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Chemical fractionation of the ethanolic extract of Eclipta prostrata yielded a series of unreported terpenoid constituents, including a rare 6/6/6/6-fused tetracyclic triterpenoid, a pentacyclic triterpenoid, two pentacyclic triterpenoid saponins, a diterpenoid and a sesquiterpenoid. Structures were assigned to these compounds on the basis of comprehensive spectroscopic analyses, with the absolute configurations of the tetracyclic triterpenoid, the diterpenoid and the sesquiterpenoid being determined via explanation of electronic circular dichroism data. Screening of these isolates in an array of bioassays revealed antibacterial, cytotoxic and α-glucosidase inhibitory activities for selective compounds. Of particular interest, the tetracyclic triterpenoid showed very strong inhibition against α-glucosidase with an IC 50 of 0.82 ± 0.18 μM, being 10 3 -fold as active as the positive control acarbose., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Fourteen chromane derivatives of seven pairs of enantiomers (1-14) have been obtained from the ethanolic extract of the flower buds of Tussilago farfara L. Their structures with absolute configurations have been elucidated by detailed spectroscopic analyses, chemical methods, and particularly comparison of experimental ECD spectra with theoretically computed ones. Biological evaluations revealed that they did not show cytoprotective, antimicrobial, and α-glucosidase inhibitory activities., (© 2019 Wiley-VHCA AG, Zurich, Switzerland.)

Two neolignan glycosides including a new one (1), along with seven iridoid glycosides (3 − 9) and nine flavonoid glycosides (10 − 18), were isolated from the leaves of Vaccinium bracteatum. Their structures were established mainly on the basis of 1D/2D NMR and ESIMS analyses, as well as comparison to known compounds in the literature. The structure of 1 with absolute stereochemistry was also confirmed by chemical degradation and ECD calculation. Selective compounds showed antiradical activity against ABTS and/or DPPH. Moreover, several isolates also suppressed the production of ROS in RAW264.7 cells and exerted neuroprotective effect toward PC12 cells. [ABSTRACT FROM AUTHOR]

Ten thiophene derivatives (1–10), including two previously undescribed ones (1 and 2), have been obtained and structurally characterized from the aerial parts of a traditional Chinese herb Eclipta prostrata. Six of them with one chiral center were identified to be scalemic mixtures, and the pure enantiomers of two isolates (1 and 3) were successfully separated via chemical derivatization and chiral HPLC, with the absolute configurations being established by analysis of optical rotations. All the thiophenes were subjected to a series of assays and compounds 9 and 10 exhibited mild antibacterial activity against Staphylococcus aureus. [ABSTRACT FROM AUTHOR]

Five selaginellin derivatives (1 and 3-6) including a new one, selaginellin T (1), and a new triarylbenzophenone analog, selagibenzophenone A (2), were isolated from the whole plants of Selaginella pulvinata. Their structures were determined by 1D- and 2D-NMR and HR-ESI-MS data. Selagibenzophenone A (2) is the first example of naturally occurring triarylbenzophenone. The results of the phosphodiesterase-4 (PDE4) inhibitory screening assays showed that compounds 1−6 exhibited potent activities with the IC50 values in the range of 1.04−9.35 μM. [ABSTRACT FROM AUTHOR]

Three new sesquiterpenoids (1 – 3) and two new sesquiterpenoid glucosides (4 & 5), along with 24 known analogues (6 – 29), were obtained from the flowers of Inula japonica. Structures of the new compounds were determined by interpretation of spectroscopic data, and their absolute configurations were established via comparison of experimental with computed ECD curves. All the isolates were tested in an in vitro cytotoxic assay against human A549, MCF-7 and MDA-MB-231 cancer cell lines, and selective ones displayed significant activity close to the positive control adriamycin. The new molecules 1 – 5 were also evaluated for their nitric oxide (NO) release inhibitory effect in murine macrophage RAW264.7 cells, with compound 1 showing comparable activity (IC 50 16.2 ± 0.8 μM) to the positive control dexamethasome. A preliminary mechanistic study of the effect of 8 toward A549 cells revealed that it could arrest cell cycle at G 2 /M phase and induce cell apoptosis in a dose-dependent manner. Unlabelled Image [ABSTRACT FROM AUTHOR]

Under the guidance of MS/MS-based molecular networking, five new clerodane diterpenoid glucosides, tinosinesides R-V (1 – 5), along with 15 known diterpenoids (6–20), were isolated from the stems of Tinospora sinensis. Compound 1 represents the first example of diterpenoid bearing a thio sugar and compound 5 is the first 18,19-dinor-clerodane with cis -fused A/B ring. The structures of the new compounds were elucidated by spectroscopic means, and their absolute configurations were established on the basis of time-dependent density functional theory (TD-DFT) based electronic circular dichroism (ECD) calculation and chemical methods. Selected compounds were evaluated for their immunomodulatory effect and several compounds could enhance the proliferation of B lymphocytes. Preliminary mechanistic studies disclosed that 3 could promote B cell generation and inhibit B cell differentiation. [Display omitted] [ABSTRACT FROM AUTHOR]

Abstract Seven new pentacyclic triterpenoids including six ursane-type, marinoids A–F (1 – 6), and one oleanane-type, marinoid G (7), along with five known analogues (8 – 12), were separated from the roots of Morinda officinalis var. officinalis. Their structures were assigned by spectroscopic means especially analysis of 2D NMR data, with the absolute configurations of 1 and 2 being determined via comparison of their experimental ECD spectra with the computed ones. Selective compounds displayed cytotoxic activity against two human osteosarcoma cell lines and also antibacterial effects against one Gram positive and one Gram negative strains. Graphical abstract Unlabelled Image [ABSTRACT FROM AUTHOR]

Twenty-seven monoterpene indole alkaloids (MIAs) including three new ones were isolated from the plant of Rhazya stricta . Their structures were elucidated by analyses of HRMS and NMR data. Secopleiocarpamine A ( 1 ) represents a novel 2,3- seco pleiocarpamine type MIA possessing a cyano group. A possible biosynthetic pathway for 1 was postulated. All compounds were evaluated for their inhibitory activities against six Candida strains, and the results showed that 2 , 5 , 12 , 21 , 23 , and 27 exhibited moderate inhibitory activities with MIC values ranging from 3.125 to 50 μg/mL. [ABSTRACT FROM AUTHOR]

Six undescribed low-polarity compounds including three rare 14-methylergostane steroids (1 – 3), one euphane triterpenoid (4) and two octadecanoic acid ethyl esters (5 and 6), along with ten previously reported terpenyl cometabolites (7 – 16), were isolated from the stems of Tinospora sagittata. Their structures were determined by detailed spectroscopic analyses and comparison with structurally related known compounds, and all of them have been reported from T. sagittata for the first time. Compounds 4 – 6 and 16 showed potent in vitro inhibitory activity against the diabetes target α -glucosidase, while compounds 10 and 14 displayed promising antibacterial effect toward Staphylococcus aureus ATCC 25923. [Display omitted] • New 14-methylergostane steroids, euphane triterpenoid and octadecanoid derivatives were separated from Tinospora sagittata. • All the compounds have been reported from Tinospora sagittata for the first time. • Compounds 4 – 6 and 16 showed potent α-glucosidase inhibitory activity. • Compounds 10 and 14 exerted promising antibacterial effect toward Staphylococcus aureus. [ABSTRACT FROM AUTHOR]

Six new compounds including four prenylated indole alkaloids (1 – 4) and two lignans (5 – 6), along with eight known cometabolites (7 – 14), were isolated from the flower buds of Tussilago farfara. Structures of the new compounds were elucidated by comparison with structurally related known analogues and also by comprehensive spectroscopic analyses. Their absolute configurations were determined by a variety of means including Mosher's method, Marfey's analysis, electronic circular dichroism (ECD) exciton chirality method and ECD calculations. Our bioassays have established that compounds 1 and 2 showed potent α -glucosidase inhibitory activity with IC 50 values of 105 ± 4.7 and 35.2 ± 3.2 μM, respectively, while the known 13 and 14 exerted moderate DPPH radical scavenging activity with IC 50 values of 45.2 ± 2.9 and 29.2 ± 2.0 μM, respectively. Unlabelled Image • Four new prenylated indole alkaloids and two new lignans were isolated from Tussilago farfara. • Structures with absolute configurations of the new compounds were fully characterized. • The new indole alkaloids 1 and 2 showed potent α -glucosidase inhibitory activity. • Two known lignans 13 and 14 exerted moderate antiradical effect. [ABSTRACT FROM AUTHOR]

Three new thiophene derivatives, ecliprostins A–C (1 – 3), have been isolated from the aerial parts of a Compositae medicinal plant Eclipta prostrata , and structures of them have been elucidated by comprehensive spectroscopic analyses. Both ecliprostins A (1) and B (2) feature an acetylenic bithiophenyl backbone and also incorporate an isovalerate moiety, while ecliprostin C (3) is a symmetrical dimer of compound 1 and represents the first example bonded via an ether bridge among the very limited natural dimers. All three compounds show antibacterial activity against Staphylococcus aureus. Three new antibacterial thiophene derivatives, including an unusual dimer with an ether bridge, were isolated and identified from the aerial parts of Eclipta prostrata. Unlabelled Image • Three new acetylenic thiophenes were isolated from the aerial parts of Eclipta prostrata. • The first example linked via an ether bond of natural acetylenic thiophene dimers was reported. • All the isolates showed antibacterial activity against Staphylococcus aureus. [ABSTRACT FROM AUTHOR]