In vitro, in vivo and in silico evaluation of the anti-inflammatory potential of Hyssopus officinalis L. subsp. aristatus (Godr.) Nyman (Lamiaceae).

ETHNOPHARMACOLOGICAL RELEVANCE

Medicinal properties of hyssop have been used in traditional medicine since ancient times, inter alia, in diseases/conditions with an inherent inflammatory process.

AIM OF THE STUDY

Accordingly, the aim of this study was to investigate the anti-inflammatory properties of hyssop herb preparations (essential oil and methanol extracts) in vivo, in vitro and in silico.

MATERIALS AND METHODS

For in vitro testing of essential oils and extracts of hyssop herb, the cyclooxygenase-1 (COX-1) and cyclooxygenase-2 (COX-2) enzyme assays were used. In vivo anti-inflammatory potential of the extracts (at doses of 50, 100 and 200 mg/kg) was assessed using the carrageenan-induced rat paw edema test. Molecular docking and dynamics were used for in silico testing of the inhibitory activity of chlorogenic (CA) and rosmarinic (RA) acids, as the dominant compounds in the tested methanol extracts against COX-1 and COX-2 enzymes.

RESULTS

Significant inhibitory activity was shown in the COX-2 test regarding extracts (essential oils did not exhibit any significant activity). Namely, all analyzed extracts, at a concentration of 20 μg/mL, showed a percentage of inhibition of COX-2 enzyme (54.04-63.04%), which did not indicate a statistically significant difference from the positive control of celecoxib (61.60%) at a concentration of 8.8 μM. In vivo testing showed that all methanol extracts of hyssop herb, at the highest test dose of 200 mg/kg in the third and fourth hours, after carrageenan administration, exhibited a statistically significant (p < 0.05) inhibitory effect on the increase in rat paw edema in relation to control. This activity is comparable or higher in relation to the reference substance, indomethacin, at a concentration of 8 mg/kg. The preliminary in silico results suggest that investigated compounds (RA and CA) showed better inhibitory activity against COX-1 and COX-2 than standard non-steroidal anti-inflammatory drug (NSAID), ibuprofen, as evident from the free binding energy (ΔG in kJ mol). The binding energies of the docked compounds to COX-1 and -2 were found to be in the range between -47.4 and -49.2 kJ mol. Ibuprofen, as the one NSAID, for the same receptors targets, showed remarkably higher binding energy (ΔG = -31.3 kJ mol to COX-1, and ΔG = -30.9 kJ mol to COX-2).

CONCLUSION

The results obtained not only support the traditional use of hyssop herb in inflammatory conditions in folk medicine, but also open the door to and the need for further in vivo testing of extracts in order to examine the molecular mechanism of anti-inflammatory activity in living systems and possibly develop a new anti-inflammatory drug or supplement.