Alkaloid presence and brine shrimp (Artemia salina) bioassay of medicinal species of eastern Nicaragua

Abstract

We used an alkaloid test and a brine shrimp bioassay to assess the bioactivity of the medicinal plants used by eastern Nicaraguan healers in traditional medicine. Ethnomedicinal uses were obtained from interviews of traditional healers. Aqueous extracts derived from 30 species of angiosperms were assayed for the presence of alkaloids and toxicity. Species tested are distributed in 30 genera and 21 families. Of the 30 species tested for alkaloids with Dragendorff’s reagent, 29 contained alkaloids. Toxicological analysis was conducted using the brine shrimp lethal assay (BSLA). Biological activity using BSLA was recorded as the median lethal concentration (LC₅₀) that kills 50% of the larvae within 24 h of contact with the aqueous plant extracts. The LC₅₀ of the shrimp was less than 2500 µg/mL for 3 (10%) species, 2500-5000 µg/mL for 9 (30%), 5001-7500 µg/mL for 7 (23%), 7501-10000 µg/mL for 3 (10%), and greater than 10000 µg/mL for 8 (27%) of the species. The members of the orders Santales and Rubiales in general contained species with greater toxicity than any other group. Struthanthus cassythoides (Struthanthus cassythoides Millsp.(Loranthaceae)). (LC₅₀ 1574 µg/mL) and Alibertia edulis (Rich.) A. Rich. (Rubiaceae) (LC₅₀ 1741 µg/mL) were the most toxic.

Keywords::

• Alkaloids
• biological screening
• cytotoxic activity
• ethnomedicinal plants

Acknowledgements

Thanks to the Garífuna, Miskitu, Rama, and Sumu people for sharing their ethnobotanical knowledge. The field assistance of Basilio Benjamin, Far Blanford, Dale Desousa, Rodney Martin, and Harry Simmons, Jr. is appreciated. The assistance of the staffs of CIDCA (Centro de Investigación y Documentación de la Costa Atlantica) and FADCANIC (Fundación Para la Autonomía y Desarrollo de la Costa Atlántica de Nicaragua) is also appreciated. Many specialists provided assistance in the identification of vouchers: Daniel Austin (Arizona-Sonora Desert Museum), Gerrit Davidse (MO), Ronald Leisner (MO), Amy Pool (MO), Warren D. Stevens (MO), and Charlotte M. Taylor (MO). Thanks to Irsa Amin and Kellyn Misset for help in the laboratory, and Allison Robinson for numerous comments on drafts of the manuscript.

Declaration of interest

This study was partially supported by grants from the National Science Foundation, The University of Connecticut Research Foundation and the Department of Ecology and Evolutionary Biology.