Abstract
Honokiol and magnolol, important anxiolytic and anti-cancer agents, have been produced in cell-suspension cultures of the endangered Mexican plant Magnolia dealbata Zucc. In vitro cultures of the plant were established, and the accumulation of honokiol and magnolol in callus and cell-suspension cultures was measured. Leaf samples were the best explants for callus establishment and metabolite production, and Murashige and Skoog medium supplemented with 1 mg/L 2, 4-dichlorophenoxyacetic acid and 1 mg/L kinetin yielded 2.3 mg/g of honokiol and 5.9 mg/g of magnolol. Bacterial and fungal contamination was inhibited with a multiple-step tissue sterilization procedure. Oxidation was inhibited with 1 g/L activated charcoal. Cell-suspension batch cultures derived from friable callus obtained from leaves of this species were grown for 30 days in shaker flasks containing Murashige and Skoog medium. Throughout the growth cycle, honokiol and magnolol levels, fresh and dry weight, and sucrose uptake were determined. The effects of carbon source concentration on biomass accumulation and the synthesis of bioactive compounds were studied. By using 3 mL of inocula supplemented with 3% (w/v) sucrose, maximum yields of honokiol (8.1 mg/g) and magnolol (13.4 mg/g) were obtained after 25 days. These yields were 300% and 382%, respectively, of the yields of honokiol and magnolol obtained from field-grown plants.