Long-term micropropagation of Balsamita major as a promising in vitro strategy for producing phenolic compounds with antioxidant capacity

The leaves of the aromatic plant Balsamita major (costmary) are known for their characteristic minty aroma and their strong antioxidant activity, mainly due to their high polyphenol content. The aim of this study was to develop a micropropagation protocol for costmary and to evaluate the phenolic production and antioxidant properties of the extracts obtained from in vitro cultures. The results indicate that costmary showed high adaptability to in vitro conditions with a high proliferation rate which was maintained for three years. Moreover, the in vitro leaves exhibited a high polyphenolic content, the same as that reported in vivo. The characterization of the leaf extracts showed that the main polyphenolic compounds were chlorogenic and isochlorogenic acid. These in vitro compounds proved to have strong antioxidant properties similar to those previously observed in vivo. Our results underline the commercial potential of in vitro cultures of Balsamita major, which accumulates polyphenols regardless of season, contrarily to field-grown plants. Micropropagation represents a viable "green" tool for producing pesticide/herbicide/pollution-free antioxidant compounds for commercial purposes.