Bioactive Constituents of Ceratonia siliqua L.: Biological Activities and Emerging Extraction Technologies — A Critical Comprehensive Review

Carob (Ceratonia siliqua L.) is a Mediterranean leguminous tree valued for its pods, leaves, and seeds, which are rich in bioactive compounds with nutritional and therapeutic potential. Despite extensive research on carob phytochemicals, a critical gap persists in the systematic evaluation and comparison of extraction techniques in terms of efficiency, selectivity, and industrial applicability. This review aims to provide a comprehensive and critical assessment of both conventional and emerging extraction methods for recovering these bioactive compounds. Traditional solvent-based methods, including aqueous and organic extractions, remain widely used due to their simplicity and efficiency. However, they are often limited by long processing times, high solvent consumption, and the potential degradation of thermolabile compounds. In contrast, emerging extraction technologies such as ultrasound-assisted extraction, microwave-assisted extraction, and supercritical fluid extraction have shown improved selectivity, higher extraction yield, and better compound stability, while reducing environmental impact. Comparative analyses indicate that extraction efficiency, including quantitative yield and bioactivity, strongly depends on both the plant part and extraction parameters. This review addresses the lack of integrated comparisons by emphasizing the importance of matrix-specific optimization strategies. It concludes that developing adaptable, scalable, and cost-effective extraction processes is essential to ensure reproducibility and facilitate the industrial application of carob-derived bioactives in food, pharmaceutical, and cosmetic sectors.