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

Abstract

Context: 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.

Materials and 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).

Conclusion: 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.

• CNS depressants
• Flor de Tila
• sedatives substances
• Ternstroemia
• Theaceae
• toxic natural products
• triterpenes

Acknowledgements

This work was supported by a grant from DGAPA IN210112 and CONACYT 82613. José Luis Balderas acknowledges fellowship from CONACYT (116413).