Aim To investigate novel bioactive and structural metabolites from marineorganisms. Methods Column chromatography in association with semi-preparative HPLC were used for theisolation of compounds. 1D and 2D NMR, IR, U...Aim To investigate novel bioactive and structural metabolites from marineorganisms. Methods Column chromatography in association with semi-preparative HPLC were used for theisolation of compounds. 1D and 2D NMR, IR, UV, and MS were employed for structure elucidation.Results From the butanol fraction of the 95% EtOH extract of the starfish Asterias rollestoni, a newcompound N^7 -2'-deoxypseudoxanthosine (1), along with sixteen known compounds, 2'-0-methyl-inosine(2), 2'-deoxyinosine (3), 2'-0-methylguanosine (4), inosine (5); thymine (6), uracil (7), thymidine(8), deoxyuridine (9), 2'-0-methyluridine (10), ( ― )-(1S, 3S)-1-methyl-1, 2, 3,4-terrahydro-β-carboline-3-carboxyl-ic acid (11), ( ― )-(1R, 3S)-1-methyl-1, 2, 3,4-tetrahydro-β-carboline-3-carboxylic acid (12) , ( ― )-(3S)- 1, 2, 3,4-tetrahydro-β-carboline-3-carboxylic acid (13), L-tryptophan (14), L-phenylalanine (15), 3-carboxyindole (16), and p-hydroxybenzoic acid (17) , have been isolated. Conclusion Compound 1 is a newnatural product, and compounds 8, 9 and 10 are isolated from natural sources for the first time, andthe known compounds except 14 and 15 are first reported from starfish Asterias rollestoni.展开更多
A new asterosaponin named novaeguinoside A, along with a known saponin, asteronyl pentaglycoside sulfate, was isolated from the starfish Culcita novaeguineae. The new compound was identified to be sodium 6α-O-{β-D-f...A new asterosaponin named novaeguinoside A, along with a known saponin, asteronyl pentaglycoside sulfate, was isolated from the starfish Culcita novaeguineae. The new compound was identified to be sodium 6α-O-{β-D-fucopyranosyl-(1→2)-β-D-fucopyranosyl-(1→4)-[β-D- quinovopyranosyl-(1→2)]-β-D-xylopyranosyl-(1→3)-β-D-quinovopyranosyl}-5α-pregn-9(11)-en- 20-one-3β-yl-sulfate by extensive spectral analysis and chemical evidence.展开更多
A new polyhydroxysteroidal glycoside, （20R,24R）-16-O-（4-O-methyl-2-acetamido-2-deoxy-β-D-galactopyranosyl）-24-ethyl- 5α-cholest-8（14）-en-313,613,713,16α-tetrol （anthenoside A, 1）, was isolated from the star...A new polyhydroxysteroidal glycoside, （20R,24R）-16-O-（4-O-methyl-2-acetamido-2-deoxy-β-D-galactopyranosyl）-24-ethyl- 5α-cholest-8（14）-en-313,613,713,16α-tetrol （anthenoside A, 1）, was isolated from the starfish Anthenea chinensis. Its structure was elucidated by extensive spectral analysis and chemical evidences. 1 exhibited significant cytotoxicity against human tumor K-562, BEL-7402 and U87MG cells.展开更多
To understand the mechanisms of starfish regeneration, the arms of adult starfish Asterias rollestoni Bell were amputated and their regeneration patterns and cellular mechanisms were studied.It was found that cells in...To understand the mechanisms of starfish regeneration, the arms of adult starfish Asterias rollestoni Bell were amputated and their regeneration patterns and cellular mechanisms were studied.It was found that cells in the outer epidermis and inner parietal peritoneum near the end of the stump began to dedifferentiate 4 d after amputation. The dedifferentiated cells in the outer epidermis proliferated,migrated to the wound site and formed a thickened pre-epidermis which would then re-differentiate gradually into ma-ture epidermis.The new parietal peritoneum formed on the coelomic side of wound might be from the curvely elongated parietal peritoneum, resulting from the dedifferentiated and proliferated cells by extension. Afterwards, the proliferated cells made the outer epidermis and inner parietal peritoneum invaginate into the interior dermis and formed blastema-like structures together with induced dedifferentiated dermal cells. Most interestingly, the arm regeneration in A. rollestoni was achieved synchronously by de novo arm-bud formation and growth, and arm-stump elongation. The crucial aspects of arm-bud formation included cell dedifferentiation, proliferation and migration, while those of arm-stump elongation included cell dedifferentiation, proliferation, invagination, and arm-wall-across blastema-like structure formation. The unique pattern and cellular mechanisms of amputated arm regeneration make it easier to understand the rapid regeneration process of adult starfish. This study may lay solid foundations for the research into mo-lecular mechanisms of echinoderm regeneration.展开更多
A variety of soft wall-climbing robots have been developed that can move in certain patterns.Most of these soft robots can only move on conventional surfaces and lack adaptability to complex surfaces.Improving the ada...A variety of soft wall-climbing robots have been developed that can move in certain patterns.Most of these soft robots can only move on conventional surfaces and lack adaptability to complex surfaces.Improving the adaptability of soft robots on complex surfaces is still a challenging problem.To this end,we study the layered structure of the starfish tube foot and the valve flap structure in the water vascular system,and use an ultrasonic stress detector to study the stiffness distribution of the arm structure.Inspired by the motion of the starfish,we present a bionic soft wall-climbing robot,which is driven by two groups of pneumatic feet and achieves body bending through active adaptation layers.We design the structure of the foot to flex to provide driving force,and there are suction cups at the end of the foot to provide suction.The soft foot has a simple structure design,adapts to a variety of surfaces,and does not damage the surface of the substrate.Variable stiffness layers achieve stiffness changes by the principle of line blocking.The Central Pattern Generator theory is introduced to coordinately control the multiple feet of the robot.After experiments,we verify the adaptability of the soft robot to curved surfaces.The research may provide a reference for the design and development of crawling soft robots on complex surfaces.展开更多
Trumpet shell(Charonia lampas sauliae)(Mollusca, Heterogastropoda, Cymatidae) has extensive economic value. Studies on the artificial larval development of C. lampas sauliae for aquaculture utilization have become esp...Trumpet shell(Charonia lampas sauliae)(Mollusca, Heterogastropoda, Cymatidae) has extensive economic value. Studies on the artificial larval development of C. lampas sauliae for aquaculture utilization have become especially important due to the finite natural resources. In the present study, the growth and survival rate of the larvae of C. lampas sauliae broodstocks fed three types of starfish diets, Asterina pectinifera Müller & Troschel 1842, A. amurensis Lütken 1871 and their mixture were compared. The larval size increased gradually between day 10 and day 20 after hatching at 15℃ and 20℃. No difference was found in body size and specific growth rate(SGR)(two-way ANOVA; P > 0.05). However, during transition from trochophore to veliger stage 20 days after hatching, significant increases in larval survival and growth rates were observed. The maximum survival rate was observed on day 10. The mean survival rate was 0.463, 0.730 and 0.515 at 15℃, and 0.369, 0.713 and 0.444 at 20 when ℃ A. pectinifera, A. amurensis and their mixture were fed, respectively. The SGR and survival rate of the larvae were definitely influenced by the diets(P < 0.05), and the effect of A. amurensis alone was higher than that of A. pectinifera alone and their mixture.展开更多
A Co-based metal-organic framework （Co-MOF） with a unique three-dimensional starfish-like nanostructure was successfully synthesized using a simple ultrasonic method. After subsequent carbonization and oxidation, a ...A Co-based metal-organic framework （Co-MOF） with a unique three-dimensional starfish-like nanostructure was successfully synthesized using a simple ultrasonic method. After subsequent carbonization and oxidation, a nanocomposite of nitrogen-doped carbon with a Co3O4 coating （Co3O4@N-C） with a porous starfish-like nanostructure was obtained. The final hybrid exhibited excellent lithium storage performance when evaluated as an anode material in a lithiumion battery. A remarkable and stable discharge capacity of 795 mAh·g^-1 was maintained at 0.5 A·g^-1 after 300 cycles. Excellent rate capability was also obtained. In addition, a full Co3O4@N-C/LiFePO4 battery displayed stable capacity retention of 95% after 100 cycles. This excellent lithium storage performance is attributed to the unique porous starfish-like structure, which effectively buffers the volume expansion that occurs during Li^＋ insertion/deinsertion. Meanwhile, the nitrogendoped carbon coating enhances the electrical conductivity and provides a buffer layer to accommodate the volume change and accelerate the formation of a stable solid electrolyte interface layer.展开更多
Comprehensive Summary Sepositoside A(1)is a prototypical cyclic steroid glycoside bearing a hybrid 16-membered ring composed of the steroid skeleton and a 1,2-trans-linked trisaccharide.Herein,we report an expedient a...Comprehensive Summary Sepositoside A(1)is a prototypical cyclic steroid glycoside bearing a hybrid 16-membered ring composed of the steroid skeleton and a 1,2-trans-linked trisaccharide.Herein,we report an expedient access toward two simplified analogues,in which the strained 16-membered ring is constructed via Au(I)-catalyzed intramolecular addition of alcohol to epoxide.A similar macroetherification in relevant steroid trisaccharides has been intensively examined,however,failed to furnish the macrocyclic skeleton of Sepositoside A.展开更多
Comprehensive Summary Luzonicosides A(1)and D(2)are the major saponins isolated from pacific starfish Echinaster Luzonicus,featuring a sterically congested 16-membered ring which is formed by bridging the C3 and C6 of...Comprehensive Summary Luzonicosides A(1)and D(2)are the major saponins isolated from pacific starfish Echinaster Luzonicus,featuring a sterically congested 16-membered ring which is formed by bridging the C3 and C6 of a 3β,6β-dihydroxy-Δ7-ene steroid with a 1,2-trans-linked linear trisaccharide via glycosidic and ether bonds,respectively.Here,we describe a formal total synthesis of starfish cyclic steroid glycosides 1 and 2.The synthetic route is highly modular and versatile,involving construction of the 16-membered macrocycles via Au(I)-catalyzed intramolecular glycosylation,highly efficient installation of unsaturated sugar moieties with ortho-hexynylbenzoates,elaboration of glucuronic acid unit via post-oxidation,and a de novo synthesis of the ether-linked pyranose unit.展开更多
Comprehensive Summary Sepositoside A(1)is the major and first cyclic steroid glycoside isolated from starfishes,which features a strained 16-membered ring formed by tethering C3 and C6 of the steroid aglycone with a l...Comprehensive Summary Sepositoside A(1)is the major and first cyclic steroid glycoside isolated from starfishes,which features a strained 16-membered ring formed by tethering C3 and C6 of the steroid aglycone with a linear trisaccharide.We conceived a convergent synthetic plan in which sepositoside A was disconnected into a disaccharide and a steroid-glucose hybrid ether.The desired 3β,6β-dihydroxy-Δ7,8-23-one aglcyone was readily prepared from dehydroepiandrosterone in 12 steps.The etherification of the 6β-hydroxy-Δ7,8-steroid with a variety of hexopyranoside-C6-electrophiles and CO_(2)-extrusion of a steroid-pyranose hybrid carbonate were extensively studied;however,formation of the desired steroid-pyranose etherate linkage has not been successful.Model studies on theβ-selective installation of the(1→2)-linked disaccharide onto the steroidal C3β-OH with the corresponding disaccharideα-imidates were also examined,however,formation of theα-glycosides prevailed.The present results force us to explore alternative approaches to construct the steroid-pyranose etherate linkage and stepwise assembly of the glycans en route to the starfish cyclic steroid glycosides,which will be presented in two articles that follow.展开更多
Objective:To isolate and characterize the antibacterial compounds from starfish Stellaster equestris(S.equestris).Methods:The whole body was extracted with high polar and medium polar solvents such as methanol and eth...Objective:To isolate and characterize the antibacterial compounds from starfish Stellaster equestris(S.equestris).Methods:The whole body was extracted with high polar and medium polar solvents such as methanol and ethanol.The antibacterial activity has been tested against human bacterial pathogens using standard disc diffusion method.Results:The starfish S.equestris was collected from Mudasalodai,southeast coast of India.the maximum zone inhibition[(9.7±0.3)mm]against Escherichia coli(E.coli)and Vibrioparahaemolyticus at 100%concentration and minimum was Staphylococcus aureus[(4.0±0.6)mm].The crude ethanol extract showed maximum zone of inhibition in E.coli[(9.70±0.33)mm]and the lowest concentration exhibited the minimum inhibition activity against all bacterial pathogens.The fractions showed the maximum inhibition zone in Klebsiella oxytoca(5.00±0.82 mm),Salmonella typhi(S.typhi)(5.00±0.82)and Staphylococcus aureus[(3.0±2.3)mm].One way ANOVA analysis of antibacterial activity showed no significant difference at 0.05%level(P>0.05).The crude ethanol extract showed the minimum inhibitory concentration against E.coli(100%),Klebsiella pneumoniae The present investigation exhibited that the crude methanol extract showed the minimum inhibitory concentration against Klebsiella pneumonia,Proteus mirabilis,S.typhi,Staphylococcus aureus and Vibrio cholerae at 100%whereas E.coli was at 75%concentration.No bacterial growth was observed against Klebsiella oxytoca at 100%concentration.Conclusions:(75%),S.typhi(100%)and Vibrio cholerae(100%).The fraction exhibited equestris have remarkable antimicrobial activities against human bacterial pathogens.Further fraction has been characterised by using GC-MS and ^(1)H and ^(13)NMR spectroscopy analysis.The result of the present study indicates that the crude and fractions of starfish S.展开更多
Objective:To investigate the antioxidant properties of starfish Luidia maculata.Methods:The crude ethanol extract was partially purified using liquid-liquid partition and size exclusion chromatography.The antioxidant ...Objective:To investigate the antioxidant properties of starfish Luidia maculata.Methods:The crude ethanol extract was partially purified using liquid-liquid partition and size exclusion chromatography.The antioxidant properties of partially purified fractions were determined using the following methods:determination of total phenolic content,DPPH radical scavenging assay,hydrogen peroxide radical scavenging assay and reducing power assay.Results:Among the five fractions,collected fraction 3,4 and 5 exhibited antioxidant potential.Total phenolic content was high(360μg GAE/g)in fraction 3.In DPPH assay,fraction 3 showed the highest IC_(50)value 0.27 mg/mL and hydrogen peroxide scavenging assay showed the highest IC_(50)value of 0.07 mg/mL in fraction 5.Whereas,fraction 3 showed the highest absorbance(0.3)in reducing power assay when compared to fraction 4 and 5.Conclusions:In conclusion,the present study shows the extract of starfish Luidia maculata(F3)possesses good antioxidant activity.展开更多
文摘Aim To investigate novel bioactive and structural metabolites from marineorganisms. Methods Column chromatography in association with semi-preparative HPLC were used for theisolation of compounds. 1D and 2D NMR, IR, UV, and MS were employed for structure elucidation.Results From the butanol fraction of the 95% EtOH extract of the starfish Asterias rollestoni, a newcompound N^7 -2'-deoxypseudoxanthosine (1), along with sixteen known compounds, 2'-0-methyl-inosine(2), 2'-deoxyinosine (3), 2'-0-methylguanosine (4), inosine (5); thymine (6), uracil (7), thymidine(8), deoxyuridine (9), 2'-0-methyluridine (10), ( ― )-(1S, 3S)-1-methyl-1, 2, 3,4-terrahydro-β-carboline-3-carboxyl-ic acid (11), ( ― )-(1R, 3S)-1-methyl-1, 2, 3,4-tetrahydro-β-carboline-3-carboxylic acid (12) , ( ― )-(3S)- 1, 2, 3,4-tetrahydro-β-carboline-3-carboxylic acid (13), L-tryptophan (14), L-phenylalanine (15), 3-carboxyindole (16), and p-hydroxybenzoic acid (17) , have been isolated. Conclusion Compound 1 is a newnatural product, and compounds 8, 9 and 10 are isolated from natural sources for the first time, andthe known compounds except 14 and 15 are first reported from starfish Asterias rollestoni.
文摘A new asterosaponin named novaeguinoside A, along with a known saponin, asteronyl pentaglycoside sulfate, was isolated from the starfish Culcita novaeguineae. The new compound was identified to be sodium 6α-O-{β-D-fucopyranosyl-(1→2)-β-D-fucopyranosyl-(1→4)-[β-D- quinovopyranosyl-(1→2)]-β-D-xylopyranosyl-(1→3)-β-D-quinovopyranosyl}-5α-pregn-9(11)-en- 20-one-3β-yl-sulfate by extensive spectral analysis and chemical evidence.
基金the National Natural Science Foundation of China(No.20502035)the National High-Tech Research and Development Project(No.2006AA09Z423)
文摘A new polyhydroxysteroidal glycoside, （20R,24R）-16-O-（4-O-methyl-2-acetamido-2-deoxy-β-D-galactopyranosyl）-24-ethyl- 5α-cholest-8（14）-en-313,613,713,16α-tetrol （anthenoside A, 1）, was isolated from the starfish Anthenea chinensis. Its structure was elucidated by extensive spectral analysis and chemical evidences. 1 exhibited significant cytotoxicity against human tumor K-562, BEL-7402 and U87MG cells.
基金supported by the funds for Natural Science Research from the Bureau of Science and Technology of Qingdao(04-2-JZ-8)
文摘To understand the mechanisms of starfish regeneration, the arms of adult starfish Asterias rollestoni Bell were amputated and their regeneration patterns and cellular mechanisms were studied.It was found that cells in the outer epidermis and inner parietal peritoneum near the end of the stump began to dedifferentiate 4 d after amputation. The dedifferentiated cells in the outer epidermis proliferated,migrated to the wound site and formed a thickened pre-epidermis which would then re-differentiate gradually into ma-ture epidermis.The new parietal peritoneum formed on the coelomic side of wound might be from the curvely elongated parietal peritoneum, resulting from the dedifferentiated and proliferated cells by extension. Afterwards, the proliferated cells made the outer epidermis and inner parietal peritoneum invaginate into the interior dermis and formed blastema-like structures together with induced dedifferentiated dermal cells. Most interestingly, the arm regeneration in A. rollestoni was achieved synchronously by de novo arm-bud formation and growth, and arm-stump elongation. The crucial aspects of arm-bud formation included cell dedifferentiation, proliferation and migration, while those of arm-stump elongation included cell dedifferentiation, proliferation, invagination, and arm-wall-across blastema-like structure formation. The unique pattern and cellular mechanisms of amputated arm regeneration make it easier to understand the rapid regeneration process of adult starfish. This study may lay solid foundations for the research into mo-lecular mechanisms of echinoderm regeneration.
文摘A variety of soft wall-climbing robots have been developed that can move in certain patterns.Most of these soft robots can only move on conventional surfaces and lack adaptability to complex surfaces.Improving the adaptability of soft robots on complex surfaces is still a challenging problem.To this end,we study the layered structure of the starfish tube foot and the valve flap structure in the water vascular system,and use an ultrasonic stress detector to study the stiffness distribution of the arm structure.Inspired by the motion of the starfish,we present a bionic soft wall-climbing robot,which is driven by two groups of pneumatic feet and achieves body bending through active adaptation layers.We design the structure of the foot to flex to provide driving force,and there are suction cups at the end of the foot to provide suction.The soft foot has a simple structure design,adapts to a variety of surfaces,and does not damage the surface of the substrate.Variable stiffness layers achieve stiffness changes by the principle of line blocking.The Central Pattern Generator theory is introduced to coordinately control the multiple feet of the robot.After experiments,we verify the adaptability of the soft robot to curved surfaces.The research may provide a reference for the design and development of crawling soft robots on complex surfaces.
基金financially supported by Chonnam National University in 2013
文摘Trumpet shell(Charonia lampas sauliae)(Mollusca, Heterogastropoda, Cymatidae) has extensive economic value. Studies on the artificial larval development of C. lampas sauliae for aquaculture utilization have become especially important due to the finite natural resources. In the present study, the growth and survival rate of the larvae of C. lampas sauliae broodstocks fed three types of starfish diets, Asterina pectinifera Müller & Troschel 1842, A. amurensis Lütken 1871 and their mixture were compared. The larval size increased gradually between day 10 and day 20 after hatching at 15℃ and 20℃. No difference was found in body size and specific growth rate(SGR)(two-way ANOVA; P > 0.05). However, during transition from trochophore to veliger stage 20 days after hatching, significant increases in larval survival and growth rates were observed. The maximum survival rate was observed on day 10. The mean survival rate was 0.463, 0.730 and 0.515 at 15℃, and 0.369, 0.713 and 0.444 at 20 when ℃ A. pectinifera, A. amurensis and their mixture were fed, respectively. The SGR and survival rate of the larvae were definitely influenced by the diets(P < 0.05), and the effect of A. amurensis alone was higher than that of A. pectinifera alone and their mixture.
基金Acknowledgements This work is supported by the National Natural Science Foundation of China （Nos. 21173001 and 21371003） and Anhui Province Key Laboratory of Environment-Friendly Polymer Materials.
文摘A Co-based metal-organic framework （Co-MOF） with a unique three-dimensional starfish-like nanostructure was successfully synthesized using a simple ultrasonic method. After subsequent carbonization and oxidation, a nanocomposite of nitrogen-doped carbon with a Co3O4 coating （Co3O4@N-C） with a porous starfish-like nanostructure was obtained. The final hybrid exhibited excellent lithium storage performance when evaluated as an anode material in a lithiumion battery. A remarkable and stable discharge capacity of 795 mAh·g^-1 was maintained at 0.5 A·g^-1 after 300 cycles. Excellent rate capability was also obtained. In addition, a full Co3O4@N-C/LiFePO4 battery displayed stable capacity retention of 95% after 100 cycles. This excellent lithium storage performance is attributed to the unique porous starfish-like structure, which effectively buffers the volume expansion that occurs during Li^＋ insertion/deinsertion. Meanwhile, the nitrogendoped carbon coating enhances the electrical conductivity and provides a buffer layer to accommodate the volume change and accelerate the formation of a stable solid electrolyte interface layer.
基金the National Natural Science Foundation of China(21901251)Shanghai Sailing Program(19YF1458400)+1 种基金Laboratory for Marine Drugs and Bioproducts of Qingdao National Laboratory for Marine Science and Technology(LMDBKF201803)is acknowledged.The CAS Pioneer Hundred Talents Program(No.2017-128)the starting up funding of Kunming Institute of Botany are greatly thanked.
文摘Comprehensive Summary Sepositoside A(1)is a prototypical cyclic steroid glycoside bearing a hybrid 16-membered ring composed of the steroid skeleton and a 1,2-trans-linked trisaccharide.Herein,we report an expedient access toward two simplified analogues,in which the strained 16-membered ring is constructed via Au(I)-catalyzed intramolecular addition of alcohol to epoxide.A similar macroetherification in relevant steroid trisaccharides has been intensively examined,however,failed to furnish the macrocyclic skeleton of Sepositoside A.
基金the financial support from the National Natural Science Foundation of China(21901251)Shanghai Sailing Program(19YF1458400)Laboratory for Marine Drugs and Bioproducts of Qingdao National Laboratory for Marine Science andTechnology(LMDBKF201803).
文摘Comprehensive Summary Luzonicosides A(1)and D(2)are the major saponins isolated from pacific starfish Echinaster Luzonicus,featuring a sterically congested 16-membered ring which is formed by bridging the C3 and C6 of a 3β,6β-dihydroxy-Δ7-ene steroid with a 1,2-trans-linked linear trisaccharide via glycosidic and ether bonds,respectively.Here,we describe a formal total synthesis of starfish cyclic steroid glycosides 1 and 2.The synthetic route is highly modular and versatile,involving construction of the 16-membered macrocycles via Au(I)-catalyzed intramolecular glycosylation,highly efficient installation of unsaturated sugar moieties with ortho-hexynylbenzoates,elaboration of glucuronic acid unit via post-oxidation,and a de novo synthesis of the ether-linked pyranose unit.
基金the financial support from the National Natural Science Foundation of China(21901251)Shanghai Sailing Program(19YF1458400)Laboratory for Marine Drugs and Bioproducts of Qingdao National Laboratory for Marine Science and Technology(LMDBKF201803).
文摘Comprehensive Summary Sepositoside A(1)is the major and first cyclic steroid glycoside isolated from starfishes,which features a strained 16-membered ring formed by tethering C3 and C6 of the steroid aglycone with a linear trisaccharide.We conceived a convergent synthetic plan in which sepositoside A was disconnected into a disaccharide and a steroid-glucose hybrid ether.The desired 3β,6β-dihydroxy-Δ7,8-23-one aglcyone was readily prepared from dehydroepiandrosterone in 12 steps.The etherification of the 6β-hydroxy-Δ7,8-steroid with a variety of hexopyranoside-C6-electrophiles and CO_(2)-extrusion of a steroid-pyranose hybrid carbonate were extensively studied;however,formation of the desired steroid-pyranose etherate linkage has not been successful.Model studies on theβ-selective installation of the(1→2)-linked disaccharide onto the steroidal C3β-OH with the corresponding disaccharideα-imidates were also examined,however,formation of theα-glycosides prevailed.The present results force us to explore alternative approaches to construct the steroid-pyranose etherate linkage and stepwise assembly of the glycans en route to the starfish cyclic steroid glycosides,which will be presented in two articles that follow.
基金Supported by University Grants Commission,Govt.of India(Grant No.UGC-39-565/2010(SR)dated 12.01.2011)
文摘Objective:To isolate and characterize the antibacterial compounds from starfish Stellaster equestris(S.equestris).Methods:The whole body was extracted with high polar and medium polar solvents such as methanol and ethanol.The antibacterial activity has been tested against human bacterial pathogens using standard disc diffusion method.Results:The starfish S.equestris was collected from Mudasalodai,southeast coast of India.the maximum zone inhibition[(9.7±0.3)mm]against Escherichia coli(E.coli)and Vibrioparahaemolyticus at 100%concentration and minimum was Staphylococcus aureus[(4.0±0.6)mm].The crude ethanol extract showed maximum zone of inhibition in E.coli[(9.70±0.33)mm]and the lowest concentration exhibited the minimum inhibition activity against all bacterial pathogens.The fractions showed the maximum inhibition zone in Klebsiella oxytoca(5.00±0.82 mm),Salmonella typhi(S.typhi)(5.00±0.82)and Staphylococcus aureus[(3.0±2.3)mm].One way ANOVA analysis of antibacterial activity showed no significant difference at 0.05%level(P>0.05).The crude ethanol extract showed the minimum inhibitory concentration against E.coli(100%),Klebsiella pneumoniae The present investigation exhibited that the crude methanol extract showed the minimum inhibitory concentration against Klebsiella pneumonia,Proteus mirabilis,S.typhi,Staphylococcus aureus and Vibrio cholerae at 100%whereas E.coli was at 75%concentration.No bacterial growth was observed against Klebsiella oxytoca at 100%concentration.Conclusions:(75%),S.typhi(100%)and Vibrio cholerae(100%).The fraction exhibited equestris have remarkable antimicrobial activities against human bacterial pathogens.Further fraction has been characterised by using GC-MS and ^(1)H and ^(13)NMR spectroscopy analysis.The result of the present study indicates that the crude and fractions of starfish S.
基金Supported by University Grants Commission G4(1)1011/12 Govt.of India.
文摘Objective:To investigate the antioxidant properties of starfish Luidia maculata.Methods:The crude ethanol extract was partially purified using liquid-liquid partition and size exclusion chromatography.The antioxidant properties of partially purified fractions were determined using the following methods:determination of total phenolic content,DPPH radical scavenging assay,hydrogen peroxide radical scavenging assay and reducing power assay.Results:Among the five fractions,collected fraction 3,4 and 5 exhibited antioxidant potential.Total phenolic content was high(360μg GAE/g)in fraction 3.In DPPH assay,fraction 3 showed the highest IC_(50)value 0.27 mg/mL and hydrogen peroxide scavenging assay showed the highest IC_(50)value of 0.07 mg/mL in fraction 5.Whereas,fraction 3 showed the highest absorbance(0.3)in reducing power assay when compared to fraction 4 and 5.Conclusions:In conclusion,the present study shows the extract of starfish Luidia maculata(F3)possesses good antioxidant activity.
