Effects of extracts and neferine from the embryo of Nelumbo nucifera seeds on the central nervous system

The effects of embryos of the seeds of Nelumbo nucifera on the central nervous system were studied in mice. MeOH extracts of embryos of Nelumbo nucifera seeds significantly inhibited locomotor activity in mice. The MeOH extract was successively partitioned between H2O and n-hexane, between H2O and CHCl3, and between H2O and n-BuOH. CHCl3 extracts strongly inhibited locomotor activity in mice, although other extracts had no effect on locomotor activity. The main alkaloid of CHCl3 extracts, neferine, dose-dependently inhibited locomotor activity in mice. Neferine induced hypothermia in mice and apparently potentiated thiopental-induced sleeping time. An anxiolytic, diazepam, decreased locomotor activity, rectal temperature and enhanced sleep elicited by thiopental, similar to neferine. In addition, neferine and diazepam showed anti-anxiety effects in the elevated plus maze test. Neferine did not affect muscle coordination by the rota-rod test. Neferine did not affect strychnine- nor picrotoxin-induced seizure. In contrast, diazepam had apparent muscle relaxant and anti-convulsant effects. These results suggest that neferine has several central effects and that neferine may participate in the efficacy of the sedative effects of embryos of the seeds of Nelumbo nucifera. The mechanisms of the sedative effects of neferine are not similar to those of diazepam.