Long-term cell suspension culture of Thymus persicus (Lamiaceae): A novel approach for the production of anti-cancer triterpenic acids

Abstract

Triterpenic acids (TAs) such as betulinic acid (BA), oleanolic acid (OA), and ursolic acid (UA) are well-known natural compounds found in many plant taxa possessive a wide spectrum of biological activities and potential medicinal uses. Thymus persicus has been already reported as a rich source of TAs. Nowadays, long-term culture is an efficient technique in increasing biosynthesis and production of specialized metabolites in the plant cell suspension cultures with the possibility of stimulation, metabolic regulation, permeabilization, and up-scaling to bioreactors. In the present study, both batch and long-term cell suspension culture (CSC) of the plant were developed for the production of these compounds. A maximum specific cell growth rate of 5.7 g day−1, a doubling time of 42 h, and the highest cell viability (94.7%) throughout the growth period were measured. The highest cell fresh weight in CSC and its long-term culture was 100.63 ± 4.2 and 171.6 ± 4.1 g L−1 at day 21 and 35 of culture, respectively. A positive correlation between cell growth and the content of TAs in long-term culture was observed. The plant cells produced the highest levels of TAs in the mid-exponential phase and held their production stability during the long-term culture period. The highest content (mg 100 g−1 DW) of BA (163.11 ± 4.3) was measured in the second week of culture, while the maximum level of OA (10.22 ± 0.1) and UA (11.01 ± 0.4) was recorded in the third week of culture period. The present findings can be interestingly considered for further commercial production of valuable TAs at large-scale cultures in bioreactors.