Anti-inflammatory activity of aqueous extracts and steroidal sapogenins of Agave americana.

Lyophilized aqueous extracts obtained from Agave americana L (Agavaceae) collected in the north of Sardinia were characterized with regard to their steroidal sapogenin content. Extracts of A. americana and genins isolated from them were evaluated for anti-inflammatory properties by testing their effects on carrageenin-induced edema. The effect of orally administered genins on gastric mucous membranes was also assessed. Lyophilized extracts administered by the intraperitoneal route at doses equivalent to 200 and 300 mg/kg of fresh plant starting material, showed good anti-inflammatory activity. Doses of genins (total steroidal sapogenins, hecogenin and tigogenin) equivalent to the amount in the lyophilized extracts produced an antiedentatous effect which was much stronger and more efficacious than that obtained with an i.p. administration of 5 mg/kg of indomethacin or dexamethasone 21-phosphate at a dose equivalent to the molar content of hecogenin administered. At the doses used to evaluate the anti-inflammatory activity, the genins did not have any harmful effect on the gastric mucous membranes. Lesions occurred when significantly higher doses of hecogenin were given, but gastric damage was still less than that caused by the drugs used for comparative purposes.

Dexamethasone apoptosis induction and glucocorticoid receptor levels in cultured normal and neoplastic cell lines.

The deletion with apoptotic mechanisms, of different normal and neoplastic cell lines [Jurkat leukemic cells, EUE epithelioid cells, normal (FG) and transformed rat fibroblasts (SGS/3A)] cultured in vitro in presence of dexamethasone, have been studied combining morphocytochemical (fluorescence microscopy), cytometric (flow cytometry) and biochemical (Radio Receptor Assay) analyses. It has been found that the synthetic glucocorticoid hormone induces an antiproliferative effect with accumulation of cells in the G1 phase and a cell loss by programmed death in some cell lines. The apoptotic incidence was found to be inversely proportional to the cytostatic effect of the hormone: the highest in EUE and Jurkat cells (in EUE cells not only affecting the G0/G1 phase of the cell cycle), the lowest in SGS/3A cells and absent in frbroblasts FG. The apoptotic degeneration, in all the cell lines studied, was characterized, morphologically and cytochemically by: a) decrease in stainability/content of cell DNA and proteins; b) condensation of cytoplasm; c) preservation of mitochondrial membrane functional integrity. In conclusion, in the presence of dexamethasone, programmed cell death was found to play a variable role during the maintenance of culture turnover in different cell lines and the incidence of degenerative phenomena does not appear to be related to glucocorticoid receptor levels.