Liquid chromatography–mass spectrometry phytochemical analysis, antioxidant, anti–inflammatory and analgesic efficacy of Origanum majorana L. aerial part extracts collected from North–Eastern of Algeria

Origanum majorana L. (Lamiaceae) has been prescribed in folk medicine for therapeutic purposes such as cancer, asthma, dizziness, rheumatism and inflammatory diseases. To evaluate for the first time the decoction (DecE) and hydro–ethanolic (HEE) extracts of the aerial part of O. majorana. The phytochemical analysis (LC–MS/MS), antioxidant, anti–inflammatory and analgesic potentials were analysed. LC–MS/MS analysis identified 17 components in the extracts. The main compounds detected in the aerial parts of O. majorana include rosmarinic acid (≥ 50%), elagic acid (≥ 20%), indomethacin along with flavonoids, phenolics, benzopyrone, hydroquinones, indolyl acetic acid. Both extracts showed potent antioxidant effects in various antioxidant assay models. Through the eggs protein denaturation assay, both plant extracts showed high in vitro anti–inflammatory effect of the order of 86.91±0.00% for DecE and 85.04±0.00 % for HEE (1.4 mg·mL-1). Acute toxicity measurement revealed no mortality or behavioral changes during the testing period, confirming the two extracts not toxic with an LD50 > 2 g·kg-1. The in vivo anti–inflammatory effects were found to be statistically significant (P<0.05), reducing the edematous response by 78.40 ± 2.52 % and 77.36 ± 3.88 % in DecE and HEE, respectively. Additionally, at a dose of 400.0 mg·kg-1, both extracts exhibited significant analgesics activity (P<0.05) against acetic acid induced abdominal constriction in mice, with inhibition rates of 78.54 ± 3.30% for DecE and 66.99 ± 1.34% for HEE. The results indicate aerial part extracts of O. majorana have potent anti–inflammatory effects and may prove to have potential health benefits.