Chemogenic silver nanoparticles enhance lignans and neolignans in cell suspension cultures of Linum usitatissimum L.

Abstract

Cell suspension culture of Linum usitatissimum is a great source of the novel and multipurpose medicinal compounds lignans and neolignans. Conventional culturing practices usually result in low yield of plant secondary metabolites; therefore, we conceived a successful mechanism to elicit production of lignans and neolignans in cell suspension cultures, simply, by addition of chemogenic Ag-NPs into the culture medium. A three stage feeding strategy (day 10, 10 and 15, and 10 and 20, respectively, after inoculation) spanning the log growth phase (day 10–20), was implemented to elicit cell suspension cultures of Linum usitatissimum. Though enhancing effects of Ag-NPs were observed at each stage, feeding Ag-NPs at day 10 resulted in comparatively, highest production of lignans (secoisolariciresinol diglucoside, 252.75 mg/l; lariciresinol diglucoside, 70.70 mg/l), neolignans (dehydrodiconiferyl alcohol glucoside, 248.20 mg/l; guaiacylglycerol-β-coniferyl alcohol ether glucoside, 34.76 mg/l), total phenolic content (23.45 mg GAE/g DW), total flavonoid content (11.85 mg QUE/g DW) and biomass (dry weight: 14.5 g/l), respectively. Furthermore, a linear trend in accumulation of lignans and neolignans was observed throughout log phase as compared to control, wherein growth non-associated trend in biosynthesis of these metabolites was observed. Optimum production of both lignans and neolignans occurred on day 20 of culture; a ten fold increase in secoisolariciresinol diglucoside, 2.8 fold increase in lariciresinol diglucoside, five fold increase in dehydrodiconiferyl alcohol glucoside and 1.75 fold increase in guaiacylglycerol-β-coniferyl alcohol ether glucoside was observed in production levels compared to control treatments, respectively.