Phytochemical insights and cytotoxicity on colon cancer cells of unisexual flower extracts from Ceratonia siliqua L. (Fabaceae)

Ceratonia siliqua L. (carob) is an evergreen tree from the Fabaceae family, native to the Mediterranean and cultivated for its economic value [ 1 ]. The species is dioecious, with male and female flowers on separate plants, though hermaphroditic individuals exist. While the fruits are known for their polyphenol, flavonoid, carbohydrate, mineral, and protein content, the chemical composition of the flowers remains less explored [ 2 ]. This study assessed the phytochemical profile of two alcoholic extracts from female (FF) and male (MF) flowers of C. siliqua using UPLC/ESI/TQ-MS, evaluating their total polyphenol and flavonoid content, antioxidant properties, and cytotoxicity on healthy and cancerous cells. The analysis revealed a higher polyphenol than flavonoid content, with qualitative and quantitative differences between extracts. MF exhibited significantly higher levels of polyphenols, gallotannins, and flavonoids, identifying 13 phenolic compounds compared to 7 in FF, including 2-digalloyl hexose, gallic acid, and quercetin. Antioxidant activity was confirmed through DPPH, SOD-like, and Catalase-like assays, with FF showing higher Catalase-like and MF higher SOD-like activity. MTT tests demonstrated the extracts’ safety on normal cells (HFF-1) and a dose-dependent cytotoxicity against cancer cells (CaCo-2). LDH release tests excluded necrosis as the primary cause of cell death. ROS and RSH level analysis indicated a 30-35% reduction in RSH content, suggesting glutathione depletion and cell cycle alteration. For the first time, this study demonstrates that carob flowers are a source of phenolic compounds with antioxidant and cytotoxic activities, potentially mediated by GSH depletion. These findings support further research into the therapeutic potential of C. siliqua flower polyphenols. Publication History Article published online: 05 March 2026 © 2026. Thieme. All rights reserved. Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany