Mutational breeding of Centella asiatica (L.) urban for medicinal purposes

Centella asiatica (L.) Urban (Apiaceae) is one of medicinal plants widely used in Thailand. The plant contains active triterpenes, i.e. asiatic acid, madecassic acid, asiaticoside, and madecassoside which possess wound healing property. The Ministry of Public Health has recommended C. asiatica for wound healing[1]. Therefore, the demand of high quality C. asiatica raw material increased. The aim of this study was to improve lines of C. asiatica via polyploid induction for supplying to the herbal industry. C. asiatica terminal buds were soaked in colchicine concentration 0.025–0.400% for 12–36h. After three passages of in vitro propagation by incubating the explants in liquid Murashige and Skoog (MS) medium with 4.45µM thidiazuron (TDZ) for 15 days they have been transfered to semi-solid MS without growth regulator for 10 weeks. The surviving plants were investigated on ploidy level by flow cytometry and chromosome number. After that the selected control and polyploid plants were transplanted to soil under greenhouse conditions for 4 months. The plants were harvested and analyzed by HPLC. The optimum conditions for polyploidy induction were 0.025–0.100% colchicine for 12–24h. We obtained 9 tetraploid and 56 mixoploid plants in M₁V₃ generation confirmed by flow cytometry and chromosome number. Tetraploid plants (M₁V₃) grew slower than mixoploid and control diploid plants and failed to grow ex vitro. The mixoploid plants (M₁V₃) demonstrated significantly higher phytomass and triterpenoid contents than those of the control diploid plant. The mixoploid plants (M₁V₇) showed genetic stability which were confirmed by flow cytometry.

Acknowledgements: Mahidol University, TRF-Master Research Grants (MAG-WI515S098)

References: 1. The Ministry of Public Health (2006) Essential Drug List of Herbal Medicinal Products. The agricultural co-operative federation of Thailand, Bangkok.