Aim To afford an environmentally benign catalytic epoxidation of carbon-carbon double bonds in organic substrates using hydrogen peroxide as an oxidant and iodine as a catalyst.Method The effects of different factors ...Aim To afford an environmentally benign catalytic epoxidation of carbon-carbon double bonds in organic substrates using hydrogen peroxide as an oxidant and iodine as a catalyst.Method The effects of different factors on the epoxidation of three unsaturated natural products were investigated by orthogonal design.Results The experimental results show that three unsaturated natural products are oxidized to the corresponding epoxides with hydrogen peroxide in the presence of 10%(mol/mol) of iodine at room temperature in high yields.Conclusion Iodine was found to be an efficient catalyst for the epoxidation of carbon-carbon double bonds in some unsaturated natural products with hydrogen peroxide at room temperature.展开更多
The determination of natural products stereochemistry remains a formidable task.Residual dipolar couplings(RDCs)induced by anisotropic media are a powerful tool for determination of the stereochemistry of organic mole...The determination of natural products stereochemistry remains a formidable task.Residual dipolar couplings(RDCs)induced by anisotropic media are a powerful tool for determination of the stereochemistry of organic molecule in solution.This review will provide a short introduction on RDCs-based methodology for the structural elucidation of natural products.Special attention is given to the current availability of alignment media in organic solvents.The applications of RDCs for structural analysis of some examples of natural products were discussed and summarized.Graphical Abstract This review provides a short introduction on RDCs-based methodology for the structural elucidation of natural products.Special attention is given to the current availability of alignment media in organic solvents.The applications of RDCs for structural analysis of some examples of natural products were discussed and summarized.展开更多
Drug discovery leading to robust and viable lead candidates’ remains a challenging scientific task, which is the transition from a screening hit to a drug candidate, requires expertise and experience. Natural product...Drug discovery leading to robust and viable lead candidates’ remains a challenging scientific task, which is the transition from a screening hit to a drug candidate, requires expertise and experience. Natural products and their derivatives have been recognized for many years as a source of therapeutic agents and of structural diversity. However, in addition to their chemical structure diversity and their biodiversity, the development of new technologies has revolutionized the screening of natural products in discovering new drugs. Applying these technologies compensates for the inherent limitations of natural products and offers a unique opportunity to re-establish natural products as a major source for drug discovery. The present article attempts to describe the utilization of compounds derived from natural resources as drug candidates, with a focus on the success of these resources in the process of finding and discovering new and effective drug compounds, an approach commonly referred to as “natural product drug discovery”.展开更多
Sensitivity analysis and structural modification techniques are used to investigate the structural modifications of a machine gun tripod which suffers from severe vibration during firing due to the resonance. The fini...Sensitivity analysis and structural modification techniques are used to investigate the structural modifications of a machine gun tripod which suffers from severe vibration during firing due to the resonance. The finite element analysis and modal test techniques are used to determine the natural frequencies of the machine gun. The sensitivities of natural frequencies with respect to the structural parameters of the tripod are obtained by the method of sensitivity analysis, and they can be used as an indication for the structural modification of the tripod so as to shift the natural frequencies effectively. By the structural modification techniques, finally, the optimal structural modifications of the tripod for desired natural frequencies are made to avoid the resonance, and this optimal structural modification is verified by re-analysis of the modified structure and the vibration contrast between original structure and modified structure. The research resulted in a successful structural modification for desired natural frequencies, which can avoid the resonance and thereby greatly improve the shooting precision of the machine gun during firing.展开更多
Despite that some approved drugs and genetically engineered vaccines against hepatitis B virus(HBV)are available for HBV patients,HBV infection is still a severe public health problem in the world.All the approved the...Despite that some approved drugs and genetically engineered vaccines against hepatitis B virus(HBV)are available for HBV patients,HBV infection is still a severe public health problem in the world.All the approved therapeutic drugs(including interferonalpha and nucleoside analogues)have their limitations.No drugs or therapeutic methods can cure hepatitis B so far.Therefore,it is urgently needed to discover and develop new anti-HBV drugs,especially nonnucleoside agents.Naturally originated compounds with enormous molecular complexity and diversity offer a great opportunity to find novel anti-HBV lead compounds with specific antiviral mechanisms.In this review,the natural products against HBV are discussed according to their chemical classes such as terpenes,lignans,phenolic acids,polyphenols,lactones,alkaloids and flavonoids.Furthermore,novel mode of action or new targets of some representative anti-HBV natural products are also discussed.The aim of this review is to report new discoveries and updates pertaining to anti-HBV natural products in the last 20years,especially novel skeletons and mode of action.Although many natural products with various skeletons have been reported to exhibit potent anti-HBV effects to date,scarcely any of them are found in the list of conventional anti-HBV drugs worldwide.Additionly,in anti-HBV mechanism of action,only a few references reported new targets or novel mode of action of antiHBV natural products.展开更多
Natural products provide an important original source of structural diversity for finding new compounds as anti-peptic ulcer drugs. The present review highlights some recent advances on gastro-protective flavonoids, t...Natural products provide an important original source of structural diversity for finding new compounds as anti-peptic ulcer drugs. The present review highlights some recent advances on gastro-protective flavonoids, terpenes, alkaloids, steroids, phenylpropanoids,glycosides and chromenes from natural herbs or traditional medicinal plants, and helps us analyze the structure-activity relationship(SAR) of natural products in healing of peptic ulcer for further drug development.展开更多
The unusual fused b-lactone vibralactone was isolated from cultures of the basidiomycete Boreostereum vibrans and has been shown to significantly inhibit pancreatic lipase.In this study,a structure-based lead optimiza...The unusual fused b-lactone vibralactone was isolated from cultures of the basidiomycete Boreostereum vibrans and has been shown to significantly inhibit pancreatic lipase.In this study,a structure-based lead optimization of vibralactone resulted in three series of 104 analogs,among which compound C1 exhibited the most potent inhibition of pancreatic lipase,with an IC50 value of 14 nM.This activity is more than 3000-fold higher than that of vibralactone.The effect of compound C1 on obesity was investigated using high-fat diet(HFD)-induced C57BL/6 J obese mice.Treatment with compound C1 at a dose of 100 mg/kg significantly decreased HFD-induced obesity,primarily through the improvement of metabolic parameters,such as triglyceride levels.展开更多
With the vigorous promotion of energy conservation and implementation of clean energy strategies,China's natural gas industry has entered a rapid development phase,and natural gas is playing an increasingly import...With the vigorous promotion of energy conservation and implementation of clean energy strategies,China's natural gas industry has entered a rapid development phase,and natural gas is playing an increasingly important role in China's energy structure.This paper uses a Generalized Weng model to forecast Chinese regional natural gas production,where accuracy and reasonableness compared with other predictions are enhanced by taking remaining estimated recoverable resources as a criterion.The forecast shows that China's natural gas production will maintain a rapid growth with peak gas of 323 billion cubic meters a year coming in 2036;in 2020,natural gas production will surpass that of oil to become a more important source of energy.Natural gas will play an important role in optimizing China's energy consumption structure and will be a strategic replacement of oil.This will require that exploration and development of conventional natural gas is highly valued and its industrial development to be reasonably planned.As well,full use should be made of domestic and international markets.Initiative should also be taken in the exploration and development of unconventional and deepwater gas,which shall form a complement to the development of China's conventional natural gas industry.展开更多
OBJECTIVE To utilize a structure-based lead optimization approach to generate novel natural product-like typeⅡ inhibitors of JAK2 using the DOLPHIN protocol.METHODS Initially,the DOLHPIN computational protocol was em...OBJECTIVE To utilize a structure-based lead optimization approach to generate novel natural product-like typeⅡ inhibitors of JAK2 using the DOLPHIN protocol.METHODS Initially,the DOLHPIN computational protocol was employed to convert an active(DFG-in)conformation of JAK2 into a typeⅡ-compatible conformation,which was used as a model for the structure-based virtual screening of 150 000 natural product-like compounds in silico.The novel biflavonoid analogues were designed and synthesized based on the structure of lead compound and then tested for JAK2 and STAT3 inhibitory activity,cytotoxicity and HCV antiviral activity.RESULTS The top eleven highest-scoring compounds were generated from the initial high-throughput virtual screening.Amentoflavone 1a,a biflavonoid from the Chinese plant Gingko biloba,emerged as a promising candidate for further biological evaluation.In dose-response experiments,amentoflavone 1ainhibited JAK2 activity in a concentration dependent fashion with an IC50 value of 5μmol·L-1.As a proof-of-concept,we designed nine analogues 1b-1j with the addition of one or more aliphatic side chains to the biflavonoid scaffold of 1a.The octyl(C8)analogue 1bdisplayed superior potency against JAK2 activity and HCV activity compared to the parent compound 1a,validating the structure-based lead optimization approach used in this study.Moreover,kinetic analysis indicated that analogue 1bexhibited a non-competitive mode of inhibition,suggesting that this compound may be a putative typeⅡ inhibitor of JAK2.CONCLUSION Amentoflavone 1ahas been identified as a JAK2 inhibitor by structure-based virtual screening of a natural product library.In silico optimization using the DOLPHIN model yielded analogues with enhanced potency against JAK2 activity and HCV activity in cellulo.Molecular modeling and kinetic experiments suggested that the analogues may function as typeⅡ inhibitors of JAK2.展开更多
Drug innovation is characterized by painstaking molecular-level syntheses and modifications as the basic components of research and development.Similarly,natural products are chemically tailored and modified based upo...Drug innovation is characterized by painstaking molecular-level syntheses and modifications as the basic components of research and development.Similarly,natural products are chemically tailored and modified based upon their structural and biological properties.To some extent,the modification of natural products is quite different from de novo structure-based drug discovery.This review describes the general strategies and principles for the modification of natural products to drugs,as illustrated by several successful medicines that originated from natural products.展开更多
A culture isolated from ascospores of Hypoxylon rickii,a xylariaceous ascomycete collected in Martinique,had yielded botryane,noreremophilane and abietane-type terpenoids in a preceding study,but additional metabolite...A culture isolated from ascospores of Hypoxylon rickii,a xylariaceous ascomycete collected in Martinique,had yielded botryane,noreremophilane and abietane-type terpenoids in a preceding study,but additional metabolites were detected by extensive HPLC–MS analysis in other fractions.Herein we report the further isolation of four new sesquiterpenoids with a silphiperfol-6-ene skeleton from extracts of H.rickii.The planar structures were elucidated by NMR and HRMS data as 13-hydroxysilphiperfol-6-ene(1),9-hydroxysilphiperfol-6-en-13-oic acid(2),2-hydroxysilphiperfol-6-en-13-oic acid(3)and 15-hydroxysilphiperfol-6-en-13-oic acid(4).For compounds 2–4 we propose the trivial names rickinic acids A–C.Their stereochemistry was assigned by ROESY correlations as well as by the specific optical rotation.Additionally,the known compounds,botryenanol,dehydrobotrydienol,cyclo(Phe-Pro),cyclo(Pro-Leu),(?)-ramulosin and aeleostearic acid were isolated.The antimicrobial and cytotoxic activities of the new compounds are also reported.展开更多
Objective: To establish the chemical profile, and to evaluate the antibacterial and modulatory activity of the ethanolic extracts of the stalk's inner bark and heartwood of Secondatia floribunda.Methods: Quantific...Objective: To establish the chemical profile, and to evaluate the antibacterial and modulatory activity of the ethanolic extracts of the stalk's inner bark and heartwood of Secondatia floribunda.Methods: Quantification of total plienols and flavonoids was determined by the FolinCiocalteu method and aluminum chloride, respectively. Phenolic compounds were identified and quantified by HPLC-DAD(High Performance Liquid ChromatographyDiodearray Detector) and the Infrared Spectroscopy was performed using the measure by Attenuated Total Reflectance with Fourier Transform(ATR-FTIR). Antibacterial assays for determination of the Minimum Inhibitory Concentration(MIC) and modification of aminoglycosides were performed by microdilution.Results: Infrared spectra showed similar characteristics, having among its main absorption bands hydroxyl group(OH). The antibacterial activity showed clinically significant results for the strains of Staphylococcus aureus and Escherichia coli. In modulation assay, synergic and antagonistic effect for both extracts was observed.Hearttwood extract in combination with antibiotics showed a significant MIC reduction at 19.8%(P<0.0001)-79.3%(P<0.01).Conclusions: This study is the first report of chemical and biological information of Secondatia floribunda suggesting that it is clinically relevant source of a new antibacterial therapy, especially due to the presence of significant levels of phenolic compounds.展开更多
Oil and gas are the major energy resources all over the world but are not renewable. According to their present reserves, the resource volumes yet to be found and the large amount of non-conventional oil and gas resou...Oil and gas are the major energy resources all over the world but are not renewable. According to their present reserves, the resource volumes yet to be found and the large amount of non-conventional oil and gas resources, there is still great potential in oil and gas production. The proportion of oil and gas in energy structure will be influenced by four major factors: 1) Potential of the world oil and gas resources; 2) Technological progress of oil and gas exploration and development; 3) Speed of the development of substitute energy resources; and 4) Variation of oil price. It is estimated that, oil and gas will still retain an important proportion in energy structure by the first half of the 21st century.展开更多
文摘Aim To afford an environmentally benign catalytic epoxidation of carbon-carbon double bonds in organic substrates using hydrogen peroxide as an oxidant and iodine as a catalyst.Method The effects of different factors on the epoxidation of three unsaturated natural products were investigated by orthogonal design.Results The experimental results show that three unsaturated natural products are oxidized to the corresponding epoxides with hydrogen peroxide in the presence of 10%(mol/mol) of iodine at room temperature in high yields.Conclusion Iodine was found to be an efficient catalyst for the epoxidation of carbon-carbon double bonds in some unsaturated natural products with hydrogen peroxide at room temperature.
基金co-supported by National Natural Science Foundation of China(21572164,U1504207)the Sino-German Center for Research Promotion(GZ1289).
文摘The determination of natural products stereochemistry remains a formidable task.Residual dipolar couplings(RDCs)induced by anisotropic media are a powerful tool for determination of the stereochemistry of organic molecule in solution.This review will provide a short introduction on RDCs-based methodology for the structural elucidation of natural products.Special attention is given to the current availability of alignment media in organic solvents.The applications of RDCs for structural analysis of some examples of natural products were discussed and summarized.Graphical Abstract This review provides a short introduction on RDCs-based methodology for the structural elucidation of natural products.Special attention is given to the current availability of alignment media in organic solvents.The applications of RDCs for structural analysis of some examples of natural products were discussed and summarized.
文摘Drug discovery leading to robust and viable lead candidates’ remains a challenging scientific task, which is the transition from a screening hit to a drug candidate, requires expertise and experience. Natural products and their derivatives have been recognized for many years as a source of therapeutic agents and of structural diversity. However, in addition to their chemical structure diversity and their biodiversity, the development of new technologies has revolutionized the screening of natural products in discovering new drugs. Applying these technologies compensates for the inherent limitations of natural products and offers a unique opportunity to re-establish natural products as a major source for drug discovery. The present article attempts to describe the utilization of compounds derived from natural resources as drug candidates, with a focus on the success of these resources in the process of finding and discovering new and effective drug compounds, an approach commonly referred to as “natural product drug discovery”.
文摘Sensitivity analysis and structural modification techniques are used to investigate the structural modifications of a machine gun tripod which suffers from severe vibration during firing due to the resonance. The finite element analysis and modal test techniques are used to determine the natural frequencies of the machine gun. The sensitivities of natural frequencies with respect to the structural parameters of the tripod are obtained by the method of sensitivity analysis, and they can be used as an indication for the structural modification of the tripod so as to shift the natural frequencies effectively. By the structural modification techniques, finally, the optimal structural modifications of the tripod for desired natural frequencies are made to avoid the resonance, and this optimal structural modification is verified by re-analysis of the modified structure and the vibration contrast between original structure and modified structure. The research resulted in a successful structural modification for desired natural frequencies, which can avoid the resonance and thereby greatly improve the shooting precision of the machine gun during firing.
基金Supported by Zhejiang Provincial Natural Science Foundation of China,No.LY14H310010Public Welfare Technology Applied Research Project of Zhejiang Province?Experimental Animal Science and Technology Project,No.2013C37020Key Project of Chinese Ministry of Education,No.212073
文摘Despite that some approved drugs and genetically engineered vaccines against hepatitis B virus(HBV)are available for HBV patients,HBV infection is still a severe public health problem in the world.All the approved therapeutic drugs(including interferonalpha and nucleoside analogues)have their limitations.No drugs or therapeutic methods can cure hepatitis B so far.Therefore,it is urgently needed to discover and develop new anti-HBV drugs,especially nonnucleoside agents.Naturally originated compounds with enormous molecular complexity and diversity offer a great opportunity to find novel anti-HBV lead compounds with specific antiviral mechanisms.In this review,the natural products against HBV are discussed according to their chemical classes such as terpenes,lignans,phenolic acids,polyphenols,lactones,alkaloids and flavonoids.Furthermore,novel mode of action or new targets of some representative anti-HBV natural products are also discussed.The aim of this review is to report new discoveries and updates pertaining to anti-HBV natural products in the last 20years,especially novel skeletons and mode of action.Although many natural products with various skeletons have been reported to exhibit potent anti-HBV effects to date,scarcely any of them are found in the list of conventional anti-HBV drugs worldwide.Additionly,in anti-HBV mechanism of action,only a few references reported new targets or novel mode of action of antiHBV natural products.
基金supported by the National Natural Science Foundation of China(No.21272136)Youth Talent Development Foundation of China Three Gorges University
文摘Natural products provide an important original source of structural diversity for finding new compounds as anti-peptic ulcer drugs. The present review highlights some recent advances on gastro-protective flavonoids, terpenes, alkaloids, steroids, phenylpropanoids,glycosides and chromenes from natural herbs or traditional medicinal plants, and helps us analyze the structure-activity relationship(SAR) of natural products in healing of peptic ulcer for further drug development.
基金The authors are grateful to the National Natural Science Foundation of China(81102348,U1132607,81373289).
文摘The unusual fused b-lactone vibralactone was isolated from cultures of the basidiomycete Boreostereum vibrans and has been shown to significantly inhibit pancreatic lipase.In this study,a structure-based lead optimization of vibralactone resulted in three series of 104 analogs,among which compound C1 exhibited the most potent inhibition of pancreatic lipase,with an IC50 value of 14 nM.This activity is more than 3000-fold higher than that of vibralactone.The effect of compound C1 on obesity was investigated using high-fat diet(HFD)-induced C57BL/6 J obese mice.Treatment with compound C1 at a dose of 100 mg/kg significantly decreased HFD-induced obesity,primarily through the improvement of metabolic parameters,such as triglyceride levels.
基金the National Social Science Funds of China (13&ZD159)the National Natural Science Foundation of China (71303258, 71373285)+1 种基金MOE (Ministry of Education in China) Project of Humanities and Social Sciences (13YJC630148)Science Foundation of China University of Petroleum, Beijing (ZX20150130) for sponsoring this joint research
文摘With the vigorous promotion of energy conservation and implementation of clean energy strategies,China's natural gas industry has entered a rapid development phase,and natural gas is playing an increasingly important role in China's energy structure.This paper uses a Generalized Weng model to forecast Chinese regional natural gas production,where accuracy and reasonableness compared with other predictions are enhanced by taking remaining estimated recoverable resources as a criterion.The forecast shows that China's natural gas production will maintain a rapid growth with peak gas of 323 billion cubic meters a year coming in 2036;in 2020,natural gas production will surpass that of oil to become a more important source of energy.Natural gas will play an important role in optimizing China's energy consumption structure and will be a strategic replacement of oil.This will require that exploration and development of conventional natural gas is highly valued and its industrial development to be reasonably planned.As well,full use should be made of domestic and international markets.Initiative should also be taken in the exploration and development of unconventional and deepwater gas,which shall form a complement to the development of China's conventional natural gas industry.
基金The project upported by Hong Kong Baptist University(FRG2/12-13/021and FRG2/13-14/008)Centre for Cancer and Inflammation Research,School of Chinese Medicine(CCIR-SCM,HKBU)+4 种基金the Health and Medical Research Fund(HMRF/11101212and HMRF/13121482)the Research Grants Council(HKBU/201811,HKBU/204612and HKBU/201913)the French National Research Agency/Research Grants Council Joint Research Scheme(A-HKBU201/12)the State Key Laboratory of Synthetic Chemistry,the Science and Technology Development Fund,Macao SAR(103/2012/A3)the University of Macao〔MYRG091(Y3-L2)-ICMS12-LCH,MYRG121(Y3-L2)-ICMS12-LCH,MRG007/LCH/2014/ICMS and MRG023/LCH/2013/ICMS〕
文摘OBJECTIVE To utilize a structure-based lead optimization approach to generate novel natural product-like typeⅡ inhibitors of JAK2 using the DOLPHIN protocol.METHODS Initially,the DOLHPIN computational protocol was employed to convert an active(DFG-in)conformation of JAK2 into a typeⅡ-compatible conformation,which was used as a model for the structure-based virtual screening of 150 000 natural product-like compounds in silico.The novel biflavonoid analogues were designed and synthesized based on the structure of lead compound and then tested for JAK2 and STAT3 inhibitory activity,cytotoxicity and HCV antiviral activity.RESULTS The top eleven highest-scoring compounds were generated from the initial high-throughput virtual screening.Amentoflavone 1a,a biflavonoid from the Chinese plant Gingko biloba,emerged as a promising candidate for further biological evaluation.In dose-response experiments,amentoflavone 1ainhibited JAK2 activity in a concentration dependent fashion with an IC50 value of 5μmol·L-1.As a proof-of-concept,we designed nine analogues 1b-1j with the addition of one or more aliphatic side chains to the biflavonoid scaffold of 1a.The octyl(C8)analogue 1bdisplayed superior potency against JAK2 activity and HCV activity compared to the parent compound 1a,validating the structure-based lead optimization approach used in this study.Moreover,kinetic analysis indicated that analogue 1bexhibited a non-competitive mode of inhibition,suggesting that this compound may be a putative typeⅡ inhibitor of JAK2.CONCLUSION Amentoflavone 1ahas been identified as a JAK2 inhibitor by structure-based virtual screening of a natural product library.In silico optimization using the DOLPHIN model yielded analogues with enhanced potency against JAK2 activity and HCV activity in cellulo.Molecular modeling and kinetic experiments suggested that the analogues may function as typeⅡ inhibitors of JAK2.
文摘Drug innovation is characterized by painstaking molecular-level syntheses and modifications as the basic components of research and development.Similarly,natural products are chemically tailored and modified based upon their structural and biological properties.To some extent,the modification of natural products is quite different from de novo structure-based drug discovery.This review describes the general strategies and principles for the modification of natural products to drugs,as illustrated by several successful medicines that originated from natural products.
基金His collection trip in Martinique has benefited from“Investissements d’Avenir”Grants of the ANR(CEBA ANR-10-LABX-0025,CNRS Cayenne and Toulouse).
文摘A culture isolated from ascospores of Hypoxylon rickii,a xylariaceous ascomycete collected in Martinique,had yielded botryane,noreremophilane and abietane-type terpenoids in a preceding study,but additional metabolites were detected by extensive HPLC–MS analysis in other fractions.Herein we report the further isolation of four new sesquiterpenoids with a silphiperfol-6-ene skeleton from extracts of H.rickii.The planar structures were elucidated by NMR and HRMS data as 13-hydroxysilphiperfol-6-ene(1),9-hydroxysilphiperfol-6-en-13-oic acid(2),2-hydroxysilphiperfol-6-en-13-oic acid(3)and 15-hydroxysilphiperfol-6-en-13-oic acid(4).For compounds 2–4 we propose the trivial names rickinic acids A–C.Their stereochemistry was assigned by ROESY correlations as well as by the specific optical rotation.Additionally,the known compounds,botryenanol,dehydrobotrydienol,cyclo(Phe-Pro),cyclo(Pro-Leu),(?)-ramulosin and aeleostearic acid were isolated.The antimicrobial and cytotoxic activities of the new compounds are also reported.
基金Brazilian institutions and research agencies FUNCAP,URCA,UFRPE,ICMBio,UFSM and FIOCRUZ
文摘Objective: To establish the chemical profile, and to evaluate the antibacterial and modulatory activity of the ethanolic extracts of the stalk's inner bark and heartwood of Secondatia floribunda.Methods: Quantification of total plienols and flavonoids was determined by the FolinCiocalteu method and aluminum chloride, respectively. Phenolic compounds were identified and quantified by HPLC-DAD(High Performance Liquid ChromatographyDiodearray Detector) and the Infrared Spectroscopy was performed using the measure by Attenuated Total Reflectance with Fourier Transform(ATR-FTIR). Antibacterial assays for determination of the Minimum Inhibitory Concentration(MIC) and modification of aminoglycosides were performed by microdilution.Results: Infrared spectra showed similar characteristics, having among its main absorption bands hydroxyl group(OH). The antibacterial activity showed clinically significant results for the strains of Staphylococcus aureus and Escherichia coli. In modulation assay, synergic and antagonistic effect for both extracts was observed.Hearttwood extract in combination with antibiotics showed a significant MIC reduction at 19.8%(P<0.0001)-79.3%(P<0.01).Conclusions: This study is the first report of chemical and biological information of Secondatia floribunda suggesting that it is clinically relevant source of a new antibacterial therapy, especially due to the presence of significant levels of phenolic compounds.
文摘Oil and gas are the major energy resources all over the world but are not renewable. According to their present reserves, the resource volumes yet to be found and the large amount of non-conventional oil and gas resources, there is still great potential in oil and gas production. The proportion of oil and gas in energy structure will be influenced by four major factors: 1) Potential of the world oil and gas resources; 2) Technological progress of oil and gas exploration and development; 3) Speed of the development of substitute energy resources; and 4) Variation of oil price. It is estimated that, oil and gas will still retain an important proportion in energy structure by the first half of the 21st century.
