Efficient In Vitro Regeneration and Camptothecin Accumulation in Camptotheca acuminata

Camptotheca acuminata produces valuable camptothecin, a potent anticancer agent. To overcome the limitations of wild resources, we developed efficient in vitro regeneration and camptothecin production systems. Key findings include: Optimal sterilization of plant material was achieved using Plant Preservative Mixture (12 min). Axillary shoot induction was most effective on MS medium with 2.5 mg/L 6-BA and 0.25 mg/L NAA, while adventitious shoot regeneration showed a preference for 1 mg/L 6-BA and 0.1 mg/L NAA. Synchronous induction reached its peak at 83.45% using MS medium with 0.5 mg/L 6-BA, 0.05 mg/L NAA, and 0.5 mg/L GA3. Shoot elongation benefited from 5 mg/L phloroglucinol and 20 mg/L CaCl2. For biomass production, 2/3 MS macroelements yielded maximum adventitious shoot biomass (50.52 mg). Rooting reached 100% efficiency on 1/2 MS medium containing 1 mg/L IBA, 0.5 mg/L NAA, 5 mg/L phloroglucinol, and 2 g/L AC, averaging 10.50 roots per shoot. The four-stage camptothecin enrichment system produced shoots containing 795.10 µg/g DW camptothecin—fivefold higher than natural leaves. This breakthrough establishes: (1) the first in vitro camptothecin enrichment platform; (2) a sustainable alternative to wild harvesting; (3) a novel circular production model for endangered medicinal plants. The optimized protocols address the challenges of camptothecin supply while demonstrating remarkable productivity enhancements through controlled in vitro culture systems.