the highest occupied molecular orbitals and the corresponding radicals spin densities of all possible ten isomeric mono-hydroxyl flavones are calculated by means of 3-parameter Becke, Lee, Yang and Parr functional. The structural factors affecting these descriptors of radical-scavenging activity are outlined. The results obtained show that the hydroxyl groups in ring A and C are more involved in the process of a radical-capturing than recently believed.展开更多
One new prenylated flavonol, 7,8-(2'',2'' -dimethylpyrano)-5,3',4'-trihydroxy-3-methoxyflavone was isolated from Hypericum japonicum. The chemical structure was determined by spectroscopic meth...One new prenylated flavonol, 7,8-(2'',2'' -dimethylpyrano)-5,3',4'-trihydroxy-3-methoxyflavone was isolated from Hypericum japonicum. The chemical structure was determined by spectroscopic methods.展开更多
基金supported by the National Natural Science Foundation of China(Nos.30271647,81073005)Shandong Province Young and Middle-Aged Scientists Research Awards Fund(No.BS2010YY032)Scientific Research Foundation for the Returned Overseas Chinese Scholars,State Education Ministry in China(No.42)
文摘This study was conducted to investigate the chemical constituents of Piper wallichii(Miq.) Hand.-Mazz. and evaluate their biological activity. Compounds were isolated by various column chromatographic methods, and their structures were elucidated on the basis of physical characteristics and spectral data. The 1, 1-diphenyl-2-picrylhydrazyl(DPPH)-scavenging activity and acetylcholinesterase(AChE)-inhibitory activity of the compounds were evaluated. Five compounds were obtained and identified as 8-C-β-D-glucopyranosylkaempferol-3-O-β-D-glucopyranoside(1), 1, 2-dihydro-6,8-dimethoxy-7-hydroxy-1-(3, 5-dimethoxy-4-hydroxyphenyl)-N1, N2-bis-[2-(4-hydroxyphenyl)ethyl]-2, 3-naphthalene dicarboxamide(2), goniothalactam(3), aristololactam A IIIa(4) and piperlonguminine(5). Compound 1 was a new flavonol C-glycoside, 2 was a rare lignanamide, which was isolated from the family Piperaceae for the first time, and compound 3 was isolated from this plant for the first time. Among them, 2 showed potent DPPH-scavenging activity, with IC50 of 31.38 ± 0.97 μmol·L-1; Compounds 2, 3, and 4 showed AChE inhibitory activity at 100 μmol·L-1, with inhibition rates of 28.57% ± 1.47%, 18.48% ± 2.41% and 17.4% ± 3.03%, respectively.
文摘A new isoprenylated flavonol, named broussonol A (1) was isolated from the leaves of Broussonetia kazinoki Sieb. The structure of broussonol A was characterized by chemical and spectral methods.
基金supported by the National Natural Science Foundation (No. 39970083).
文摘A new flavonol glycoside, isorhamnetin-3-O-b-D-xyloside, was isolated from the extract of leaves and twigs of Alchornea davidii (Euphorbiaceae). Its structure was established on the basis of the spectral analysis and chemical degradation. Antimicrobial assay showed that it moderately inhibited the growth of test bacteria (Staphylococcus aureus, Bacillus subtilis and Pseudomonas fluorescens) and fungi (Candida albicans, Aspergillus niger and Trichophyton rubrum) with MICs at 50 g/mL.
文摘A new flavonol glycoside, named neosmitilbin was isolated form the rhizome of Smilax glabra. Its structure and absolute configuration were elucidated on the basis of spectroscopic studies.
文摘Three new flavonol glycosides were isolated from the leaves of Helicia nilagirica Beed.. The structures were elucidated as kaempferol-3-O-b-D-xylopyranosyl-(16)-b-D-glyco- pyranosyl-(12)-a-L-rhamnopyranoside, quercetin-3-O-b-D-xylopyranosyl-(16)-b-D-glycopy- ranosyl-(12)-[-b-D-xylopyranosyl-(14)]-a-L-rhamnopyranoside, and quercetin-3-O-b-D- xylopyranosyl-(16)-b-D-glycopyranosyl-(12)-a-L-rhamnopyranoside, named as Helicianeoside A、B and C, respectively.
文摘The cell cycle checkpoint system play a pivotal role in the cellular DNA damage response, and the discovery of checkpoint inhibitors is expected to sensitize current cancer therapies. Checkpoint signaling cascades are critically modulated by ATM (ataxia telangiectasia-mutated) and its related molecules. Generally, ATM primarily responds to ionizing irradiation-induced DNA double-strand breaks. Heavy ions from an accelerated carbon ion beam have been used to cure cancer because they are more effective than ionizing irradiation such as X-ray and γ-radiation in terms of biological damage. In a previous study, we demonstrated that a persimmon leaf flavonol (PLF) promoted the cytotoxic effect of chemotherapeutic agents on cancer cells through inhibition of checkpoint activities, especially in the ATM dependent pathway. The present study investigated whether PLF inhibits checkpoint activity during the DNA damage response induced by heavy ion irradiation. Treatment with PLF significantly increased the cytotoxicity of heavy ion irradiation in A549 adenocarcinoma cells. The phosphorylation of checkpoint proteins such as p53, SMC1, and Chk1 was increased by heavy ions. PLF reduced the phosphorylation of checkpoint proteins. Pre-treatment with PLF significantly prevented the decrease of mitotic cells in heavy ion-exposed cells. We further evaluated tumor volume in SCID mice inoculated with human lung adenocarcinoma A549 cells. The combination treatment of PLF and heavy ion resulted in a decrease of tumor volume compared with controls, although PLF itself did not exhibit any effect. These results indicate that PLF inhibits tumor growth through modulation of the DNA damage response. PLF may be useful for clinical application in combination with heavy ion radiotherapy.
文摘Two new diacetylated flavonol glycosides, kampferol-3-O--3? 6?diacetylglucopyrano- side and quercetin-3-O--3? 6?diacetylglucopyranoside were isolated from knoxia corymbosa. Their structures were elucidated by spectroscopic evidents.
文摘Two new flavonol glycosides, tamarixetin 3-O-β-D-xylopyranosyl-（1-2）-α-L-ribopyranoside （1） and tamarixetin 3-O-α-L-ribopyranoside （2） were isolated from the leaves of Bridelia tomentosa. Their structures were elucidated by 1D and 2D NMR analysis, as well as MS and IR spectra.
文摘A new prenylated flavonol, maackiaflavonol, was isolated from the ethanol extract of the roots of Maackia tenuifolia. Its structure was elucidated as 7-hydrox-8-prenylflavonol by means of spectroscopic analysis (UV, IR, MS, NMR and 1H-1H COSY) and confirmed by total synthesis.
基金the National Natural Science Foundation of China(No.2042030 and 20572133)for financial support.
文摘A new benzofuranolignan austrafuran A （1） and a new flavonol derivative 5,7,2′,4′-tetrahydroxy-3-methoxyflavone （2） were isolated from the stem of Morus australis. Their structures were determined on the basis of spectroscopic evidences.
文摘Flavonols were extracted from Acanthopanax Senticosus Harms by Soxhlet extraction（SE）,atmospheric pressure microwave-assisted extraction（AMAE） and pressurized microwave-assisted extraction（PMAE）.The influences of experimental conditions,such as concentration of ethanol in the eluent,microwave irradiation time,etc.on the extraction yield were studied.Four flavonols（hyperin,rutin,quercitrin and quercetin） in the extracts were determined quantitatively by HPLC method.The experimental results demonstrate the advantages of PMAE and AMAE over those of conventional SE,that is the extraction time is dramatically reduced,and the yields of flavonols are effective improved.Although the yield of flavonols is higher and the extraction time is shorter by PMAE than those of AMAE,flavonols are easy to be decomposed over a certain time.
文摘A new flavonol oligosaccharide, quercetin-3-O-[b-D-xylopyranosyl-(12)- a-L-rhamnopyranosyl-(16)]-b-D-glucopyranoside-3-O-b-D-glucopyranoside, named aescuflavoside was isolated from Aesculus chinensis. Its structure was elucidated by spectra FAB-MS, 1D NMR and 2D NMR including 1H NMR, 13C NMR, HMQC and HMBC techniques.
文摘The enthalpies of bond dissociations of the hydroxyl groups, the energy of the highest occupied molecular orbitals and the corresponding radicals spin densities of all possible ten isomeric mono-hydroxyl flavones are calculated by means of 3-parameter Becke, Lee, Yang and Parr functional. The structural factors affecting these descriptors of radical-scavenging activity are outlined. The results obtained show that the hydroxyl groups in ring A and C are more involved in the process of a radical-capturing than recently believed.
文摘One new prenylated flavonol, 7,8-(2'',2'' -dimethylpyrano)-5,3',4'-trihydroxy-3-methoxyflavone was isolated from Hypericum japonicum. The chemical structure was determined by spectroscopic methods.
