[show abstract][hide abstract] ABSTRACT: The fungal transformation of cedryl acetate (1) was investigated for the first time by using Cunninghamella elegans. The metabolites obtained include, 10β-hydroxycedryl acetate (3), 2α, 10β-dihydroxycedryl acetate (4), 2α-hydroxy-10-oxocedryl acetate (5), 3α,10β-dihydroxycedryl acetate (6), 3α,10α-dihydroxycedryl acetate (7), 10β,14α-dihydroxy cedryl acetate (8), 3β,10β-cedr-8(15)-ene-3,10-diol (9), and 3α,8β,10β -dihydroxycedrol (10). Compounds 1, 2, and 4 showed α-glucosidase inhibitory activity, whereby 1 was more potent than the standard inhibitor, acarbose, against yeast α-glucosidase. Detailed docking studies were performed on all experimentally active compounds to study the molecular interaction and binding mode in the active site of the modeled yeast α-glucosidase and human intestinal maltase glucoamylase. All active ligands were found to have greater binding affinity with the yeast α-glucosidase as compared to that of human homolog, the intestinal maltase, by an average value of approximately -1.4 kcal/mol, however, no significant difference was observed in the case of pancreatic amylase.
European journal of medicinal chemistry 02/2013; 62C:764-770. · 3.27 Impact Factor
[show abstract][hide abstract] ABSTRACT: Aims One of the aims of this research work is the isolation and identification of various constituents of two medicinally important plants (Iris loczyiand and Iris unguicularis). Secondly, the prime aim is the biological evaluation of these natural products to discover new potential inhibitors of α-glucosidase enzyme and protein glycation. Main methods Plants of the genus Iris contain a variety of secondary metabolites. Chromatographic techniques were applied for the isolation of different compounds from Iris loczyi and from Iris unguicularis. All the isolated compounds were screened for their α-glucosidase enzyme inhibition and antiglycation potential.Key findings It is shown in the results that two compounds (Kaempferol and 8-Methoxyeriodictyol) isolated from plant Iris unguicularis and compounds (Arborinone and 5,7-Dihydroxy-2',6-dimethoxyisoflavone) isolated from plant Iris loczyi possess promising activity against α-glucosidase enzyme as compare to acarbose which is used as a standard α-glucosidase inhibitor in this study. A flavanone (2',5-dihydroxy-6,7-methylenedioxy) isolated from Iris loczyi was explored as most active anti-glycating agent. Significance α-glucosidase enzyme is a therapeutic target to treat carbohydrate mediated diseases. In this study various inhibitors of α-glucosidase are identified which might be important for the management of diabetes. Similarly, antiglycation agents may have application for the management of late diabetic complications.
[show abstract][hide abstract] ABSTRACT: Duboscic acid (1), a triterpenoid with a unique carbon backbone, was isolated from Duboscia macrocarpa Bocq. It is the first member of a new class of triterpenoids, for which the name "dubosane" is proposed. Duboscic acid has a potent α-glucosidase inhibition, and its structure was unambiguously deduced by a single-crystal X-ray diffraction study.
[show abstract][hide abstract] ABSTRACT: Two new triterpenoids, 18alpha,19beta-20(30)-taraxasten-3beta,21alpha-diol (cichoridiol) (1) and 17-epi-methyl-6-hydroxyangolensate (intybusoloid) (2), were obtained from the methanolic extract of seeds of Cichorium intybus along with 11 known compounds, lupeol (3), friedelin (4), beta-sitosterol (5), stigmasterol (6), betulinic acid (7), betulin (8), betulinaldehyde (9), syringic acid (10), vanillic acid (11) 6,7-dihydroxycoumarin (12), and methyl-alpha-D-galactopyranoside (13). Compounds 1, 1a, and 11 showed a good alpha-glucosidase inhibitory activity.
Journal of Natural Products 06/2008; 71(5):910-3. · 3.29 Impact Factor
[show abstract][hide abstract] ABSTRACT: Fractionation of stem barks of Terminalia superba yielded two new ellagic acid derivatives, 3,4'-di-O-methylellagic acid 3'-O-beta-D-xylopyranoside (1) and 4'-O-galloy-3,3'-di-O-methylellagic acid 4-O-beta-D-xylopyranoside (2) together with known 3,3'-di-O-methylellagic acid, ellagic acid and 3,3'-di-O-methylellagic acid 4'-O-beta-D-xylopyranoside. Compounds (1) and (2) showed significant alpha-glucosidase inhibition activity and possessed significant immunoinhibitory activities with no cytotoxic effects.
CHEMICAL & PHARMACEUTICAL BULLETIN 06/2008; 56(6):847-50. · 1.56 Impact Factor
[show abstract][hide abstract] ABSTRACT: Four alkaloids named piperumbellactams A-D (1-4) were isolated from branches of Piper umbellatum together with known N-hydroxyaristolam II (5), N-p-coumaroyl tyramine (6), 4-nerolidylcatechol (7), N-trans-feruloyltyramine, E-3-(3,4-dihydroxyphenyl)-N-2-[4-hydroxyphenylethyl]-2-propenamide, beta-amyrin, friedelin, apigenin 8-C-neohesperidoside, acacetin 6-C-beta-d-glucopyranoside, beta-sitosterol, its 3-O-beta-d-glucopyranoside and its 3-O-beta-d-[6'-dodecanoyl]-glucopyranoside. Glycosidase inhibition, antioxidant and antifungal activities of these compounds were evaluated. Compounds 1-3 showed moderate alpha-glucosidase enzyme inhibition with IC50 values 98.07+/-0.44, 43.80+/-0.56 and 29.64+/-0.46, respectively. In DPPH radical scavenging assay, compounds 2, 3 and 6 showed potent inhibitory activity while compounds 4, 5 and 7 showed potent antifungal activity.
[show abstract][hide abstract] ABSTRACT: The biotransformation of a pentacyclic triterpene, oleanolic acid (1), with Fusarium lini afforded two oxidative metabolites, 2alpha,3beta-dihydroxyolean-12-en-28-oic acid (2), and 2alpha,3beta,11beta-trihydroxyolean-12-en-28-oic acid (3). Metabolite 3 was found to be a new compound. The structures were characterized on the basis of spectroscopic studies. These metabolites exhibited a potent inhibition of alpha-glucosidase enzyme.
Natural Product Research 05/2008; 22(6):489-94. · 1.03 Impact Factor
[show abstract][hide abstract] ABSTRACT: Three new sesquiterpene lactones, (4betaH)-5alpha-hydroxy-8alpha-(2-methylbut-2-enoyloxy)-2-oxo-1(10),11(13)-guaiadien-12,6alpha-olide (1), (4betaH)-8alpha-(2-methylbut-2-enoyloxy)-2-oxo-1(5),10(14),11(13)-guaiatrien-12,6alpha-olide (2) and 2,5-epoxy-2beta-hydroxy-4alpha-methoxy-8alpha-(2-methylbut-2-enoyloxy)-4(15),10(14),11(13)-germacratrien-12,6alpha-olide (3), have been isolated from roots and stems of Elephantopus mollis together with two known sesquiterpene lactones (4, 5). The identification of the isolates was accomplished by spectroscopic methods. Compounds (1-5) exhibited significant cytotoxic activities against mouse neuroblastoma B104 cells.
CHEMICAL & PHARMACEUTICAL BULLETIN 03/2008; 56(2):231-3. · 1.56 Impact Factor
[show abstract][hide abstract] ABSTRACT: A new geranylated isoflavone, 7-O-geranyl-6-methoxypseudobaptigenin (1) was isolated from the stem barks of Millettia conraui, along with known compounds 5-methoxydurmillone (2), conrauinone A (3), beta-amyrine (4), sitosterol (5), 3-O-beta-D-glucopyranosyl sitosterol (6) and n-docosanol (7). Compounds 1 and 4 showed a significant alpha-glucosidase inhibitory activity. The structures of the compounds were determined by analysis of their spectroscopic data.
CHEMICAL & PHARMACEUTICAL BULLETIN 10/2007; 55(9):1402-3. · 1.56 Impact Factor
[show abstract][hide abstract] ABSTRACT: In addition to fatty acids, a mixture of sterols (beta-sitosterol, stigmasterol, campesterol and stigmastanol), lupeol, arctigenin methylether, sesamin, vanillic acid (1), 2,6-dimethoxy-1,4-benzoquinone (2), betulinic acid and two pentacyclic triterpene acetates were isolated from Fagara tessmannii Engl. They were identified as 3beta-acetoxy-16beta-hydroxybetulinic acid (3a) and 3beta,16beta-diacetoxybetulinic acid (3b), and their structures were established using 1 and 2D NMR spectra and by comparison with published data. Two derivatives of the compounds were prepared. Some isolated compounds were evaluated for their antifungal and antibacterial activities. Compounds 1 and 3a showed significant inhibition of alpha-glucosidase.
[show abstract][hide abstract] ABSTRACT: Diseases are manifestations of complex biological processes in living systems. Through the applications of molecular biology and genetics, many diseases are now under- stood at the molecular level. This has provided researchers opportunities to develop lead mol- ecules with the capacity of blocking a particular disease mechanism. Diabetes is a complex metabolic disorder, characterized by hyperglycemia. The first objective of antidiabetic chemotherapy is to achieve normal glycemic index. Recently, major discoveries have been made to understand how the disease progresses and manifests its complications. We have used this growing understanding to work toward discovery of effective α-glucosidase in- hibitors and antiglycation agents of natural and synthetic origins. Reliable bench-top bio- chemical assays were employed, and several new molecular entities were studied with refer- ence to their structure-activity relationships.
Pure and Applied Chemistry - PURE APPL CHEM. 01/2007; 79(12):2263-2268.
[show abstract][hide abstract] ABSTRACT: The CH2Cl2/MeOH extract of the stem bark of Oriciopsis glaberrima ENGL. afforded four new acridone alkaloids namely oriciacridone C, D, E and F along with six known compounds: atalaphyllidine, oleanolic acid, butulinic acid, beta-sitosterol, stigmasterol, glucoside of stigmasterol and one synthetically known acridone: 1,3,5-trihydroxy-4-prenylacridone. The structures were established on the basis of MS, 1D and 2D NMR experiments. The acridones 1, 4 and 5 showed potent activity against alpha-glucosidase, while the acridones 1-5 showed moderate free radical scavenging activity against 1,1-diphenyl-2-picrylhydrazyl (DPPH).
CHEMICAL & PHARMACEUTICAL BULLETIN 04/2006; 54(3):292-6. · 1.56 Impact Factor
[show abstract][hide abstract] ABSTRACT: One new prenylated 1,4-anthraquinone and three new prenylated anthranols, named kengaquinone (1) and kenganthranols A (2), B (3), and C (4), were isolated from a hexane extract of the stem bark of Harungana madagascariensis. Six known compounds including anthraquinones, anthrones, and xanthones were also isolated and identified. The structures of the new compounds were determined by analysis of spectroscopic data and comparison with data of previously known analogues. Some isolated compounds (3-5, 7-11) were evaluated for their alpha-glucosidase inhibition activity. Compounds 3, 4, 8, and 11 showed significant activity, whereas compounds 7, 9, and 10 were inactive in this test.
Journal of Natural Products 03/2006; 69(2):229-33. · 3.29 Impact Factor
[show abstract][hide abstract] ABSTRACT: The investigation of the chemical constituents of Symplocos racemosa Roxb led to the isolation of two new glycosides, symcomoside A (1) and symcomoside B (2), together with one known glycoside, tortoside C (3), which is reported for the first time from this plant. The structures of the new compounds were determined by 1D and 2D homonuclear and heteronuclear NMR spectroscopy, from chemical evidence and by comparison with published data for closely related compounds. Symcomoside B (2) showed potent inhibitory activity against alpha-glucosidase in a concentration-dependent fashion with an IC50 value of 0.733 +/- 0.033 mM whereas symcomoside A (1) showed very weak inhibitory activity against alpha-glucosidase (9.90% in 0.70 mM).
Magnetic Resonance in Chemistry 07/2005; 43(6):486-8. · 1.53 Impact Factor