New protopine alkaloids from Aristolochia constricta reduce morphine withdrawal in vitro.

The present study examines the effect of four new protopine alkaloids (1-4) isolated and purified from the aerial parts of Aristolochia constricta (Aristolichiaceae) on morphine withdrawal in vitro. The results of our experiments indicate that the pure compounds (1-4) significantly and in a concentration-dependent manner reduced the morphine withdrawal. The results of the present study suggest that these new protopine alkaloids may be potential anti-addictive agents.

Flavonol glycosides from Aristeguietia discolor reduce morphine withdrawal in vitro.

The effects of extracts, partially purified fractions and four flavonol glycosides 1-4 from Aristeguietia discolor were investigated on the naloxone-precipitated withdrawal contraction of the acute morphine dependent guinea-pig ileum in vitro. After a 4 min in vitro exposure to morphine a strong contraction of guinea-pig isolated ileum was observed after the addition of naloxone. Both MeOH extract (50, 100 and 200 mg/mL), the partially purified fractions I, L, M and N (50, 100 and 200 mg/mL) and flavonol glycosides 1-4 (1 x 10(-4) 5 x 10(-5) 1 x 10(-5) M), injected 10 min before morphine, were capable of blocking the naloxone-induced contraction after exposure to morphine in a concentration-dependent fashion. The results of the present paper suggest that flavonol glycosides from Aristeguietia discolor may play an important role in the control of morphine withdrawal.

Phytochemical and pharmacological studies of Guettarda acreana.

The present study examines the effects of the extracts [petroleum ether, CHCl3, CHCl3/MeOH (9:1) and MeOH], partially purified fractions and pure compounds from Guettarda acreana on the electrically induced contractions (E.C.I.) of the isolated guinea-pig ileum. The results of the experiments indicate that CHCl3/MeOH (9:1), MeOH extract, and the MeOH soluble part from CHCl3/MeOH extract tested at concentrations of 1.2, 2.5, and 5 micrograms/ml, dose-dependently reduced the guinea-pig ileum contractions. Furthermore, some partially purified fractions I-IV from the MeOH extract, each tested at the same concentrations of the extracts, and some pure compounds (6 x 10(-6), 3 x 10(-6), 1 x 10(-6) M) isolated from the above fractions significantly reduced, in a dose-dependent manner, the electrical contractions of the ileum. The active compounds were identified as the known indole alkaloids strictosidic acid, lyalosidic acid, 5 alpha-carboxystrictosidine, strictosidine, and sickingine, as well as the known quinic acid derivatives 5-caffeoylquinic acid, 4,5-dicaffeoylquinic acid, and shikimic acid by spectral data. Two known quinovic acid glycosides and a new triterpenic glycoside, quinovic acid 3 beta-O-alpha-rhamnopyranosyl-(1-->3)-(beta-glucopyranosyl-(1-->6)-beta- glucopyranoside, were also isolated and their structures established by NMR and M5 data.

Isoquinoline alkaloids from Argemone mexicana reduce morphine withdrawal in guinea pig isolated ileum.

The present study examined the effect of the MeOH extract, partially purified fraction (IV), and pure compounds from Argemone mexicana L. (Papaveraceae) on the morphine withdrawal in guinea pig isolated ileum. The MeOH extract, the partially purified fraction (IV), and the pure compounds isolated from A. mexicana significantly and in a concentration-dependent manner reduced the morphine withdrawal. Since the pure compounds were identified as protopine and allocryptopine, the observed effects could be related to these compounds. The results of the present study suggest that isoquinoline alkaloids may be potential agents in the treatment of drug abuse.

Neuropharmacological effects of extracts from Sickingia williamsii.

Sickingia williamsii Standl. (Rubiaceae) is used in Peruvian folk medicine for its analgesic and anti-inflammatory activity. In this study we have examined the pharmacological profiles of petroleum ether, chloroform, chloroform-methanol (9:1) and methanol extracts of the tree. Both chloroform-methanol (250, 500 or 750 mg kg-1, p.o.) and methanol (125, 250 or 500 mg kg-1, p.o.) extracts significantly reduced both the locomotor activity and motor co-ordination of mice; they also prolonged sleep induced by pentobarbital, although no significant cataleptic response was observed. These extracts did not have a significant impact on the nociceptive threshold in the hot-plate and tail-flick tests. Petroleum ether and chloroform extracts did not, furthermore, induce any significant pharmacological effects. The results of the study suggest that these extracts possess neurosedative-like properties.