Aryltetralol and aryltetralone lignans from Holostylis reniformis

Aryltetralol and aryltetralone lignans were isolated from the hexane extracts of the roots of Holostylis reniformis. Their structures were determined by spectroscopic methods and chemical transformations. (c) 2006 Elsevier Ltd. All rights reserved.

Antiplasmodial activity of aryltetralone lignans from Holostylis reniformis

Extracts from Holostylis reniformis were tested in vivo against Plasmodium berghei and in vitro against a chloroquine-resistant strain of Plasmodium falciparum. The hexane extract of the roots was the most active, causing 67% reduction of parasitemia in vivo. From this extract, six lignans, including a new (7 ' R,8S,8 ' S)-3 ',4 '-methylenedioxy-4,5-dimethoxy-2,7 '-cyclolignan-7-one, were isolated and tested in vitro against P. falciparum. The three most active lignans showed 50% inhibitor concentrations of <= 0.32 mu M. An evaluation of minimum lethal dose (30%) values showed low toxicity for these lignans in a hepatic cell line (Hep G2A16). Therefore, these compounds are potential candidates for the development of antimalarial drugs.

Aryltetralone lignans and 7,8-seco-lignans from Holostylis reniformis

Aryltetralone lignans and two 7,8-seco-lignans were isolated from the acetone and hexane extracts of the roots of Holostylis reniformis, together with (-)-galbacin. Their structures were determined by spectroscopic methods. © 2004 Elsevier Ltd. All rights reserved.

Biosynthesis of antimalarial lignans from Holostylis reniformis

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Métodos de obtenção de lignanas de Holostylis reniformis provenientes de duas regiões brasileiras

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Terpenos e lignanas de Aristolochiaceae

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Microbial Transformations of Aryltetralone and Aryltetralin Lignans by Cunninghamella echinulata and Beauveria bassiana

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Microbial transformations of Aryltetralone and Aryltetralin Lignans by Cunninghamella echinulata and Beauveria bassiana

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Cytotoxic lignans from the stems of Styrax camporum (Styracaceae)

An ethanolic extract from the stems of Styrax camporum Pohl (Styracaceae), a plant traditionally used for gastrointestinal diseases, was fractionated and subjected to flash chromatography and afforded two benzofuran lignans, egonol and homoegonol, and one furofuran lignan, (+/-) syringaresinol, which were identified by spectral data interpretation. Their cytotoxic activities against Hep-2 (larynx epidermoid carcinoma), HeLa (human cervix carcinoma) and C6 (rat glioma) cell lines were evaluated using the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide) assay at several concentrations for 24 h. Activities could be observed for egonol against C6 (IC50 = 3.2 mu g/mL) and Hep-2 (IC50 = 3.6 mu g/mL) cell lines, and for homoegonol against C6 (IC50 = 4.9 mu g/mL) and HeLa (IC50 =- 5.3 mu g/mL) cells.

Trypanocidal tetrahydrofuran lignans from Peperomia blanda

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Evaluation of insecticidal activity of diterpenes and lignans from Aristolochia malmeana against Anticarsia gemmatalis

The insecticidal activity of hexane extracts from the roots and leaves of Aristolochia malmeana was evaluated against Anticarsia gemmatalis larvae by topical application. Extract from the roots was the most active and caused 50% mortality in larvae at 308.4 mu g/mu L. From this extract, a clerodane diterpene, (-)-kolavenic acid, and three lignans, (-)-kusunokinin, (-)-hinokinin, and (8S,8'R,9S)cubebin, were isolated by chromatography and partition procedures and then evaluated for their insecticidal activities either individually or in pairs. (-)-Kusunokinin showed higher activity against A. gemmatalis (LD10 = 9.3, LD50 = 230.1 mu g/mu L) than the crude extract, and its activity was dosedependent, whereas the other constituents did not exhibit any significant activity. Together with (-)kusunokinin and (-)-hinokinin, (-)-copalic acid, (-)-2-oxokolavenic acid, (-)-ent-6-beta-hydroxy-copalic acid, (8R,8'R,9R)- and (8R,8'R,9S)-cubebins, (-)-fargesin, and (-)-phillygenin were isolated from the hexane extract of the leaves. The compounds were identified on the basis of spectroscopic analysis.

Toxicity of lignans to symbiotic fungus of leaf-cutting ants

Lignans from Virola sebifera Aubl., Virola sp., and Otoba parvifolia (Mkfg.) A. Gentry (Myristicaceae) inhibited the in vitro growth of the fungus cultivated by leaf-cutting ants of the species Atta sexdens rubropilosa Forel (Hymenoptera: Formicidae). A comparison of activity among the lignans was obtained.

Flavonoids and lignans from Virola surinamensis twigs and their in vitro activity against Trypanosoma cruzi

Dichloromethane extracts from twigs of Virola surinamensis (Myristicaceae) showed in vitro trypanosomicidal activity against trypomastigote form of Trypanosoma cruzi. The extract, fractionated by preparative circular chromatography and preparative high-performance liquid chromatography yielded two steroids, two lignans, five flavonoids, and one polyketide. Among the isolated compounds, the lignans presented the highest trypanosomicidal activity.

nor-Lignans from the leaves of Styrax ferrugineus (Styracaceae) with antibacterial and antifungal activity

Chemical examination of the leaves of Styrax ferrugineus yielded 5-[3'-(β-D-glucopyranosyloxy)propyl]-7-methoxy-2-(3',4'-dime-thoxyphenyl) benzofuran, along with the known nor-lignans 5-(3'-hydroxypropyl)-7-methoxy-2-(3',4'-methylenedioxyphenyl) benzofuran, 5-(3'-hydroxypropyl)-7-methoxy-2-(3',4'-dimethoxyphenyl)benzofuran, 5-[3'-(β-D-glucopyranosyloxy)propyl]-7-methoxy-2-(3', 4'-methylenedioxyphenyl)benzofuran and the lignan, dihydrodehydrodiconiferyl alcohol. All arylpropanoids isolated showed antibacterial and antifungal activities. The structures of the isolates were established by spectroscopic analysis. (C) 2000 Elsevier Science Ltd.