The root of Solanum sisymbriifolium Lam (Solanceae), a perennial herb, has been used as a traditional medicine possessing diuretic and antihypertensive properties in Paraguay. It was reported that extracts from this plant exerted hypotensive effects in rats. Nuatigenosido was isolated from the extract as one of the prospective active compounds. We have investigated its pharmacological actions. The current study demonstrated the following results: (1) Nuatigenosido at 100 mg=kg and 1 mg=kg i.v. lowered blood pressure in rats, (2) nuatigenosido at 10 À6 and 10 À5 M augmented the contractile force in the right atrium of a bullfrog, and (3) nuatigenosido at 10 À7 M increased the overshoot amplitude in frog atrial myocytes, action potential durations were shortened, the calcium current (I Ca ) was increased, and the delayed outward potassium current was increased. From these results, it is suggested that nuatigenosido may play an important role in the therapeutic effects of this herb.

Kyllinga brevifolia Rottb., Cyperaceae, rhizomes have been widely used in the Paraguayan folk medicine as digestive, diuretic, sedative, tonic, antispasmodic and sudorifi c. The purpose of this study is to characterize the putative sedative, anxiolytic effects of the crude hydro-ethanolic extract (CEKb) and fractions of the rhizome of K. brevifolia, in male mice. The behaviour of mice was assessed in the open fi eld, hole board, rota-rod and elevated plus-maze (EPM) test. Oral treatment with single doses of 10, 100 and 1000 mg/kg of CEKb and 10 mg/kg of ethyl acetate fraction (KbF-ethyl-ac) increased the duration of the sleeping time induced by pentobarbital. Oral administration of 1, 10 and 100 mg/kg of CEKb and 0.1, 1 and 10 mg/kg of KbFethyl-ac also signifi cantly increased the time-spent and arm entries into open arms of the elevated plus maze (EPM) versus control group. These fi ndings indicate that K. brevifolia exerts a weak sedative and an interesting anxiolytic-like effect in mice and suggest its potential usefulness for the treatment of anxiety in humans.

The aim of this work was to determine the acute toxicity of hydro-alcoholic extract of S. rhombifolia L. (EHASr), and its influence on general behavior, sleeping time induced by pentobarbital, intestinal transit migration and the effect on spontaneous contractile response of intestinal smooth muscles isolated from mice. Neither oral doses up to 3.000 mg/kg nor intraperitoneal dose up to 1.000 mg/kg denoted toxic symptoms, respectively. Oral administration of 100.0 mg/kg of EHASr promotes statistically significant increase of charcoal marker migration (** p <0.01) in the intestinal transit test. By other hand, individual doses of 0.001, 0.005, 0.01 and 0.05 mg/mL of EHASr did not modify the spontaneous contractile responses of ileum and jejunum muscles. However, the recovery contractile response of both smooth muscles to ACh 10 -7 M, were increased significantly according to each EHASr pre-treatment The presences of alkaloids, tannins, saponins and steroids and/or triterpenes were detected by qualitative phytochemical assay of EHASr. In conclusion, based on results, oral administration of EHASr is safe, well tolerated and increased the intestinal migration of charcoal marker in mice. This finding is correlated to the popular use of S. rhombifolia and encourages us to perform further specific chemical and pharmacological studies.

The objective of this work was to determine the analgesic and anti-inflammatory activity of Aloysia polystachya (Griseb.) Moldenke (Verbenaceae) in experimental models of acute pain and inflammation in mice. Methods of pain induced by caudal pressure (Randall-Selitto), chemical stimulation (acetic acid or the writhing test), and thermal stimulation (hot plate) were used to study analgesic effects. Additionally, edema of the paw induced by injection of 1% carrageenan was used to evaluate the anti-edema activity of A. polystachya. Oral doses of 100 and 200 mg/kg of crude extract of A. polystachya (CEAp) significantly reduced the sensibility to painful stimuli induced by the application of pressure in the tail comparable with an analgesic effect (p < 0.05) in a non-dose dependent manner. Additionally, the number of abdominal contortions was significantly reduced in comparison with the control group and with similar strength to the group treated with Indomethacin 10.0 mg/kg. Similarly, in the model of pain induced by thermal stimulation, it was observed that the groups treated with CEAp presented statistically significant analgesic activity in comparison with the control group and with a similar intensity to the group treated with morphine 6.0 mg/kg. Finally, a statistically significant reduction of edema induced by 1% carrageenan was observed with oral administration of 100 mg/kg of CEAp in comparison to the positive control of edema in a manner similar to the group treated with Indomethacin 10 mg/kg. Based on these results, it was concluded that the CEAp possesses the capacity to increase pain threshold in three pre-clinical models of pain induced (mechanical pressure, chemically and thermally) in mice, compatible with an analgesic effect. Also, CEAp demonstrated antiedematous capacity in carrageenan-induced paw edema in mice, concordant with anti-inflammatory effect using the plethysmography method. These pharmacological effects are potentially due to the presence of verbascoside in CEAp. Additionally, these experimental results are correlated with the popular use of CEAp and present a variety of opportunities for pharmaceutical research such as the development of innovative phytopharmaceuticals.

No abstract