Thiophene acetylenes and furanosesquiterpenes from Xanthopappus subacaulis and their antibacterial activities

Jatrolignans C and D: New Neolignan Epimers from Jatropha curcas

Two new neolignans jatrolignans, C (1) and D (2), a pair of epimers, were isolated from the whole plants of Jatropha curcas L. (Euphorbiaceae). Their structures were determined with HRESIMS, IR, and NMR data analysis, and electronic circular dichroism (ECD) experiments via a comparison of the experimental and the calculated ECD spectra. Their antichlamydial activity was evaluated in Chlamydia abortus. They both showed dose-dependent antichlamydial effects. Significant growth inhibitory effects were observed at a minimum concentration of 40 μM.

Thiophenes-Naturally Occurring Plant Metabolites: Biological Activities and In Silico Evaluation of Their Potential as Cathepsin D Inhibitors

Naturally, thiophenes represent a small family of natural metabolites featured by one to five thiophene rings. Numerous plant species belonging to the family Asteraceae commonly produce thiophenes. These metabolites possessed remarkable bioactivities, including antimicrobial, antiviral, anti-inflammatory, larvicidal, antioxidant, insecticidal, cytotoxic, and nematicidal properties. The current review provides an update over the past seven years for the reported natural thiophene derivatives, including their sources, biosynthesis, spectral data, and bioactivities since the last review published in 2015. Additionally, with the help of the SuperPred webserver, an AI (artificial intelligence) tool, the potential drug target for the compounds was predicted. In silico studies were conducted for Cathepsin D with thiophene derivatives, including ADMET (drug absorption/distribution/metabolism/excretion/and toxicity) properties prediction, molecular docking for the binding interaction, and molecular dynamics to evaluate the ligand-target interaction stability under simulated physiological conditions.

Ethnobotany and the Role of Plant Natural Products in Antibiotic Drug Discovery

The crisis of antibiotic resistance necessitates creative and innovative approaches, from chemical identification and analysis to the assessment of bioactivity. Plant natural products (NPs) represent a promising source of antibacterial lead compounds that could help fill the drug discovery pipeline in response to the growing antibiotic resistance crisis. The major strength of plant NPs lies in their rich and unique chemodiversity, their worldwide distribution and ease of access, their various antibacterial modes of action, and the proven clinical effectiveness of plant extracts from which they are isolated. While many studies have tried to summarize NPs with antibacterial activities, a comprehensive review with rigorous selection criteria has never been performed. In this work, the literature from 2012 to 2019 was systematically reviewed to highlight plant-derived compounds with antibacterial activity by focusing on their growth inhibitory activity. A total of 459 compounds are included in this Review, of which 50.8% are phenolic derivatives, 26.6% are terpenoids, 5.7% are alkaloids, and 17% are classified as other metabolites. A selection of 183 compounds is further discussed regarding their antibacterial activity, biosynthesis, structure-activity relationship, mechanism of action, and potential as antibiotics. Emerging trends in the field of antibacterial drug discovery from plants are also discussed. This Review brings to the forefront key findings on the antibacterial potential of plant NPs for consideration in future antibiotic discovery and development efforts.

Polyacetylene and phenolic constituents from the roots of Codonopsis javanica

Chemical investigation of the roots of Codonopsis javanica resulted in isolation of 12 compounds, including one new polyacetylene, codojavanyol (1), one new phenolic glycoside, codobenzyloside (7), and 10 known compounds, (2E,8E)-9-(tetrahydro-2H-pyran-2-yl)nona-2,8-diene-4,6-diyl-1-ol (2), lobetyol (3), lobetyolin (4), lobetyolinin (5), cordifolioidyne B (6), benzyl-α-L-arabinopyranosyl (1-6)-β-D-glucopyranoside (8), (Z)-8-β-D-glucopyranosyloxycinnamic acid (9), syringin (10), syringaresinol (11), and tryptophan (12). Their structures were elucidated by 1 D and 2 D NMR and MS spectroscopic analyses in comparison with the data reported in the literature. The stereochemistry of the C-2' position of 1 was identified based on time-dependent density functional theory (TDDFT) electronic circular dichroism (ECD) calculation. Among the isolates, compounds 3-5 were shown to have weak cytotoxicity toward three human carcinoma cell lines, including lung (A549), liver (HepG2), and breast (MCF7), with the induction of 41.4 to 55.6% cell death at the concentration of 100 µM.

1-Nitro-4-(1-propyn-1-yl)benzene

The title compound, C9H7NO2, was prepared by alkynylation of 4-iodonitrobenzene with 1,3-dilithiopropyne in the presence of 1 equivalent of CuI and catalytic amounts of Pd(PPh3)2Cl2. The complete molecule is generated by crystallographic twofold symmetry with the C—N and C—C[triple-bond]C—C units lying on the rotation axis. No directional interactions beyond normal van der Waals contacts could be identified in the packing.

Traditional Tibetan medicinal plants: a highlighted resource for novel therapeutic compounds

Around 70-80% of drugs used in traditional Tibetan medicine (TTM) come from Qinghai Tibet Plateau, the majority of which are plants. The biological and medicinal culture diversity on Qinghai Tibet Plateau are amazing and constitute a less tapped resource for innovative drug research and development. Meanwhile, the problem of the exhausting Tibetan medicine resources is worrying. Here, the latest awareness, as well as the gaps of the traditional Tibetan medicinal plant issues in drug development and clinical usage of TTM compounds, was systematically reviewed and highlighted. The TTM resource studies should be enhanced within the context of deeper and more extensive investigations of molecular biology and genomics of TTM plants, phytometabolites and metabolomics and ethnopharmacology-based bioactivity, thus enabling the sustainable conservation and exploitation of Tibetan medicinal resource.

Two new thiophene polyacetylene glycosides from Atractylodes lancea

Phytochemical investigation on the rhizomes of Atractylodes lancea led to the isolation of two new thiophene polyacetylene glycosides (1 and 2) and six known compounds (3-8). Their structures were elucidated based on the extensive spectroscopic data (UV, IR, 1D and 2D NMR, and HRESIMS). The absolute configurations of new compounds were established by calculated and experimental circular dichroism. All the compounds were assessed on the lipopolysaccharide-induced NO production in BV2 cells and compounds 3, 7, and 8 showed moderate inhibitory activities.