Irritant potential of some constituents from the seeds of Caesalpinia bonducella (L.) fleming.

The irritant potential of four triterpenoids, isolated for the first time from the seeds of Caesalpinia bonducella, identified as alpha-amyrin [12-ursen-3beta-ol], beta-amyrin [12-oleanex-3beta-ol], lupeol [lup-20(29)-en-3beta-ol] and lupeol acetate [lup-20(29)-en-3beta-yl acetate] was investigated by open mouse ear assay, evaluating their ID50 (irritant dose in 50% animals) after acute effects and by irritant units (IU) after chronic effects. Alpha-Amyrin, lupeol acetate and beta-amyrin were the most potent and persistent irritant compounds with red weals of 1.5-2.1 cm diameter areas of the animal skin and with lowest ID50 = 0.078, 0.186 and 0.190mg/10 microl after 1.5, 2.10 and 3.5h, respectively. Their reactions lasted for 24 h with IU = 2.5; 0.312 and 1.25 mg/10 microl, respectively. Lupeol was the least irritant and least persistent compound with ID50 = 0.603 mg/10 microl after 4.5 h. Its reaction subsided before 24 h.