Isolation and immunomodulatory effect of homoisoflavones and flavones from Agave sisalana Perrine ex Engelm

Abstract

Three known flavones and seven known homoisoflavonoids were isolated from the methanolic extract of the leaves of Agave sisalanaPerrine ex Engelm. Their structures were elucidated on the basis of spectroscopic analysis. The isolated compounds were also evaluated for immunopharmacological activity. PBMC were used as target cells, and cell proliferation was determined by (3)H-thymidine uptake. (+/-)-3,9-Dihydroeucomin (4), dihydrobonducellin (5), and 5,7-dihydroxy-3-(4'-hydroxybenzyl)-4-chromanone (7) showed inhibitory effects on PBMC proliferation activated by PHA with IC(50) values 19.4, 73.8, and 58.8 microM, respectively. All three compounds significantly inhibited the production of IL-2 and IFN-gamma in activated PBMC in a concentration-dependent manner.

Figure 1

Chemical structure of compound 1-10.

Figure 2

The impairment of IL-2 and IFN-γ production in PBMC treated with compounds 4, 5, and 7. PBMC (2×10⁵ cell/well) were treated with 6.25, 12.5, 25, 50, and 100 µM of compounds 4, 5, and 7 with or without PHA (5 µg/mL) for 3 days. Cyclosporin A (5 µM) was used as positive control. Then, the cell supematants were collected and IL-2 (a) and IFN-γ (b) concentration were determined by EIA. Each of the point is the mean ± SD of three independent experiments.