Summary: Callus was produced from hypocotyl sections of in vitro germinated seedlings of Cynanchum acutum on Murashige and Skoog media (1962) containing 0.5 -4.0 mg/l a-Naphthalene acetic acid in combination with 0.2-1.0 mg/l Benzyl adenine. After 12 weeks in culture both fresh and dry weights (g) were significantly higher on 0.5 mg/l NAA and 0.2 mg/l BA. Cardiac glycoside concentration was highest (1.2 mg/g DW) on the same growth regulators combination. Flavonoids were highest (0.198 mg/g) on 0.5mg/l NAA and 1.0 mg/l BA. Twenty eight weeks old callus gave highest cardiac glycosides (1.3 mg/g) on media lacking BA and 0.5 mg/l NAA. Flavonoids concentration (0.27 mg/g) was highest on the same auxin concentration in the presence of 0.2 mg/l BA. Regeneration from callus cultures was obtained when 8-weeks old callus was subcultured on MS hormone free media for 6 weeks. Shoots were rooted on MS supplemented with 0.1 mg/l NAA and acclimatized in growth chamber. Adventitious shoots showed significantly higher CG (6.5 and 4.3 mg/g) than the wild plants (2.8), while regenerants gave comparable concentration (2.3) to the wild. Flavonoids were slightly lower in concentration in adventitious shoots (0.19) and regenerants (0.18) than the wild plant (0.27). Five cell lines were initiated from 8 weeks old individual callus pieces on NAA and BA containing media. Twenty weeks old cell line (1) showed higher CG (3.46) than the wild type and slightly lower flavonoid content (0.149). Plating of 12weeks old suspension on MS containing NAA and BA followed by hormone free media resulted in shoot regeneration, that were rooted and acclimatized. This represents the first report for regeneration from in vitro culture of C. acutum, as well as, the production of cardenolides and flavonoids from cultures to concentrations that are comparable to wild plants
