engleski

The effect of drying procedure on the content of pigments and antioxidant properties of some medicinal plants

At present, a great number of evidence emerges regarding the beneficial effects of medicinal plants rich in bioactive substances, resulting with a growing interest of pharmaceutical, food and cosmetic industries in these natural remedies. In this study the contents of total phenols, anthocyanins, carotenoids, as well as chlorophylls a and b in 4 fresh and solar dried medicinal plants were determined spectrophotometrically. Lemon balm (Melissa officinalis L.), marigold (Calendula officinalis L.), brown knapweed (Centaurea jacea) and borage (Borago officinalis) were dried at different temperatures (30°C, 50°and 70°C). In order to evaluate the impact of drying conditions on the antioxidant properties of separate pigment extracts, the obtained extracts of carotenoids, chlorophylls, total phenols and anthocyanins were evaluated for their antioxidant capacity using the ABTS radical scavenging assay. According to the obtained results, increased drying temperature leads to a decrease in the content of pigments of medicinal plants. The highest content of carotenoids was determined in fresh marigold, fresh borage contained the highest content of total chlorophyll, fresh purple flowers of brown knapweed exhibited the highest content of total anthocyanins, while lemon balm dryed at elevated temperature exhibited the highest phenolic content. Chlorophyll extracts exhibited the highest antioxidant capacity, while the aqueous extracts prepared for the evaluation of total phenol content provided the poorest antioxidant properties.

Medicinal plants; Drying; Chlorophyll; Carotenoids; Polyphenols; Antioxidant capacity

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