Abstract
Cassia tora root cultures were established to study anthraquinone production and as an alternative source of anthraquinone. In this study, several plant defence-based techniques were used to enhance aloe-emodin production in Cassia tora root cultures. Elicitation and the initial optimisation of exposure time and culture age suggested that 100 mg/L yeast extract was the most efficient elicitor, with the highest efficiency during early to mid-stationary growth phase. The elicited root produced approximately 2.7-2.9 folds-improvement in aloe-emodin content when compared with the control. The efficiency of the elicitor tended to increase along with the exposure time. Extending the elicitation period to the end of culture cycle (9-10 days) increased the production up to 6.21 times (5.740 ± 0.584 mg/gDW). Simultaneous double elicitation and sequential double elicitation also showed their effectiveness on aloe-emodin production. Aloe-emodin production was improved up to 9.09 times higher than the control by a simultaneous add-on of 50 mg/L chitosan with 100 mg/L yeast extract. Meanwhile, sequential elicitation of 50 mg/L chitosan for 24 hours prior to elicitation by yeast extract improved the production up to 11.27 times higher than the control. Both treatment styles exhibited a particular advantage toward the extracellular accumulation, which might facilitate the use of two-phase culture or in conjunction with other enhancing techniques.
Effects of Sequential and Simultaneous Double Elicitation on Aloe-Emodin Production in Cassia Tora Root Cultures