In vitro propagation of North American ginseng (Panax quinquefolius L.)

North American ginseng (NAG) (Panax quinquefolius L.) is a medicinally important plant with multiple uses in the natural health product industry. As seed propagation is time-consuming because of the slow growth cycle of the plant, in vitro propagation using a bioreactor system was evaluated as an effective approach to accelerate plant production. An efficient method was developed to multiply nodal explants of NAG using liquid-culture medium and a simple temporary immersion culture vessel. The effects of plant growth regulators, phenolics, and chemical additives (activated charcoal, melatonin, polyvinylpolypyrrolidone, and ascorbic acid) were evaluated on in vitro-grown NAG plants. The highest number (12) of shoots per single node was induced in half-strength Schenk and Hildebrandt basal medium containing 2.5 mg/l kinetin, in which 81% of the cultured nodes responded. In a culture medium with 0.5 mg/l alpha-naphthalene acetic acid (NAA), roots were induced in 78% of the explants compared to 50% with a medium containing indole-3-acetic acid. All of the resulting plants appeared phenotypically normal, and 93% of the rooted plants were established in the greenhouse. Phenolic production increased significantly (P < 0.05) over a 4-wk culture period with a negative impact on growth and proliferation. Activated charcoal (AC; 50 mg/l) significantly reduced total phenolic content and was the most effective treatment for increasing shoot proliferation. Shoot production increased as the phenolic content of the cultures decreased. The most effective treatment for NAG development from cultured nodal explants in the bioreactor was 2.5 mg/l kinetin, 0.5 mg/l NAA, and 50 mg/l AC in liquid culture medium. This protocol may be useful in providing NAG tissues or plants for a range of ginseng-based natural health products.