Two new sesquiterpene lactones from Sonchus arvensis

Two new sesquiterpene lactones, 1β,15-diacetoxy-5,7α,6,11β(H)-eudesm-3,4-en-6,12-olide (1) and 1β-hydroxy-3,4-en-15-O-β-glucopyranosyl-5,7α,6,11β(H)-eudesman-6,12-olide (2), were isolated from Sonchus arvensis L. (Asteraceae), together with ten known compounds. Their structures were elucidated through spectroscopic and chemical methods. All these known compounds except oleanolic acid (11) were isolated from the genus Sonchus for the first time. Selected new compounds were evaluated for antibacterial activity; unfortunately, they showed weak or no activities against Streptococcus mutans ATCC 25175.     

Two new sesquiterpene lactones from Ixeris sonchifolia

The structures of two new sesquiterpene lactones, 11,13beta-dihydroixerin Z (1) and Ixerin Z2 (2) isolated from Ixeris sonchifolia were determined to be 3-hydroxy-1(10),3-guaiadiene-12,6-olide-2-one-3-O-beta-D-glucopyranoside and 1(10),3,11 (13)-guaiatriene-12,6-olide-2-one-3-O-[6'-(4"-hydroxybenzyl lactyl)]-beta-D-glucopyranoside, respectively on the basis of detailed spectral analysis.     

Two new sesquiterpene lactones from Ixeris chinensis

Phytochemical investigation of Ixeris chinensis NAKAI (Asteraceae) has resulted in the isolation of a new guaianolide-type sesquiterpene lactone, ixerochinolide (1) as well as the related glucoside, ixerochinoside (2). In addition, the known guaianolides, 8beta-hydroxy-3-oxo-guaia-4(15),10(14),11(13)-trien-1alpha,5alpha,6beta,7alphaH-12,6-olide (8beta-hydroxydehydrozaluzanin), 8beta,15-dihydroxy-2-oxo-guaia-1(10),3,11(13)-trien-5alpha,6beta,7alphaH-12,6-olide (lactucin), 3beta,8alpha,10alpha-trihydroxy-guaia-4(15),11(13)-dien-1alpha,5alpha,6beta,7alphaH-12,6-olide (10alpha-hydroxy-10,14-dihydro-desacylcynaropicrin) and 3beta-D-glucopyranosyloxy-8beta-(p-hydroxyphenylacetyloxy)-guaia-4(15),10(14),11(13)-trien-1alpha,5alpha,6beta,7alphaH-12,6-olide (8-epicrepioside) were identified. The structures were determined on the basis of spectral analyses, especially 1- and 2D NMR. Compound 1 exhibited significant cytotoxicity against human PC-3 tumor cells.     

Two new sesquiterpene lactones from the fruits of Illicium jiadifengpi

Two new seco-prezizaane-type sesquiterpenes, 3,4-dehydroneomajucin (1) and 1,2,3,4-tetradehydroneomajucin (2), were isolated from the fruits of Illicium jiadifengpi. The structure of these compounds was determined using 1D and 2D NMR and ESI-MS. The isolates were evaluated for their anti-hepatitis B virus activities on the Hep G2.2.15 cell line. The inhibitory rates of compounds 1 and 2 on the HBeAg and HBsAg expression were 30.08 ± 3.09% and 11.43 ± 1.92% at a concentrations of 68.00 μM and 7.88 ± 1.21% and 16.96 ± 4.24% at a concentration of 68.50 μM, respectively.     

Two new sesquiterpene lactones with the sulfonic acid group from Saussurea lappa

Two new sesquiterpene lactones with the unusual sulfonic acid group, 13-sulfo-dihydrosantamarine (1) and 13-sulfo-dihydroreynosin (2), have been isolated from the roots of Saussurea lappa C. Their structures, including the absolute configurations, were elucidated by spectroscopic methods.     

Antimicrobial sesquiterpenoids from Laurus nobilis L

Activity-guided fractionations of leaf extracts from Laurus nobilis L. led to the isolation of a known sesquiterpene lactone, deacetyl laurenobiolide (1). Compound 1 showed antimicrobial activity against periopathic pathogens (Actinomyces viscosus, Porphyromonas gingivalis, Prevotella intermedia and Actinobacillus actinomycetemcomitans), opportunistic Gram-positive bacteria (Staphylococcus aureus and Streptococcus pyogenes) and fungi (Candida albicans, Cryptococcus neoformans and Aspergillus fumigatus). Furthermore, acetylation and cyclisation of deacetyl laurenobiolide (1) yielded laurenobiolide (2) and a new compound, (5S,6R,7S,8S,10R)-6,8-dihydroxyeudesma-4(15),11(13)-dien-12-oic acid 12,8-lactone (3), respectively. Compounds 2 and 3 also showed antimicrobial activities. All compounds 1-3 demonstrated growth inhibitory effects with minimum inhibitory concentrations ranging from 31 to 1000?μg?mL(-1). This is the first report of compounds 1-3 showing antimicrobial activities.     

Trypanocidal terpenoids from Laurus nobilis L

Trypanocidal constituents of dried leaves of Laurus nobilis L. (Lauraceae) were examined. Activity-guided fractionation of the methanol extract resulted in the isolation of two guaianolides, dehydrocostus lactone (1) and zaluzanin D (2), and a new p-menthane hydroperoxide, (1R,4S)-1-hydroperoxy-p-menth-2-en-8-ol acetate (3). The minimum lethal concentrations of these compounds against epimastigotes of Trypanosoma cruzi were 6.3, 2.5, and 1.4 microM, respectively.     

Structure of new sesquiterpene lactones from Inula germanica

Summary It has been established that the substance isolated previously fromInula germanica L. is a mixture of two new sesquiterpene lactones: germanin A and germanin B.On the basis of chemical reactions and a study of IR, UV, NMR, and mass spectra, structures (I) and (XVI), respectively, are proposed for germanin A and germanin B.All-Union Scientific-Research Institute of Medicinal Plants. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 578–589, September–October, 1974.     

Structure of new sesquiterpene lactones from Inula germanica

Chemistry of Natural Compounds - It has been established that the substance isolated previously fromInula germanica L. is a mixture of two new sesquiterpene lactones: germanin A and germanin B. On...     

Three new sesquiterpene lactones from the pericarps of Illicium merrillianum

Structures of three new sesquiterpene lactones 1-3, isolated from the pericarps of Illicium merrillianum, have been assigned as 14-O-benzoylfloridanolide, 2,10-epoxy-3-dehydroxypseudoanisatin and 7-O-methylpseudomajucin on the basis of spectroscopic data and chemical transformation. The structure of 2, having an ether linkage between C-2 and C-10, has been confirmed by X-ray crystallographic analysis.     

Corrosion inhibition of mild steel by Laurus nobilis leaves extract as green inhibitor

The efficiency of Laurus nobilis leaves?? extract as a corrosion inhibitor for mild steel in acidic medium (1?M H₂SO₄) was investigated by use of the electrochemical techniques potentiodynamic polarization, electrochemical impedance spectroscopy, and polarization resistance measurements. According to the experimental results, L. nobilis extract acts as a good corrosion inhibitor. In the presence of the inhibitor, corrosion potential shifted toward a more negative value than for the blank solution. Inhibitor efficiency increased with increasing inhibitor concentration, as expected. According to the potentiodynamic polarization results the corrosion of mild steel increased with increasing temperature both in the presence and absence of the inhibitor. The activation energy (E _a) of the corrosion process was calculated from the variation of corrosion current density with temperature.     

Two new withanolide lactones from flos daturae

Chemical investigation of the 50% ethanol eluate fraction from a macroporous resin of flowers of Datura metel L. collected in the Jiangsu Province of China resulted in the isolation of two new withanolides, baimantuoluoline G (1) and baimantuoluoside H (2). Their structures were elucidated as (12β,6β,22R)-1,10-seco-6,12,27-trihydroxy-26-oxo-witha-3,5,24-trienolide-1-oic acid-ε-lactone (1) and (5β,6α,12β,22R)-5,6,12,27-tetra-hydroxy-1,26-dioxo-witha-2,24-dienolide-27-O-β-glucopyranoside (2) on the basis of extensive spectroscopic analysis (1D, 2D-NMR and HRESIMS) and chemical studies.     

Two novel sesquiterpene lactones,cytotoxic vernolide-A and -B,from Vernonia cinerea

Bioassay-directed fractionation of an ethanolic extract of stems of Vernonia cinerea has resulted in the isolation of two novel sesquiterpene lactones, vernolide-A and -B. Their structures were elucidated on the basis of spectroscopic analysis. Biological evaluation showed that vernolide-A demonstrated potent cytotoxicity against human KB, DLD-1, NCI-661, and Hela tumor cell lines (ED(50)=0.02, 0.05, 0.53, 0.04 microg/ml for KB, DLD-1, NCI-661, and Hela, respectively); vernolide-B had marginal cytoxicity (ED(50)=3.78, 5.88, 6.42 microg/ml for KB, NCI-661, and Hela, respectively).     

Two new cyclic diarylheptanoids from the stems of Ostryopsis nobilis

Two new cyclic diarylheptanoids named ostryopsitrienol(1) and ostryopsitriol(2),together with six known compounds,were isolated from the stems of endemic medicinal plant of Ostryopsis nobilis (Betulaceae).The structures of the new compounds were elucidated by means of HRMS,~1D NMR,~2D NMR and X-ray crystallography analysis.     

Rhaposerine and rhaserolide, new sesquiterpene lactones fromRhaponticum serratuloides

Two new crystalline guaianolides,viz., rhaposerine and rhaserolide, were isolated from an ethanolic extract of the above-ground part of the plantRhaponticum serratuloides by column chromatography along with sesquiterpene lactones,viz., centaurepensin and acroptilin, which have been found in other plants. The chemical structures of the title lactones were established by¹H and¹³C NMR spectroscopy and 2D¹H−¹H (COSY) and¹³C−¹H (COSY and COLOC) NMR spectroscopy. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 2010–2014, October, 1999.