Active compounds and biological activity of in vitro cultures of some Echinacea purpurea varieties

Abstract

Background

Plant cell cultures have developed rapidly in recent years for the synthesis of selected natural products. This study was conducted to evaluate the effect of yeast extract, jasmonic acid, phenylalanine, and tyrosine on total caffeic acid and polysaccharide production in callus cultures of two Echinacea varieties, namely Double Decker and Rubinstern. The biological activities (antioxidant, antimicrobial and cytotoxic activities) of different Echinacea extracts were also evaluated.

Results

Data revealed the effect of yeast extract on calli of the two varieties. Double Decker calli recorded maximum caffeic acid derivatives and total hydrolysable sugars after 30 days of cultivation using 1.5 g/l and 1.0 g/l yeast extract respectively whereas, in Rubinstern calli, the maximum caffeic acid derivatives and total hydrolysable sugars were recorded at 1.0 g/l after 30 days. Using 50 mM jasmonic acid, Double Decker calli recorded maximum values of caffeic acid derivatives and total hydrolysable sugars after 15 days. In Rubinstern calli, caffeic acid derivatives and total hydrolysable sugar recorded maximum values after 30 days at 200 mM jasmonic acid and after 15 days at 50 mM jasmonic acid, respectively. In Double Decker variety, caffeic acid derivatives and total hydrolysable sugars recorded maximum values at 100 mg/l phenylalanine. Rubinstern calli recorded maximum value of caffeic acid derivatives at 100 mg/l phenylalanine and total hydrolysable sugars at 50 mg/l phenylalanine. As for tyrosine, maximum values of caffeic acid derivatives and total hydrolysable sugars recorded at 150 mg/l with Double Decker calli. Rubinstern calli recorded maximum value of caffeic acid derivatives and total hydrolysable sugars at 150 and 50 mg/l tyrosine, respectively. The biological activities of the different Echinacea extracts showed that maximum antioxidant activity (89.2%) was recorded with Rubinstern calli. Also, the maximum value of cell death (78.2%) was observed with the extract of Rubinstern calli. For antibacterial activity, most extracts showed inhibitory effect against Bacillus subtilis and Staphylococcus aureus growth.

Conclusion

Both elicitors (yeast extract and jasmonic acid) and precursors (phenylalanine and tyrosine) have a clear effect on natural products of the two Echinacea varieties. The investigated Echinacea extracts (in vitro and in vivo plants and calli of the two varieties) showed moderate activity against tested microbial strains.