Isolation of alpha-glucosidase inhibitors produced by an endophytic fungus, Colletotrichum sp. TSC13 from Taxus sumatrana.

Colletotrichum sp. have potential to act as antidiabetic agent, due to its alpha-glucosidase inhibitory. Therefore, the objective of present study was to isolate and identify the bioactive compounds responsible for the alpha-glucosidase inhibitory activity in Colletotrichum sp. TSC13. The methanol extract of TSC13 mycelia, was partitioned with n-hexane, chloroform and ethyl acetate. The n-hexane fraction exhibited the strongest alpha-glucosidase inhibitory activity. Column chromatography of this fraction resulted in 8 sub-fractions (F1-8). Fraction 3 (F3) which showed 71.4 +/- 2.4% inhibition was analysed further. Analysis using GC-MS after methylation of F3 and comparison to spectra databases and confirmation using authentic sample standards showed that F3 had two saturated fatty acid methyl esters, palmitic acid and stearic acid methyl esters and three unsaturated fatty acid methyl esters, oleic acid, linoleic acid and linoleinic acid methyl esters. Unsaturated fatty acids showed higher activity than the saturated fatty acids and the methyl esters form of unsaturated fatty acids showed slightly less active than the free acids. Further analysis using an ethyl acetate extract, it was confirmed that most of the fatty acids were present in the form of free acids. Therefore, it was concluded that the alpha-glucosidase inhibitor compounds in Colletotrichum sp. TSC13 were unsaturated fatty acids. This is the first report that a Colletotrichum sp. from T. sumatrana has alpha-glucosidase inhibitory activity.

Screening of endophytic fungi having ability for antioxidative and alpha-glucosidase inhibitor activities isolated from Taxus sumatrana.

Endophytic microbes are considered as an important source of natural products. They show antibiotic, anticancer, antioxidative and antidiabetic activities. Therefore, there are many reports on the isolation and bioactivity screening of endophytic fungi from various plants including Taxus species. Taxus sumatrana (Miq.) de Laub is found in Indonesia. The objective of this study is to conduct an in vitro screening of 14 endophytic fungi isolated from Taxus sumatrana having antioxidative and alpha-glucosidase inhibitor activities. Each endophytic fungus was cultured for 7 days and the fungal mycelium and medium were extracted with methanol and ethyl acetate, respectively, to produce each extract. The antioxidative activity of each extract was tested by DPPH free radical scavenging activity and beta-carotene bleaching assays, whereas antidiabetic activity was tested based on alpha-glucosidase inhibitor activity. The screening results showed that fungal mycelia of TSC 13 had the best alpha-glucosidase inhibitor activity and TSC 24 had the best antioxidative activity. Isolation of bioactive compounds from TSC 13 and TSC 24 is being conducted. This is the first report that endophytic fungi isolated from T. sumatrana exhibited anti alpha-glucosidase inhibitory and anti oxidative activities.

Isolation of beta-(1-3) glucan compound from the water extract of indonesian jamur tanduk (Termitomyces eurirrhizus Berk).

Jamur Tanduk (Termitomyces eurirrhizus Berk) is one of uncultivated edible mushrooms from genus Termitomyces found in various regions in Indonesia. The purpose of this study is to analyze the chemical structure of its beta-glucan compound that possesses bioactivity as lowering cholesterol levels. Isolation and identification of beta-glucan compound from water extract of Jamur tanduk (local name), Termitomyces eurirrhizus Berk collected in Sumedang has been done. beta-glucan was isolated with Wasterlund methods and obtained as white powder. Isolated compound was identified based on interpretation of spectroscopies data such as Ultra-Violet (UV), Infra-Red (IR) and nuclear magnetic resonance one dimensional such as 1Hidrogen-Nuclear Magnetic Resonance (1H-NMR), 13Carbon- 13C-NMR) and Distortionless Enhancement by Polarization Transfer (DEPT) and two dimensional such as Correlation spectroscopy (COSY), Hetero Multiple Quantum Connectivity (HMQC) and Hetero Multiple Bond Connectivity (HMBC). The determination of molecule weight of sample based on viscosity measurements and obtained that beta-glucan has 322 molecules of glucose.

Fatty acid methyl ester from Neurospora intermedia N-1 isolated from Indonesian red peanut cake (oncom merah).

The objective of this study was to identify the Fatty Acid Methyl Ester (FAME) from Neurospora intermedia N-1 that isolated from Indonesian red peanut cake (oncom). FAME profiles have been used as biochemical characters to study many different groups of organisms, such as bacteria and yeasts. FAME from N. intermedia N-1 was obtained by some stages of extraction the orange spores and fractination using a chromatotron. The pure compound (1) was characterized by 500 mHz NMR (1H and 13C), FTIR and LC-MS. Summarized data's of 1H and 13C NMR spectra of compound 1 contained 19 Carbon, 34 Hydrogen and 2 Oxygen (C19H34O2). The position of the double bonds at carbon number 8 and 12 were indicated in the HMBC spectrum (2D-NMR). LC-MS spectrum indicates molecular weight of the compound 1 as 294 which is visible by the presence of protonated molecular ion [M+H] at m/z 295. Methyl esters of long chain fatty acids was presented by a 3 band pattern of IR spectrum with bands near 1249, 1199 and 1172 cm(-1). We suggested that the structure of the pure compound 1 is methyl octadeca-8,12-dienoate. The presence methyl octadeca-8,12-dienoate in N. intermedia is the first report.

Identification of cytotoxic constituent of Indonesian sponge Kaliapsis sp. (Bowerbank).

Identification of cytotoxic constituent of Indonesian sponge Kaliapsis sp. has been conducted. The structure identification was judged based on the spectroscopic data, namely, ultraviolet, MS, one and two-dimensional 1H-NMR and 13C-NMR methods. The cytotoxic constituent was identified as 1-(tetrahydro-4-hydroxy-5-(hydroxymethyl)furan-2-yl)-5-methyl pyrimidine-2,4(1H,3H)-dione. This constituent hasn't been isolated from sponges as natural product.

Antioxidant compound from the rhizomes of Kaempferia rotunda L.

This research aimed to investigate the antioxidant effect from rhizomes of K. rotunda for finding the active compounds by DPPH free radical scavenging activity assay. The chloroform-soluble extract of the rhizomes of K. rotunda showed significant scavenging effect on the on 1,1-diphenyl-2-picryl hydrazyl (DPPH) free radicals (IC50 = 180 microg mL(-1)). Two compounds of the chloroform-soluble extract were isolated and identified. Compound 1, 2'-hydroxy-4,4',6'-trimethoxy-chalcone was found as the active constituent (IC50 = 142 microg mL(-1)). Compound 2, (+)-crotepoxide, was inactive (IC50 = 1516 microg mL(-1)). The structures of compounds 1 and 2 were identified based on the basis of spectral evidence, Mass Spectrophotometry (MS) and 2D-NMR (2 dimension of Nuclear Magnetic Resonance) data including Heteromolecular Multiple Quantum Coherence (HMQC) and Heteromolecular Multiple Bond Correlation (HMBC) and comparison to published values.

Inhibitory effect of koji Aspergillus terreus on alpha-glucosidase activity and postprandial hyperglycemia.

The compounds that could inhibit the activity of a-glucosidase are potentially used for antidiabetic by suppressing postprandial hyperglycemia. This research aimed to investigate the hypoglycemic activity in A. terreus koji extracted by ethyl acetate. The extracts was dissolved in methanol: water (1:4), followed by fractionations with n-hexane, methylene chloride and ethyl acetate. Each fraction was assayed for its activity against a-glucosidase. The active fraction was purified by column chromatography using silica gel and resin as adsorbent. The kopi extract showed potential as alpha-glucosidase inhibition with IC50 <10 microg mL(-1) and showed combination of non-competitive and uncompetitive inhibition mode against a-glucosidase. Ethyl acetate fraction showed potential as inhibitor alpha-glucosidase with IC50 = 8.6 microg mL(-1). In animal experiment, active fraction (F10-4) of ethyl acetate fraction suppressed the increase of postprandial blood glucosidase level compare to the control. Thus it showed potential as alpha-glucosidase inhibitor and demonstrated depressed postprandial blood glucose level and may have potential use in the management of type 2 diabetes.