The South China Sea(SCS) is one of the most productive and accumulative marginal shelves of organic carbon in the world. To expound the transformation and preservation of organic carbon in the Northeast SCS, where abu...The South China Sea(SCS) is one of the most productive and accumulative marginal shelves of organic carbon in the world. To expound the transformation and preservation of organic carbon in the Northeast SCS, where abundant oil and gas resources have been reported, compound specific sterols in free(FR), base hydrolytic(BH), and acid hydrolytic(AH) forms were analyzed in surface and columnar sediments in May, 2016. The results showed that the total contents of sterols detected ranged from 0.15 to 3.74 ppm dry weight in the surface sediments, and gradually decreased from 3.41 to0.17 ppm dry weight from surface to deep sediments, in which cholesterol(27^(△5)) was the most abundant component. Sterols mainly existed in the BH form(54.51%-74.20%), followed by the FR form(25.50%-45.49%) and then the AH form(0-3.77%) in turn, in the surface sediments. BH and FR sterols accounted for 0-49.08% and 50.92%-100% in the columnar sediments, while AH sterols were undetectable. The contents of specific sterols indicated that, the primary source of marine organic carbon was about 5 times as much as that from terrestrial input. More and more FR sterols transformed into BH sterols with increasing sedimentary depth, and BH sterols absolutely dominated in sediment depths under 25 cm. The forms of Sterols C27 were maintained at a relative consistence state, but Sterols C28 to C30 degraded gradually during the sedimentation process. It was suggested that the stability of sterols, based on the chemical structures, might be the primary factor controlling their degradation and preservation in deeper sediments. These results would help to understand the organic carbon(OC) transformation in a hydrate formation area in a marginal sea.展开更多
Compositional data on the sterol and alcohol fractions isolated from deep-sea marine sediments from the Okinawa Trough were obtained to determine the relative contribution from. marine and terrestrial inputs. Followin...Compositional data on the sterol and alcohol fractions isolated from deep-sea marine sediments from the Okinawa Trough were obtained to determine the relative contribution from. marine and terrestrial inputs. Following extraction, the sterol plus alcohol fraction was isolated by layer chromatography, derivatized with BSTFA and then analysed by capillary GC and GC-MS. A suite of C26-C29 stenols and stanols and C30-C32 keto - alcohols were identified in the sediments. The thermal stability of the compounds in these sediments was studied by heating portions of the surface sediment in glass tubes fpr 16 hours at temperatures from 50℃ to 200℃.The C27 stanol/stenol ratio increased when temperatures went up to 175℃ , but the distribution of C30-C32 Keto - alcohols remained unaffected. At 200℃ most of the sterols and Keto - alcohols were destroyed.展开更多
The effects of low ratio of n-6/n-3 polyunsaturated fatty acids(PUFA)have been clarified against atherosclerosis.Increasing evidence indicated that plant sterols(PS)have a significant cholesterol-lowering effect.This ...The effects of low ratio of n-6/n-3 polyunsaturated fatty acids(PUFA)have been clarified against atherosclerosis.Increasing evidence indicated that plant sterols(PS)have a significant cholesterol-lowering effect.This study explored the effects of PS combined with n-6/n-3(2:1)PUFA on atherosclerosis and investigated the possible mechanism.In ApoE−/−mice,the milk fat in high fat diets was replaced with n-6/n-3(2:1)PUFA alone or supplemented with 6%PS for 16 weeks.Results demonstrated that PS combined with PUFA exerted commentary and synergistic effects on ameliorating atherosclerosis,improving lipid metabolism and lipid deposition in liver,and alleviating inflammatory response.These changes were accompanied with decreased serum TC,TG,LDL-C and increased fecal cholesterol efflux,as well as the lower inflammatory cytokine CRP,IL-6,TNF-α.It is suggested that the underlying mechanism of PS combined with n-6/n-3(2:1)PUFA promoting the fecal cholesterol efflux may be mediated by liver X receptorα/ATP-binding cassette transporter A1 pathway.展开更多
Two new triterpenoids(1 and 2)and a new sterol(3),together with six known constituents(4–9),were isolated from the leaves and twigs of Melia azedarach.Their chemical structures were elucidated on the basis of spectro...Two new triterpenoids(1 and 2)and a new sterol(3),together with six known constituents(4–9),were isolated from the leaves and twigs of Melia azedarach.Their chemical structures were elucidated on the basis of spectroscopic analysis.展开更多
Two new sterol have been isolated from the South China Sea marine organism.Compound 1 was isolated from the sponge Polymastia sobustia and compound 2 was obtained from the soft coral Sinularia inexplicata. Their struc...Two new sterol have been isolated from the South China Sea marine organism.Compound 1 was isolated from the sponge Polymastia sobustia and compound 2 was obtained from the soft coral Sinularia inexplicata. Their structures were established as 3β-hydroxy-stigmast-5en-7-one and 24 - methylene cholestan -3β, 66, 9α,19 -tetrol by variety of spectral analysis such as IR, EIMS, 1DNMR, 1H-1H COSY HMQC, HMBC, NOESY.展开更多
The purpose of the study was to establish an analytical method to simultaneously determine multiple sterols in tobacco leaves rapidly and accurately.In this gas chromatography-triple quadruple tandem mass spectrometry...The purpose of the study was to establish an analytical method to simultaneously determine multiple sterols in tobacco leaves rapidly and accurately.In this gas chromatography-triple quadruple tandem mass spectrometry(GC-MS/MS)based method,various conditions for sterols extraction were assessed and the instrumental operation parameters were optimized with 5α-cholane as an internal standard.Using this method,eight plant sterols,namely lanosterol,campesterol,chenodeoxycholic acid,cholesterol,β-sitosterol,stigmasterol,dihydrotachysterol and ergosterol,were separated in less than 30 min.The linear correlation coefficients were over 0.998 9,the low detection limits were in the range of 0.010 3-0.141 4 μg/g.The recoveries were from 87.30% to 115.60%,with low standard deviations.In conclusion,this method demonstrates good repeatability,accuracy,and high sensitivity,and is best suited for rapid analysis of multiple sterols in tobacco leaves.展开更多
From the aerial parts of Clerodendrum colebrookianum Walp., two new C29 sterols colebrin A and colebrin B, were isolated, along with a known compound, clerosterol. The structures of the new compounds were elucidated o...From the aerial parts of Clerodendrum colebrookianum Walp., two new C29 sterols colebrin A and colebrin B, were isolated, along with a known compound, clerosterol. The structures of the new compounds were elucidated on the basis of spectral evidence.展开更多
Free sterols from rice dry embryo reduce the onset phase transition temperature and widen the transition range of total polar lipids and phosphatidylglycerol, which increases the membrane fluidity below their phase tr...Free sterols from rice dry embryo reduce the onset phase transition temperature and widen the transition range of total polar lipids and phosphatidylglycerol, which increases the membrane fluidity below their phase transition temperature and decreases the fluidity of membranes above their phase transition temperature. And 50% of free sterols result in a complete disappearance of phase transition. The fluidity of other main components of polar lipids is decreased by free sterols above 0℃. The results confirm that free sterols can modulate membrane lipid fluidity.展开更多
The northern South China Sea(NSCS)is significantly influenced by the Kuroshio intrusion and the coastal currents.Our knowledge on the roles of both currents on phytoplankton spatial variations is still inadequate.Here...The northern South China Sea(NSCS)is significantly influenced by the Kuroshio intrusion and the coastal currents.Our knowledge on the roles of both currents on phytoplankton spatial variations is still inadequate.Here,we investigated the concentrations of phytoplankton biomarkers and their proportions in surface suspended particles from 47 sites of the NSCS during summer of 2017 and 2019.Brassicasterol/epi-brassicasterol,dinosterol,and C37 alkenones were used as proxies of biomass for diatoms,dinoflagellates,and haptophytes,respectively,and their sum indicating total phytoplankton biomass.A three end-member mixing model was applied to quantitatively assess the influence extent of the Kuroshio intrusion and the coastal currents.Our results showed that the Kuroshio intrusion and the coastal currents contributed equally to the overall surface water masses in the study area;however,the two currents had distinct effects on the spatial distribution of phytoplankton.For phytoplankton biomass,the eutrophic coastal currents were likely to be the main controlling factors,while the impact of the Kuroshio intrusion was weak and stimulated significant increases in phytoplankton biomass only at certain boundary sites.For phytoplankton community structures,the Kuroshio and its intrusion were the main factors,resulting in an increase in the proportions of dinoflagellates and haptophytes.The proportion of diatoms slightly increased due to the influence of the coastal currents.Our study quantifies the effects of the Kuroshio and the coastal currents on phytoplankton in the NSCS in terms of hydrological parameters,providing an important basis for the understanding of ecological functions and biogeochemical cycles in marginal sea-open ocean boundary regions.展开更多
Objective: This study focused on the antibacterial and anti-proliferative activity of extracts from Carica papaya and Cocos nucifera roots. Methodology: The minimum inhibitory concentration and the minimum bactericida...Objective: This study focused on the antibacterial and anti-proliferative activity of extracts from Carica papaya and Cocos nucifera roots. Methodology: The minimum inhibitory concentration and the minimum bactericidal concentration of the extracts on Escherichia coli, Pseudomonas aeruginosa, Streptococcus mutans, and Staphylococcus aureus were deduced by the microdilution method. The anti-biofilm activity was determined on all four strains and anti-quorum sensing activity by inhibition of violacein production in Chromobacterium violaceum. Anti-proliferative activity on prostate cultured cancer cells was evaluated by MTT assay. Sterols and triterpenes were also assayed in this study. Results: The methanolic extract of Carica papaya showed the best anti-biofilm effect with a percentage inhibition of 66.10 ± 1.79. The methanolic extract of Cocos nucifera had the strongest inhibition on the production of quorum sensing (61.42 ± 0.28). In addition, the methanolic extract of Cocos nucifera roots showed the best cytotoxic effect on prostate cancer LNCaP cell lines (IC<sub>50</sub> = 26.98 ± 2.6 μg/mL) and Carica papaya on the PC-3 lines (IC<sub>50</sub> = 127.20 ± 5.99 μg/mL). The extracts were also rich in triterpenes and sterols. Conclusion: This study provides support for the ethnomedical use of Carica papaya and Cocos nucifera roots as an antimicrobial and anticancer.展开更多
Fuzhuan brick-tea(FZT)has long been consumed for its supposed weight loss and lipid-lowering benefi ts.In this study,we show that the regulation of fat storage in Caenorhabditis elegans from a water extract of FZT was...Fuzhuan brick-tea(FZT)has long been consumed for its supposed weight loss and lipid-lowering benefi ts.In this study,we show that the regulation of fat storage in Caenorhabditis elegans from a water extract of FZT was affected by cholesterol levels.We found that FZT signifi cantly decreased fat storage under normal cholesterol levels or in a cholesterol-free diet,while lipid accumulation was increased for a high cholesterol diet.Moreover,this mechanism may involve the conserved sterol regulatory element-binding protein(SREBP)/mediator-15(MDT-15)signaling pathway and the nuclear hormone receptor NHR-80.In addition,lipid synthesis-related genes inhibited by FZT were partially affected by a cholesterol-free diet.Thus,our fi ndings suggested that the potential lipid-lowering effects of FZT may depend on the cholesterol level,which may help to improve the consumption of FZT.展开更多
Endometrial carcinoma(EMC)is associated with obesity;however,the underlying mechanisms have not yet been elucidated.Peroxisome proliferator-activated receptor alpha(PPARα)is a nuclear receptor that is involved in lip...Endometrial carcinoma(EMC)is associated with obesity;however,the underlying mechanisms have not yet been elucidated.Peroxisome proliferator-activated receptor alpha(PPARα)is a nuclear receptor that is involved in lipid,glucose,and energy metabolism.PPARαreportedly functions as a tumor suppressor through its effects on lipid metabolism;however,the involvement of PPARαin the development of EMC remains unclear.The present study demonstrated that the immunohistochemical expression of nuclear PPARαwas lower in EMC than in normal endometrial tissues,suggesting the tumor suppressive nature of PPARα.A treatment with the PPARαactivator,irbesartan,inhibited the EMC cell lines,Ishikawa and HEC1A,by down-regulating sterol regulatory element-binding protein 1(SREBP1)and fatty acid synthase(FAS)and up-regulating the tumor suppressor genes p21 and p27,antioxidant enzymes,and AT-rich interaction domain 1A(ARID1A).These results indicate the potential of the activation of PPARαas a novel therapeutic approach against EMC.展开更多
The mass spectrometric fragmentation of TMS derivatives of sterols was studied and analyzed based on the mass spectrometry of the TMS derivatives of standards.The double bond numbers and the degree of the methylize,al...The mass spectrometric fragmentation of TMS derivatives of sterols was studied and analyzed based on the mass spectrometry of the TMS derivatives of standards.The double bond numbers and the degree of the methylize,alkylize and the related position in the sterol nucleus and the side chains were confirmed by the characteristic ions.Total lipids were extracted using Bligh-Dyer method.Sterols were isolated by solvent partition with chloroform-hexane(1 ∶4,by volume),derivated by BSTFA,and analyzed by GC-MS.The regular pattern was used for identifying the sterols in a dinoflagellate from the Symbodinium sp.展开更多
Objective: To explore anti-inflammatory activities of organic extract and its semi-purified fractions(ethanol, acetone, methanol/dichloromethane) from the Mediterranean gorgonian Eunicella singularis. Methods: The ant...Objective: To explore anti-inflammatory activities of organic extract and its semi-purified fractions(ethanol, acetone, methanol/dichloromethane) from the Mediterranean gorgonian Eunicella singularis. Methods: The anti-inflammatory and analgesic activities were evaluated, using the carrageenan-induced rat paw edema model and the acetic acid writhing test in mice. The gastroprotective activity was determined using HCl/Et OH induced gastric ulcers in rats. The purification and structure elucidation of compound(s) from the more effective fraction were determined by chromatographic and spectroscopic methods and in comparison with data reported in the literature. Results: The fraction F-Et OH showed an important antiinflammatory activity associated with significant analgesic and gastroprotective properties. The purification and structure elucidation of compound(s) from this fraction lead to the identification of one diterpenoid and four sterols. Conclusions: These results suggested that components from the active fraction can be used to treat various anti-inflammatory diseases.展开更多
The aim of this review is to enlighten the critical roles that the liver plays in cholesterol metabolism. Liver transplantation can serve as gene therapy or a source of gene transmission in certain conditions that aff...The aim of this review is to enlighten the critical roles that the liver plays in cholesterol metabolism. Liver transplantation can serve as gene therapy or a source of gene transmission in certain conditions that affect cholesterol metabolism, such as low-density-lipoprotein(LDL) receptor gene mutations that are associated with familial hypercholesterolemia. On the other hand, cholestatic liver disease often alters cholesterol metabolism. Cholestasis can lead to formation of lipoprotein X(Lp-X), which is frequently mistaken for LDL on routine clinical tests. In contrast to LDL, Lp-X is non-atherogenic, and failure to differentiate between the two can interfere with cardiovascular risk assessment, potentially leading to prescription of futile lipid-lowering therapy. Statins do not effectively lower Lp-X levels, and cholestasis may lead to accumulation of toxic levels of statins. Moreover, severe cholestasis results in poor micellar formation, which reduces cholesterol absorption, potentially impairing the cholesterol-lowering effect of ezetimibe. Apolipoprotein B-100 measurement can help distinguish between atherogenic and non-atherogenic hypercholesterolemia. Furthermore, routine serum cholesterol measurements alone cannot reflect cholesterol absorption and synthesis. Measurements of serum non-cholesterol sterol biomarkers- such as cholesterol precursor sterols, plant sterols, and cholestanol- may help with the comprehensive assessment of cholesterol metabolism. An adequate cholesterol supply is essential for liver-regenerative capacity. Low preoperative and perioperative serum cholesterol levels seem to predict mortality in liver cirrhosis and after liver transplantation. Thus, accurate lipid profile evaluation is highly important in liver disease and after liver transplantation.展开更多
Our overall knowledge of the medicinal uses of plants suggests that natural compounds could be useful in the treatment of cutaneous fungal infections in tropical regions. Furthermore, the possibilities of treatment us...Our overall knowledge of the medicinal uses of plants suggests that natural compounds could be useful in the treatment of cutaneous fungal infections in tropical regions. Furthermore, the possibilities of treatment using plant extracts may be even broader than is already known when one considers plants that have not been extensively studied in this context, such as the regional species Phoenix dactylifera and Ziziphus spina-christi. This study compared the antimicrobial activity of Phoenix dactylifera and Ziziphus spina-christi extracts in terms of their biochemical and molecular effects on Candida albicans (ATCC CA 10231). These effects included altered levels of intracellular sterols, changes in the permeability of the cell membrane, and changes in the TEF1: QRTTEF1, CaERG1: ERG1, CdERG12: CdERG1, and ERG25: ERG25 genes. Scanning electron microscopy (SEM) was used to identify morphological characteristics, and energy-dispersive X-ray spectroscopy (EDAX) analyses were conducted. In treated samples, the SEM and EDAX analyses showed cell cavities and shrinkage of the cell wall, and the number of cells was reduced to only a few abnormal cells as compared with that in the untreated samples. Yttrium was detected in the cells treated with Z. spina-christi, and high levels of osmium were detected in the cells treated with P. dactylifera. Compared with control cells, cells exposed to the concentration 150 μl/ml of Z. spina-christi extract had an average sterol concentration that was nearly 3 times higher, while the concentration was 5.5 times higher for cells treated with the 150 μl/ml of P. dactylifera extract. The ethanol extracts affected the permeability of C. albicans cell membrane. Gene sequencing showed gaps and mismatches in the ERG1, ERG12, and ERG25 genes after treatment with P. dactylifera and Z. spina-christi extracts compared with that in the controls. The results were highly significant (p ≤ 0.01). We conclude that the ethanol extracts of P. dactylifera and Z. spina-christi have antimicrobial activity through several mechanisms in the yeast cell.展开更多
Background: Plants have for a long time been used as medicines to treat ailments. Cassia abbreviata (C. abbreviata) is one of the plants that has been widely used in the management of a range of ailments, including ma...Background: Plants have for a long time been used as medicines to treat ailments. Cassia abbreviata (C. abbreviata) is one of the plants that has been widely used in the management of a range of ailments, including malaria, diarrhea, and abscesses. Aim: This study was conducted to investigate the phytochemical composition of crude extracts of the roots, leaves, and stem bark of C. abbreviata. Materials and Methods: This was a laboratory-based study in which the fresh leaves, stem bark, and roots of C. abbreviata were collected, thoroughly cleaned, chopped into small pieces, and kept at room temperature until fully dry. The dried plant parts were powdered separately and stored separately in airtight containers for the phytochemical investigation. Ethanol (96% v/v) or distilled water was used for the extraction of components of the coarse powder. The mixtures were separately filtered, and the filtrates were reduced to a concentrated semisolid mass by drying in a water bath at 40?C. Thereafter, phytochemical analysis for flavonoids, phenolics, tannins, saponins, alkaloids, terpenoids, glycosides, carbohydrates, and proteins was done. Results: The phytochemical analysis of the ethanolic extracts revealed the presence of high concentrations of tannins, reducing sugars, and sterols in the stem bark and roots. Flavonoids, phenolics, and proteins were present in high concentrations in the stem bark, while anthraquinone, glycosides, and alkaloids were present in the leaves and roots, respectively. Conclusion: C. abbreviata plant contains a wide range of phytochemical constituents. Depending on the solvent used for extraction, various compositions of phytochemicals are obtained in each part of the tree. However, extraction with ethanol showed a better concentration than with water for most of the phytochemicals.展开更多
基金supported by National Key R&D Program of China (No. 2018YFC0309200)National Natural Science Foundation of China (No. 41176064 and No. 41427803)
文摘The South China Sea(SCS) is one of the most productive and accumulative marginal shelves of organic carbon in the world. To expound the transformation and preservation of organic carbon in the Northeast SCS, where abundant oil and gas resources have been reported, compound specific sterols in free(FR), base hydrolytic(BH), and acid hydrolytic(AH) forms were analyzed in surface and columnar sediments in May, 2016. The results showed that the total contents of sterols detected ranged from 0.15 to 3.74 ppm dry weight in the surface sediments, and gradually decreased from 3.41 to0.17 ppm dry weight from surface to deep sediments, in which cholesterol(27^(△5)) was the most abundant component. Sterols mainly existed in the BH form(54.51%-74.20%), followed by the FR form(25.50%-45.49%) and then the AH form(0-3.77%) in turn, in the surface sediments. BH and FR sterols accounted for 0-49.08% and 50.92%-100% in the columnar sediments, while AH sterols were undetectable. The contents of specific sterols indicated that, the primary source of marine organic carbon was about 5 times as much as that from terrestrial input. More and more FR sterols transformed into BH sterols with increasing sedimentary depth, and BH sterols absolutely dominated in sediment depths under 25 cm. The forms of Sterols C27 were maintained at a relative consistence state, but Sterols C28 to C30 degraded gradually during the sedimentation process. It was suggested that the stability of sterols, based on the chemical structures, might be the primary factor controlling their degradation and preservation in deeper sediments. These results would help to understand the organic carbon(OC) transformation in a hydrate formation area in a marginal sea.
基金Supported by the National Natural Foundation of China
文摘Compositional data on the sterol and alcohol fractions isolated from deep-sea marine sediments from the Okinawa Trough were obtained to determine the relative contribution from. marine and terrestrial inputs. Following extraction, the sterol plus alcohol fraction was isolated by layer chromatography, derivatized with BSTFA and then analysed by capillary GC and GC-MS. A suite of C26-C29 stenols and stanols and C30-C32 keto - alcohols were identified in the sediments. The thermal stability of the compounds in these sediments was studied by heating portions of the surface sediment in glass tubes fpr 16 hours at temperatures from 50℃ to 200℃.The C27 stanol/stenol ratio increased when temperatures went up to 175℃ , but the distribution of C30-C32 Keto - alcohols remained unaffected. At 200℃ most of the sterols and Keto - alcohols were destroyed.
基金This study was supported by the National Natural Science Foundation of China(No.81873518).
文摘The effects of low ratio of n-6/n-3 polyunsaturated fatty acids(PUFA)have been clarified against atherosclerosis.Increasing evidence indicated that plant sterols(PS)have a significant cholesterol-lowering effect.This study explored the effects of PS combined with n-6/n-3(2:1)PUFA on atherosclerosis and investigated the possible mechanism.In ApoE−/−mice,the milk fat in high fat diets was replaced with n-6/n-3(2:1)PUFA alone or supplemented with 6%PS for 16 weeks.Results demonstrated that PS combined with PUFA exerted commentary and synergistic effects on ameliorating atherosclerosis,improving lipid metabolism and lipid deposition in liver,and alleviating inflammatory response.These changes were accompanied with decreased serum TC,TG,LDL-C and increased fecal cholesterol efflux,as well as the lower inflammatory cytokine CRP,IL-6,TNF-α.It is suggested that the underlying mechanism of PS combined with n-6/n-3(2:1)PUFA promoting the fecal cholesterol efflux may be mediated by liver X receptorα/ATP-binding cassette transporter A1 pathway.
基金Joint Fund of NSFC and NSFY(No.U1132604)Key Program of MOST of CHINA(Nos.2007BAD32B03 and SB2007FY400)Foundation of State Key Laboratory of Phytochemistry and Plant Resources in West China(P2010-ZZ14).
文摘Two new triterpenoids(1 and 2)and a new sterol(3),together with six known constituents(4–9),were isolated from the leaves and twigs of Melia azedarach.Their chemical structures were elucidated on the basis of spectroscopic analysis.
文摘Two new sterol have been isolated from the South China Sea marine organism.Compound 1 was isolated from the sponge Polymastia sobustia and compound 2 was obtained from the soft coral Sinularia inexplicata. Their structures were established as 3β-hydroxy-stigmast-5en-7-one and 24 - methylene cholestan -3β, 66, 9α,19 -tetrol by variety of spectral analysis such as IR, EIMS, 1DNMR, 1H-1H COSY HMQC, HMBC, NOESY.
文摘The purpose of the study was to establish an analytical method to simultaneously determine multiple sterols in tobacco leaves rapidly and accurately.In this gas chromatography-triple quadruple tandem mass spectrometry(GC-MS/MS)based method,various conditions for sterols extraction were assessed and the instrumental operation parameters were optimized with 5α-cholane as an internal standard.Using this method,eight plant sterols,namely lanosterol,campesterol,chenodeoxycholic acid,cholesterol,β-sitosterol,stigmasterol,dihydrotachysterol and ergosterol,were separated in less than 30 min.The linear correlation coefficients were over 0.998 9,the low detection limits were in the range of 0.010 3-0.141 4 μg/g.The recoveries were from 87.30% to 115.60%,with low standard deviations.In conclusion,this method demonstrates good repeatability,accuracy,and high sensitivity,and is best suited for rapid analysis of multiple sterols in tobacco leaves.
文摘From the aerial parts of Clerodendrum colebrookianum Walp., two new C29 sterols colebrin A and colebrin B, were isolated, along with a known compound, clerosterol. The structures of the new compounds were elucidated on the basis of spectral evidence.
文摘Free sterols from rice dry embryo reduce the onset phase transition temperature and widen the transition range of total polar lipids and phosphatidylglycerol, which increases the membrane fluidity below their phase transition temperature and decreases the fluidity of membranes above their phase transition temperature. And 50% of free sterols result in a complete disappearance of phase transition. The fluidity of other main components of polar lipids is decreased by free sterols above 0℃. The results confirm that free sterols can modulate membrane lipid fluidity.
基金The study was supported by the National Natural Science Foundation of China(No.41876118)the Global Climate Changes and Air-Sea Interaction Program(No.GASI-02-PAC-ST-Wwin)This is MCTL(Key Laboratory of Marine Chemistry Theory and Technology)contribution#281.
文摘The northern South China Sea(NSCS)is significantly influenced by the Kuroshio intrusion and the coastal currents.Our knowledge on the roles of both currents on phytoplankton spatial variations is still inadequate.Here,we investigated the concentrations of phytoplankton biomarkers and their proportions in surface suspended particles from 47 sites of the NSCS during summer of 2017 and 2019.Brassicasterol/epi-brassicasterol,dinosterol,and C37 alkenones were used as proxies of biomass for diatoms,dinoflagellates,and haptophytes,respectively,and their sum indicating total phytoplankton biomass.A three end-member mixing model was applied to quantitatively assess the influence extent of the Kuroshio intrusion and the coastal currents.Our results showed that the Kuroshio intrusion and the coastal currents contributed equally to the overall surface water masses in the study area;however,the two currents had distinct effects on the spatial distribution of phytoplankton.For phytoplankton biomass,the eutrophic coastal currents were likely to be the main controlling factors,while the impact of the Kuroshio intrusion was weak and stimulated significant increases in phytoplankton biomass only at certain boundary sites.For phytoplankton community structures,the Kuroshio and its intrusion were the main factors,resulting in an increase in the proportions of dinoflagellates and haptophytes.The proportion of diatoms slightly increased due to the influence of the coastal currents.Our study quantifies the effects of the Kuroshio and the coastal currents on phytoplankton in the NSCS in terms of hydrological parameters,providing an important basis for the understanding of ecological functions and biogeochemical cycles in marginal sea-open ocean boundary regions.
文摘Objective: This study focused on the antibacterial and anti-proliferative activity of extracts from Carica papaya and Cocos nucifera roots. Methodology: The minimum inhibitory concentration and the minimum bactericidal concentration of the extracts on Escherichia coli, Pseudomonas aeruginosa, Streptococcus mutans, and Staphylococcus aureus were deduced by the microdilution method. The anti-biofilm activity was determined on all four strains and anti-quorum sensing activity by inhibition of violacein production in Chromobacterium violaceum. Anti-proliferative activity on prostate cultured cancer cells was evaluated by MTT assay. Sterols and triterpenes were also assayed in this study. Results: The methanolic extract of Carica papaya showed the best anti-biofilm effect with a percentage inhibition of 66.10 ± 1.79. The methanolic extract of Cocos nucifera had the strongest inhibition on the production of quorum sensing (61.42 ± 0.28). In addition, the methanolic extract of Cocos nucifera roots showed the best cytotoxic effect on prostate cancer LNCaP cell lines (IC<sub>50</sub> = 26.98 ± 2.6 μg/mL) and Carica papaya on the PC-3 lines (IC<sub>50</sub> = 127.20 ± 5.99 μg/mL). The extracts were also rich in triterpenes and sterols. Conclusion: This study provides support for the ethnomedical use of Carica papaya and Cocos nucifera roots as an antimicrobial and anticancer.
基金supported by the National Natural Science Foundation of China(31801547)Some C.elegans strains were provided by CGC,which is funded by the NIH Office of Research Infrastructure Programs.
文摘Fuzhuan brick-tea(FZT)has long been consumed for its supposed weight loss and lipid-lowering benefi ts.In this study,we show that the regulation of fat storage in Caenorhabditis elegans from a water extract of FZT was affected by cholesterol levels.We found that FZT signifi cantly decreased fat storage under normal cholesterol levels or in a cholesterol-free diet,while lipid accumulation was increased for a high cholesterol diet.Moreover,this mechanism may involve the conserved sterol regulatory element-binding protein(SREBP)/mediator-15(MDT-15)signaling pathway and the nuclear hormone receptor NHR-80.In addition,lipid synthesis-related genes inhibited by FZT were partially affected by a cholesterol-free diet.Thus,our fi ndings suggested that the potential lipid-lowering effects of FZT may depend on the cholesterol level,which may help to improve the consumption of FZT.
基金supported by JSPS KAKENHI Grant Number 18K09285.
文摘Endometrial carcinoma(EMC)is associated with obesity;however,the underlying mechanisms have not yet been elucidated.Peroxisome proliferator-activated receptor alpha(PPARα)is a nuclear receptor that is involved in lipid,glucose,and energy metabolism.PPARαreportedly functions as a tumor suppressor through its effects on lipid metabolism;however,the involvement of PPARαin the development of EMC remains unclear.The present study demonstrated that the immunohistochemical expression of nuclear PPARαwas lower in EMC than in normal endometrial tissues,suggesting the tumor suppressive nature of PPARα.A treatment with the PPARαactivator,irbesartan,inhibited the EMC cell lines,Ishikawa and HEC1A,by down-regulating sterol regulatory element-binding protein 1(SREBP1)and fatty acid synthase(FAS)and up-regulating the tumor suppressor genes p21 and p27,antioxidant enzymes,and AT-rich interaction domain 1A(ARID1A).These results indicate the potential of the activation of PPARαas a novel therapeutic approach against EMC.
文摘The mass spectrometric fragmentation of TMS derivatives of sterols was studied and analyzed based on the mass spectrometry of the TMS derivatives of standards.The double bond numbers and the degree of the methylize,alkylize and the related position in the sterol nucleus and the side chains were confirmed by the characteristic ions.Total lipids were extracted using Bligh-Dyer method.Sterols were isolated by solvent partition with chloroform-hexane(1 ∶4,by volume),derivated by BSTFA,and analyzed by GC-MS.The regular pattern was used for identifying the sterols in a dinoflagellate from the Symbodinium sp.
文摘Objective: To explore anti-inflammatory activities of organic extract and its semi-purified fractions(ethanol, acetone, methanol/dichloromethane) from the Mediterranean gorgonian Eunicella singularis. Methods: The anti-inflammatory and analgesic activities were evaluated, using the carrageenan-induced rat paw edema model and the acetic acid writhing test in mice. The gastroprotective activity was determined using HCl/Et OH induced gastric ulcers in rats. The purification and structure elucidation of compound(s) from the more effective fraction were determined by chromatographic and spectroscopic methods and in comparison with data reported in the literature. Results: The fraction F-Et OH showed an important antiinflammatory activity associated with significant analgesic and gastroprotective properties. The purification and structure elucidation of compound(s) from this fraction lead to the identification of one diterpenoid and four sterols. Conclusions: These results suggested that components from the active fraction can be used to treat various anti-inflammatory diseases.
文摘The aim of this review is to enlighten the critical roles that the liver plays in cholesterol metabolism. Liver transplantation can serve as gene therapy or a source of gene transmission in certain conditions that affect cholesterol metabolism, such as low-density-lipoprotein(LDL) receptor gene mutations that are associated with familial hypercholesterolemia. On the other hand, cholestatic liver disease often alters cholesterol metabolism. Cholestasis can lead to formation of lipoprotein X(Lp-X), which is frequently mistaken for LDL on routine clinical tests. In contrast to LDL, Lp-X is non-atherogenic, and failure to differentiate between the two can interfere with cardiovascular risk assessment, potentially leading to prescription of futile lipid-lowering therapy. Statins do not effectively lower Lp-X levels, and cholestasis may lead to accumulation of toxic levels of statins. Moreover, severe cholestasis results in poor micellar formation, which reduces cholesterol absorption, potentially impairing the cholesterol-lowering effect of ezetimibe. Apolipoprotein B-100 measurement can help distinguish between atherogenic and non-atherogenic hypercholesterolemia. Furthermore, routine serum cholesterol measurements alone cannot reflect cholesterol absorption and synthesis. Measurements of serum non-cholesterol sterol biomarkers- such as cholesterol precursor sterols, plant sterols, and cholestanol- may help with the comprehensive assessment of cholesterol metabolism. An adequate cholesterol supply is essential for liver-regenerative capacity. Low preoperative and perioperative serum cholesterol levels seem to predict mortality in liver cirrhosis and after liver transplantation. Thus, accurate lipid profile evaluation is highly important in liver disease and after liver transplantation.
文摘Our overall knowledge of the medicinal uses of plants suggests that natural compounds could be useful in the treatment of cutaneous fungal infections in tropical regions. Furthermore, the possibilities of treatment using plant extracts may be even broader than is already known when one considers plants that have not been extensively studied in this context, such as the regional species Phoenix dactylifera and Ziziphus spina-christi. This study compared the antimicrobial activity of Phoenix dactylifera and Ziziphus spina-christi extracts in terms of their biochemical and molecular effects on Candida albicans (ATCC CA 10231). These effects included altered levels of intracellular sterols, changes in the permeability of the cell membrane, and changes in the TEF1: QRTTEF1, CaERG1: ERG1, CdERG12: CdERG1, and ERG25: ERG25 genes. Scanning electron microscopy (SEM) was used to identify morphological characteristics, and energy-dispersive X-ray spectroscopy (EDAX) analyses were conducted. In treated samples, the SEM and EDAX analyses showed cell cavities and shrinkage of the cell wall, and the number of cells was reduced to only a few abnormal cells as compared with that in the untreated samples. Yttrium was detected in the cells treated with Z. spina-christi, and high levels of osmium were detected in the cells treated with P. dactylifera. Compared with control cells, cells exposed to the concentration 150 μl/ml of Z. spina-christi extract had an average sterol concentration that was nearly 3 times higher, while the concentration was 5.5 times higher for cells treated with the 150 μl/ml of P. dactylifera extract. The ethanol extracts affected the permeability of C. albicans cell membrane. Gene sequencing showed gaps and mismatches in the ERG1, ERG12, and ERG25 genes after treatment with P. dactylifera and Z. spina-christi extracts compared with that in the controls. The results were highly significant (p ≤ 0.01). We conclude that the ethanol extracts of P. dactylifera and Z. spina-christi have antimicrobial activity through several mechanisms in the yeast cell.
文摘Background: Plants have for a long time been used as medicines to treat ailments. Cassia abbreviata (C. abbreviata) is one of the plants that has been widely used in the management of a range of ailments, including malaria, diarrhea, and abscesses. Aim: This study was conducted to investigate the phytochemical composition of crude extracts of the roots, leaves, and stem bark of C. abbreviata. Materials and Methods: This was a laboratory-based study in which the fresh leaves, stem bark, and roots of C. abbreviata were collected, thoroughly cleaned, chopped into small pieces, and kept at room temperature until fully dry. The dried plant parts were powdered separately and stored separately in airtight containers for the phytochemical investigation. Ethanol (96% v/v) or distilled water was used for the extraction of components of the coarse powder. The mixtures were separately filtered, and the filtrates were reduced to a concentrated semisolid mass by drying in a water bath at 40?C. Thereafter, phytochemical analysis for flavonoids, phenolics, tannins, saponins, alkaloids, terpenoids, glycosides, carbohydrates, and proteins was done. Results: The phytochemical analysis of the ethanolic extracts revealed the presence of high concentrations of tannins, reducing sugars, and sterols in the stem bark and roots. Flavonoids, phenolics, and proteins were present in high concentrations in the stem bark, while anthraquinone, glycosides, and alkaloids were present in the leaves and roots, respectively. Conclusion: C. abbreviata plant contains a wide range of phytochemical constituents. Depending on the solvent used for extraction, various compositions of phytochemicals are obtained in each part of the tree. However, extraction with ethanol showed a better concentration than with water for most of the phytochemicals.
