Chronic intraperitoneal and oral treatments with hesperidin induce central nervous system effects in mice.

Hesperidin (HN) is a flavanone glycoside abundantly found in citrus fruits. This flavonoid mediated central nervous system activity following intraperitoneal (i.p.) acute treatment. The responses of mice after the chronic i.p. (4 and 30 mg/kg/day) or the oral intake administration of this drug (20, 50 and 100 mg/kg/day) were studied by using the holeboard, the plus-maze and the locomotor activity tests. Hesperidin, chronically administered by the i.p. route, exerted a decrease in the locomotor and exploratory activities, thus evidencing a depressant activity. In turn, the chronic oral intake of this flavonoid induced anxiolytic-like effects. These varied responses could be attributed to the different routes of administration that could lead to the production of diverse active metabolites.

Neuroactive flavonoid glycosides from Tilia petiolaris DC. extracts.

Pharmacological assay guided purification of an ethanol extract of Tilia petiolaris DC. inflorescences resulted in the isolation and identification of isoquercitrin (ISO), quercetin 3-O-glucoside-7-O-rhamnoside (QUE) and kaempferol 3-O-glucoside-7-O-rhamnoside (KAE). The behavioral actions of these glycosylated flavonoids were examined in the hole board, locomotor activity and thiopental-induced loss of righting reflex tests in mice. QUE (10 and 30 mg/kg) and KAE (30 mg/kg), intraperitoneally (i.p.) administered to mice, reduced all the parameters measured in the hole board test, but ISO (30 mg/kg) only reduced the number of rearings. Meanwhile QUE at 30 mg/kg i.p. also decreased the ambulatory locomotor activity and increased the sodium thiopental-induced time of loss of the righting reflex suggesting a clear depressant action. The above results demonstrate the occurrence of neuroactive flavonoid glycosides in Tilia.

Central nervous system depressant action of flavonoid glycosides.

The pharmacological effects on the central nervous system (CNS) of a range of available flavonoid glycosides were explored and compared to those of the glycosides 2S-hesperidin and linarin, recently isolated from valeriana. The glycosides 2S-neohesperidin, 2S-naringin, diosmin, gossipyn and rutin exerted a depressant action on the CNS of mice following i.p. injection, similar to that found with 2S-hesperidin and linarin. We demonstrate in this work that these behavioural actions, as measured in the hole board, thiopental induced sleeping time and locomotor activity tests, are unlikely to involve a direct action on gamma-aminobutyric acid type A (GABA(A)) receptors. The corresponding aglycones were inactive, pointing to the importance of the sugar moieties in the glycosides in their CNS depressant action following systemic administration. The pharmacological properties of the flavonoid glycosides studied here, in addition to our previous results with hesperidin and linarin, opens a promising new avenue of research in the field.