Extraction of Bioactive Compounds from Aegean Plant Byproducts

Plant byproduct and herb samples were collected from Lemnos Island, North Aegean, Greece, between June and October 2021. The samples consisted of bitter byproducts from orange (Citrus aurantium) peel (n = 5), lemon (Citrus limon) peel (n = 5), rosehip (Rosa canina) seed (n = 5), as well as mountain tea (Sideritis spp.) (n = 10), St. John’s wort (Hypericum perforatum) (n = 10), dittany (Origanum dictamnus) (n = 5), pennyroyal (Mentha pulegium L.) (n = 10), lemon balm (Melissa oficinallis) (n = 5), spearmint (Mentha spicata L.) (n = 10), and lavender (Lavandula angustifolia) (n = 5). At least 5 samples were used from each food product and pooled together. All samples were dried in a drying heating oven (Binder GmbH, Tuttlingen, Germany) at 60 °C for 12 h and kept in sealed bags until extract preparation.
Extracts were prepared by adding in a flask 2 g of each herb or 10 g of each plant byproduct to 100 mL of dH₂O. Each flask was then placed in an Elmasonic P 70 H ultrasound water bath (Elma-Hans Schmidbauer GmbH & Co., Singen, Germany) at 70 °C and 80 Hz for 60 min. Filtration of the extracts was performed by filter paper.