Toxic rather than neuropharmacological effect of Ternstroemia sylvatica fruits and identification of 28-O-[β-l-6-rhamnopyranosyl]-R1-barrigenol as a new compound with toxic effects in mice.

BACKGROUND

Fruits of Ternstroemia sylvatica Schltdl. and Cham. (Theaceae) are used in Mexican traditional medicine to alleviate anxiety, sleep disorders and seizures; however, the active principles have not been identified.

OBJECTIVE

To identify the neuroactive principles of T. sylvatica fruits using neuropharmacological tests on mice.

METHODS

The methanol and aqueous extracts of pericarp or seeds of T. sylvatica fruits were intraperitoneally administered (1-562 mg/kg, single doses) to mice. The exploratory cylinder, hole board, open field, Rota-rod and sodium pentobarbital-induced hypnosis tests were used to evaluate the CNS depressant effect after 30 min single administration of extracts. From aqueous seeds extract, triterpene glycoside 28-O-[β-l-6-rhamnopyranosyl]-R1-barrigenol was isolated an active compound.

RESULTS

Crude extracts of T. sylvatica fruits, separated from seed and pericarp, showed sedative effect in mice. The aqueous (ED50 = 4.9 ± 0.8 mg/kg) seed extracts is the most active among them. This extract also decrease locomotor activity and disrupt motor coordination of mice. This extract was also the most toxic extract (LD50 = 5.0 ± 1.4 mg/kg; i.p.). The triterpene glycoside 28-O-[β-l-6-rhamnopyranosyl]-R1-barrigenol was identified in this extract as one of the active sedative compounds (ED50 = 0.12 ± 0.01 mg/kg) also with toxic effect (LD50 = 1.11 ± 0.23 mg/kg).

CONCLUSIONS

The results suggest that T. sylvatica fruits has toxic activity rather than CNS depressant activity in mice and that this effect might be related to the presence of 28-O-[β-l-6-rhamnopyranosyl]-R1-barrigenol, one of the active principles of T. sylvatica fruits with sedative and toxic effect.