In vivo anti-inflammatory activities of Plantago major extract and fractions and analysis of their phytochemical components using a high-resolution mass spectrometry

Background and purpose: Plantago major has been applied as a herbal remedy for centuries. However, studies on anti-inflammatory activities and their chemical ingredients are limited. The objective of this study was to investigate the anti-inflammatory properties of P. major in three animal models and its phytochemical contents.

Experimental approach: Dichloromethane extract (DCM) of P. major was fractionated with n-hexane to yield the soluble (SHF) and insoluble (IHF) fractions. The anti-inflammatory activities of DCM, SHF, and IHF were evaluated using rat’s paw edema induced by carrageenan, thioglycolate-induced leukocyte emigration in the mice, and rheumatoid arthritis (RA) induced by complete Freund’s adjuvants in rats. The chemical
constituents were analyzed using a high-resolution mass spectrometer (HRMS).

Findings / Results: The DCM, SHF, and IHF inhibited paw edema in the rats and reduced the leukocyte migration in the mice. At dose 560 mg/kg, the percentage of inhibitory was 47.33%, 55.51%, and 46.61% for the DCM, IHF, and SHF, respectively. In the RA animal model, IHF at 280 and 560 mg/kg reduced osteoclast formation and COX-2 expression compared to diclofenac. Some compounds namely oleic acid, linoleic acid,
palmitic acid, and oleamide identified in the DCM, IHF, and SHF may be responsible for these activities.

Conclusion and implications: This study showed that P. major has several in-vivo anti-inflammatory activities.