Effect of extraction method and particle size of plant material on the yield of bioactive compounds and antioxidant activity of aqueous extracts from Matricaria chamomilla L. flower

Chamomile ( Matricaria chamomilla L.) is a widely used medicinal herb valued for its rich essential oil content and a broad spectrum of bioactive compounds with confirmed pharmacological properties. This study investigated the effect of different aqueous extraction techniques, cold-brew, hot-water, ultrasound-assisted extraction (bath and probe), pressurized hot water extraction, and sample origin in combination with three particle size fractions (whole flowers, 10 mm, and 4 mm) on the phytochemical content, antioxidant activity of chamomile extracts, and chemical composition of essential oils. Pressurized hot water extraction exhibited the highest recovery not only in total phenolic content and antioxidant activity but also in the yield of individual phenolic compounds and coumarins, followed by conventional hot-water extraction. Cold-brew and ultrasound-assisted methods were markedly less efficient for all evaluated parameters. Chlorogenic acid was determined as the dominant compound, with its concentration increasing with both temperature and decreasing particle sizes. In contrast, apigenin-7-glucoside exhibited an inverse trend; its yield decreased with fragmentation of the plant matrix. While the chemical composition of water chamomile extracts was strongly influenced by both sample origin and particle sizes, the particle size of the sample had minimal impact on the chemical profiling of chamomile essential oils, as revealed by multivariate statistics. The obtained results provide an applied perspective for the development of chamomile-derived products, emphasizing the need to align extraction technology and raw material quality to achieve reproducible phytochemical composition and biological efficiency. • Extraction conditions and particle size affect chamomile phytochemical profiles • Finer particle size increases chlorogenic acid content, decreases apigenin-7-glucoside • PCA shows distinct profiles in aqueous extracts of whole vs. processed samples • Essential oil composition depends mainly on sample origin rather than fragmentation