The bioactive compounds in extracts are prone to degradation by oxidation, heat, or light. Nanoencapsulation is one of the best techniques to keep the properties of these chemical compounds. The aim of this study was the extraction of Melissa officinalis (MO) and nanoencapsulation of the extract via chitosan as a biodegradable polymer. In this research, extraction of MO was investigated using various extraction methods and nanoencapsulation with MO extract was carried out via ionic gelation technique. The effectiveness of the extracts was evaluated by measuring the total phenolic content (TPC), antioxidant activity, and extraction efficiency of the solid contents. The highest efficiency was achieved for microwave-assisted extraction with the utmost values in each parameter. (TSC) was 22.81% and amounts of the TPC and antioxidant activity were 311.94 mg Gallic acid and 36 mg diphenyl picryl hydrazyl (DPPH) per 1g of the plant, respectively. Morphology study by field emission scanning electron microscopy (FE-SEM) indicated spherical shape nanoparticles with a diameter of 25nm. The size of the nanoparticles was evaluated by the Dynamic Light Scattering (DLS) technique for various concentrations of the used extracts in the encapsulation process. For 1.0, 3.0, and 5.0 mg /mL concentration, mean diameters were 24, 118, and 145 nm, respectively. Results indicated that microwave-assisted extraction was the best extraction method for MO and the encapsulation of MO extract could be created successfully with different particle sizes for the protection of bioactive compounds. Since MO is a beneficial herbal plant, the development of this research is recommended
