Enhancement of Phytochemical Compounds Using Biotic and Abiotic Elicitors in Purple Coneflower (Echinacea purpurea L.)

Abstract:

Background: Phytochemicals also known secondary metabolites, naturally occurring in medicinal and aromatic plants, are of considerable importance for plant survival and human health. Objective: The objective of this study was to increase accumulation of caffeic acid and alkamide, using biotic and abiotic stresses conditions driving cell defense systems, in cell suspension cultures in purple coneflower (Echinacea purpurea L.). Methods: As biotic and abiotic elicitors, yeast extract (0, 25, 50 and 100 mg l^-1), chitosan (0, 25, 50 and 100 mg l^-1), sorbitol (0, 5, 25 and 50 g l^-1), cadmium chloride (0, 5, 25 and 50 μM) and silver nitrate (0, 5, 25 and 50 μM) solutions were used in an eight-day cell culture. The cells were daily harvested up to the third day of the culture in cadmium chloride and silver nitrate, whereas up to the seventh day of the culture in the other applications. Alkamide and caffeic acid contents in harvested cells were determined using GC-MS device. Results: The contents of alkamide and caffeic acid, as compared to the control, increased by 1.3 and 0.5 times with 50 mg l^-1 yeast application. In the applications of 25 g l^-1 sorbitol and 100 mg l^-1 chitosan, alkamide content increased by 0.8 and 1.5 fold, but the amounts of caffeic acid increased by 2.5 and 3.1 fold, in comparison to the control culture. The highest amounts of alkamide in cadmium chloride and silver nitrate (105 and 127 μg g^-1 dw, respectively) were obtained after 24 h from starting culture, while caffeic acid content reached its highest value (27 and 38 μg g^-1 dw, respectively) after 72 h. Conclusion: This study indicated that biotic and abiotic stress factors, by driving cell defense systems, had a great potential for increasing caffeic acid and alkamide in vitro conditions in purple coneflower.

Key words: Alkamide, Caffeic acid, Callus culture, Secondary metabolites.