Establishment of Momordica charantia hairy root cultures for the production of phenolic compounds and determination of their biological activities

Momordica charantia is an important vegetable crop and is also used in traditional medicine. The production of secondary metabolites from hairy root cultures of Indian M. charantia (IMC) and Korean M. charantia (KMC) along with their biological activities (antioxidant and antimicrobial activities) were compared. The explants (leaves, cotyledons, hypocotyls, roots, and nodes) from in vitro seedlings were inoculated with Agrobacterium-rhizogenes strains (KCTC 2703 and KCTC 2704) for the induction of hairy roots. Established transgenic clones of hairy roots were confirmed by polymerase chain reaction (PCR), reverse transcription-PCR and sequencing using rolC specific primers. Hairy roots cultured in MS liquid medium supplemented with 3 % sucrose showed the highest accumulation of biomass [95.11 g/l fresh mass (FM) and 10.61 g/l dry mass (DM) in IMC and 93.58 g/l FM and 10.12 g/l DM in KMC]. The flask cultures of IMC and KMC increased in their biomass up to 9.6- and 9.4-fold after 20 days of culture. MS basal liquid medium supplemented with 3 % sucrose was superior for the growth of hairy roots compared with other culture media evaluated (B5, NN and N6), for biomass and phenolic compounds production. A total of 27 phenolic compounds were identified by ultra-performance liquid chromatography analysis. The flavonoids (catechin, myricetin and quercetin) and the phenolic acids (gallic acid, chlorogenic acid, gentisic acid and salicylic acid) levels were highly increased in hairy roots than in untransformed control roots. The metabolites such as ferulic acid, rutin, naringenin and naringin levels were decreased significantly in the hairy roots compared with untransformed roots. Due to these metabolic variations, the antioxidant and antimicrobial activities were increased with hairy roots compare to untransformed roots. In terms of biomass, phenolic compounds and biological activities the hairy roots of IMC were superior to KMC was observed. This is the first report describing the production of phenolic compounds and biological activities from hairy root cultures of M. charantia.