Chemical composition, antioxidant and anticholinesterase activity of Melissa officinalis

• In this study, it was demonstrated the in vitro inhibitory effect of gallic acid in the MMP-2 activity.
• Ethyl acetate fraction from M. officinalis presented the highest flavonoids content and antioxidant properties.
• Ethyl acetate fraction from M. officinalis exhibited a moderate inhibition of cerebral acetylcholinesterase.
• M. officinalis could be further investigated for the treatment of Alzheimer's disease, due its antioxidant and anticholinesterase activity.
• Gallic acid could be also a promising drug in the treatment of Alzheimer's disease due its antioxidant and MMP-2 inhibitory activities showed here.

Oxidative stress is associated with various diseases, in particular those related with the central nervous system, such as Alzheimer's disease. Based on the various benefits of Melissa officinalis, we investigated the chemical composition and antioxidant activity of different fractions from M. officinalis extract. Furthermore, the fraction with the highest antioxidant activity was tested as a potential acetylcholinesterase (AChE) inhibitor. Gallic acid, an important water soluble constituent of M. officinalis, was tested on the matrix metalloproteinase-2 (MMP-2) activity. High performance liquid chromatography (HPLC), gas chromatography coupled with mass spectrometry (GC–MS) and nuclear magnetic resonance (NMR) were used to analyze the chemical composition of M. officinalis. TBARS, DPPH, epinephrine autoxidation were used to verify antioxidant properties of M. officinalis or its constituents. Ethyl acetate fraction presented the highest flavonoids content as well as the antioxidant activities when compared with other tested fractions. The ethyl acetate fraction was also a weak inhibitor of brain AChE. Moreover, gallic acid inhibited MMP-2 activity. In conclusion, M. officinalis ethyl acetate fraction should be further investigated for its possible use in the treatment of oxidative stress related diseases, such as Alzheimer's disease.