The present study was designed to determine the major chemical constituents of the leaves of Rhododendron dauricum L. Compounds were isolated and purified by various chromatographic methods, and their structures were ...The present study was designed to determine the major chemical constituents of the leaves of Rhododendron dauricum L. Compounds were isolated and purified by various chromatographic methods, and their structures were elucidated by physicochemical properties and spectral data. The present study identified two new C-methyl flavanones, 5, 7, 3', 5'-tetrahydroxy-6, 8-di-C-methyl flavanone(1) and 5, 4'-dihydroxy-8-C-methylflavanone-7-O-β-D-glucopyranoside(2), and one new flavonoid glycoside, quercetin-3-O-β-D-(6''-O-cinnamoyl)-galactoside(3), along with seven known compounds, including syzalterin(4), poriolin(5), farrerol-7-O-β-D-glucopyranoside(6), myrciacetin(7), quercetin-3-O-β-D-(6-p-hydroxy-benzoyl)-galactoside(8), quercetin-3-O-β-D-(6-p-coumaroyl)-galactoside(9), and 5, 7, 3', 5'-tetrahydroxyl flavanone(10). Compounds 1-3 were determined to be new flavonoids; compounds 4-6 were isolated from this species for the first time; and compounds 7-10 were reported for the first time from this genus.展开更多
This study aims to verify the concept of niches at multiple spatial scales in plant communities.To this end,we analyzed the niche characteristic of Rhododendron dauricum plant communities in Northeast China at three s...This study aims to verify the concept of niches at multiple spatial scales in plant communities.To this end,we analyzed the niche characteristic of Rhododendron dauricum plant communities in Northeast China at three spatial scales.At the local scale,we calculated the Importance Value(IV)of species in five communities in the north of the Da Hinggan Mountains.At the intermediate scale,we examined five communities in their entirety,calculated the niche breadth of the species,and integrated niche overlap and interspecific association to analyze interspecific relationships.Further,the generalized additive model(GAM)was used to analyze the impact of topography and soil factors on niche characteristics.At the regional scale,we analyzed the geographical distribution of dominant species of R.dauricum plant communities in Northeast China and used principal component analysis(PCA)to analyze the impact of geographical and climate factors on species distribution.The results show that at the local scale,the IV of the species in each community varies widely.At the intermediate scale,species with a wide niche breadth tend to have a high value for IV.Larix gmelinii,Betula platyphylla,R.dauricum,Ledum palustre,and Vaccinium vitis-idaea had a relatively wide niche breadth and a high niche overlap,and the interspecific associations were almost all positive.Elevation and soil nutrients were the most dominant environmental factors.At the regional scale,species with a wide niche breadth tend to have a wide range of distribution,and temperature and precipitation were the most dominant environmental factors.This study suggests that the niche characteristics at three scales are both related and different.Niche characteristics at the local scale were various and labile,and niche characteristics at the intermediate and regional scales were relatively regular.These results show some degree of consistency with previous studies from an evolutionary perspective.The action mechanisms of these communities are related to differences in the dominant environmental factors.In addition,the integration of niche overlap and interspecific association determine interspecific relationships more accurately.展开更多
BACKGROUND： Recent studies have demonstrated that phenolic alkaloids from Menispermum dauricum （PAMD） can protect the heart and brain from ischemia/reperfusion injury, and promote neuron survival by inhibiting neur...BACKGROUND： Recent studies have demonstrated that phenolic alkaloids from Menispermum dauricum （PAMD） can protect the heart and brain from ischemia/reperfusion injury, and promote neuron survival by inhibiting neuronal Bax and upregulating Bcl-2 expression following ischemia/reperfusion. OBJECTIVE： To investigate the neuroprotective effects of PAMD versus exogenous melatonin against ischemia/reperfusion injury. DESIGN, TIME AND SETTING： Observation and comparison experiments at a cellular level were performed at the Department of Biochemistry and Molecular Biology, Tongji Medical College of Huazhong University of Science and Technology between February 2007 and February 2008. MATERIALS： PAMD （95% purity） was provided by Kunming Institute of Botany, Chinese Academy of Sciences; melatonin was provided by Sigma, USA. METHODS： N2a mouse neuroblastoma cells were cultured in vitro deprived of glucose, serum and oxygen for 90 minutes, then cultured in normal medium containing different concentrations of PAMD （0.1, 1.0, 10 mg/L） or melatonin （1, 10, and 100 μmol/L）. Cells cultured in normal conditions served as a control. MAIN OUTCOME MEASURES： The culture solution was collected to determine the content of ex- citatory neurotransmitters such as glutamic acid and aspartic acid; cell viability was detected by MTT methods; reactive oxygen species production was determined by fluorescence spectroscopy; mito- chondrial transmembrane potential （？Ψm） was detected by laser confocal scanning; cytochrome C was measured by western blotting; and caspase-3 activity was determined by visible spectropho- tometry. RESULTS： Melatonin and PAMD both promoted oxygen-glucose-serum deprivation-mediated N2a cell survival （P 〈 0.01） and inhibited glutamic acid release （P 〈 0.01）, but melatonin did not inhibit aspartic acid production. The protective effects were the strongest using melatonin 100 μmol/L and PAMD 10 mg/L, so subsequent experiments were the performed at those doses. Although PAMD could no longer maintain mitochondrial transmembrane potential 6 hours after reperfusion, its in- hibitory effects on cytochrome C release from mitochondria and scavengers of reactive oxygen species were stronger than those of melatonin （P 〈 0.01）. However, its inhibitory effect on caspase-3 activity was weaker than that of melatonin： PAMD could inhibit caspase-3 activity 12 hours after reperfusion （P 〈 0.01）, but melatonin inhibited caspase-3 activity 28 hours after reperfusion （P 〈 0.01）. CONCLUSION： The results show that melatonin and PAMD have neuroprotective effects, but that the mechanisms are varied. Melatonin can maintain mitochondrial transmembrane potential, but its inhibitory effects on cytochrome C release, caspase-3 activity, and reactive oxygen species scav-enging are different from those of PAMD.展开更多
A novel diterpenoid with an unprecedented 5/6/5/7 tetracyclic system, rhodauricanol A(1), five new grayanane-derived diterpenoids, dauricanols A-E(2-6), and five known ones(7-11) were isolated from the flowers of Rhod...A novel diterpenoid with an unprecedented 5/6/5/7 tetracyclic system, rhodauricanol A(1), five new grayanane-derived diterpenoids, dauricanols A-E(2-6), and five known ones(7-11) were isolated from the flowers of Rhododendron dauricum. Rhodauricanol A(1) possesses a unique 5/6/5/7 tetracyclic ring system featuring a 16-oxa-tetracyclo[11.2.1.0^(1,5).0^(7,13)]hexadecane core. Dauricanols A-C(2-4) are the first1,3-dioxolane conjugates of grayanane diterpenoids and 5-hydroxymethylfurfural and vanillin, respectively, and dauricanols D(5) and E(6) represent the first examples of 6-deoxy-1,5-seco-grayanane diterpenoids. Their structures were determined by spectroscopic methods, quantum chemical calculation including ^(13)C NMR-DP4+ analysis and ECD calculation, and single-crystal X-ray diffraction analysis. Plausible biosynthetic pathways for 1-4 were proposed. All the isolates showed significant analgesic activities,and dauricanols B(3) and C(4) showed more potent analgesic activities than the positive control, morphine.展开更多
The extract from leaves of Rhododendron dauricum L. was extracted with 95% alcohol by common method for studying its insecticidal activities. The chemical components of the alcohol extract and relative contents were a...The extract from leaves of Rhododendron dauricum L. was extracted with 95% alcohol by common method for studying its insecticidal activities. The chemical components of the alcohol extract and relative contents were analyzed by GC-MS. The insecticidal activities of the alcohol extract were tested on the 2nd？3rd instar larvae of Lymantria dispar L. for five days. Five concentrations of the extract samples were designed as 50, 10, 5, 1, and 0.5 g？L？1. The results show that the alcohol extracts from leaves of R. dauricum exhibited insecticidal activities against larvae of L. dispar. The corrected mortality of larvae of L. dispar for was over 50% for both contact toxicity and stomach toxicity at the extract concentration of ≥ 5 g·L？1 after five days of application. The insecticidal activity in contact toxicity is more effect than stomach toxicity for the alcohol extract. Twenty compounds, with total GC relative contents of 93.81% in the alcohol extract from leaves of R. dauricum were identified. The main chemical components in the extract are： （1） 4,5-Dihydro-5-oxo-3-（p-tolyl） isoxazole, with a relative content of 40.03%; （2） 1,3-Benzenediol, 5-methyl-2-（3,7,11-trimethyl-2,6,10- dodecatrienyl）-, （E,E）-, the relative content 18.27%; （3） 3,6-Diphenyl- 1,2,3,4,5,6,7,8-octahydro-1,8-acridinedione, the relative content 3.89%; （4） 6H-[1,2,4]Triazolo[1,5-a]indole, 4a,5,7,8,8a,9-hexahydro-9- methylene-, the relative content 2.99%; （5） 7-Amino-4-methyl-1,8- naphthyridin-2-ol, the relative content 2.64%; （6） 4-Methyl-2,6- dihydroxyquinoline, the relative content 2.63%; （7） 2,4,6- Triaminoquinazoline, the relative content 2.27%; （8） 2（1H）-Quinolinone, 4-hydroxy-1-methyl-, the relative content 2.02%.展开更多
Two pairs of novel 6/6/6/9 tetracyclic merosesquiterpenoid enantiomers,dauroxonanols A(1)and B(2),possessing an unprecedented 9,15-dioxatetracyclo[8.5.3.0^(4.17).0^(14.18)]octadecane core skeleton,were isolated from R...Two pairs of novel 6/6/6/9 tetracyclic merosesquiterpenoid enantiomers,dauroxonanols A(1)and B(2),possessing an unprecedented 9,15-dioxatetracyclo[8.5.3.0^(4.17).0^(14.18)]octadecane core skeleton,were isolated from Rhododendron dauricum.The nuclear magnetic resonance(NMR)spectra of 1 and 2 showed very broad resonances,and^(13)C NMR spectrum of 1 exhibited only 13 instead of 22 carbon resonances.These broadening or missing NMR resonances led to a great challenge to elucidate their structures using NMR data analysis.Their structures and absolute configurations of 1 and 2 were finally determined by single crystal X-ray diffraction analysis,chiral separation,and electronic circular dichroism(ECD)calculations.Plausible biosynthetic pathways for 1 and 2 are proposed.Conformational analysis,density functional theory(DFT)calculations,and dynamic NMR assigned the coalescent NMR phenomena of 1 and 2 to the conformational changes of the flexible oxonane ring.Dauroxonanols A(1)and B(2)showed potentα-glucosidase inhibitory activities,2-8 times potent than acarbose,an antidiabetic drug targetingα-glucosidase in clinic.展开更多
Kalmane diterpenoids,featuring a 5/8/5/5 tetracyclic carbon skeleton,are very rare in nature.The flowers of Rhododendron dauricum L.(Ericaceae)were phytochemically investigated for the first time,leading to the isolat...Kalmane diterpenoids,featuring a 5/8/5/5 tetracyclic carbon skeleton,are very rare in nature.The flowers of Rhododendron dauricum L.(Ericaceae)were phytochemically investigated for the first time,leading to the isolation of eight kalmane diterpenoids(1-8)including four new ones,named rhodokalmanols A-D(1-4).The structures of 1-8 were elucidated by comprehensive spectroscopic methods and ic NMR-DP4+analysis,and the absolute configurations of 1,2,4,and 5 were defined by single-crystal X-ray diffraction analysis with Cu Kαradiation.Rhodokalmanol A(1)represents the first 5,8-epoxykalmane diterpenoid and also the first kalm-15(16)-ene diterpenoid.Rhodokalmanols BD(2-4)are the first examples of kalm-7(8)-ene,kalm-16(17)-ene,and 8α-methoxykalmane diterpenoids,respectively.All the isolated kalmane diterpenoids 1-8 exhibited significant analgesic effects,and rhodokalmanol C(3)and kalmanoi(8)expressed more potent analgesic activity than morphine at doses of 0.2 and 0.04 mg/kg.The preliminary structure-activity relationships of kalmane diterpenoids as potent analgesics are discussed.展开更多
基于中国知网引文数据库、Web of Science TM(WOS)核心合集数据,对兴安杜鹃的相关主题文献进行查阅筛选,共计获取82篇中文文献和56篇外文文献。利用CiteSpace对文献进行图谱绘制,总结热门研究话题并提出展望。结果显示,挥发性成分分析...基于中国知网引文数据库、Web of Science TM(WOS)核心合集数据,对兴安杜鹃的相关主题文献进行查阅筛选,共计获取82篇中文文献和56篇外文文献。利用CiteSpace对文献进行图谱绘制,总结热门研究话题并提出展望。结果显示,挥发性成分分析、应用途径、基因表达、提取物的药用价值及其毒理研究是其经济价值的研究热点,建立繁育技术体系、扩大种群数量、发掘综合利用价值是其应用技术研究的热点,保护与开发是其今后研究的主攻方向。展开更多
Since two asymmetric centres are usually present in the bisbenzylisoquinolines,the circular dichroism is known to be an important method to elucidate their stereochemistry.We studied the relationships of the CD spectr...Since two asymmetric centres are usually present in the bisbenzylisoquinolines,the circular dichroism is known to be an important method to elucidate their stereochemistry.We studied the relationships of the CD spectra with the stereochemistry of synthetic RR-(1),SS-(2),RS-daurisoline(3) and SR-daurisoline(4).By comparision of the CD spectrum of natural daurisoline(1)from Menis- permum dauricum(Menispermaceae)with those of synthetic enantiomers,the absolute configuration was established as RR-daurisoline(1).展开更多
基金supported by the National Natural Science Foundation of China(No.81373956)
文摘The present study was designed to determine the major chemical constituents of the leaves of Rhododendron dauricum L. Compounds were isolated and purified by various chromatographic methods, and their structures were elucidated by physicochemical properties and spectral data. The present study identified two new C-methyl flavanones, 5, 7, 3', 5'-tetrahydroxy-6, 8-di-C-methyl flavanone(1) and 5, 4'-dihydroxy-8-C-methylflavanone-7-O-β-D-glucopyranoside(2), and one new flavonoid glycoside, quercetin-3-O-β-D-(6''-O-cinnamoyl)-galactoside(3), along with seven known compounds, including syzalterin(4), poriolin(5), farrerol-7-O-β-D-glucopyranoside(6), myrciacetin(7), quercetin-3-O-β-D-(6-p-hydroxy-benzoyl)-galactoside(8), quercetin-3-O-β-D-(6-p-coumaroyl)-galactoside(9), and 5, 7, 3', 5'-tetrahydroxyl flavanone(10). Compounds 1-3 were determined to be new flavonoids; compounds 4-6 were isolated from this species for the first time; and compounds 7-10 were reported for the first time from this genus.
基金Under the auspices of National Key Research and Development Program of China(No.2016YFC0500306)。
文摘This study aims to verify the concept of niches at multiple spatial scales in plant communities.To this end,we analyzed the niche characteristic of Rhododendron dauricum plant communities in Northeast China at three spatial scales.At the local scale,we calculated the Importance Value(IV)of species in five communities in the north of the Da Hinggan Mountains.At the intermediate scale,we examined five communities in their entirety,calculated the niche breadth of the species,and integrated niche overlap and interspecific association to analyze interspecific relationships.Further,the generalized additive model(GAM)was used to analyze the impact of topography and soil factors on niche characteristics.At the regional scale,we analyzed the geographical distribution of dominant species of R.dauricum plant communities in Northeast China and used principal component analysis(PCA)to analyze the impact of geographical and climate factors on species distribution.The results show that at the local scale,the IV of the species in each community varies widely.At the intermediate scale,species with a wide niche breadth tend to have a high value for IV.Larix gmelinii,Betula platyphylla,R.dauricum,Ledum palustre,and Vaccinium vitis-idaea had a relatively wide niche breadth and a high niche overlap,and the interspecific associations were almost all positive.Elevation and soil nutrients were the most dominant environmental factors.At the regional scale,species with a wide niche breadth tend to have a wide range of distribution,and temperature and precipitation were the most dominant environmental factors.This study suggests that the niche characteristics at three scales are both related and different.Niche characteristics at the local scale were various and labile,and niche characteristics at the intermediate and regional scales were relatively regular.These results show some degree of consistency with previous studies from an evolutionary perspective.The action mechanisms of these communities are related to differences in the dominant environmental factors.In addition,the integration of niche overlap and interspecific association determine interspecific relationships more accurately.
基金the National Natural Science Foundation of China, No. 30570555
文摘BACKGROUND： Recent studies have demonstrated that phenolic alkaloids from Menispermum dauricum （PAMD） can protect the heart and brain from ischemia/reperfusion injury, and promote neuron survival by inhibiting neuronal Bax and upregulating Bcl-2 expression following ischemia/reperfusion. OBJECTIVE： To investigate the neuroprotective effects of PAMD versus exogenous melatonin against ischemia/reperfusion injury. DESIGN, TIME AND SETTING： Observation and comparison experiments at a cellular level were performed at the Department of Biochemistry and Molecular Biology, Tongji Medical College of Huazhong University of Science and Technology between February 2007 and February 2008. MATERIALS： PAMD （95% purity） was provided by Kunming Institute of Botany, Chinese Academy of Sciences; melatonin was provided by Sigma, USA. METHODS： N2a mouse neuroblastoma cells were cultured in vitro deprived of glucose, serum and oxygen for 90 minutes, then cultured in normal medium containing different concentrations of PAMD （0.1, 1.0, 10 mg/L） or melatonin （1, 10, and 100 μmol/L）. Cells cultured in normal conditions served as a control. MAIN OUTCOME MEASURES： The culture solution was collected to determine the content of ex- citatory neurotransmitters such as glutamic acid and aspartic acid; cell viability was detected by MTT methods; reactive oxygen species production was determined by fluorescence spectroscopy; mito- chondrial transmembrane potential （？Ψm） was detected by laser confocal scanning; cytochrome C was measured by western blotting; and caspase-3 activity was determined by visible spectropho- tometry. RESULTS： Melatonin and PAMD both promoted oxygen-glucose-serum deprivation-mediated N2a cell survival （P 〈 0.01） and inhibited glutamic acid release （P 〈 0.01）, but melatonin did not inhibit aspartic acid production. The protective effects were the strongest using melatonin 100 μmol/L and PAMD 10 mg/L, so subsequent experiments were the performed at those doses. Although PAMD could no longer maintain mitochondrial transmembrane potential 6 hours after reperfusion, its in- hibitory effects on cytochrome C release from mitochondria and scavengers of reactive oxygen species were stronger than those of melatonin （P 〈 0.01）. However, its inhibitory effect on caspase-3 activity was weaker than that of melatonin： PAMD could inhibit caspase-3 activity 12 hours after reperfusion （P 〈 0.01）, but melatonin inhibited caspase-3 activity 28 hours after reperfusion （P 〈 0.01）. CONCLUSION： The results show that melatonin and PAMD have neuroprotective effects, but that the mechanisms are varied. Melatonin can maintain mitochondrial transmembrane potential, but its inhibitory effects on cytochrome C release, caspase-3 activity, and reactive oxygen species scav-enging are different from those of PAMD.
基金supported by the Fund of State Key Laboratory of Phytochemistry and Plant Resources in West China (NoP2022-KF08)National Natural Science Foundation of China (Nos.22107033 and U1703109)the Scientific Research Project of Traditional Chinese Medicine of Hubei Provincial Health Commission (No. ZY2021M056)。
文摘A novel diterpenoid with an unprecedented 5/6/5/7 tetracyclic system, rhodauricanol A(1), five new grayanane-derived diterpenoids, dauricanols A-E(2-6), and five known ones(7-11) were isolated from the flowers of Rhododendron dauricum. Rhodauricanol A(1) possesses a unique 5/6/5/7 tetracyclic ring system featuring a 16-oxa-tetracyclo[11.2.1.0^(1,5).0^(7,13)]hexadecane core. Dauricanols A-C(2-4) are the first1,3-dioxolane conjugates of grayanane diterpenoids and 5-hydroxymethylfurfural and vanillin, respectively, and dauricanols D(5) and E(6) represent the first examples of 6-deoxy-1,5-seco-grayanane diterpenoids. Their structures were determined by spectroscopic methods, quantum chemical calculation including ^(13)C NMR-DP4+ analysis and ECD calculation, and single-crystal X-ray diffraction analysis. Plausible biosynthetic pathways for 1-4 were proposed. All the isolates showed significant analgesic activities,and dauricanols B(3) and C(4) showed more potent analgesic activities than the positive control, morphine.
文摘The extract from leaves of Rhododendron dauricum L. was extracted with 95% alcohol by common method for studying its insecticidal activities. The chemical components of the alcohol extract and relative contents were analyzed by GC-MS. The insecticidal activities of the alcohol extract were tested on the 2nd？3rd instar larvae of Lymantria dispar L. for five days. Five concentrations of the extract samples were designed as 50, 10, 5, 1, and 0.5 g？L？1. The results show that the alcohol extracts from leaves of R. dauricum exhibited insecticidal activities against larvae of L. dispar. The corrected mortality of larvae of L. dispar for was over 50% for both contact toxicity and stomach toxicity at the extract concentration of ≥ 5 g·L？1 after five days of application. The insecticidal activity in contact toxicity is more effect than stomach toxicity for the alcohol extract. Twenty compounds, with total GC relative contents of 93.81% in the alcohol extract from leaves of R. dauricum were identified. The main chemical components in the extract are： （1） 4,5-Dihydro-5-oxo-3-（p-tolyl） isoxazole, with a relative content of 40.03%; （2） 1,3-Benzenediol, 5-methyl-2-（3,7,11-trimethyl-2,6,10- dodecatrienyl）-, （E,E）-, the relative content 18.27%; （3） 3,6-Diphenyl- 1,2,3,4,5,6,7,8-octahydro-1,8-acridinedione, the relative content 3.89%; （4） 6H-[1,2,4]Triazolo[1,5-a]indole, 4a,5,7,8,8a,9-hexahydro-9- methylene-, the relative content 2.99%; （5） 7-Amino-4-methyl-1,8- naphthyridin-2-ol, the relative content 2.64%; （6） 4-Methyl-2,6- dihydroxyquinoline, the relative content 2.63%; （7） 2,4,6- Triaminoquinazoline, the relative content 2.27%; （8） 2（1H）-Quinolinone, 4-hydroxy-1-methyl-, the relative content 2.02%.
基金supported by the National Natural Science Foundation of China(Nos.22207036,22277034,22477034,and 22107033)Interdisciplinary Research Program of Huazhong University of Science and Technology(No.2023JCYJ037)International Cooperation Project of Hubei Provincial Key R&D Plan(No.2023EHA040)。
文摘Two pairs of novel 6/6/6/9 tetracyclic merosesquiterpenoid enantiomers,dauroxonanols A(1)and B(2),possessing an unprecedented 9,15-dioxatetracyclo[8.5.3.0^(4.17).0^(14.18)]octadecane core skeleton,were isolated from Rhododendron dauricum.The nuclear magnetic resonance(NMR)spectra of 1 and 2 showed very broad resonances,and^(13)C NMR spectrum of 1 exhibited only 13 instead of 22 carbon resonances.These broadening or missing NMR resonances led to a great challenge to elucidate their structures using NMR data analysis.Their structures and absolute configurations of 1 and 2 were finally determined by single crystal X-ray diffraction analysis,chiral separation,and electronic circular dichroism(ECD)calculations.Plausible biosynthetic pathways for 1 and 2 are proposed.Conformational analysis,density functional theory(DFT)calculations,and dynamic NMR assigned the coalescent NMR phenomena of 1 and 2 to the conformational changes of the flexible oxonane ring.Dauroxonanols A(1)and B(2)showed potentα-glucosidase inhibitory activities,2-8 times potent than acarbose,an antidiabetic drug targetingα-glucosidase in clinic.
基金This work was financially supported by the Scientific Research Project of Traditional Chinese Medicine of Hubei Provincial Health Commission(ZY2021M056)the Open Project of State Key Laboratory of Chemistry and Molecular Engineering of Medicinal Resources(No.CMEMR-2021-B03)。
文摘Kalmane diterpenoids,featuring a 5/8/5/5 tetracyclic carbon skeleton,are very rare in nature.The flowers of Rhododendron dauricum L.(Ericaceae)were phytochemically investigated for the first time,leading to the isolation of eight kalmane diterpenoids(1-8)including four new ones,named rhodokalmanols A-D(1-4).The structures of 1-8 were elucidated by comprehensive spectroscopic methods and ic NMR-DP4+analysis,and the absolute configurations of 1,2,4,and 5 were defined by single-crystal X-ray diffraction analysis with Cu Kαradiation.Rhodokalmanol A(1)represents the first 5,8-epoxykalmane diterpenoid and also the first kalm-15(16)-ene diterpenoid.Rhodokalmanols BD(2-4)are the first examples of kalm-7(8)-ene,kalm-16(17)-ene,and 8α-methoxykalmane diterpenoids,respectively.All the isolated kalmane diterpenoids 1-8 exhibited significant analgesic effects,and rhodokalmanol C(3)and kalmanoi(8)expressed more potent analgesic activity than morphine at doses of 0.2 and 0.04 mg/kg.The preliminary structure-activity relationships of kalmane diterpenoids as potent analgesics are discussed.
文摘基于中国知网引文数据库、Web of Science TM(WOS)核心合集数据,对兴安杜鹃的相关主题文献进行查阅筛选,共计获取82篇中文文献和56篇外文文献。利用CiteSpace对文献进行图谱绘制,总结热门研究话题并提出展望。结果显示,挥发性成分分析、应用途径、基因表达、提取物的药用价值及其毒理研究是其经济价值的研究热点,建立繁育技术体系、扩大种群数量、发掘综合利用价值是其应用技术研究的热点,保护与开发是其今后研究的主攻方向。
基金This work was supported by the National Natural Science Foundation of China.
文摘Since two asymmetric centres are usually present in the bisbenzylisoquinolines,the circular dichroism is known to be an important method to elucidate their stereochemistry.We studied the relationships of the CD spectra with the stereochemistry of synthetic RR-(1),SS-(2),RS-daurisoline(3) and SR-daurisoline(4).By comparision of the CD spectrum of natural daurisoline(1)from Menis- permum dauricum(Menispermaceae)with those of synthetic enantiomers,the absolute configuration was established as RR-daurisoline(1).
