Comparative toxicological studies of Heracleum maximum W. Bartram and Psoralea corylifolia L. seed extracts on brine shrimp (Artemia salina) and wistar rats

This study sought to elucidate the reason for the traditional use of Psoralea corylifolia (PC) over Heracleum maximum (HM) for treating vitiligo, though seeds from both plants are rich in a class of phototoxic compounds called furanocoumarins, that are effective in treating vitiligo. Toxicity studies were carried out by LD50 experiments on wistar male and female rats, and the physiochemical parameters associated with toxicity were evaluated. The toxicity results were correlated to the elemental profile obtained for the two plants using laser-induced breakdown spectroscopy (LIBS). The phototoxic/toxic properties of the ethanolic extracts of the seeds of the two plants were compared using brine shrimp bioassay. The PC extract showed lower toxicity levels under long-wave UV light (365 nm) than the HM extract, where 100% mortality was observed at the lowest concentration tested (30 mu g/ml). Under dark conditions, the LD50 for HM (63.93 +/- 6.63 mu g/ml) was also lower than that of PC, where only 53.7% mortality was observed at the highest concentration tested (237.1 mu g/ml),further suggesting that HM seeds are more toxic than PC seeds. The findings indicate that HM seeds have not been used in traditional medicine for skin ailments because of relatively higher levels of animal toxicity and hence the potential for adverse effects.