Antinociceptive Action of Moringa peregrina is Mediated by an Interaction with α2-Adrenergic Receptor

摘要

Background: Moringa peregrina (M. peregrina) is an edible, drought-resistant tree that is native to semi-arid countries. It is used as a painkiller in folk medicine. Aims: To study the antinociceptive effects of the leaf extract of M. peregrina in mice. Study Design: Animal experimentation. Methods: We employed thermal (hot plate and tail-immersion tests) and chemical (writhing and formalin tests) pain models in male BALB/c mice (eight animals per group) to investigate the mechanisms involved in the antinociceptive actions of M. peregrina . Additionally, we identified the chemical constituents present in the extract of M. peregrina by using liquid chromatography-mass spectrometry analysis, and predicted the possible active constituents that interact with the receptor based on molecular docking simulations. Results: In the writhing test, 200 mg/kg of M. peregrina extract restricted abdominal cramps by up to 55.97% (p0.001). Further, it reduced the time of paw-licking in the early and late phases of formalin test by up to 56.8% and 65.5%, respectively, as compared to the percentage inhibitions of 50.5% and 48.4% produced by 30 mg/kg diclofenac sodium in the early and late phases, respectively (p0.05). This effect was abrogated by yohimbine (1 mg/kg, intraperitoneally), but not by methysergide (5 mg/kg, intraperitoneally), in the late phase only, which indicates that the action of M. peregrina in formalin test is not mediated by 5-HT2 serotonin receptors, but rather via αsub2/sub-adrenergic receptors. In the hot plate test, but not on tail-immersion test, the high dose (400 mg/kg) of the extract increased the latency time after 30 minutes of its administration. Yohimbine antagonized the action of M. peregrina in the hot plate test. Based on LC-MS analysis, the major constituents found in M. peregrina methanolic extract were chrysoeriol 7-O-diglucoside, lupeol acetate, quercetin, and rutin. Depending on the molecular docking results, the activity of M. peregrina extract could be due to the binding of chrysoeriol 7-O-diglucoside, quercetin, and rutin to the αsub2/sub-adrenergic receptor. Conclusion: Interaction with the αsub2/sub-adrenergic receptor serves as a possible mechanism of the M. peregrina analgesic effect.