Advances in extracting bioactive constituents from Medicago sativa L. (Alfalfa): A systematic approach of green and conventional techniques

Abstract

Medicago sativa L. (alfalfa) is increasingly recognized as a rich source of health-promoting phytochemicals whose efficient, sustainable recovery remains technically challenging. This systematic review revises current extraction strategies and associated bioactive profiles, providing an evidence-based roadmap to obtain extracts valuable for the food, nutraceutical and pharmaceutical sectors. A PRISMA-guided search of PubMed, Scopus and Web of Science (literature up to March 2025) yielded 80 eligible studies. These investigations collectively report 124 distinct bioactive constituents-classified into 13 chemotypes (alkaloids, amino-acid derivatives, carbohydrates, carotenoids, coumarins, coumestans, flavonoids, phenolics, pigments, saponins, sterols, terpenoids and vitamins)-isolated from alfalfa leaves, stems, roots or seeds. Extraction technologies were grouped as conventional (maceration, Soxhlet, hydrodistillation) or innovative (ultrasound-, microwave-, enzyme-, pulsedelectric-field and supercritical-fluid-assisted methods). Meta-comparison shows that innovative technologies-particularly ultrasound-assisted extraction, supercritical COQ (with ethanol as co-solvent) achieves equal or superior yields of key flavonoids, phenolics and triterpene saponins while reducing solvent consumption (30-90 ), energy use (40-70 ) and thermal degradation relative to conventional techniques.