- Four new triterpenes from Ilex cornuta Lindley
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Two new lupane-type triterpenes, 24β-hydroxylupenone (1) and 3β-hydroxy-lup-20(29)-en-24-al (2), and two new ursane-type triterpenes, 28-formyloxy-3β-hydroxy-urs-12-ene (3) and 28-formyloxy-3β-acetoxy- urs-12-ene (4), together with 26 known triterpenes (5
- Lee, Seung Young,Kim, Ho Kyung,Lee, Kang Ro
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- Biocatalytic allylic hydroxylation of unsaturated triterpenes and steroids by Bacillus megaterium CGMCC 1.1741
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In this study, we described the microbial catalyzed allylic oxidation by Bacillus megaterium CGMCC 1.1741 of three Δ12-pentacyclic triterpenes, erythrodiol (1), uvaol (2), hederagenin (3) and of four steroids including Δ5-steroids, diosgenin (4), pennogenin (5), 25(R,S)-ruscogenin (6) and Δ4-steroid, diosgenone (7). As a result, fourteen metabolites were generated with allyl hydroxyl moiety. Ten (1a-c, 2a, 2c, 3a, 5a-b, and 6a-b) of them were new natural products and their structures were determined on the basis of 1D/2D NMR and HR-MS data. Biocatalytic allylic oxidation by B. megaterium CGMCC 1.1741 is thus a potential non-toxic and efficient alternative method toward metal-mediated oxidation procedures in the synthesis of natural products and medicines.
- Ge, Haixia,Li, Guolong,Shen, Pingping,Wang, Wei,Wang, Weiwei,Xu, Shaohua,Yu, Boyang,Zhang, Jian
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- Cytotoxic and NF-κB and mitochondrial transmembrane potential inhibitory pentacyclic triterpenoids from Syzygium corticosum and their semi-synthetic derivatives
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Syzygium is a large genus of flowering plants, with several species, including the clove tree, used as important resources in the food and pharmaceutical industries. In our continuing search for anticancer agents from higher plants, a chloroform extract of the leaves and twigs of Syzygium corticosum collected in Vietnam was found to be active toward the HT-29 human colon cancer cell line. Separation of this extract guided by HT-29 cells and nuclear factor-kappa B (NF-κB) inhibition yielded 19 known natural products, including seven triterpenoids, three ellagic acid derivatives, two methylated flavonoids, a cyclohexanone, four megastigmanes, a small lactone, and an aromatic aldehyde. The full stereochemistry of (+)-fouquierol (2) was defined for the first time. Biological investigations showed that (+)-ursolic acid (1) is the major cytotoxic component of S. corticosum, which exhibited also potent activities in the NF-κB and mitochondrial transmembrane potential (MTP) inhibition assays conducted, with IC50 values of 31 nM and 3.5 μM, respectively. Several analogues of (+)-ursolic acid (1) were synthesized, and a preliminary structure-activity relationship (SAR) study indicated that the C-3 hydroxy and C-28 carboxylic acid groups and 19,20-dimethyl substitution are all essential in the mediation of the bioactivities observed for this triterpenoid.
- Ren, Yulin,Anaya-Eugenio, Gerardo D.,Czarnecki, Austin A.,Ninh, Tran Ngoc,Yuan, Chunhua,Chai, Hee-Byung,Soejarto, Djaja D.,Burdette, Joanna E.,de Blanco, Esperanza J. Carcache,Kinghorn, A. Douglas
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supporting information
p. 4452 - 4460
(2018/07/31)
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- Ursolic acid derivatives as potential antidiabetic agents: In vitro, in vivo, and in silico studies
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(Table presented.). Protein tyrosine phosphatase 1B (PTP-1B) has attracted interest as a novel target for the treatment of type 2 diabetes, this because its role in the insulin-signaling pathway as a negative regulator. Thus, the aim of current work was to obtain seven ursolic acid derivatives as potential antidiabetic agents with PTP-1B inhibition as main mechanism of action. Furthermore, derivatives 1–7 were submitted in vitro to enzymatic PTP-1B inhibition being 3, 5, and 7 the most active compounds (IC50?=?5.6, 4.7, and 4.6?μM, respectively). In addition, results were corroborated with in silico docking studies with PTP-1B orthosteric site A and extended binding site B, showed that 3 had polar and Van der Waals interactions in both sites with Lys120, Tyr46, Ser216, Ala217, Ile219, Asp181, Phe182, Gln262, Val49, Met258, and Gly259, showing a docking score value of ?7.48?Kcal/mol, being more specific for site A. Moreover, compound 7 showed polar interaction with Gln262 and Van der Waals interactions with Ala217, Phe182, Ile219, Arg45, Tyr46, Arg47, Asp48, and Val49 with a predictive docking score of ?6.43?kcal/mol, suggesting that the potential binding site could be localized in the site B adjacent to the catalytic site A. Finally, derivatives 2 and 7 (50?mg/kg) were selected to establish their in vivo antidiabetic effect using a noninsulin-dependent diabetes mice model, showing significant blood glucose lowering compared with control group (p?.05).
- Guzmán-ávila, Ricardo,Flores-Morales, Virginia,Paoli, Paolo,Camici, Guido,Ramírez-Espinosa, Juan José,Cerón-Romero, Litzia,Navarrete-Vázquez, Gabriel,Hidalgo-Figueroa, Sergio,Yolanda Rios, Maria,Villalobos-Molina, Rafael,Estrada-Soto, Samuel
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- Practical Synthesis of α-Amyrin, β-Amyrin, and Lupeol: The Potential Natural Inhibitors of Human Oxidosqualene Cyclase
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A practical synthesis of α-amyrin (1), β-amyrin (2), and lupeol (3) was accomplished in total yields of 32, 42, and 40% starting from easily available ursolic acid (4), oleanolic acid (5), and betulin (6), respectively. Remarkably, these three natural pentacyclic triterpenes exhibited potential inhibitory activity against human oxidosqualene cyclase.
- Chen, Dongyin,Xu, Fengguo,Zhang, Pu,Deng, Jie,Sun, Hongbin,Wen, Xiaoan,Liu, Jun
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- Microbial transformation of cadina-4,10(15)-dien-3-one, aromadendr-1(10)-en-9-one and methyl ursolate by Mucor plumbeus ATCC 4740
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The sesquiterpenes cadina-4,10(15)-dien-3-one (1) and aromadendr-1(10)-en-9-one (squamulosone) (14) along with the triterpenoid methyl ursolate (21) were incubated with the fungus Mucor plumbeus ATCC 4740. Substrates 1,14 and ursolic acid (20) were isolated from the plant Hyptis verticillata in large quantities. M. plumbeus hydroxylated 1 at C-12 and C-14. When the iron content of the medium was reduced, however, hydroxylation at these positions was also accompanied by epoxidation of the exocyclic double bond. In total nine new oxygenated cadinanes have been obtained. Sesquiterpene 14 was converted to the novel 2α,13-dihydroxy derivative along with four other metabolites. Methyl ursolate (21) was transformed to a new compound, methyl 3β,7β,21β-trihydroxyursa-9(11),12-dien-28-oate (22). Two other triterpenoids, 3β,28-dihydroxyurs-12-ene (uvaol) (23) and 3β,28-bis(dimethylcarbamoxy)urs-12-ene (24) were not transformed by the microorganism, however.
- Collins, Dwight O.,Ruddock, Peter L. D.,Grasse, Jessica Chiverton de,Reynolds, William F.,Reese, Paul B.
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p. 479 - 488
(2007/10/03)
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- NAPHTHOQUINONES AND TRITERPENES FROM SOME ASIAN DIOSPYROS SPECIES
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Investigation of the stem bark, wood and/or fruit of nine Asian Diospyros spp. (Ebenaceae) has revealed a range ot triterpenes and naphthoquinones typical of the genus.In addition to lupeol, betulin and betulinic acid, which were present in all samples, seven other triterpenes were isolated and identified.Six of the nine species also yielded naphthoquinones.In two species these were based on 2-methyljuglone (plumbagin) and in the other four on 7-methyljuglone.Key Word Index -- Diospyros spp; Ebenaceae; simple and dimeric naphthoquinones; triterpenes; oleanane-type; ursane-type.
- Zakaria, Muhamad Bin,Jeffreys, J. A. D.,Waterman, Peter G.,Zhong, Shou-Ming
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p. 1481 - 1484
(2007/10/02)
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- Triterpenoids of the Bark of Pieris japonica D. Don (Japenese Name: Asebi). II. 13C Nuclear Magnetic Resonance of the γ-Lactones of Ursane- and Oleane-type Triterpenes
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Eight triterpenoids and a sterol were isolated from the bark of Pieris japonica D.Don (Japenese name: asebi, Ericaceae) and have been elucidated as 3β-acetoxyurs-11-en-28,13-olide, 3β-acetoxy-12α-hydroxyolean-28,13-olide, 3β-acetoxy-28-hydroxyurs-12-ene, 3β,28-dihydroxyurs-12-ene, 3β-acetoxyurs-12-en-28-al, taraxeryl-acetate, taraxerol, taraxerone and β-sitosterone by a combination of chemical and spectroscopic studies. 13C Nuclear magnetic resonance spectral analysis of several γ-lactones of the ursane and oleanane series was undertaken, and all the carbons were assigned by means of single frequency off-resonance and selective decoupling methods and by comparison of the signals with those of methyl esters of acetyl ursolic acid and acetyl oleanolic acid.Keywords - Pieris japonica; bark; triterpenoid; ursane-type γ-lactone; oleanane-type γ-lactone; 1H-NMR; 13C-NMR
- Katai, Masaaki,Terai, Tadamasa,Meguri, Haruo
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p. 1567 - 1571
(2007/10/02)
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- OXIDATIVE TRANSFORMATIONS OF TRITERPENOIDS OF THE URSANE AND OLEANANE SKELETA WITH HYDROGEN PEROXIDE. INTRODUCTION OF 11,12-DOUBLE BOND AND 13(28)OXIDE MOIETY IN THE URSANE SYSTEM
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Treatment of oleanolic acid acetate (1b) with H2O2 in boiling HOAc gave the epoxy-γ-lactone 2b and the 12-hydroxy-γ-lactone 3b.The total absence of the 12-ketodihydro acid 4b among the oxidation products of 1b has been rationalised.The results of this reaction with several isomeric pairs of triterpenoids of the ursane and oleanane skeleta bearing functional groups at C-17 other than a carboxyl group show that for any appreciable oxidation involving the intermediacy of a 12β,13β-epoxide 6a or 6b, the 17-carboxyl group is an essential requirement.An intramolecular epoxidation of 12,13-double bond of 1a and 1b by 17-percarboxy acid formed in situ has been envisaged.The reactions aiming at introducing 11,12-double bond and 13(28)-oxide moiety in the ursane system are described.The desired compound 2c was obtained by treatment of the triol 1p with TsOH.With H2O2/TsOH, 1p, however, gave besides 2c, the rearranged product 8a.The difference in the chemical behaviour of 1p and 1q has been explained.Treatment of 2e with H2O2 in boiling HOAc gave the epoxide 2f.The mechanism of formation of 2a and 2b is discussed in the light of this observation.
- Majumder, P. L.,Bagchi, A.
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p. 649 - 656
(2007/10/02)
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