Endemic plants of Puerto Rico: brine shrimp lethality and antibacterial activity.

A total of 49 endemic plants of Puerto Rico were evaluated for their toxicological and antibacterial activities. The toxicological analysis was conducted with brine shrimp (Artemia salina Leach) lethality bioassay and the antibacterial screening was carried out by means of the agar diffusion test. In the toxicological bioassay, six plant extracts showed LC-50 values below 200 g/ml., indicating the potential presence of bioactive compounds. In the antibacterial screening, over 80% of the plant extracts displayed activity against gram positive bacteria, whereas only 6% of the extracts inhibited the growth of the gram negative bacteria.