Biological functions of garlic (Allium sativum l.) and its active compounds against pathogens

Garlic (Allium sativum L.), a globally cultivated plant with significant medicinal and culinary value, contains over 200 bioactive compounds, including allicin, organosulfur compounds, phenolic compounds, vitamins, and minerals. These components contribute to its diverse biological activities, such as antioxidant, cardio-protective, anti-cancer, anti-inflammatory, immunomodulatory, anti-diabetic, and antimicrobial properties. Allicin, the primary active compound, exhibits broad-spectrum antimicrobial activity by inhibiting essential enzymes and disrupting pathogen membranes through thiol group interactions. This study reviews antifungal, antibacterial, and antiviral effects of garlic against pathogens. Garlic extracts demonstrate efficacy against human pathogenic fungi like Aspergillus, Candida, and Cryptococcus, as well as plant pathogens such as Fusarium oxysporum and Botrytis cinerea. Its antibacterial activity targets both gram-positive (Staphylococcus aureus) and gram-negative bacteria (Escherichia coli), with differential susceptibility due to variations in bacterial membrane composition. Moreover, garlic shows potential in controlling postharvest diseases and seed-borne bacteria like Ralstonia solanacearum. The antiviral properties of garlic, particularly its ability to interact with viral phospholipids, highlight its role in combating infectious diseases. Modern extraction techniques, such as ultrasound-assisted extraction and supercritical fluid extraction, enhance the yield and stability of bioactive compounds. Overall, garlic represents a versatile natural resource with immense therapeutic and agricultural applications. Continued research into its bioactive compounds will further optimize its use in medicine and sustainable agriculture.