Lignans neolignans, and related compounds

Xanthones are a class of heterocyclic natural products that have been widely studied for their pharmacological potential. In fact, they have been serving as scaffolds for the design of derivatives focusing on drug development. One of the main study targets of xanthones is their anticancer activity. Several compounds belonging to this class have already demonstrated cytotoxic and antitumor effects, making it a promising group for further exploration. This review therefore focuses on recently published studies, emphasizing their natural and synthetic sources and describing the main mechanisms of action responsible for the anticancer effect of promising xanthones.

Xanthones and Cancer: from Natural Sources to Mechanisms of Action.

Four new macrophyllin-type bicyclo[3.2.1]octanoid neolignans, (7S,8R,3′S,5′R)-Δ8′-5,5′,3′-trimethoxy-3,4-methylenedioxy-2′,3′,4′,5′-tetrahydro-2′,4′-dioxo-7.3′,8.5′-neolignan (cinerin A), 1, (7R,8R,3′S,4′R,5′R)-Δ8′-4′-hydroxy-5,5′-dimethoxy-3,4-methylenedioxy-2′,3′,4′,5′-tetrahydro-2′-oxo-7.3′,8.5′-neolignan (cinerin B), 2, (7S,8R,3′R,4′S,5′R)-Δ8′-4′-hydroxy-5,5′,3′-trimethoxy-3,4-methylenedioxy-2′,3′,4′,5′-tetrahydro-2′-oxo-7.3′,8.5′-neolignan (cinerin C), 3, and (7S,8R,2′R,3′S,5′R)-Δ8′-2′-hydroxy-5,5′-dimethoxy-3,4-methylenedioxy-2′,3′,4′,5′-tetrahydro-4′-oxo-7.3′,8.5′-neolignan (cinerin D), 4, along with the known diterpene kaurenoic acid 5, were isolated from the leaves of Pleurothyrium cinereum. The structures and configuration of these compounds were determined by extensive spectroscopic analysis. Cinerins A−D (1−4) were tested for their inhibition efficacy of platelet activating factor (PAF)-induced aggregation of rabbit platelets. Compound 3 was the most potent PAF antagonist. Compounds 1−5 were t...

Macrophyllin-Type Bicyclo[3.2.1]octanoid Neolignans from the Leaves of Pleurothyrium cinereum

PAF-antagonistic bicyclo[3.2.1]octanoid neolignans from leaves of Ocotea macrophylla Kunth. (Lauraceae).

Benzylisoquinoline alkaloids and eudesmane sesquiterpenes from Ocotea pulchella

Bicyclo[3.2.1]Octanoid neolignans from Licaria brasiliensis☆

Cordatin is a furan diterpenoid with a clerodane skeleton isolated from Croton palanostigma Klotzsch (Euphorbiaceae). This natural product shows significant antiulcerogenic activity, similar to cimetidine (Tagamet®), a compound used for the treatment of peptic ulcers. The crystal structure of cordatin was obtained by X-ray diffraction and its geometrical parameters were compared with theoretical calculations at the B3LYP theory level. The IR and NMR (1H and 13C chemical shifts and coupling constants) spectra were obtained and compared with the theoretical calculations. The B3LYP theory level, with the 6-31G(d,p) and 6-311G(d,p) basis set, provided IR absorption values close to the experimental data. Moreover, theoretical NMR parameters obtained in both gas phase and chloroform solvent at the B3PW91/DGDZVP, B3LYP/6-311+G(2d,p), and B3PW91/6-311+G(2d,p) levels showed good correlations with the experimental results. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2008

Crystal structure and theoretical study of IR and 1H and 13C NMR spectra of cordatin, a natural product with antiulcerogenic activity

The ethyl acetate extract of the roots of Moutabea guianensis gave 1,6-dihydroxy-4,7,8-trimethoxy-9H-xanthen-9-one (1), a new xanthone. The isolation was accomplished by column chromatography on silica gel and the structural elucidation of this compound was established by spectroscopic analyses including 1D and 2D NMR and HRESIMS.

Gisele Maria S. P. Guilhon

Papers

Bicyclo[3.2.1]Octanoid neolignans from Licaria brasiliensis☆

Crystal structure and theoretical study of IR and 1H and 13C NMR spectra of cordatin, a natural product with antiulcerogenic activity

A new xanthone from Moutabea guianensis Aubl.