CHEMICAL COMPOSITION AND ANTINOCICEPTIVE ACTIVITY OF ESSENTIAL OIL FROM Myrcia rostrata DC. (MYRTACEAE) IN ANIMAL MODELS

There are approximately 300 Myrcia DC. species in Brazil. The antimicrobial, anti-inflammatory and antinociceptive activities of some of these species have been described in the literature. The present study aimed to analyze the chemical composition and evaluate the antinociceptive activity of essential oil from fresh Myrcia rostrata DC. leaves. The oil was obtained by hydrodistillation in a Clevenger-type apparatus and chemical analysis was conducted by GC/FID and GC/MS. The acute oral toxicity and the rota rod tests were executed beforehand. The nociceptive tests (acetic acid-induced writhing, formalin and hot plate) were performed with the oil at doses of 75, 150 or 300 mg kg(-1). Of the constituents identified, 95.24% were sesquiterpenes, carotol (17.68%) being the major compound. The essential oil caused no obvious signs of toxicity, nor did it affect the motor coordination of the animals. In conclusion, the animals that received the oil, especially at 300 mg kg(-1), demonstrated a lower number of writhes (1.62 versus 27.88 +/- 2.75), a decrease in paw-licking time in both phases of the formalin test, and increased latency on the hot plate when compared to the control group.