Ekarin Saifah

Bisamides from Aglaia edulis

The leaves of Aglaia edulis afforded a new bisamide, aglaiduline, and two new sulfur-containing bisamides, aglaithioduline and aglaidithioduline. Their structures were established from spectroscopic studies. The sulfur-containing amides exhibited slight antiviral activity against herpes simplex virus types 1 and 2.

Synthesis of glabridin derivatives as tyrosinase inhibitors

A novel 3″,4″-dihydroglabridin was successfully prepared for studying on tyrosinase inhibitory activity. The result demonstrated that 3″,4″-dihydroglabridin exhibited higher activity than glabridin (IC50 value = 11.40 μM), which is probably due to the 4-substituted resorcinol skeleton and the lacking of double bond between carbon atom 3″ and 4″ on its structure giving more conformational flexibily to interact with the enzyme more effectively. In addition, various acylated derivatives were synthesized as glabridin prodrugs. The chemical and enzymatic hydrolysis of prodrugs revealed that the diacetate ester was rapidly hydrolyzed by porcine liver esterase with the half-life of 2.36 minute, while those of the dihexanoate was 14.8 hour. Both of them were sufficiently stable in phosphate buffer, both pH 5.5 and 7.4, at 37°C with more than 15 days half-life.

A new pterocarpan from Erythrina fusca

A new pterocarpan, 3-hydroxy-10-(3-hydroxy-3-methylbutyl)-9- methoxypterocarpan (1), together with seven known compounds, sandwicensin (2), erythrisenegalone (3), citflavanone (4), liquiritigenin (5), lonchocarpol A (6), lupinifolin (7) and 8-prenyldaidzein (8), were isolated from the stem bark of Erythrina fusca. The structure of 1 was determined on the basis of spectroscopic analyses. Among these compounds, lonchocarpol A (6) exhibited strongly antibacterial activities in vitro against Staphylococcus aureus, Bacillus subtilis and Enterococcus faecalis. Compounds (2, 3, 6 and 7) exhibited weakly antimycobacterial activity with minimum concentrations (MICs) of 100, 50, 50 and 25 µg/mL, respectively.

Biologically active constituents of Aglaia erythrosperma

From the fruits and leaves of Aglaia erythrosperma (Meliaceae), 10 chemical constituents were isolated and identified, i.e. the dammarane triterpenoids cabraleadiol (1), cabraleahydroxylactone (2), ethyl eichlerianoate (3), eichlerialactone (4), aglinin A (5), cabralealactone (6), the aglaialactone 5,6-desmethylenedioxy-5-methoxy-aglalactone (7), the flavagline 4′-demethoxy-3′,4′-methylenedioxy-methyl rocaglate (8) and two coumarins: scoparone and scopoletin. Flavagline 8 exhibited antimalarial activity with an IC50 value of 7.30 µg mL−1 and was strongly cytotoxic against small cell lung cancer (NCI-H187), epidermoid carcinoma (KB) and breast cancer (BC) cell lines, with IC50 values of 2.17, 2.10 and 0.11 µg mL−1, respectively. Aglinin A (5) displayed moderate cytotoxicity against all the three cancer cell lines, whereas ethyl eichlerianoate (3), cabralealactone (6) and the aglaialactone 7 were exclusively cytotoxic to NCI-H187 cell line. Cabraleahydroxylactone (2) showed antiviral activity against herpes simplex virus type-1 with an IC50 value of 3.20 µg mL−1, in comparison with the standard acyclovir (IC50 = 1.90 µg mL−1). When tested for antimycobacterial activity against Mycobacterium tuberculosis H37Ra, compounds 1–4 and 6–8 displayed minimum inhibitory concentration in the range of 25–50 µg mL−1.

Aglairubine: Structure revision of a chemotaxonomically interesting bisamide in Aglaia (Meliaceae)

Summary. The bisamide aglairubine was isolated from different Aglaia species. The original structure was revised on the basis of FDMS and 2D-NMR data. Since all isolates were obtained from species belonging to the section Amoora of the genus Aglaia, aglairubine might serve as a taxonomic marker.