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Graphical Abstract:

Graphical Abstract:

The coronavirus disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has led to more than 5 million deaths worldwide to date. Due to the limited therapeutic options so far available, target-based virtual screening with LC/MS support was applied to identify the novel and high-content compounds 1–4with inhibitory effects on SARS-CoV-2 in Vero E6 cells from the plant Dryopteris wallichiana. These compounds were also evaluated against SARS-CoV-2 in Calu-3 cells and showed unambiguous inhibitory activity. The inhibition assay of targets showed that compounds 3and 4mainly inhibited SARS-CoV-2 3CLpro, with effective Kdvalues. Through docking and molecular dynamics modeling, the binding site is described, providing a comprehensive understanding of 3CLpro and interactions for 3, including hydrogen bonds, hydrophobic bonds, and the spatial occupation of the B ring. Compounds 3and 4represent new, potential lead compounds for the development of anti-SARS-CoV-2 drugs. This study has led to the development of a target-based virtual screening method for exploring the potency of natural products and for identifying natural bioactive compounds for possible COVID-19 treatment.

Errors in elucidating the structures of four natural classes of prenylated aromatic compounds with 2,3-epoxy, 2,3-dihydroxy, and cyclization with an ortho-phenolic hydroxyl to give a pyran or furan ring moiety are frequent and inevitable. Based on rigorous literature research and a series of chemical transformation experiments, a rule for the rapid determination of these four classes of prenylated derivates based on 13C NMR data was formulated, and 57 corrections featuring these fragments were accordingly reported.

Twelve hitherto unknown tandem prenylated p-hydroxybenzoic acid derivatives, namely, oberoniamyosurusins A–L, together with five known derivatives, were isolated from an EtOH extract of the whole parts of the plant Oberonia myosurus. Compounds 10, 13, and 17exhibited moderate inhibitory activity against Staphylococcus aureussubsp. aureusATCC29213 with MIC50values ranging from 7.6 to 23 μg/mL. To determine the biosynthetic pathway of this class of tandem prenyl-substituted compounds, the full-length transcriptome of O. myosuruswas sequenced, yielding 19.09 Gb of clean data and 10 949 nonredundant sequences. Two isoforms of p-hydroxybenzoic acid prenyltransferases were annotated and functionally characterized as the enzymes that might be involved in the biosynthesis of nervogenic acid (13) in Pichia pastoris.

The first total synthesis of gastrodinol, an unprecedented poly-p-cresol-substituted natural product with a rearranged and reconstructed C ring moiety, is reported. Our synthesis features a convergent fragment approach. The Sonogashira coupling reaction forges the two segments together to furnish the conjugated ene–yne. Photocatalytic 6π electrocyclization followed by spontaneous aromatization is used to construct the tetrasubstituted B ring at the late stage. Further study shows that gastrodinol exhibits significant cytotoxic activity against five human cancer cell lines in vitro(IC502.5–3.8 μM).

Investigation of the 95% EtOH extract of stems of Dendrobium findlayanumafforded four new seco-dendrobines, findlayines A–D (1–4); two known dendrobines, dendrobine (5) and 2-hydroxydendrobine (6); and four new phenolic compounds, dendrofindlaphenols A–C (7, 9, and 10) and 6″-de-O-methyldendrofindlaphenol A (8). Compounds 1and 2are the first seco-dendrobines possessing a seven-membered lactam moiety, with 3and 4derived from the oxidative cleavage of the C-2–C-3 bond of dendrobine. The structures were established using spectroscopic methods and by comparison with literature data. The absolute configurations of 1–4were confirmed via single-crystal X-ray diffraction data. Cytotoxic activity assays against HL-60, SMMC-7721, A-549, MCF-7, and SW480 human cancer cell lines revealed IC50values ranging from 2.3 to 5.3 μM for compound 7, from 19.4 to 34.4 μM for 8, and from 49.4 to 96.8 μg/mL for the EtOAc extract. An assay of the inhibition of NO production with RAW 264.7 cells indicated that 8had an IC50value of 21.4 μM, and the EtOAc extract, 10.5 μg/mL. The EtOAc extract possessed DPPH radical scavenging activity of 69.93% at 100 μg/mL.

Herein, a gold-catalyzed cascade reaction of yne-enones with iminooxindoles has been developed through a cascade cycloisomerization/(3 + 2) annulation process. This approach provides a straightforward and efficient route for the synthesis of functionalized 3,2′-pyrrolidinyl-spirooxindoles in high reactivity and broad substrate scope with excellent cis-selectivity. Moreover, the subsequent functionalization of furan units allows for the diverse synthesis of spirooxindole derivatives, which have demonstrated good antitumoral activity.

Abstract: Aqueous ethanol extracts of powdered stems of Dendrobium loddigesiiafforded three new phenolics including threo-7-O-ethyl-9-O-(4-hydroxyphenyl)propionyl-guaiacylglycerol (1), (R)-4,5,4'-trihydroxy-3,3',a-trimethoxybibenzyl (2) and (S)-5,5',7-trihydroxy-3',4'-dimethoxyflavanone (3), together with eleven known analogues. Their structures were determined by extensive spectroscopic analysis. To identify natural antioxidants, whitening, and anti-aging agents, the abilities of these phenolics were assessed to scavenge the 1,2-diphenyl-2-picrylhydrazyl (DPPH) radical, their abilities to inhibit tyrosinase production, and their abilities to stimulate collagen production by human dermal fibroblasts-adult (HDFa) assay. It was found that compounds 1, 4–8, 13and 14exhibited significant DPPH radical scavenging activities, compound 10exhibited tyrosinase inhibitory activity (IC5037.904 µg/mL), and compound 9showed significant collagen production with an EC50value of 3.182 µg/mL. These results suggest that phenolic constituents from D. loddigesiimay be candidate antioxidants, skin-whitening and/or anti-aging agents. Graphic Abstract:

Prof. Zhou Jun, Academician of Chinese Academy of Sciences (1999), is a phytochemist and medicinal chemist of China. He is one of the pioneers of Kunming Institute of Botany, CAS and a major founder of the State Key Laboratory of Phytochemistry and Plant Resources in West China. The chemical compositions of some TCM from genus of Dioscorea, Aconitum, Panax, Paris, Cynanchum, Gastrodia, Dendrobiumetc. and family Asclepiadaceae, Caryophyllaceae, Hypoxidaceae etc. have been explored by Prof. Zhou′s team as steroids, triterpenoids, alkaloids, cyclic peptides and phenols etc., which revealed the main active composition of those TCM such as Panax notoginseng, Paris yunnanensisand Gastrodia elata.

Graphical Abstract:

To isolate and identify the bioactive phytochemicals from the leaves of Camellia nitidissima.

Dendrowardol C (1)—a novel sesquiterpenoid, with an unprecedented 4/5/6/6 tetracyclic carbon backbone, together with two known cyclopacamphane-type sesquiterpenoids; dendronobilin I (2) and dendrobane A (3) were isolated from the stems of Dendrobium wardianumWarner. The structure of 1was established on the basis of spectroscopic data and the absolute configuration was determined by single-crystal X-ray diffraction crystallography. The hypothetical biosynthetic pathway of 1was postulated. Compound 1showed no cytotoxic activity against human tumor cell lines HL-60, SMMC-7721, A-549, MCF-7, and SW480.

15 compounds, including two new ones crepidatuols A (1) and B (2) were isolated from the stems of Dendrobium crepidatum. The planar structures of these compounds were elucidated by spectroscopic methods (NMR, MS, UV, and IR) and comparison with those from literatures. 10 compounds were send for enhancing activities on nerve growth factor (NGF) medicated neurite outgrowth in PC12 cells and the results indicated that crepidatuol A (1), confusarin and 3-(2-acetoxy-5-methoxy)-phenylpropanol showed enhancing activities at the concentration of 10.0 µM.

Two novel skeleton-rearranged norlignans, breviscaside A (1) and breviscapin B (2), have been isolated from the rhizomes of Curculigo breviscapa. Their structures were established on the basis of spectroscopic techniques, especially the 2D NMR spectral analysis

Two new iridoids, volvaltrates A and B (1and 2), and three new sesquiterpenoids, E-(−)-3β,4β-epoxyvalerenal (3), E-(−)-3β,4β-epoxyvalerenyl acetate (4), and mononorvalerenone (5), together with five known iridoids and two known sesquiterpenoids were isolated from the roots of Valeriana officinalis. The structures and relative configurations of 1−5were elucidated by spectroscopic evidence. Compound 1was an unusual iridoid with an oxygen bridge connecting C-3 and C-10, forming a cage-like structure, and compound 5was a mononorsesquiterpenoid.

Novel podophyllotoxin xyloside derivatives 8to 11were synthesized and evaluated for their cytotoxicities against a panel of 5 human cancer cell lines (HL-60, SMMC-7721, A-549, MCF-7, SW480) using [3-(4,5-dimethyl-thiazol-2-yl)-2,5-diphenyltetrazolium bromide] assays. These derivatives showed good to moderate activities, with compound 9having an IC50value of 4.42 μM against the A-549 cell line. Overall, compound 9might be a promising candidate for further development.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.