Abstract

Nephrolepis exaltata (L.) Schott decreases the heartbeats of cockroaches and it was postulated that the plant could be an anticholinesterase agent and could have effects. It was performed: (a) In vitro: hydroalcoholic extract of N. exaltata was pharmacognostically characterized, the cholinesterase activity determined with 1.0 and 3.0 mg/ml, comparing to positive control and negative control, and the preliminary toxicity was evaluated with 5 mg/plate through Salmonella/microsome assay using TA100 strain; (b) Ex vivo:  2, 5, or 10 mg of extract was assayed on mouse phrenic nerve-diaphragm preparation using conventional myographic technique; and (c) In vivo: 2.0, 1.0 or 0.5 g of extract was exposed to Allium cepa root cells, using onions bulbs for further measuring and microscopic analysis. The cholinesterase activities (U/L, n=3) of 1.0 and 3.0 mg/mL fern extract were of 2,866.6 ± 200.7 and 3,092.9 ± 214.2, respectively, versus 87.1 ± 58.1 (p<0.05) for positive control. The extract showed the absence of micronucleus and inhibited the root growth reaching 100% at 2 mg.  The plant has no anticholinesterase activity, it is not toxic on bacterial reverse mutation or nerve-muscle parameters and is not genotoxic on A. cepa assay, but inhibits the root growth of A. cepa.

Key words: Allium cepa, cholinesterase, fern, pharmacognosy, Salmonella.