Anti-asthmatic and antioxidant activity of flavonoids isolated from Mentha longifolia subspecies typhoides (Briq.) Harley. and Mentha longifolia subspecies schimperi (Briq.) Briq. on ovalbumin-induced allergic asthma in mice: In-vivo and in-silico study.

Ethnopharmacological Relevance: Mentha longifolia L. has been employed to treat cough, lung inflammation, and bronchial asthma disorders.

Aim Of The Study: Our study was carried out to investigate the medicinal effect of the flavonoids derived from M. longifolia, specifically didymin, linarin, rutin, and TMF, as well as the whole extracts of M. longifolia subsp. typhoides and M. longifolia subsp. schimperi, in comparison to dexa, in a mice model of ovalbumin-allergic asthma (OVA).

Methods: After inhaling OVA, the mice developed acute asthma symptoms. Mice were subjected orally to Dexa and/or isolated flavonoids. The study assessed total and differential leukocyte counts, LDH concentration, and total protein concentration in BALF, reduced levels of GSH and total NOx products in lung tissues and analyzed the lung specimens by staining them with hematoxylin and eosin (H & E).

Results: Histopathological analysis of the right lung lobes demonstrated that the isolated flavonoids exhibited a significant anti-inflammatory effect higher than Dexa as shown by decreasing the overall and distinct leukocyte counts, LDH levels, and total protein levels in BALF, as compared to the OVA group (p < 0.05). TMF was the most effective and the other tested flavonoids are more effective than Dexa but less than TMF. In addition, all tested flavonoids and Dexa significantly (p < 0.05) mitigated OVA-induced oxidative stress as evidenced by diminished lung NOx level and elevated GSH level. Computational docking studies proved recognition of didymin, linarin, rutin, and TMF to the human leukocyte elastase binding sites.

Conclusion: The tested flavonoids; didymin, linarin, rutin, and TMF successfully inhibit Ova-induced allergic asthma in mice through their anti-inflammatory and antioxidant activities and may represent promising candidate as a remedy for allergic asthma.