A new naphthoquinone and other antibacterial constituents from the roots of Xanthium sibiricum

Reinvestigating the chemical constituents of the roots of Xanthium sibiricum led to the isolation of a new naphthoquinone (1), together with 13 known compounds (2–14). Their structures were elucidated by using spectroscopic analyses, including HR-ESI-MS, 1D and 2D NMR, and by comparing their NMR data with those of related compounds. Compound 1 showed moderate antibacterial activity against Escherichia coli, Bacillus subtilis, Micrococcus tetragenus and Staphylococcus aureus, while 6 and 12 showed stronger antibacterial activity than the positive control ciprofloxacin against E. coli, with minimum inhibitory concentration values of 0.17 and 0.35 μg/mL, respectively.     

Relative stereochemistry of a diterpene from Salvia cinnabarina

The relative stereochemistry of 3,4-secoisopimara-4(18),7,15-triene-3-oic acid, a diterpenoid with antispasmodic, hypotensive and antibacterial activities isolated from Salvia cinnabarina, was determined by an X-ray diffraction analysis of a single crystal of a suitable crystalline derivative.     

A new diterpene glycoside from Rabdosia rubescens

A new ent-kaurene beta-D-glucoside was isolated from Rabdosia rubescens, together with the known compounds oridonin, ponicidin, and pedalitin. The structure of new compound was determined, on the basis of spectral data and X-ray crystallographic analysis, to be ent-7 beta,20-epoxy-kaur-16-ene-1 beta,6 alpha,7 alpha,14 alpha,15 alpha-pentanol 1-O-beta-D-glucopyranoside.     

A new casbane diterpene from Euphorbia pekinensis

A new casbane diterpenoid, referred to as pekinenin G, together with one cembrane diterpene and four known casbane diterpenoids were isolated from the roots of Euphorbia pekinensis. Their structures were elucidated on the basis of spectroscopic studies and comparison with related known compounds. The six compounds showed different cytotoxic activities against four human cancer cell lines.     

A new diterpene glycoside from Stevia rebaudiana

From the commercial extract of the leaves of Stevia rebaudiana, a new diterpene glycoside was isolated besides the known steviol glycosides including stevioside, rebaudiosides A-F, rubusoside and dulcoside A. The new compound was identified as 13-[(2-O-β-D-glucopyranosyl-3-O-β-D-glucopyranosyl-β-D-glucopyranosyl)oxy] ent-kaur-16-en-19-oic acid-(2-O-α-L-rhamnopyranosyl-β-D-glucopyranosyl) ester (1) on the basis of extensive spectroscopic (NMR and MS) and chemical studies.     

A new furanoid diterpene from Caesalpinia pulcherrima

A new cassane-type diterpene isovouacapenol E (1) was isolated from the leaves of Caesalpinia pulcherrima, together with the known compounds caesaldekarin A (3), spathulenol (4), caryophyllene oxide (5), phytol, and sitosterol. The structure of 1 was elucidated by spectral data interpretation.     

New adduct of abietane-type diterpene from Salvia leriifolia Benth.

A new adduct of abietane-type diterpene, salvialeriicone (1), was isolated from Salvia leriifolia Benth., along with a new chemical entity nor-abietane diterpene, 2-isopropyl-8,8-dimethyl-7,8-dihydrophenanthrene-1,4,5(6H)-trione (2). Their structures were determined using mass spectrometry, and 1D- and 2D-NMR spectroscopy.     

Cytotoxic triterpenes from Salvia buchananii roots

A pentacyclic triterpene, named salvibuchanic acid (1), together with five known compounds, were isolated from the roots of Salvia buchananii Hedge (Lamiaceae). The structural characterisation of all compounds was performed by spectroscopic analyses, including 1D and 2D NMR and HRESIMS experiments. The lupane triterpene (1) and hyptadienic acid (2) were investigated for their potential cytotoxic activity on Jurkat, HeLa and MCF7 cell lines. Both compounds showed an interesting antiproliferative activity with similar potency in all cell lines. By means of flow cytometric studies, hyptadienic acid (2) induced in HeLa cells a S cell cycle block, while 1 elicited both cytostatic and cytotoxic responses.     

A new labdane diterpene from the rhizomes of Alpinia officinarum

A new labdane diterpene, (Z)-12,14-labdadien-15(16)-olide-17-oic acid (1), and a new natural cadinane sesquiterpene, 4-isopropyl-6-methyl-1-naphthalenemethanol (2), were isolated from the ethanolic extract of the rhizomes of Alpinia officinarum, together with three other products, galangin (3), kaempferol (4) and quercetin (5). Their structures were elucidated by using extensive spectroscopic methods. Compounds 1 and 2 showed no remarkable cytotoxic activity against HeLa and HepG2 cancer cell lines with IC₅₀>50 μg mL^? 1.     

A new labdane diterpene from the flowers of Solidago canadensis

A new labdane diterpene, 9alpha,16xi-dihydroxy-6-oxo-7,13-labdadien-15,16-olide (solicanolide, 1) and six known compounds identified as quercetin (2), 3-O-caffeoylquinic acid (3, neochlorogenic acid), 5-O-caffeoylquinic acid (4, chlorogenic acid), 4,5-di-O-caffeoylquinic acid (5), 3,5-di-O-caffeoylquinic acid (6) and 3,4-di-O-caffeoylquinic acid (7) were isolated from the flowers of Solidago canadensis. To our knowledge, compound 7 was isolated for the first time in S. canadensis. This work describes the isolation of compounds 1-7 and the structure elucidation of a new compound identified as compound 1. Solicanolide (1) showed cytotoxic activity against A549 (IC(50): 13+/-2 microM), DLD-1 (IC(50): 26+/-2 microM) and WS1 (IC(50): 17+/-1 microM) cell lines.     

A new diterpene from the leaves of Andrographis paniculata Nees

Phytochemical investigation of the methanolic extract of the leaves of Andrographis paniculata Nees yielded a minor, new diterpene, 21-nor-3,19-isopropylidine-14-deoxy-ent-labda-8(17),13-dien-16,15-olide (1), together with five known labdane type diterpenes, andrographolide 3, 14-deoxyandrographolide 4, 14-deoxy-12-hydroxyandrographolide 5, 14-deoxy-11,12-dihydroandrographolide 6, neoandrographolide 7, and two acids, cinnamic acid 8, and ferulic acid 9. The chemical structures were established by spectroscopic analyses, including 1D- and 2D-NMR spectroscopic experiments, and on the basis of HR-ESI MS analyses. The methanolic extract of the leaves exhibited moderate antibacterial and antifungal activities at a dose of 200 microg/mL in comparison with the reference standards.     

A new tigliane-type diterpene from Euphorbia dracunculoides Lam

One new tigliane-type diterpene, 4-deoxy-4(β)H-8-hydroperoxyphorbol-12-benzoate-13-isobutyrate (1), together with two known diterpenoids, 3-acetyl-5,8-dibenzoyl-14α-propanoyl-13,17-epoxy-7-myrsinaone diterpene with C9–C10 cyclised to form an additional lactone ring (2), Euphodendriane A (3) have been isolated from the whole plants of Euphorbia dracunculoides Lam. Their structures were elucidated by means of extensive spectroscopic analysis (NMR and HR-ESI-MS) and comparison with data reported in the literature. This is the first isolation of 8-hydroperoxy tigliane diterpene (1) from the genus of Euphorbia. All compounds were evaluated for their antifungal activities.     

A new ent-clerodane diterpene from the aerial parts of Baccharis gaudichaudiana

A new ent-clerodane diterpene, named bacchariol (1) was isolated from the aerial parts of Baccharis gaudichaudiana DC. (Compositae), together with known ent-clerodane diterpenes (2, 3), eight known flavonoids (4-11) and 3, 5-dicaffeoylquinic acid (12). Their structures were determined by spectroscopic analyses. Flavonoids (7, 8, 11) and 12 showed moderate scavenging activities toward 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radicals.     

A new labdane-type diterpene from the bark of Juniperus chinensis Linn

From the bark of Juniperus chinensis Linn., a new labdane-type diterpene, methyl 14,15-dihydroxy-8(17),12E-labdadien-19-oate (1a), together with nine known compounds, trans-communic acid, cis-communic acid, 15,16-bisnor-13-oxo-8(17),11E-labdadien-19-oic acid, sandaracopimaric acid, 7-oxosandaracopimaric acid, sugiol, 7-oxototarol, alpha-cedrol and beta-sitosteryl-1-O-beta-glucopyranoside were isolated. The structures of those compounds were elucidated based on spectral analysis and chemical evidences.     

New highly oxidized diterpene quinones from Salvia fruticulosa (labiatae)

The structures of fruticulins A and B, two highly oxidized diterpene quinones isolated from Salvia fruticulosa, were determined by spectroscopic methods, chemical transformations and X-ray crystallographic analysis of one of them. The free phenol derivative of fruticulin A was also isolated as a natural product.     

A new myrsinol-type diterpene polyester from Euphorbia dracunculoides Lam

A new myrsinol-type diterpene polyester, 14-deoxo-3β-O-propinoyl-2α,5α,7β,15β-tetra-O-acetyl-14α-O-benzoyl-myrsinol (1), and its known analogue, 14-deoxo-3β-O-prorionyl-5α,15β-di-O-acetyl-7β-O-nicotinoyl-myrsinol-14β-acetate (2), together with a monoterpenoid, pubinernoid A (3), two indole alkaloids, neoechinulin A (4) and dihydroxyisoechinulin A (5), two benzene derivatives, siringin (6) and (3-methoxyphenyl) acetic acid (7), were isolated from the 70% acetone extract of the aerial parts of Euphorbia dracunculoides Lam. Their structures were elucidated on the basis of spectroscopic evidence and comparison with literature reports. The absolute configuration of 1 was deduced by comparing experimental and calculated ECD spectra. Among them, compounds 4 and 5 were first obtained from the plant source. In addition, the ¹³C NMR data of compound 2 was reported for the first time.