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

Advances in chromatography-based methods for screening active compounds from natural products / 药学学报

Natural products have been a major source of leading compounds in drug discovery. How to effectively screen active compounds from complex matrix remains an interesting topic. In this review, we comprehensively summarized advanced liquid chromatography based approaches in natural products screening, including pre-column, on-column and post-column screening methods. Their advantages, disadvantages and prospect are also discussed.

Effects of active fraction from Pegasus laternarius Cuvier on proliferation and apoptosis of human cervical cancer HeLa cells / 中国药理学通报

Aim To isolate HeLa cell proliferation-inhibitory active fraction from Pegasus laternarius Cuvier and explore its potential apoptosis-inducing mechanism.Methods To obtain the active fraction,the ethanol extract of Pegasus laternarius Cuvier was chromatographed by silica gel and sephadex LH-20 columns;MTT assay was used to evaluate the proliferation-inhibitory ability of active fraction on HeLa cells;AO/EB,PI and Annexin V-FITC/PI fluorescent staining flow cytometry were used to evaluate its apoptosis-inducing ability;the possible mechanism was investigated by analyzing the enzyme activity of caspase-3 and the protein expression of apoptosis-related genes in tumor cells.Results A fraction of C22 with high HeLa proliferation-inhibitory activity was isolated,with a yield of 0.73 ‰ and an IC50 of 36.3 mg · L-1;fraction C22 could increase the proportion of cells in sub-G0/G1 phase,phosphatidylserine eversion and other typical cell apoptosis in a dose-dependent manner;fraction C22 could down-regulate the expression of Bcl-2 and increase the enzyme of caspase-3 in HeLa cells.Conclusions The active fraction C22 from Pegasus laternarius Cuvier can inhibit the proliferation of HeLa cells by inducing apoptosis.The effect of inducing apoptosis may be conducted through mediating the mitochondrial Bcl2/caspase pathway.

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.

Isoflavone formononetin from red propolis acts as a fungicide against Candida sp

Abstract A bioassay-guided fractionation of two samples of Brazilian red propolis (from Igarassu, PE, Brazil, hereinafter propolis 1 and 2) was conducted in order to determine the components responsible for its antimicrobial activity, especially against Candida spp. Samples of both the crude powdered resin and the crude ethanolic extract of propolis from both locations inhibited the growth of all 12 tested Candida strains, with a minimum inhibitory concentration of 256 µg/mL. The hexane, acetate and methanol fractions of propolis 1 also inhibited all strains with minimum inhibitory concentration values ranging from 128 to 512 µg/mL for the six bacteria tested and from 32 to 1024 µg/mL for the yeasts. Similarly, hexane and acetate fractions of propolis sample 2 inhibited all microorganisms tested, with minimum inhibitory concentration values of 512 µg/mL for bacteria and 32 µg/mL for yeasts. The extracts were analyzed by HPLC and their phenolic profile allowed us to identify and quantitate one phenolic acid and seven flavonoids in the crude ethanolic extract. Formononetin and pinocembrin were the major constituents amongst the identified compounds. Formononetin was detected in all extracts and fractions tested, except for the methanolic fraction of sample 2. The isolated isoflavone formononetin inhibited the growth of all the microorganisms tested, with a minimum inhibitory concentration of 200 µg/mL for the six bacteria strains tested and 25 µg/mL for the six yeasts. Formononetin also exhibited fungicidal activity against five of the six yeasts tested. Taken together our results demonstrate that the isoflavone formononetin is implicated in the reported antimicrobial activity of red propolis.

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.

In vitro Antimicrobial Activity of Five Egyptian Plant Species.

In this study, five Egyptian species were tested for their In vitro antimicrobial activities. The antimicrobial screening was carried out via disc diffusion method toward four strains of the clinical antibiotic resistant pathogens including Escherichia coli, Staphylococcus aureus, Candida albicans and Aspergillus niger. Among the methanolic extracts screened, Azadirachta indica, Tectona grandis and Ficus sycomorus showed a broad antimicrobial spectrum against three strains with inhibition zones between 13-27 mm followed by Gmelina arborea and Ficus microcarpa with inhibition zones between 11-17 mm, all plants showed no activity against Aspergillus niger except Gmelina arborea with inhibition zones 12 mm. Penicillin G was used as positive control at concentration of 100 μg/disc with inhibition zones (Staphylococcus aureus 28mm, Escherichia coli 22mm, Candida albicans 25mm and Aspergillus niger 0mm). Owing to the high activity of the methanolic extracts, these extracts were defatted via petroleum ether then were fractionated via; chloroform, ethyl acetate and n-butanol. The n-butanol of Azadirachta indica was the most active against Candida albicans (25 mm), ethyl acetate of Ficus sycomorus against Staphylococcus aureus (18 mm), n-butanol of Gmelina arborea against Staphylococcus aureus (17 mm) and n-butanol of Ficus microcarpa against Staphylococcus aureus (15 mm). These results suggest that the tested plants may be effective potential sources of natural antimicrobials, and are potent inhibitors of antibiotic resistant pathogens.

Identification and characterization of a potent anticancer fraction from the leaf extracts of Moringa oleifera L.https://docs.google.com/forms/d/1RkQLeYfiMvE7SKcdOXv9Acm5eXRjmvleic5FYjjX1TE/viewform?fbzx=6173639259593088622

Anticancer potential of Moringa oleifera L. extracts have been well established. However, there are no reports on the isolated molecules/fractions from these extracts which are responsible for the anticancer/cytotoxic activity. Thus, in the present study, we explored the same. The n-hexane, chloroform, ethyl acetate, methanol extracts of the M. oleifera leaves and 15 fractions (F1 to F15) of ethyl acetate extract were evaluated for their in vitro and in vivo anticancer activity using Hep-2 cell lines and Dalton’s lymphoma ascites model in mice, respectively. Among the tested samples, the F1 fraction showed potential cytotoxic effect in Hep-2 cell lines with a CTC50 value of 12.5 ± 0.5 µg/ml. In vivo studies with the doses 5 and 10 mg/kg, p.o. demonstrated significant reduction in body weight and increased the mean survival time compared to the control group. These results were also comparable to the standard, 5-Fluorouracil, treated animals. We have also successfully isolated and characterized the anticancer fraction, F1 from the leaves of M. oleifera L.

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.

Siderochelins with anti-mycobacterial activity from Amycolatopsis sp. LZ149 / 中国天然药物

Three new compounds, namely siderochelins D (2), E (3), and F (4), together with one known siderochelin A (1), were isolated from Amycolatopsis sp. LZ149 and elucidated by spectroscopic analyses including1D- and 2D-NMR and X-ray single crystal diffraction. Compounds 1-3 showed antibacterial activity against Mycobacterium smegmatis.

In vitro antiviral activity of Chamaecrista nictitans (Fabaceae) against herpes simplex virus: biological characterization of mechanisms of action

We have previously identified a crude extract of the plant Chamaecrista nictitans (Fabaceae) with antiviral activity against herpes simplex virus. The main objectives of this research were to identify the step of the replication cycle of herpes simplex inhibited by the extract, and to attempt to characterize the chemical characteristics of this extract. The crude extract from--Chamaecrista nictitans (Fabaceae) was extracted with a mixture of diclorometane/methanol, and further fractionated following a bioassay-guided protocol using a combination of preparative thin layer and column chromatography. Toxicity and bioassay experiments were carried out in monolayers of Vero cells. The antiviral activity of the extract was assessed by total inhibition of cytopathic effect after three-day incubation. The highest concentration of the extract which was not toxic to the cells was 200 ptg/ml. Western blot and immunofluorescence techniques were used to elucidate the antiviral mechanism of the extract by infecting Vero cells with the virus at different times and monitoring the synthesis of viral proteins. A 60 kDa protein was detected at 2 hr and 8 hr post-infection but no additional proteins were synthesized at later time intervals, and cytopathic effect was not observed after 24 hr. This result indicates that the extract acts at the intracellular level in order to inhibit late transcription. However, it does not inhibit transcription/translation of early viral proteins. These results were confirmed by immunofluorescence experiments. A strong fluorescent signal was observed in control cell monolayers at 24 hr post infection, accompanied with a clear cytopathic effect. In contrast, in the presence of acyclovir or the extract, cells showed very discrete immunofluorescence, characterized by a punctuated pattern, and no cytopathic effect was observed. Neutralization assays were performed using pre-incubation of virus with either specific herpes simplex-1 antiserum, 200...