Somatic embryogenesis, plant regeneration, and the evaluation of camptothecin content in Nothapodytes foetida

Somatic embryogenesis and plant regeneration have been achieved in Nothapodytes foetida, which is known for its rich source of anti-cancer and anti-AIDS alkaloids. Callus cultures were initiated from immature zygotic embryos cultured on Murashige and Skoog's (MS) medium supplemented with 2,4-dichlorophenoxyacetic acid, 6-benzyladenine (BA), and kinetin. MS medium devoid of plant growth regulators favored the development of globular somatic embryos that differentiated further into plantlets. Plantlet regeneration efficiency was effectively increased on MS medium supplemented with BA. Over 90% of the in vitro plantlets survived when transferred to the soil. Alkaloids were detected in different stages of somatic embryos, regenerated plantlets, and different parts of the 2-yr-old regenerated plants. The somatic embryos contains camptothecin (0.011% dry weight, DW) and 9-methoxycamptothecin (0.0028% DW). Two-year-old field-grown plants obtained from somatic embryos were analyzed and contained higher levels of camptothecin (0.20% DW) and 9-methoxycamptothecin (0.097% DW) accumulated in roots, followed by stem and leaves. Alkaloids were quantified and identified by TLC and HPLC.