Chemical Constituents, Biological Activities and Molecular Docking Studies of Root and Aerial Part Essential Oils from Erigeron sublyratus Roxb. ex DC. (Asteraceae).

In this study, the volatile components of Erigeron sublyratus essential oils and their anti-inflammatory and cytotoxic activities were investigated for the first time. Gas chromatography-mass spectrometry (GC-MS) analysis revealed that a total of 28 components were identified in the root and aerial part essential oils. Among them, cis-lachnophyllum ester (53.4-64.2%), followed by germacrene D (5.6-8.6%), trans-ß-ocimene (2.6-7.5%), ß-caryophyllene (4.7-6.8%), ß-myrcene (2.0-6.3%), and (E)-ß-famesene (4.8-5.0%) were principal components. The root essential oil significantly inhibited nitric oxide (NO) production on LPS-induced RAW264.7 cells (IC50 = 1.41 ± 0.10 µg/mL) as compared to standard, dexamethasone (IC50 = 5.43 ± 0.54 µg/mL). Besides, both root and aerial part essential oils exhibited cytotoxic activity against MCF-7, SK-LU-1, and HepG2 (IC50 from 1.11 ± 0.04 to 1.70 ± 0.05 µg/mL). Molecular docking simulation results show that (E)-ß-farnesene exhibits the strongest binding energy among the studied compounds with the VEGFR-2 enzyme (ΔG = -7.295 kcal/mol), while δ-cadinene demonstrates the strongest affinity (ΔG = -8.047 kcal/mol) towards the COX-2 enzyme. Furthermore, hydrophobic interactions were indicated to be the main contributors to the binding ability in the studied protein-ligand complex. These findings proposed that E. sublyratus can be exploited for its anti-inflammatory and anti-cytotoxicity potential.

Recent achievements in the synthesis of benzimidazole derivatives.

Benzimidazoles are a class of heterocyclic compounds in which a benzene ring is fused to the 4 and 5 positions of an imidazole ring. Benzimidazole refers to the parent compound, while benzimidazoles are a class of heterocyclic compounds having similar ring structures, but different substituents. Benzimidazole derivatives possess a wide range of bioactivities including antimicrobial, anthelmintic, antiviral, anticancer, and antihypertensive activities. Many compounds possessing a benzimidazole skeleton have been employed as drugs in the market. The application of benzimidazoles in other fields has also been documented. The synthesis of benzimidazole derivatives has attracted much attention from chemists and numerous articles on the synthesis of this class of heterocyclic compound have been reported over the years. The condensation between 1,2-benzenediamine and aldehydes has received intensive interest, while many novel methods have been developed. In this article, we will give a comprehensive review of studies on the synthesis of benzimidazole, which date back to 2013. We have also tried to describe reaction mechanisms as much as we can. The work might be useful for chemists who work in the synthesis of heterocycles or drug chemistry.

Anti-inflammatory and Antiphytopathogenic Fungal Activity of 2,3-seco-Tirucallane Triterpenoids Meliadubins A and B from Melia dubia Cav. Barks with ChemGPS-NP and In Silico Prediction.

Two new rearranged 2,3-seco-tirucallane triterpenoids, meliadubins A (1) and B (2), along with four known compounds, 3-6, were isolated from the barks of Melia dubia Cav. Compound 2 exhibited a significant inflammatory inhibition effect toward superoxide anion generation in human neutrophils (EC50 at 5.54 ± 0.36 µM). It bound to active sites of a human inducible nitric oxide synthase (3E7G) through interactions with the residues of GLU377 and PRO350, which may benefit in reducing the neutrophilic inflammation effect. The ChemGPS-NP interpretation combined with bioactivity assay and in silico prediction results suggested 2 to be an agent for targeting iNOS with different mechanisms as compared to a selected set of current approved drugs. Moreover, compounds 1 and 2 showed remarkable inhibition against the rice pathogenic fungus Magnaporthe oryzae in a dose-dependent manner with IC50 values of 137.20 ± 9.55 and 182.50 ± 18.27 µM, respectively. Both 1 and 2 displayed interactions with the residue of TYR223, a key active site of trihydroxynaphthalene reductase (1YBV). The interpretation of 1 and 2 in the ChemGPS-NP physical-chemical property space indicated that both compounds are quite different compared to all members of a selected set of reference compounds. In light of demonstrated biological activity and in silico prediction experiments, both compounds possibly exhibited activity against phytopathogenic fungi via a novel mode of action.

The antioxidative potential of procyanidin B1: DFT (density functional theory) and docking approaches.

Procyanidin B1 is one of the natural dimeric flavonoids. It has established a great role in antioxidative activity. In the current study, we wish to provide crucial information on its antioxidative action by the DFT computational and docking approaches. From point of thermodynamic view, at the M062X/6-311G(d,p) level, the HAT (hydrogen atom transfer) and SPL-ET (sequential proton loss-electron transfer) are principal antioxidative routes of this compound in gas and methanol, respectively. OH groups of two phenyl rings of this molecule are likely to be the best antiradical sites. In the kinetics of the interactions with HOO• radicals, OH groups of phenyl rings have also generated the best ΔG# (Gibbs free energy of activation) and rate constant K. The antioxidative action of procyanidin B1 is further confirmed by its chelation to metal ions, in which complex formation with Cu2+ having lower binding energy is more stable than complex formation with Zn2+. Docking study revealed that the antioxidative activity of procyanidin B1 involved human tyrosinase enzyme inhibition through interaction with essential residues, focusing on the OH groups of two phenyl rings.

Recent Development in the Synthesis of Thiazoles.

BACKGROUND: Thiazole-containing compounds are widely found in natural products as well as synthetic sources. Many thiazole-based compounds possess a broad spectrum of bioactivities, and some of them are well-known drugs in the markets. The use of thiazole derivatives in other fields such as organic materials, cosmetics, and organic synthesis has also been widely reported. Due to a wide range of applicability, the synthesis of thiazole-containing compounds has attracted extensive interest from chemists, and many studies in the synthesis of thiazole skeleton have been reported recently. OBJECTIVE: This review article will discuss recent studies in the synthesis of thiazoles (from2012). Besides the well-established Hantzsch thiazole synthesis, a large number of novel methods have been developed for the synthesis of thiazole derivatives. In most cases, reaction mechanisms have also been described. CONCLUSION: The synthesis of thiazole derivatives has drawn great attention from chemists, and many studies in the synthesis of these heterocycles have been reported recently. The classical method, the Hantzsch thiazole synthesis has received great research interest from chemists. Moreover, many new methods have been established to synthesize thiazole-derived compounds. Unquestionably, more and more approaches to access thiazole skeleton will appear in the literature. The application of well-established thiazole synthesis methods to the synthesis of drugs, organic materials, and natural products will almost certainly be studied.

Recent Achievement in the Synthesis of Benzo[b]furans.

BACKGROUND: Benzo[b]furan derivatives are oxygen-containing heterocyclic compounds consisting of fused benzene and furan rings and are present in a large number of natural and non-natural compounds. This class of compounds has a wide spectrum of biological activities, such as antiarrhythmic, anticancer, inflammatory, antioxidant, antimicrobial, and antiviral. Furthermore, benzo[b]furan derivatives have also been applied in various areas, such as organic electroluminescence device materials and organic dyes, photosensitizing material, organic synthesis as building blocks or intermediates. Because of a broad range of applicability, the synthesis of benzo[b]furan derivative has drawn great attention of chemists and many studies on the synthesis of this class of compounds have been reported recently. This review will give an overview of benzo[b]furan preparation based on studies dating back to the year 2012. OBJECTIVE: In this review, recent development in the synthesis of benzo[b]furans are discussed. There has been increasingly new methodologies for the construction of benzo[b]furans skeleton to improve efficiency or develop environmentally friendly procedures. In some studies, reaction mechanisms were also outlined. CONCLUSION: Many methods for the synthesis of benzo[b]furans have been reported recently. Most of them involve cyclization or cycloisomerization processes. Unquestionably, more imaginative strategies for the construction of benzo[b]furan skeleton will be established in the near future. Application of known methods to natural products or drug synthesis, on industrial scale for the synthesis of economically or medicinally important benzo[ b]furans will probably be paid attention to.