Tannin production in hairy root cultures of Lawsonia inermis

Abstract

Summary Hairy root cultures of Lawsonia inermis , induced by a co-culture method using Agrobacterium rhizogenes strain NCIB 8196, were established and the accumulation of phenolic constituents in the normal and transformed root cultures were investigated. The hairy roots produced three polyphenols, (+)-catechin (1), 1,2,3,6-tetra-O-galloyl-β-D-glucose (2) and 1,2,3,4,6-penta-O-galloyl-β-D-glucose (3), as confirmed by HPLC. The highest yields of hydrolyzable tannins, i.e. galloylglucoses (2 and 3), were observed in the transformed roots maintained in the dark and cultured in hormone-free Murashige and Skoog liquid medium (0.43% and 3.04% of dry weight for compounds 2 and 3, respectively). The effects of nutrient composition on tannin biosynthesis were investigated. This study demonstrated, for the first time, the capability of biosynthesis of galloylglucoses in the transgenic L. inermis root cultures.