Trends in accumulation of pharmacologically important antioxidant-secondary metabolites in callus cultures of Linum usitatissimum L

Linum usitatissimum: L. is well-known for production of pharmacologically important secondary metabo-lites. Due to their tremendous beneficial effects on human health, these compounds are receiving greater attention throughout the World, especially in the treatment of various types of cancers. In present study, we have developed an efficient protocol for production of lignans like secoi-solariciresinol diglucoside (SDG) and lariciresinol diglucoside (LDG) and neo-lignans like dehydrodiconiferyl alcohol glucoside (DCG) and guaiacylglycerol-beta-coniferyl alcohol ether glucoside (GGCG) by exploiting in vitro callus cultures of Flax. These cultures were established from stem and leaf explants, inoculated on Murashige and Skoog (MS) media supplemented with various concentrations of alpha-naphthalene acetic acid (NAA), thidiazuron (TDZ) and 6-benzyl adenine (BA). Results revealed that the leafderived calli (1.0 mg/l NAA) accumulated highest levels of biomass (DW; 15.7 g/l) and antioxidant activity, while highest production of total phenolics (111.09 mg/l) and flavonoids (45.02 mg/l) were observed in stem-derived calli (1.0 mg/l NAA). The high-performance liquid chromatography (HPLC) analysis revealed that the stem-derived calli (1.0 mg/l NAA) accumulated optimum concentrations of SDG (2.7 +/- 0.021 mg/g DW), LDG (9.8 +/- 0.062 mg/g DW) and DCG (13.8 +/- 0.076 mg/g DW), while leaf-derived calli (1.0 mg/l NAA) showed optimum accumulation of GGCG (3.8 +/- 0.022 mg/g DW) as compared to all other treatments. These results provided definite evidence that the NAA differentially influence the production of lignans and neo-lignans in callus culture of Flax. This study opens new dimensions to devise strategies to enhance the production of these valuable metabolites.