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Ethnobotanically in Indonesia, Diospyros celebica Bakh is recognized as having antidiabetic activity. This study aimed to isolate antidiabetic compounds from the leaves of Eboni (Diospyros celebica). D. celebica leaves were dried and extracted with 96% ethanol, then fractionated and purified guided by antioxidant activity test, a-glucosidase inhibitory test, and dipeptidyl peptidase-4 (DPP-4) inhibitory test until bioactive isolates were obtained. The isolates were identified and their structures were determined based on NMR 1H, 13C, 2D, and LCMS/MS spectroscopic data. Extracts and fractions have potential antioxidant (DPPH), glucosidase inhibitor, and DPP-4 inhibitor activities as well as containing flavonoids and polyphenols. From the ethyl acetate fraction, isolate 26a-2 namely 3,5-digalloyl-(-)- epiafzelechin was obtained which was active as a DPPH scavenger, glucosidase inhibitor, and DPP4 inhibitor. The extracts, fractions, and flavonoid compounds in D. celebica leaves have the potential for antidiabetic drug candidates. [ABSTRACT FROM AUTHOR]

A randomized controlled trial was conducted on three formulas of an herbal drink containing green "gamboeng" tea fortified with bay leaf and cinnamon bark at various concentrations. One gram of mixed formula was brewed in hot water at 700 C-90 0C for 10-15 minutes, and the yield of each plant was determined. We also determined the phenolic content and lipase inhibition activity of each formula. We obtained a yield of each plant with green "gamboeng" tea (66.2 %), bay leaves (10.7 %), and cinnamon bark (44.8 %). Green "gamboeng" tea has the highest percentage of phenolic compound 30.25 ± 1.201 %. Inhibition lipase activity was calculated using an Elisa reader at  =405 nm. We have three formulas with the highest lipase inhibition activity. For the three formulas, a mixture of green "gamboeng" tea, bay leaf, and cinnamon bark was F-3.2 (80.598%), F-4.1(74.306), and F-5.2 (80.299%). We also conducted acute toxicity for the formulas above using rats as an animal model. We observed the body weight, organ weight, motoric, and mortality of rats during 14 days of observation, after using the formula with the concentration of 3.75, 7.5, and 15 g/kg body weight. We also used a control group of rats in this experiment. The results of acute toxicity showed no mortality of rats from the lowest to the highest doses. We concluded that LD50 of the three formulas was > 15 g/kg body weight. Between the treated groups and the control groups for organ weight and motoric activity showed no significant difference. Our conclusion is that this herbal formula drink has an activity for lipase inhibition, and is also safe for consumption by humans that suffer from obesity. [ABSTRACT FROM AUTHOR]

Hepatitis B virus (HBV) is a leading cause of chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma. Current therapeutic drugs for chronic HBV infection use IFN and nucleos(t)ide analogs; however, their efficacy is limited. Thus, there is an urgent need to develop new antivirals for HBV therapy. In this study, we identified a plant-derived polyphenolic bioflavonoid, amentoflavone, as a new anti-HBV compound. Amentoflavone treatment dose-dependently inhibited HBV infection in HBV-susceptible cells with HepG2-hNTCP-C4 and primary human hepatocyte PXB-cells. A mode-of-action study showed that amentoflavone inhibits the viral entry step, but not the viral internalization and early replication processes. Attachment of HBV particles as well as HBV preS1 peptide to HepG2-hNTCP-C4 cells was inhibited by amentoflavone. The transporter assay revealed that amentoflavone partly inhibits uptake of sodium taurocholate cotransporting polypeptide (NTCP)-mediated bile acid. Furthermore, effect of various amentoflavone analogs on HBs and HBe production from HBV-infected HepG2-hNTCP-C4 cells was examined. Robustaflavone exhibited comparable anti-HBV activity to that of amentoflavone and an amentoflavone-7,4', 4‴-trimethyl ether derivative (sciadopitysin) with moderate anti-HBV activity. Cupressuflavone or the monomeric flavonoid apigenin did not exhibit the antiviral activity. Amentoflavone and its structurally related biflavonoids may provide a potential drug scaffold in the design of a new anti-HBV drug inhibitor targeting NTCP., (© 2023 The Societies and John Wiley & Sons Australia, Ltd.)

The development of fluorescent silica nanoparticles (SNP-RB) from natural amorphous silica and its performance as an Escherichia coli ( E. coli ) biosensor is described in this paper. SNP-RB was derived from silica recovered from geothermal installation precipitation and modified with the dye, Rhodamine B. The Fourier Infrared (FTIR) confirms the incorporation of Rhodamine B in the silica matrix. Transmission Electron Microscopy (TEM) micrographs show that the SNP-RB had an irregular structure with a particle diameter of about 20-30 nm. The maximum fluorescence spectrum of SNP-RB was recorded at 580 nm, which was further applied to observe the detection performance of the fluorescent nanoparticles towards E. coli . The sensing principle was based on the fluorescence-quenching mechanism of SNP-RB and this provided a wide linear E. coli concentration range of 10-10 5 CFU/mL with a limit detection of 8 CFU/mL. A rapid response time was observed after only 15 min of incubation of SNP-RB with E. coli . The selectivity of the biosensor was demonstrated and showed that the SNP-RB only gave quenching response only to live E. coli bacteria. The use of SNP-RB as a sensing platform reduced the response time significantly compared to conventional 3-day bacterial assays, as well having excellent analytical performance in terms of sensitivity and selectivity.

The active α-glucosidase inhibitor compounds in the endophytic fungus Colletotrichum sp. TSC13 were found to be the unsaturated fatty acids (oleic, linoleic and linolenic acids). These compounds have potential as antidiabetic agents. The aim of the present study is to investigate the effects of various media composition on growth (mycelium dry weight) and the fatty acids content (μg mg(-1) mycelium DW) of Colletotrichum sp. TSC13 in relation to its α-glucosidase inhibitory activity. For that purpose, the experiments were set up by varying the carbon and nitrogen sources, metal ions and desaturase and fatty acid synthase inhibitors in the media. Colletotrichum sp. TSC13 grown on potato dextrose broth (PDB) was used as control. The α-glucosidase inhibitory activities were (range from 43.9 ± 2.5 to 88.6 ± 5.2%) at 10 μg mL(-1). This activity seemed to correlate with the unsaturated fatty acids content of the samples. Different sugars as carbon source experiment showed that xylose gave the highest growth (938.7 ± 141.6 mg). However, the highest fatty acids content was obtained from fructose medium which containing linoleic acid (38.8 ± 4.9 μ g mg(-1) DW). Soluble starch gave better growth (672.5 ± 62.3 mg) but very low fatty acids content (2.8 ± 0.1 μg mg(-1) DW) was obtained. Yeast extract was the best nitrogen source. Fatty acids production was better as compared to beef extract and soytone. This is the first report of various media compositions on fatty acids content in Colletotrichum sp. TSC13 in relation to its α-glucosidase inhibitory activity.

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.

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.