Table 5.

Biological activities, toxicology, and side effects of Monoterpenes present in Ocimum tenuiflorum.

Secondary metabolites	Biological activities	Toxicology and side effect	References
α-Pinene	• Antibacterial activity • Antifungal activity • Antileishmania activity • Anti-inflammatory activity • Neuroprotective activity • Antiapoptotic activity • Antitumor activity, insecticidal activity	• At 200 μg/mL, BEAS-2B cellular viability decreased • Respiratory and skin irritation	[131–133]
Limonene	• Antibacterial activity • Antioxidant effect • Antidiabetic activity • Anti-inflammatory effect • Anticancer effect • Gastroprotective effect • Antistress effect	• Skin and eye irritation	[134–140]
Estragole	• Anti-inflammatory • Antioxidant • Antibacterial activity	• Genotoxic carcinogen • Hepatocellular adenoma	[141, 142]
Eugenol	• Antioxidant • Antibacterial activity • Anti-inflammatory activity	• LD50 value > 1930 mg·kg−1 in rodents • Excess use may cause vomiting, gastroenteritis, and systemic toxicity • May cause liver and kidney damage • Seizures • Coma • Bronchial irritation • Dizziness • Rapid breathing	[143–147]
Terpineol	• Antioxidant activity • Anticancer activity • Anticonvulsant activity • Insecticidal activity • Antiulcer activity	• Mild skin irritation or dermatologic allergic response • Eye irritation • Respiratory irritation • Skin irritation • Germ cell mutagenicity • Carcinogenicity, reproductive toxicity	[148, 149]