LC-TOFMS analysis, in vitro and in silico antioxidant activity on NADPH oxidase, and toxicity assessment of an extract mixture based on Marrubium vulgare L. and Dittrichia viscosa L.

Abstract

Plants and their derived compounds constitute a strong basis as potential drug and as novel therapeutic approach for the management of many diseases and illnesses. In this study we explored the chemical composition of the hydro-ethanolic extracts of M. vulgare and D. viscosa and their mixture. The antioxidant activity of these extracts was evaluated using the ABTS assay. Next, we examined the acute toxicity and sub-acute toxicity of the mixture. The molecular docking was conducted to discover the potential of compounds detected on NADPH oxidase. In the extract of D. viscosa the results revealed the presence of 4 compounds P-coumaric acid, caffeic acid, palmitic acid and stearic acid. In M. vulgare, only 3 compounds were identified: caffeic acid, stearic acid and palmitic acid which give the lowest ppm error (-5.67). The mixture of the two plants showed the presence of 2 fatty acids (palmitic acid and stearic acid), caffeic acid and daidzein. Concerning the antioxidant activity, the mixture (IC₅₀=0.13±0.04 mg/mL) has the highest effect in the inhibition of ABTS followed by M. vulgare (IC₅₀=0.143±0.03 mg/mL) and D. viscosa (IC₅₀=0.162±0.05 mg/mL). The results of the acute toxicity showed that for 14 days and even a few hours after the administration of the mixture to the rats did not show any sign of toxicity, for the 2 doses administered (1000 and 2000 mg/kg). During 28 days of the test, no sign of toxicity was observed in the rats treated with the two doses (500 and 800 mg/kg). No significant difference was observed between the control group and the groups treated with the two doses in ALP, UREA, and CREA and a slight elevation of AST was observed in the group treated with the 500 mg/kg dose. Daidzein, myricetin, and vanillic acid were the molecules most active against NADPH oxidase with a glide gscore of -7.13, -6.597, and -6.12 kcal/mol,a glide emodel of  -60.845, -67.752, and -45.821 kcal/mol, and a glide energy -40.807, -47.249, and -27.679 kcal/mol. In conclusion, both plants are effective as antioxidant agents and their mixture showed no sign of toxicity as herbal preparation.