Frutescones H–R (1–11), new sesqui- or monoterpene-based meroterpenoids, were isolated from the aerial parts of Baeckea frutescens. Their structures and absolute configurations were established by means of spectroscopic analyses (HRESIMS, 1D and 2D NMR, and ECD), as well as single-crystal X-ray crystallography of 1, (−)-7, and 9. The anti-inflammatory activities of all isolates were evaluated by measuring their inhibitory effects on NO production in LPS-stimulated RAW 264.7 macrophages, and the structure–activity relationships of 1–11 are also discussed. Compound 8 exhibited anti-inflammatory activity with an IC50 value of 0.36 μM, which might be related to the regulation of the NF-κB signaling pathway via the suppression of p65 nuclear translocation and the consequent decrease of IL-6 and TNF-α.

The present study was designed to investigate the chemical constituents of the roots of Cyathula officinalis. Compounds were isolated by silica gel, Sephadex LH-20, ODS column chromatography, and preparative HPLC. Their structures were determined on the basis of 1D and 2D NMR techniques, mass spectrometry, and chemical methods. One new oleanane-type triterpenoid saponin, 28-O-[α-L-rhamnopyranosyl-(1→3)-β-D-glucuronopyranosyl-(1→3)-β-D-glucopyranosyl] hederagenin (1), was isolated from the roots of Cyathula officinalis. The anti-inflammatory activities of the isolates were evaluated for their inhibitory effects against LPS-induced nitric oxide (NO) production in RAW 264.7 macrophages cells. Compounds 2, 4, and 6 exhibited moderate anti-inflammatory activities.

•Three new compounds were isolated from Leontopodium leontopodioides..•The structures of the new compounds were characterized by spectroscopic analyses.•Some phenolic acids displayed potent cyclooxygenases inhibitory activities.Two new ent-kaurene diterpenoids, 13α,15α-dihydroxy-18-carboxy-19-nor-ent-kaur-16-ene-2β-O-(2′-angelate)-β-d-glucopyranoside (leontocin A, 1), 13α,15α-dihydroxy-18-carboxy-19-nor-ent-kaur-16-ene-2β-O-(2′-angelate-6′-acetyl)-β-d-glucopyranoside (leontocin B, 2), and one new lignan, 2,3-bis[(3,4-di-hydroxyphenyl)methylene]-monoethyl ester-butanedioic acid (leontolignan A, 3), together with three known phenolic acids (4-6) were isolated from the aerial parts of Leontopodium leontopodioides (Asteraceae). Their structures were elucidated by chemical and spectroscopic methods. All isolates were evaluated for their anti-inflammatory activities by measuring their inhibitory effects against cyclooxygenase-1 and 2 in vitro.Download high-res image (186KB)Download full-size image

Frutescone A–G [(1–6), (+)-7, (−)-7], a new group of naturally occurring tasmanone-based meroterpenoids, were isolated from the aerial parts of Baeckea frutescens L. Compounds 1 and 4 featured a rare carbon skeleton with an unprecedented oxa-spiro[5.8] tetradecadiene ring system, existing as two favored equilibrating conformers in CDCl3 solution, identified by variable-temperature NMR. The regioselective syntheses of 4–7 were achieved in a concise manner by a biomimetically inspired key hetero-Diels–Alder reaction “on water”. Compounds 1, 4, and 5 exhibited moderate cytotoxicities in vitro.

Andrographolide sodium bisulphite (ASB) injection was widely used in China for the treatment of infectious diseases. The chemical analysis of ASB injection resulted in the isolation of four new related impurities (2, 3, 5, 6), together with two known compounds (1, 4). The structures of the new compounds were elucidated by 1D and 2D NMR, high-resolution mass spectrometry, Mo2(OAc)4-induced circular dichroism and ECD calculation. Among them, 1 and 2 were two unprecedented photocyclization derivatives of isocopalane diterpene. The generation of the primary impurity 1 was proved to be an intramolucular 6-exo carbonyl radical cyclization of ASB through a novel sulfonyl group transfer. This finding furnished a facile photocyclization methodology to afford 1 in good yield with excellent regioselectivity. The possible mechanism for the formation of the related impurities was also discussed.

•Related impurities of etimicin key intermediate P1 were detected by HPLC methods.•Four major related impurities were isolated from P1 by column chromatograpy.•Their structures were established by means of LC–MSn and NMR techniques.•Three impurities are new compounds and all NMR data were first reported.•The possible mechanism for the formation of these impurities is discussed.Etimicin intermediate 3,2″,6″-N,N,N-triacetyl gentamicin C1a (P1), is a key intermediate of etimicin, which is a semi-synthetic aminoglycoside antibiotic effective to both gram-positive and gram-negative bacteria infections. Four major related impurities of P1 were detected by HPLC–ELSD and ESI–MSn methods. Weakly acidic cation exchange resin, CM-sephadex and silica gel column chromatography were used for the isolation and purification of four major impurities. By means of ESI–MSn and NMR analysis, related impurities were characterized as 3,2″-N,N-diacetyl gentamicin C1a (1), 3,2″,6″-N,N,N-triacetyl gentamicin C2b (2), 2″-N-acetyl gentamicin C1a (3), and 2″,6″-N,N-diacetyl gentamicin C1a (4). Impurities 1, 2, 4 are novel compounds and the NMR data of these isolates were first reported in this paper. The possible mechanism for the formation of these impurities is also discussed.

Phytochemical investigation of the ethanol extract of the aerial parts of Artemisia rupestris resulted in the isolation of three new guaiane sesquiterpenes, (1R,7R,10S)-1-hydroxy-3-oxoguaia-4,11(13)-dien-12-oic acid (1), (1R,7R,10S)-10-hydroxy-3-oxoguaia-4,11(13)-dien-12-oic acid (2), pechueloic acid 12-O-β-d-glucopyranoside (3), together with 12 known compounds (4–15). The structures of these new compounds were established on the basis of extensive spectroscopic analysis and electronic circular dichroism (ECD) calculation. All isolates were evaluated for their in vitro inhibitory effects on nitric oxide (NO) production in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages cells, and the structure–activity relationships were also discussed.