α-Glucosidase inhibitors from the husks of rice Oryza sativa L.

Rice husk is one of the most plentiful agriculture by-products in rice producing areas, which harbors a substantial proportion of biological metabolites, however, it has not been well studied. As an attempt to utilize it as a productive manner, phytochemical investigation on rice husk has performed and led to the isolation of three undescribed (1, 2, and 7), along with twelve known components (3-6, and 8-15). Those chemical structures were elucidated based on massive spectroscopic methods. Among them, compounds 4, 6-8, and 10-13 have been shown to act as α-glucosidase inhibitors. Notably, the most active compounds, 10/11, demonstrated comparable α-glucosidase inhibitory effect (IC50 = 1.83 ± 0.11 µg/mL) to that of 1-deoxynojirimycin (IC50 = 1.02 ± 0.16 µg/mL). For the molecular docking simulation studies, compounds 10/11 showed relative binding interactions with α-glucosidase enzyme (PDB ID: 3A4A) that similar to those reference inhibitors. Additionally, the crude extract of O. sativa demonstrated better α-glucosidase inhibitory effect to that of isolated components, with the IC50 value at 1.25 ± 0.07 µg/mL.

Secondary Metabolites from the Fresh Leaves of Pinus yunnanensis Franch.

Fifteen metabolites, including two flavonols (1-2), three lignans (3-5), and ten diterpenoids (6-15), were isolated from the leaves of Pinus yunnanensis. Among them, flavanonol (1) were identified as undescribed flavonol derivative with natural rarely B-ring fission lactone. Massive spectroscopic methods, the DP4+ probabilities and CD/ECD calculations were applied to establish the structure of component 1. Among these compounds, taxifolin (2) showed potent cytotoxicity, having IC50 values from 21.33 to 45.48 µg/mL, it also showed broad antibacterial activity against human pathogens with MIC values from 32 to 64 µg/mL.

Antibacterial anthraquinone dimers from marine derived fungus Aspergillus sp.

As a continue investigation of the bioactive secondary metabolites from marine derived fungi, two new anthraquinone dimers (1, 2), along with three known anthraquinones (3-5) and two known xanthones (6, 7) were isolated from the marine-derived fungus Aspergillus versicolor. Their structures, including the absolute configurations, were elucidated by NMR, HRMS, and comparison with reported ones. Among them, compounds 1 and 2 were identified as anthraquinone dimers which dimerized by a rare C-O-C ether linkage, and both of them showed selective antibacterial activity against Gram-positive Staphylococcus aureus; whilst compound 6 exhibited moderate cytotoxicity against human cancer cell lines.

Biotransformation of 20(R)-panaxatriol by the fungus Aspergillus flavus Link AS 3.3950.

Microbial transformation of 20(R)-panaxatriol by the fungus Aspergillus flavus Link AS 3.3950 was performed. Four new (1-4), along with two previously reported metabolites (5 and 6), were obtained. Their chemical structures were elucidated on the basis of extensive spectroscopic analyses. Furthermore, the inhibitory effects of those compounds on K562/ADR, Du-145, Hela, MCF-7 and HepG2 cell lines were evaluated by MTT assay. Among them, compound 15ß-hydroxy-20(R)-panaxatriol (4) exhibited selective inhibitory effects on human leukaemic progenitor cells K562/ADR through arresting cell cycle, which was associated with obvious decrease of cyclin B1, cyclin D1 and cyclin-dependent kinase (CDK) 1/2/4/6 protein expression.

Arvensic acids A-D, novel heptasaccharide glycosidic acids as the alkaline hydrolysis products of crude resin glycosides from Convolvulus arvensis.

In this study, a resin glycoside fraction with cytotoxic activity was isolated from the alcoholic extract of C. arvensis whole plants. To describe the chemical feature of the resin glycosides, the fraction was alkaline hydrolyzed and four novel glycosidic acids, named arvensic acids A-D (1-4), were isolated. Their structures were thoroughly elucidated on the basis of spectroscopic data and chemical evidences. They all possess a same heptasacharride core, consisting of one D-fucose, two L-rhamnose and four d-glucose units. The difference among these glycosidic acids was placed on the aglycone, which is 12S-hydroxypentadecanoic acid for 1, 12S-hydroxyhexadecanoic acid for 2, 3S,12S-dihydroxypentadecanoic acid for 3, and 3S,12S- dihydroxyhexadecanoic acid for 4. These aglycones are rarely found in the structures of resin glycosides and are firstly identified in the genus Convolvulus.

Activated production of silent metabolites from marine-derived fungus Penicillium citrinum.

As an attempt to utilize of rare earth elements as a novel method to activate the silent genes in fungus, the marine-derived fungus Penicillium citrinum was cultured under ordinary laboratory fermentation conditions in the presence of scandium chloride (ScCl3, 50 µM), and chemical investigation led to the isolation and characterization of three new peptide derivatives (1-3), along with four known pyrrolidine alkaloids (4-7). Those structures were elucidated by spectroscopic data interpretation, as well as chemical reactions. Comparative metabolic profiling of the culture extracts (with/without scandium chloride) indicated that compounds 1-3 scarcely detected in the absence of ScCl3. In addition, the antibacterial and cytotoxic activities of all isolated products were evaluated.

Medicinal uses, pharmacology, and phytochemistry of Convolvulaceae plants with central nervous system efficacies: A systematic review.

Central nervous system (CNS) disorders play a major impact on individual lives and place a severe strain on health care resources. Convolvulaceae is a family comprising approximately 1,600-1,700 species grouped in 55-60 genera, and many species are reported to have an effect on CNS functions. A systematic review of the literature studies was carried out to summarize available evidences on Convolvulaceae plants with CNS efficacies. This review is based on various data sources such as Google Scholar, Web of Science, Scopus, PubMed, and Wanfang Data. A total of 200 related articles were included in this review. According to the research result, 54 Convolvulaceae species are suggested to display CNS efficacies historically, and 46 species have been evaluated for their CNS efficacies. In addition, 67 compounds from 16 Convolvulaceae species are recognized to possess CNS efficacies. Despite great progress made through pharmacology and phytochemistry studies on CNS active Convolvulaceae species, more exploratory research is needed to gain a better understanding of the CNS efficacies of this plant family.

(R)-panaxadiol by whole cells of filamentous fungus Absidia coerulea AS 3.3382.

The microbial transformation of 20(R)-panaxadiol (PD) by the fungus Absidia coerulea AS 3.3382 afforded three new and three known metabolites. The structures of the metabolites were characterized as 3-oxo-20(R)-panaxadiol (1), 3-oxo-7ß- hydroxyl-20(R)-panaxadiol (2), 3-oxo-22ß-hydroxyl-20(R)-panaxadiol (3), 3-oxo- 7ß,22ß-dihydroxyl-20(R)-panaxadiol (4), 3-oxo-7ß,24ß-dihydroxyl-20(R)-panaxadiol (5), and 3-oxo-7ß,24α-dihydroxyl-20(R)-panaxadiol (6). Among them, 2-4 were new compounds. In addition, compounds 3 and 4 exhibited significant anti-hepatic fibrosis activity.

Antichlamydial Dimeric Indole Derivatives from Marine Actinomycete Rubrobacter radiotolerans.

Chlamydiae are widely distributed pathogens of human populations, which can lead to serious reproductive and other health problems. In our search for novel antichlamydial metabolites from marine derived-microorganisms, one new (1) and two known (2, 3) dimeric indole derivatives were isolated from the sponge-derived actinomycete Rubrobacter radiotolerans. The chemical structures of these metabolites were elucidated by NMR spectroscopic data as well as CD calculations. All three metabolites suppressed chlamydial growth in a concentration-dependent manner. Among them, compound 1 exhibited the most effective antichlamydial activity with IC50 values of 46.6 ~ 96.4 µM in the production of infectious progeny. Compounds appeared to target the mid-stage of the chlamydial developmental cycle by interfering with reticular body replication, but not directly inactivating the infectious elementary body.

Antituberculosis compounds from a deep-sea-derived fungus Aspergillus sp. SCSIO Ind09F01.

Eleven diketopiperazine and fumiquinazoline alkaloids (1-11) together with a tetracyclic triterpenoid helvolic acid (12) were obtained from the cultures of a deep-sea derived fungus Aspergillus sp. SCSIO Ind09F01. The structures of these compounds (1-12) were determined mainly by the extensive NMR, ESIMS spectra data and by comparison with previously described compounds. Besides, anti-tuberculosis, cytotoxic, antibacterial, COX-2 inhibitory and antiviral activities of these compounds were evaluated. Gliotoxin (3), 12,13-dihydroxy-fumitremorgin C (11) and helvolic acid (12) exhibited very strong anti-tuberculosis activity towards Mycobacterium tuberculosis with the prominent MIC50 values of <0.03, 2.41 and 0.894 µM, respectively, which was here reported for the first time. Meanwhile gliotoxin also displayed significant selective cytotoxicities against K562, A549 and Huh-7 cell lines with the IC50 values of 0.191, 0.015 and 95.4 µM, respectively.

Acetylcholinesterase inhibitory dimeric indole derivatives from the marine actinomycetes Rubrobacter radiotolerans.

Investigation of the bioactive secondary metabolites of the marine actinomycetes Rubrobacter radiotolerans led to the isolation and characterization of two naturally rare dimeric indole derivatives (1 and 2). The structures of these new compounds were elucidated by spectroscopic data interpretation, and the absolute configurations were assigned by CD calculations. The acetylcholinesterase (AchE) inhibitory activity of compounds 1 and 2 was evaluated, both of which showed moderate activity with IC50 values of 11.8 and 13.5µM, respectively.

Two Δ6-desaturase-like genes in common carp (Cyprinus carpio var. Jian): structure characterization, mRNA expression, temperature and nutritional regulation.

Δ6-Desaturase is the rate-limiting enzyme involved in highly unsaturated fatty acid (HUFA) biosynthesis. There is very little information on the evolution and functional characterization of Δ6Fad-a and Δ6Fad-b in common carp (Cyprinus carpio var. Jian). In the present study, the genomic sequences and structures of two putative Δ6-desaturase-like genes in common carp genome were obtained. We investigated the mRNA expression patterns of Δ6Fad-a and Δ6Fad-b in tissue, hatching carp embryos, larvae by temperature shock and juveniles under nutritional regulation. Our results showed that the two Δ6Fad genes had identical coding exon structures, being comprised of 12 coding exons, and with introns of distinct size and sequence composition. They were not allelic variants of a single gene. Both Δ6Fad genes were highly expressed in liver, intestine (pyloric caeca) and brain. The Δ6Fad-a and Δ6Fad-b mRNAs showed an increase in expression from newly hatched to 25 days after hatching. The expression levels of Δ6Fad-a were obviously regulated by temperature, whereas Δ6Fad-b was not affected by temperature. The regulation of Δ6Fad-a and Δ6Fad-b in response to dietary fatty acid composition was determined in liver, brain and intestine (pyloric caeca) of common carp fed with diets: diet1with fish oil (FO) rich in n-3 HUFA, diet2 with corn oil (CO, 18:2n-6) and diet3 with linseed oil (LO, 18:3n-3). The differential expression of Δ6Fad-a and Δ6Fad-b genes in liver, brain and intestine in common carps was fed with different oil sources, respectively. Further work is in progress to determine the mechanism of differential expression of the Δ6Fad-a and Δ6Fad-b genes in different tissues and the roles of transcription factors in regulating HUFA synthesis.

A new cyclic tetrapeptide from the jellyfish-derived fungus Phoma sp.

A new cyclic tetrapeptide (1), along with known congeners (2, 3), was isolated from the fungus Phoma sp. derived from the giant jellyfish Nemopilema nomurai. The absolute configuration of 1 was determined using the modified Mosher's method and Marfey's method. Compound 1 displayed a weak suppressive effect on the production of nitric oxide (NO) in murine macrophage cells (RAW264.7) without notable cytotoxicity.

Cytotoxic cytochalasins from the endozoic fungus Phoma sp. of the giant jellyfish Nemopilema nomurai.

Four new cytochalasin derivatives (1-4), together with cytochalasin B (5), were isolated from the fungus Phoma sp. obtained from the giant jellyfish Nemopilema nomurai. The planar structure and relative stereochemistry were established by analysis of 1D and 2D NMR data. The absolute configuration was defined by the modified Mosher's method. The compounds showed significant cytotoxicity against a small panel of human solid tumor cell lines (A549, SK-OV-3, SK-MEL-2, XF 498, and HCT15) with IC(50) values in the range of 0.5-30 µM. The cytochalasin B (5) showed obvious cytotoxicity with IC(50) of 7.9 µM against HeLa human cervical carcinoma cells.

Antibacterial polyketides from the jellyfish-derived fungus Paecilomyces variotii.

Four new polyketides (1-4) were isolated from the fungus Paecilomyces variotii, which was derived from the jellyfish Nemopilema nomurai. The planar structures and relative configurations of these polyketides were elucidated on the basis of spectroscopic analyses, including 2D NMR experiments. The compounds showed inhibitory activity against pathogenic bacteria including methicillin-resistant Staphylococcus aureus 3089 and multi-drug-resistant Vibrio parahemolyticus 7001 with MIC values in the range 5-40 µg/mL.

A new thiaziedione from the fruits of Xanthium sibiricum.

A novel sulphur-containing compound named xanthiazinone (1) was isolated from the ethanolic extract of the fruits of Xanthium sibiricum, along with four known compounds, xanthiazone (2), xanthiside (3), xanthienopyran (4) and 5-hydroxypyrrolidin-2-one (5). Their structures were determined on the basis of spectroscopic techniques.