RESUMO
This work aimed to characterize and evaluate the antihypertensive effect of the (-)-ß-pinene/ß-cyclodextrin (ßP/ß-CD) complex. The complex was prepared through physical mixture and slurry complexation methods and was analyzed through differential scanning calorimetry, thermogravimetry/derivative thermogravimetry, fourier transform infrared spectroscopy, diffraction X-ray, docking and scanning electron microscopy. Normotensive or L-NAME-induced hypertensive rats were used in pharmacological experiments. Mean arterial pressure (MAP) was determined with direct blood pressure measurements from the abdominal aorta. The drugs were orally administrated and their effects were recorded during 48 hours. Vascular effects of ßP were evaluated in isolated ring of mesenteric artery. The physicochemical characterization showed ßP/ß-CD complex formation. In hypertensive rats (MAP = 156±16 mmHg), the complex, but not ßP alone, promoted hypotension at 36 and 48 hours after administration (MAP = 124±3 and 110±5 mmHg, respectively). In arterial rings, ßP vasorelaxed rings precontracted with phenylephrine (Emax = 105±6%), which was not changed after the removal of the vascular endothelium (Emax = 108±4%), after the pre-contraction with KCl 80 mM (Emax = 107±8%) or S(-)-BayK8644 (Emax = 107±5%), or after incubation with TEA (Emax = 113±4%). Finally, ßP inhibited CaCl2- and sodium-orthovanadate-induced contractions. In conclusion, the slurry complexation method was the best among them. Pharmacological results demonstrated that the complex promoted antihypertensive effect. Furthermore, ßP induced endothelium- independent vasorelaxation possibly caused by the inhibition of the Ca2+ influx through L-type Ca2+ channel associated to a decrease in calcium sensitivity.
