Effect of different drying methods on quantity and quality of active substances of Purple coneflower (Echinacea purpureae L.)

The genus Echinacea (family Asteraceae), commonly known as purple coneflower, is an important medicinal plant that has been used for centuries, customarily as a treatment for the common cold, coughs, bronchitis, upper respiratory infections, and some inflammatory conditions . The present study was carried out to evaluate the effect of six different methods of drying to obtain the highest of active substances from Echinacea purpurea. To determine the effect of drying methods on quantity and quality of active substances, the samples were dried with six drying methods (sun, shade, greenhouse and industrial-drying at 50° C, 60° C and 80 ° C). Active substances of aerial parts were extracted by ultrasonic method and the amounts caffeic acid derivatives, alkamides (8/9) were measured by using high performance liquid chromatography analysis, and also total phenolics determined with spectrophotometer. The results showed that different drying methods had significant effects on active substances. Samples dried in greenhouse had higher amounts of chlorogenic acid (3.18 mg/g.dw), echinacoside (4.29 mg/g.dw), cynarin (1.55 mg/g.dw) and total phenols contents (363 mg / g.dw). Also, samples dried in shade had higher amounts of caftaric acid (25.8 mg / g.dw), cichoric acid (36.57 mg / g.dw) and alkamides (361.1 μg / g.dw).  Greenhouse drying and shade-drying were proper methods of drying to achieve more amounts of active compounds in E. purpurea.