Table 1.

Protective effects of onion and its main constituents against natural agents induced toxicity

Agent	Type of toxicity	Type of study	Study design and dose of garlic/ garlic component evaluated	Effect demonstrated	References
Aflatoxin	Heart, liver, and kidney toxicities	In-vivo, male Sprague-Dawley rats	Ethanolic onion extract (2 weeks, 5 mg/kg, p.o.)	The protective role of these extracts may be due to their rich content of organosulfur compounds, which act as a precursor of GSH, which conjugates with aflatoxin-epoxide and results in the inhibition of epoxide binding to DNA	(31)
Clostridium botulinium	-	In-vitro, Meat slurry	onion oil (45 mg) was dissolved in miglyol to a final volume of 1.0 mL	Onion oil reduces Toxin concentration produced in meat slurry systems by C. botulinum type A, B, and C	(33)
Clostridium difficile	Cell toxicity	In-vitro, the Vero (African green monkey kidney) and HT-29 (human colon carcinoma)	Fresh onion bulb extract	Fresh onion bulb extracts reduced toxin production and activity significantly.	(34)
Nicotine	Lung toxicity	In-vivo, Sprague-Dawley adult male albino rats	Onion extract (18 weeks, p.o.)	Antioxidative and anti-lipid peroxidative mechanisms.	(14)
LPS	Bone marrow toxicity	In-vitro, MC3T3-E1 cells,	Quercetin	Restored LPS-suppressed bone mineralization and the mRNA and protein expression levels of osteoblast-specific genes such as Osterix (OSX), runt-related transcription factor 2 (Runx2), alkaline phosphatase (ALP) and osteocalcin (OCN)	(21)
LPS	Cell toxicity	In-vitro, BV-2 microglial cells, N27-A cells	Methanol extract of onion	Onion extract takes protective action against LPS and MPP+, and upregulates the antioxidant enzymes that could potentially be used in the therapy of neurodegenerative diseases	(41)
N. n. karachiensis toxin	Hematotoxicity	In-vitro , hen’s egg yolk mixture	Ethanolic onion extract (0.1 to 0.6 mg/mL)	Neutralize snake venom proteins due to the abundance of miscellaneous secondary metabolites.	(35)
N. n. karachiensis toxin	Heart, liver, kidney, and musculoskeletal toxicities	In-vivo, male rabbits	Ethanolic onion extract (100 mg/kg, sc)	Secondary metabolites pose a hindrance in the binding of different snake venom enzymes to their potential targets.	(36)
N. n. karachiensis toxin	Hematotoxicity	In-vitro	Methanolic onion extract	Secondary metabolites created disturbances in binding of 5í-nucleotidases to their receptor(s), therefore resulted in the recovery of different toxicities.	(39)
N. n. karachiensis toxin	Hematotoxicity	In-vitro, hen’s egg yolk mixture	Ethanolic onion extract (0.1 to 0.6 mg/mL)	Neutralize snake venom proteins due to the abundance of miscellaneous secondary metabolites.	(37)
Histamine	Gastrointestinal toxicity	In-vivo, rats	allylsulfide, allyldisulfide and quercetin	By inhibition of gastric secretion stimulation effect of histamine.	(42)