In this paper, two new compounds, ent-16α-hydroxy-15β-hydroxymethylbeyeran-19-oic acid 4 and its ethyl ester 5 were synthesized in good yield with a facile method that has never been reported. The mechanism of this ...In this paper, two new compounds, ent-16α-hydroxy-15β-hydroxymethylbeyeran-19-oic acid 4 and its ethyl ester 5 were synthesized in good yield with a facile method that has never been reported. The mechanism of this reaction was discussed and the mono-hydroxymethylation of carbonyl compound with two α-hydrogens via Tollens＇ reaction was firstly achieved. Compounds 2-5 were tested for activity of inhibition against glycosidases, among which 5 displays good inhibition of β-glucosidase and α-mannase, respectively.展开更多
Stevioside（1）, an ent-kaurene glycoside commercially extracted from Stevia rebaudiana Bertoni is used as a non-caloric sweetener for food in many countries. The increasing demand for low calory and natural food cont...Stevioside（1）, an ent-kaurene glycoside commercially extracted from Stevia rebaudiana Bertoni is used as a non-caloric sweetener for food in many countries. The increasing demand for low calory and natural food contributes to the increasing popularity of that glycoside. It has recently been demonstrated that stevioside and its derivatives have inhibitory effects on the inflammatory ear edema of mice and suppress the tumor-promoting effect in mouse skin.展开更多
The title compound was prepared and its crystal structure was determined using X-ray crystallographic method. The crystal is orthorhombic, space group is P212121 with a= 1. 1114(2) nm, b=1.7677(3) nm, c=1.8312(3) nm; ...The title compound was prepared and its crystal structure was determined using X-ray crystallographic method. The crystal is orthorhombic, space group is P212121 with a= 1. 1114(2) nm, b=1.7677(3) nm, c=1.8312(3) nm; Z=8. The geometric structure and conformation of the title compound obtained by MMX molecular mechanics calculation are in agreement with those obtained from X-ray determination.展开更多
Cyclodextrin metal-organic framework(CD-MOF)as a highly porous supramolecular carrier could be one of the solutions to the insolubility of isosteviol(STV).The solubility of STV was lower than20.00 ng/mL at pH 1.0 and ...Cyclodextrin metal-organic framework(CD-MOF)as a highly porous supramolecular carrier could be one of the solutions to the insolubility of isosteviol(STV).The solubility of STV was lower than20.00 ng/mL at pH 1.0 and pH 4.5,whilst its solubility increased to 20,074.30 ng/mL at pH 6.8 and129.58 ng/mL in water with a significant pH-dependence.The in vitro release profiles of STV from STV@CD-MOF(0.5:1)were pH-independent in distinct pH media and closed to be thoroughly released but no such release profiles were observed for STV@CD-MOF(1:1)owing to nanoclusters formation.The bioavailability of STV@CD-MOF(1:1)in rats was 8.67-fold higher than that of STV,and was1.32-and 1.27-fold higher than that of STV@CD and STV@CD-MOF(0.5:1).Our results indicated that the inclusion mechanism played a primary role when STV in CD-MOF was at a low loading ratio,while the increasement in bioavailability at a high loading ratio,which was attributed to the nanocluster mechanism.This was confirmed by molecular simulation.In conclusion,CD-MOF is a promising system for STV loading,overcoming the insolubility and to improve the bioavailability of this natural compound.展开更多
Isosteviol-amino acid conjugates were synthesized and used as chiral catalysts for the asymmetric three-component Mannich reaction with hydroxyacetone as donor molecule. Good yields （up to 98%） and excellent stereos...Isosteviol-amino acid conjugates were synthesized and used as chiral catalysts for the asymmetric three-component Mannich reaction with hydroxyacetone as donor molecule. Good yields （up to 98%） and excellent stereoselectivities （up to 97 ： 3 dr and 99% ee） were achieved in a short reaction time. In addition, syn- or anti-configurations of a-hydroxy-β-amino carbonyl compounds were obtained as main products with different chiral catalysts.展开更多
基金the National Natural Science Foundation of China(20372059)Natural Science Foundation of Henan Province for the financial support(0311020500).
文摘In this paper, two new compounds, ent-16α-hydroxy-15β-hydroxymethylbeyeran-19-oic acid 4 and its ethyl ester 5 were synthesized in good yield with a facile method that has never been reported. The mechanism of this reaction was discussed and the mono-hydroxymethylation of carbonyl compound with two α-hydrogens via Tollens＇ reaction was firstly achieved. Compounds 2-5 were tested for activity of inhibition against glycosidases, among which 5 displays good inhibition of β-glucosidase and α-mannase, respectively.
基金Supported by the National Natural Science Foundation of China(No.20572103).
文摘Stevioside（1）, an ent-kaurene glycoside commercially extracted from Stevia rebaudiana Bertoni is used as a non-caloric sweetener for food in many countries. The increasing demand for low calory and natural food contributes to the increasing popularity of that glycoside. It has recently been demonstrated that stevioside and its derivatives have inhibitory effects on the inflammatory ear edema of mice and suppress the tumor-promoting effect in mouse skin.
基金Supported by the National Natural Science Foundation of China
文摘The title compound was prepared and its crystal structure was determined using X-ray crystallographic method. The crystal is orthorhombic, space group is P212121 with a= 1. 1114(2) nm, b=1.7677(3) nm, c=1.8312(3) nm; Z=8. The geometric structure and conformation of the title compound obtained by MMX molecular mechanics calculation are in agreement with those obtained from X-ray determination.
基金financial support from the National Science Foundation for Young Scientists of China(No.81803441)the National Science and Technology Major Projects for the Major New Drugs Innovation and Development(No.2018ZX09721002-009,China)+1 种基金the National Natural Science Foundation of China(No.81873019)the University Synergy Innovation Program of Anhui Province(GXXT-2020-025)
文摘Cyclodextrin metal-organic framework(CD-MOF)as a highly porous supramolecular carrier could be one of the solutions to the insolubility of isosteviol(STV).The solubility of STV was lower than20.00 ng/mL at pH 1.0 and pH 4.5,whilst its solubility increased to 20,074.30 ng/mL at pH 6.8 and129.58 ng/mL in water with a significant pH-dependence.The in vitro release profiles of STV from STV@CD-MOF(0.5:1)were pH-independent in distinct pH media and closed to be thoroughly released but no such release profiles were observed for STV@CD-MOF(1:1)owing to nanoclusters formation.The bioavailability of STV@CD-MOF(1:1)in rats was 8.67-fold higher than that of STV,and was1.32-and 1.27-fold higher than that of STV@CD and STV@CD-MOF(0.5:1).Our results indicated that the inclusion mechanism played a primary role when STV in CD-MOF was at a low loading ratio,while the increasement in bioavailability at a high loading ratio,which was attributed to the nanocluster mechanism.This was confirmed by molecular simulation.In conclusion,CD-MOF is a promising system for STV loading,overcoming the insolubility and to improve the bioavailability of this natural compound.
基金Project supported by the National Natural Science Foundation Of China （No. 20772113）.
文摘Isosteviol-amino acid conjugates were synthesized and used as chiral catalysts for the asymmetric three-component Mannich reaction with hydroxyacetone as donor molecule. Good yields （up to 98%） and excellent stereoselectivities （up to 97 ： 3 dr and 99% ee） were achieved in a short reaction time. In addition, syn- or anti-configurations of a-hydroxy-β-amino carbonyl compounds were obtained as main products with different chiral catalysts.
