Anti-hyperglycemic fraction from Alternanthera sessilis L. leaves gets elucidated following bioassay-guided isolation and mass spectrometry

Abstract The anecdotal use of Alternanthera sessilis L. as a relief for diabetes has been known in the Philippines for generations, and antidiabetic activity of similar varieties in other countries is likewise documented. However, the compounds responsible for this activity remain unclear. This study aims to isolate the anti-hyperglycemic fraction of local A. sessilis leaves and identify the compounds in this fraction. Methanol extract of A. sessilis leaves and its hexane, ethyl acetate (ASE), and water fractions were administered to alloxan-induced diabetic mice. ASE (250mg/kg) had the highest anti-hyperglycemic activity at 6-h post-treatment (25.81%±12.72%), with almost similar blood glucose reduction rate as metformin (30.13±3.75%, p=0.767). Repeated fractionation employing chromatographic separation techniques followed by in vivo anti-hyperglycemic assay yielded partially purified subfractions. A. sessilis ethyl acetate subfraction 4-2 (100mg/kg) displayed remarkable suppression of blood glucose rise in diabetic mice at 6-h post-treatment (26.45±3.75%, p<0.0001), with comparable activity with metformin (100mg/kg, 27.87±5.65%, p=0.652). Liquid chromatography/mass spectrometry showed eight distinct peaks, with four peaks annotated via the Traditional Chinese Medicine library and custom library for A. sessilis. Among these, luteolin, apigenin, ononin, and sophorabioside were identified as putative compounds responsible for the anti-hyperglycemic activity. This result provided basis for the reported anecdotal claims and potential utility of the local variety of A. sessilis leaves as sources of anti-hyperglycemic agents

Bioassay-guided isolation of functional components from hot water extract of Chlorella pyrenoidosa / 生物工程学报

The main functional ingredients of hot water extract of Chlorella pyrenoidosa (CPE) were investigated through a bioassay-guided fractionation based on free radical scavenging and macrophage proliferation effects. The main functional ingredients of CPE were polysaccharides (PS) that were isolated by high pressure extraction, Sevag method, ethanol precipitation and ultrafiltration separation. Crude polysaccharides were further separated and purified by ion exchange chromatography DEAE52 and size exclusion chromatography Sephadex G-100. The purified fractions were analyzed by gel permeation chromatography. Molecular weights of the purified fractions PS-1-4-2, PS-1-3-2 and PS-2-3-3 were 3.97×10⁴, 2.28×10⁴ and 4.1×10³ Da, respectively. Bioassay-guided fractionation results indicated that CPE could remove free radicals and promote Ana-1 cells proliferation, mainly due to its various components working together. The components of free radicals scavenging mainly concentrated in PS-1-3, PS-1-4, PS-2-3 and PS-2-4. The components of Ana-1 proliferation mainly concentrated in PS-1-3, PS-1-4 and PS-2-3. This study established the activity screening method of main functional component from CPE, and got three new functional ingredients. It can be used to guide the development of high value products, further promote the industrialization process of microalgae energy, and realize microalgae 'high value products, microalgae energy and microalgae carbon' integration of exemplary role.

Bioassay-Guided Isolation and Identification of Compounds from Arecae Pericarpium with Anti-inflammatory, Anti-oxidative, and Melanogenesis Inhibition Activities

This study describes the anti-inflammatory, anti-oxidant, and melanogenesis inhibition activities of methanol extract and various organic solvent fractions of Arecae Pericarpium. We examined the inhibition of lipopolysaccharide (LPS)-induced nitric oxide (NO) production in RAW 264.7 cells, 1,1-diphenyl-2-picrylhydrazine (DPPH) scavenging activity, mushroom tyrosinase inhibition activity and melanin contents. The study showed that, among all tested fractions, methylene chloride fraction showed the strongest inhibition of LPS-induced NO production in RAW 264.7 cells (IC₅₀ value 8.89 µg/mL) and DPPH radical scavenging activity (EC₅₀ value 21.39 µg/mL). Methylene chloride and ethyl acetate fractions similarly inhibited mushroom tyrosinase activity. Methanol extract exhibited strongest reduction of melanin content in B16F10 melanoma cells. Based on the bioactivity assay results, methylene chloride and ethyl acetate fractions were further separated. Eight phenolic compounds were isolated, which are dimeric syringol (1), catechol (2), 4-hydroxybenzaldehyde (3), vanillin (4), 4-hydroxyacetophenone (5), apocynin (6), protocatechuic acid (7) and 4-hydroxybenzoic acid (8). Among the isolated compounds tested, catechol showed the strongest inhibition of LPS-induced NO production in RAW 264.7 cells. Catechol also showed the concentration-dependent NF-κB inhibition activity. Arecae Pericarpium might have potentials to be developed as anti-inflammatory agent or dermatological product for skin-whitening agent.

Taxonomic characterization and isolation of antitrypanosomal compound from Streptomyces sp. FACC-A032 isolated from Malaysian forest soil

Aims: The present study is aimed at taxonomic characterization and isolation of active compound MS01 from Streptomyces sp. FACC-A032 which exhibited strong antitrypanosomal activity (IC50 0.02 μg/mL). Methodology and results: Isolate FACC-A032 was characterized based on its cultural, morphological, physiological and genomic properties. Isolate FACC-A032 was tentatively identified as Streptomyces sp. Biochemical analysis of diaminopimelic acid (DAP) isomer of whole-cell hydrolysates further confirmed the isolate FACC-A032 that contained LL-DAP isomer as species belonging to the genus Streptomyces. The inoculum for submerged cultures of isolate FACCA032 was prepared from cultures on ISP2 agar. After eight days of growth at 28  2 °C and 200 rpm in fermentation medium M3, fermentation broth was extracted with butanol and the crude extracts (solvent layer) were separated and dried in vacuo. Further studies were carried out to isolate the active compound from the culture extracts of isolate FACCA032. Using bioassay-guided isolation, crude extract was partitioned based on different polarity. After which, the resulting elutes were tested for antitrypanosomal activity. The active fraction was analyzed with HPLC-DAD analysis. Based on the analysis, major peak in the active fraction was collected using HPLC preparative. Active compound MS01 was isolated and structure elucidated using NMR spectroscopy. Conclusion, significance and impact of study: Bioassay-guided isolation techniques used in this study had discovered an active antitrypanosomal compound, staurosporine, from Streptomyces sp. FACC-A032. This is the first discovery of staurosporine, a protein kinase inhibitor, from Malaysian soil actinobacteria Streptomyces sp. Therefore, the study demonstrated the potential of Malaysian soil actinobacteria as antitrypanosomal therapeutic agent.