Preparation and biological activity of nanocapsulated Glycyrrhiza glabra L. var. glabra

Glycyrrhiza glabra is a medicinal plant found in Asia, the Mediterranean and parts of southern Europe. It used for the treatment of upper respiratory tract ailments including coughs, hoarseness, sore throat and bronchitis. In this study, natural polymers, chitosan and alginate were used for preparing nanocapsules containing turmeric oil and a methanol extract of G. glabra. The antimicrobial activity of G. glabra as an extract and in a nanocapsule was investigated. In the preparation of nanocapsules, a three‐step procedure involving emulsification, cross‐linking with calcium chloride and solvent removal was used. Morphological characteristics of the nanocapsules were investigated by particle size using transmission electron microscopy. The results showed that turmeric oil‐to‐extract ratio, surfactant and molecular weight of chitosan all affect the size of the nanocapsule produced. An oil‐to‐extract ratio of 10:10 mg/ml, Tween 80 and low molecular weight chitosan resulted in the optimal (smallest) nanoparticle size.