Effects of organic and conventional production systems on the content of bioactive substances in four species of medicinal plants

This paper aimed to compare the content of compounds with antioxidant properties in four species of medicinal plants, rosemary, peppermint, lemon balm and sage grown under organic and conventional conditions in 2 consecutive years. The dry matter and vitamin C content was determined according to Polish Standards; carotenoids and polyphenols were analysed by high-performance liquid chromatography. Organic medicinal plants contained significantly more dry matter, vitamin C, phenolic acids and total flavonoids than the plants from conventional production. On the other hand, conventional plants contained significantly more carotenoids than the organic ones. A high content of beneficial bioactive compounds in medicinal plants, especially coming from organic farming, is an important prerequisite for their use in a healthy diet.