Pharmacological effects of Nephrolepis exaltata L. (fern) aqueous extract on an insect-based model (Nauphoeta cinerea)

Abstract

In this work we used semi-isolated heart of the cockroach Nauphoeta cinerea for the investigation of the pharmacological effects of extracts (aqueous, 1:1, 1:2, 1:4 and 1:8) from Nephrolepis exaltata L. leaves, a popular ornamental fern considered to be safe. The use of insects in experimental studies has grown due to the easy handling, proliferation/growing assuring its rapid obtention, and absence of ethical issues. An aqueous extract 0.2 % was obtained after maceration of 1 g N. exaltata leaves powder with 20 mL of distilled water (1:20). Diluted extracts in water were obtained to have the following proportion 1:1, 1:2, 1:4 and 1:8. Experiments (n=4) consisted of 200 μL addition onto semi-isolated heart preparation of N. cinerea with concomitant heart beating counting. Aqueous, 1:1 and 1:2 extracts paralyzed completely the heart beatings of cockroachs (p<0.05 compared to saline control), but not 1:4 or 1:8, which showed only a slight decline (p>0.05 compared to saline control). A preliminary thin layer chromatography showed the presence of unidentifi ed terpenoid in aqueous extract of N. exaltata. These pharmacological fi ndings of N. exaltata can be exploited for future use as insecticide or as dose-dependently cholinergic agent. Introduction