Increased Antioxidant Activity, Despite Reduced Rosmarinic AcidAccumulation in Methanolic Extracts, of Spearmint (Mentha spicata L.)Plantlets Regenerated In Vitro

摘要

One hundred spearmint (Mentha spicata) plantlets were regenerated from apical shoot segments of ten fieldgrowndonor plants. Although the accumulation of rosmarinic acid and total phenolics in vitro was almost half than invivo, regenerants demonstrated a tenfold-higher hydrogen peroxide compared to the donor plants. This finding may havebeen associated with the increased activity of hydroxyphenylpyruvate reductase, a key enzyme of the phenolic biosyntheticpathway and the increased production of yet unidentified phenolic compounds in vitro. This process of in vitro cultureassociated with a reduction of rosmarinic acid and total phenolics and with an increase of the antioxidant capacity indicatedthe possible promotion of in vitro-specific biosynthetic pathways.