Global Regulators to Activate Silent Biosynthetic Gene Clusters

Genome mining has recently emerged as a powerful strategy to discover novel microbial secondary metabolites. However, more than 50% of biosynthetic gene clusters are not transcribed under standardized laboratory culture condition. Several methods have been applied to activate silent biosynthetic gene clusters in the microbes so far. Among the regulatory systems for production of secondary metabolites, global regulators, which affect transcription of genes through regulatory cascades, typically govern the production of small molecules. In this review, global regulators to affect production of microbial secondary metabolites were discussed.

Endophytic Fungi Inhabiting Medicinal Plants and Their Bioactive Secondary Metabolites

Endophytes are defined as microorganisms that spend part of lifetime interior of plant tissues without causing negative effects. They have been used for agricultural purpose, biofuel production, bioremediation, medication, etc. In particular, endophytes have been emerged as a good source for bioactive secondary metabolites. A large number of secondary metabolites are currently being reported. In this report, we focus on the secondary metabolites that were originated from endophytic fungi inhabiting medicinal plants. They were classified into several groups such as nitrogenous compounds, steroids, sulfide-containing metabolites, terpenoids, polyketides, and miscellaneous for discussion of chemical structures and biological activities.

Medicinal Herbs Effective Against Atherosclerosis: Classification According to Mechanism of Action

Atherosclerosis is a widespread and chronic progressive arterial disease that has been regarded as one of the major causes of death worldwide. It is caused by the deposition of cholesterol, fats, and other substances in the tunica intima which leads to narrowing of the blood vessels, loss of elasticity, and arterial wall thickening, thus causing difficulty in blood flow. Natural products have been used as one of the most important strategies for the treatment and prevention of cardiovascular diseases for a long time. In recent decades, as interests in natural products including medicinal herbs have increased, many studies regarding natural compounds that are effective against atherosclerosis have been conducted. The purpose of this review is to provide a brief over-view of the natural compounds that have been used for the treatment and prevention of atherosclerosis, and their mechanisms of action based on recent research.

Chemical Investigation on an Endophytic fungus Gibberella moniliformis JS1055 Derived from a Halophyte Vitex rotundifolia

Chemical investigation of the ethyl acetate extract of Gibberella moniliformis JS1055 endophytic fungus derived from a halophyte, Vitex rotundifolia, led to the isolation of nine compounds including 7-butyl-6,8-dihydroxy-3(R)-pent-11-enylisochroman-1-one (1), 7-butyl-6,8-dihydroxy-3(R)-pentylisochroman-1-one (2), 7-butyl-6,8-dihydroxy-3(R)-pentylisochroman-1-one (3), 5α,8α-epidioxyergosta-6,9(11),22-trien-3-ol (4), ergosterol peroxide (5), tetradecanoic acid (6), 8-O-methylfusarubin (7), nicotinic acid (8) and adenosine (9). They were identified by extensive spectroscopic data analysis including 1D, 2D (¹H-¹H COSY, HSQC, HMBC) NMR, and ESIMS. All the isolates (1

Chemical Constituents Identified from Fruit Body of Cordyceps bassiana and Their Anti-Inflammatory Activity

Cordyceps bassiana is one of Cordyceps species with anti-oxidative, anti-cancer, anti-inflammatory, anti-diabetic, anti-obesity, anti-angiogenic, and anti-nociceptive activities. This mushroom has recently demonstrated to have an ability to reduce 2,4-dinitrofluorobenzene-induced atopic dermatitis symptoms in NC/Nga mice. In this study, we further examined phytochemical properties of this mushroom by column chromatography and HPLC analysis. By chromatographic separation and spectroscopic analysis, 8 compounds, such as 1,9-dimethylguanine (1), adenosine (2), uridine (3), nicotinamide (4), 3-methyluracil (5), 1,7-dimethylxanthine (6), nudifloric acid (7), and mannitol (8) were identified from 6 different fractions and 4 more subfractions. Through evaluation of their anti-inflammatory activities using reporter gene assay and mRNA analysis, compound 1 was found to block luciferase activity induced by NF-κB and AP-1, suppress the mRNA levels of cyclooxygenase (COX)-2 and tumor necrosis factor (TNF)-α. Therefore, our data strongly suggests that compound 1 acts as one of major principles in Cordyceps bassiana with anti-inflammatory and anti-atopic dermatitis activities.

Aldose Reductase Inhibitory Alkaloids from Corydalis ternata

A methanolic extract of Corydalis ternata having aldose reductase inhibitory activity was examined as a possible aldose reductase (ALR2) inhibitor, a key enzyme involved in diabetic complications. Seven alkaloids, tetrahydrocoptisine (1), corydaline (2), tetrahydropalmatine (3), isocorybulbine (4), corybulbine (5), dehydrocorydaline (6), and N-methyltetrahydroberbinium (7) were isolated from CHCl₃ fraction of C. ternata methanol extract. Among them, compounds 1, 5, and 7 exhibited 5.04 ± 1.97%, 5.00 ± 1.26%, and 1.80 ± 2.33% inhibitions, respectively at 40 µM. The activities of the single compounds were not comparable to that of the whole extract, suggesting that the whole combination of each single compound was responsible for the activity of the extract as shown in many cases of natural medicines. Even though this is the second report on aldose reductase inhibition activity of C. ternata, recombinant human aldose reductase was employed in this study unlike in the previous report. Furthermore, the aldose reductase inhibitory activities of isocorybulbine, corybulbine, and N-methyltetrahydroberbinium, to the best of our knowledge, were evaluated for the first time in this study. These results suggest a use of the extract of C. ternata for ameliorating diabetic complications.

Antibiotic Components from the Rhizomes of Curcuma zedoaria

Two terpenoids, including one uniquely aromatized one (1), were isolated from CH2Cl2-soluble fraction of MeOH extracts of Curcuma zedoaria. They were identified to be a sesquiterpene ketolactone (1) and orobanone (2), respectively on the basis of their NMR data. The structure of compound 1 was confirmed by X-ray chrystallography and the reported NMR assignments for 1 were revised in this study. Antibiotic activities for compounds 1 and 2 were evaluated using disk diffusion assay. Compound 1 showed potent antibacterial activities against Listeria monocytogenes and Staphylococcus pseudointermedius while compound 2 was active against Bacillus cereus.

Anti-Inflammatory and PPAR Transactivational Effects of Oleanane-Type Triterpenoid Saponins from the Roots of Pulsatilla koreana

In this study, 23 oleanane-type triterpenoid saponins were isolated from a methanol extract of the roots of Pulsatilla koreana. The NF-kappaB inhibitory activity of the isolated compounds was measured in TNFalpha-treated HepG2 cells using a luciferase reporter system. Compounds 19-23 inhibited TNFalpha-stimulated NF-kappaB activation in a dose-dependent manner, with IC50 values ranging from 0.75-8.30 microM. Compounds 19 and 20 also inhibited the TNFalpha-induced expression of iNOS and ICAM-1 mRNA. Moreover, effect of the isolated compounds on PPARs transcriptional activity was assessed. Compounds 7-11 and 19-23 activated PPARs the transcriptional activity significantly in a dose-dependent manner, with EC50 values ranging from 0.9-10.8 microM. These results suggest the presence of potent anti-inflammatory components in P. koreana, and will facilitate the development of novel anti-inflammatory agents.