Agro-morphological yield-attributed traits, essential oil content, phytochemical composition, and biological activities of some Medicago species

Medicago species (Fabaceae) have garnered significant interest due to their rich array of natural phytochemicals, i.e. saponins, phenolics, and tannins, which exhibit a diverse range of medicinal and biological properties, including the ability to lower blood sugar and fat levels, as well as possessing antimicrobial, antioxidant, and anticancer effects. This study investigated various agro-morphological yield-attributed traits, essential oil characteristics, content of pigments, total triterpene saponins, condensed tannin, total phenolic, and total flavonoids, and biological activity of the three cultivated populations of six Medicago species collected across Iran. The highest fresh (1044.15 ± 5.35–1153.38 ± 2.61 g/m2) and dry (199.60 ± 1.71–274.48 ± 2.24 g/m2) weight and leaf area index (4.61 ± 0.21–5.83 ± 0.52) were measured in the cultivated populations of M. sativa. The essential oil content ranged from 0.02% to 0.17% (w/w) among the studied samples. A total of 26 chemical compounds 96.08‒99.90% of the essential oils were identified. n-Nonanal (52.21‒66.50%), dimethoxy-(E)-citral (5.22‒7.93%), terpinen-4-ol (1.55‒6.98%), citronellol (4.13‒6.78%), and α-terpineol (2.13‒4.89%) were the major components. Positive and negative significant correlation of antioxidant activity (DPPH and FRAP) (p < 0.01) with total anthocyanin (r = –0.57, r = 0.72), triterpene saponin (r = –0.75, r = 0.81), total phenolic (r = –0.90, r = 0.97), and total flavonoid content (r = –0.87, r = 0.86) were obtained. The highest antibacterial and antifungal activities of the EOs were obtained against Staphylococcus aureus (MIC: 0.062 mg/ml) and Candida glabrata (MIC: < 0.016 mg/ml), respectively. The results demonstrated the superior growth characteristics, valuable phytochemical compositions, and strong biological activities of the studied cultivated populations of Medicago. In general, populations of M. phrygia, M. monspeliaca, and M. sativa are distinguished as promising candidates for further exploitation in breeding and production programs aimed at improving both agricultural productivity and pharmaceutical applications, as well as exploring innovative applications in food safety and pest management.