Phytochemical diversity and antioxidant potential of four Egyptian Allium species

Abstract

Abstract Background Allium genus encompasses widely consumed vegetables including onion, Welsh onion, garlic, and leek which are known for their rich bioactive compound content. Methods In the present study, the total phenolic and flavonoid contents, vitamin composition, in addition antioxidant capacities of alcoholic extracts from four Egyptian Allium species: A. cepa (red onion), A. fistulosum (Welsh onion), A. sativum (garlic), and A. porrum (leek), were investigated. Standard spectrophotometric assays (Folin–Ciocalteu, aluminum chloride) and antioxidant assays (DPPH, ABTS, and FRAP) were employed. Results A. cepa exhibited the greatest total phenolic content (135.69 ± 1.89 mg GAE/g), while A. porrum showed the greatest flavonoid content (25.15 ± 0.52 mg RE/g). Vitamin profiling revealed A. fistulosum contained the highest levels of vitamin B6 and was the only species to contain vitamin C. Antioxidant activity varied by assay: A. fistulosum demonstrated the strongest DPPH and ABTS radical scavenging activities (4.37 ± 0.09 µg Eq/mg and 62.27 ± 2.86 µg Eq/mg, respectively), while A. porrum exhibited the highest reducing power in the FRAP assay (49.98 ± 1.76 µg Eq/mg). Conclusion These findings highlight the health-promoting potential of four Egyptian Allium species, supporting their inclusion into functional foods and nutraceuticals. Their high content of bioactive substances, particularly natural antioxidants and critical vitamins, makes them interesting candidates for dietary therapies to prevent oxidative stress-related illnesses. This study provides the first comprehensive comparative analysis of these four Allium species collected from Egypt, conducted under standardized extraction and analytical conditions, thereby offering new insights into their unique phytochemical composition and antioxidant profiles.