Anti-inflammatory and apoptotic activities of pomolic acid isolated from Cecropia pachystachya.

The dichloromethane extract and pomolic acid ( 5) obtained from leaves of Cecropia pachystachya both reduced carrageenan-induced paw oedema in mice. Interestingly, while the triterpenoid inhibited the in vivo production of interleukin-1beta by 39 %, it had no effect on tumour necrosis factor-alpha production. We also demonstrated that both the dichloromethane extract and 5 inhibited the viability of human polymorphonuclear (PMN) cells in a time- and dose-dependent fashion. The PMN membrane integrity was determined with the aid of flow cytometry by means of the exclusion of propidium iodide as assay. Although the cell membrane integrity was altered, neither the extract nor 5 produced cellular necrosis. Moreover, the development of hypodiploid nuclei and DNA fragmentation in the PMN cells were both dependent on dose and time. Finally, in the annexin V-FITC binding assay, compound 5 increased the total of apoptotic cells by 42 % at 100 microM and by 71 % at 200 microM with respect to the control group. In conclusion, both the dichloromethane extract of ambay and isolated compound 5 inhibit the viability of PMN cells through apoptosis. Since they can regulate human neutrophil functions in this way, it is likely that these substances can also limit inflammation.