HIV-1 protease and HIV-1 integrase inhibitory substances from Eclipta prostrata

The bioassay-guided fractionation for anti-HIV-1 integrase activity led to the isolation of six compounds from the whole plant extract of Eclipta prostrata extract. They were identified as 5-hydroxymethyl-(2,2':5',2'')-terthienyl tiglate (1), 5-hydroxymethyl-(2,2':5',2'')-terthienyl agelate (2), 5-hydroxymethyl-(2,2':5',2'')-terthienyl acetate (3), ecliptal (4), orobol (5) and wedelolactone (6). Of these, compound 6 showed the highest activity against HIV-1 integrase (IN) with an IC50 value of 4.0+/-0.2 microm, followed by compound 5 (IC50=8.1+/-0.5 microm), whereas the four terthiophene compounds (1-4) were inactive (IC50>100 microm). Regarding HIV-1 protease (PR) inhibitory activity, compound 1 exhibited appreciable activity against HIV-1 PR with an IC50 of 58.3+/-0.8 microm, followed by compound 4 (IC50=83.3+/-1.6 microm) and compound 3 (IC50=93.7+/-0.8 microm), while compounds 2, 5 and 6 were inactive against HIV-1 PR (IC50>100 microm). This is the first report of anti-HIV-1 IN activities for wedelolactone (6), a coumarin derivative, and orobol (5), an isoflavone derivative. This study supports the use of E. prostrata in AIDS patients, which is in accord with its traditional use by Thai traditional doctors for curing blood related diseases.

Cytotoxic rotenoloids from the stems of Derris trifoliata

A new rotenoloid, designated 7a-O-methylelliptonol, was isolated from hexane and CH2Cl2 extracts from the stems of Derris trifoliata together with ten known compounds. Their structures were determined by spectroscopic methods, mainly 1D and 2D NMR. The cytotoxicity of all compounds was also evaluated against human cancer cell lines.Key words: Derris trifoliata, Leguminosae, 7a-O-methylelliptonol, cytotoxicity, rotenoloids.

Potential anti-allergic ent-kaurene diterpenes from the bark of Suregada multiflora

Two ent-kaurene diterpenes, ent-16-kaurene-3beta,15beta,18-triol (1) and ent-3-oxo-16-kaurene-15beta,18-diol (2), were isolated from a dichloromethane extract of the bark of Suregada multiflora along with five known diterpenes:ent-16-kaurene-3beta,15beta-diol (3), abbeokutone (4), helioscopinolide A (5), helioscopinolide C (6) and helioscopinolide I (7). Their structures were elucidated on the basis of spectroscopic analysis. Compounds 1-7 possessed appreciable anti-allergic activities in RBL-2H3 cells model with IC50 values ranging from 22.5 to 42.2 microM.

Anti-HIV-1 protease activity of compounds from Boesenbergia pandurata

Searching for anti-HIV-1 protease (PR) inhibitors of Thai medicinal plants led to the isolation of a new cyclohexenyl chalcone named panduratin C (1) and chalcone derivatives (2-6) from the methanol extract of Boesenbergia pandurata rhizomes. The known compounds were identified to be panduratin A (2), hydroxypanduratin A (3), helichrysetin (4), 2',4',6'-trihydroxyhydrochalcone (5), and uvangoletin (6). The structures of all compounds were elucidated on the basis of chemical and spectroscopic methods. It was found that 3 possessed the most potent anti-HIV-1 PR activity with an IC50 value of 5.6 microM, followed by 2 (IC50 = 18.7 microM), whereas other compounds exhibited only mild activity. Structure-activity relationships of these compounds on anti-HIV-1 PR activity are summarized as follows: (1) hydroxyl moiety at position 4 conferred higher activity than methoxyl group; (2) prenylation of dihydrochalcone was essential for activity; (3) hydroxylation at position 4''' reduced activity; and (4) introduction of double bond at C1' and C6' of chalcone gave higher activity. As regards active constituents contained in B. pandurata rhizomes, hydroxypanduratin A (3) and panduratin A (2) are active principles against HIV-1 PR.

New cytotoxic cardenolide glycoside from the seeds of Cerbera manghas

A new cytotoxic cardenolide glycoside, 3beta-O-(2'-O-acetyl-alpha-L-thevetosyl)-14beta-hydroxy-7-en-5beta-card-20(22)-enolide, (7,8-dehydrocerberin), together with five known cardenolides, 17beta-neriifolin, deacetyltanghinin, tanghinin, cerberin and 2'-O-acetyl-cerleaside A were isolated from the seeds of Cerbera manghas L. Their structures were elucidated by 1D- and 2D-NMR techniques as well as UV, IR and mass spectral data. 7,8-Dehydrocerberin, deacetyltanghinin and tanghinin exhibited cytotoxic activities against oral human epidermoid carcinoma (KB), human breast cancer cell (BC) and human small cells lung cancer (NCI-H187).

Cytotoxic cardenolide glycoside from the seeds of Cerbera odollam

A cardenolide glycoside, 3 beta-O-(2'-O-acetyl-l- thevetosyl)-15(14-->8)-abeo-5 beta-(8R)-14-oxo-card-20(22)-enolide (2'-O-acetyl cerleaside A), was isolated from a methylene chloride extract of the seeds of Cerbera odollam, together with four known compounds: cerleaside A, 17 alpha-neriifolin, 17 beta- neriifolin and cerberin. Their structures were elucidated by spectroscopic methods. All compounds except cerleaside A exhibited cytotoxic activities against oral human epidermoid carcinoma (KB), human breast cancer cell (BC) and human small cell lung cancer (NCI-H187).