Biological screening of select Puerto Rican plants for cytotoxic and antitumor activities.

OBJECTIVE: The objective of this study was to evaluate the cytotoxic and anticancer activities of extracts from 7-species of endemic and native plants from Puerto Rico. METHODS: The plant species selected for this study were Canella winterana, Croton discolor, Goetzea elegans, Guaiacum officinale, Pimenta racemosa, Simarouba tulae, and Thouinia striata. The dried plant material was extracted with a 1:1 mixture of CH2CI2-MeOH. The resulting crude extract was suspended in water and extracted with solvents of different polarities. The extracts were evaluated for their cytotoxic effects against Artemia salina and 3 breast cancer cell lines. RESULTS: About 50% of the extracts evaluated against Artemia salina exhibited LC50 values of less than or equal to 200 µg/mL. The strongest activity was detected in the chloroform and ethyl acetate extracts of Guaiacum officinale, with lethality values below 10 µg/mL. The extracts were further evaluated for their bioactivity as possible inhibitors of several breast cancer cell lines, with the extracts from Simarouba tulae and Croton discolor showing the highest percentages of growth inhibition. The dose- effect data analysis for the crude extracts of the different plants also confirms the high cytotoxicities of Guaiacum officinale, Simarouba tulae, and Croton discolor. CONCLUSION: Based on our results, we concluded that the Simarouba, Croton, and Guaiacum plant extracts show cytotoxic and anticancer activities that merit closer investigation in order to identify the chemical compounds responsible for these bioactivities.