Central nervous system activities of two diterpenes isolated from Aloysia virgata.

C. WASOWSKI; M. MARDER

PHYTOMEDICINE

ELSEVIER GMBH

Año: 2011 vol. 18 p. 393 - 401

0944-7113

Using the guide of a competitive assay for the benzodiazepine binding site in the gamma-aminobutyric acid type A receptor (GABAA), two active diterpenes were isolated from the aerial parts of Aloysia virgata (Ruiz & Pavon) A.L. Jussieu var. platyphylla (Briquet) Moldenke. These compounds; identified as (16R)-16, 17, 18-trihydroxyphyllocladan-3-one (1) and (16R)-16, 17-dihydroxyphyllocladan-3-one (2) on the basis of spectral data; competitively inhibited the binding of [3H]-FNZ to the benzodiazepine binding site with Ki (S.E.M) values of 56 (19) microM and 111 (13) microM, respectively. The behavioral actions of these diterpenes, intraperitoneally (i.p.) administered in mice, were examined in the plus-maze, holeboard, locomotor activity and light/dark tests. Compound 1 exhibited anxiolytic-like effects in mice evidenced by a significant increase of the parameters measured in the holeboard test (the number of head dips at 0.3 mg/kg and 3 mg/kg, the rears at 1 mg/kg and the time spent head dipping at 3 mg/kg), in the plus-maze assay (the percentage of open arm entries at 1 mg/kg) and in the light/dark test (the time in light and the number of transitions at 1 mg/kg). Compound 2 augmented the number of rearings in the holeboard apparatus (at 0.3 and 1 mg/kg) and the locomotor activity (at 1 mg/kg). These results reveal the presence of neuroactive compounds in Aloysia virgata.