Production of allantoin, rabdosiin and rosmarinic acid in callus cultures of the seacoastal plant Mertensia maritima (Boraginaceae)

A callus culture of the extreme halophyte seacoastal plant Mertensia maritima (Boraginaceae) was established from apical shoots of the plant using a modified Murashige and Skoog medium supplemented with 6-benzyladenine (0.5 mg/L) and alpha-naphthaleneacetic acid (2.0 mg/L). Three main compounds, (-)-R-allantoin, (+)-rabdosiin and rosmarinic acid, were isolated from extracts of M. maritima calli by liquid chromatography and identified by H-1 and C-13 NMR, UV, ECD and HPLC-MS. Quantitative HPLC analysis showed that the calli produce (+)-rabdosiin (0.14% dry wt), rosmarinic acid (0.74% dry wt) and (-)-R-allantoin (3.7% dry wt). Allantoin was detected in plant cell cultures for the first time. All of these metabolites were also present in lower quantities in different parts of the plant. The presence of rabdosiin and rosmarinic acid, in combination with the skin-conditioning agent (-)-R-allantoin, represents a potentially useful novel composition for skin protection.