Essential oil from Eugenia stipitata McVaugh leaves exhibits antinociceptive effect via opioid receptor activation

Eugenia stipitata McVaugh, a species of the Myrtaceae family, is widely distributed in tropical regions and has traditionally been used by local communities to treat mouth and throat inflammation, stomach pain, wounds, fever, diarrhea, and other inflammatory conditions. This study aimed to investigate the effects of the essential oil from E. stipitata (EsEO) in experimental pain models in mice, evaluating its potential as an alternative analgesic therapy. Mice were treated with EsEO and tested in formalin, tail immersion, and hot plate models to assess antinociceptive effects. Pharmacological antagonists were used to investigate the mechanism, suggesting opioid receptor involvement. Behavioral responses and latencies were measured post-treatment. EsEO significantly reduced neurogenic and inflammatory pain responses in all tests. In the formalin test, both early and late phases showed decreased pain behaviors. Similar reductions were observed in the tail immersion and hot plate tests. The major constituents appear to exert both central and peripheral analgesic effects. The use of antagonists indicated that the antinociceptive mechanism of the essential oil involves, at least in part, the modulation of the opioid pathway. EsEO exhibited significant antinociceptive activity and presents itself as a promising natural alternative for pain management. These findings support further research into the mechanisms and therapeutic potential of natural products for the development of safer and more effective analgesics.