Evaluation of basil essential oils for antifungal and anti-aflatoxigenic activity against Aspergillus flavus

Essential oils of basil herbs such as nyazbo or sweet basil (Ocimum basilicum), holy basil or tulsi (O. tenuiflorum), and African or clove basil (O. gratissimum) have traditionally been used for their therapeutic potential. These medicinal herbs are being cultivated and consumed globally, and the increasing demand for antimicrobial and antifungal natural products has led to the assessment of the potential of essential oils of medicinal plants to inhibit mycelial growth rather than synthetic fungicides. Thus, the present study explored natural alternatives to inhibit mycelial growth (Aspergilus flavus) and aflatoxin production. Linalool (25.40%), methyl chavicol (37.63%), and eugenol (39.52%) were identified as chief compounds in the EOs of O. basilicum, O. tenuiflorum, and O. gratissimum respectively. Ocimum tenuiflorum EO demonstrated the highest inhibitory activity at 0.75 µL mL^{- 1} against Aspergillus flavus and totally inhibited the synthesis of aflatoxin B₁ (AFB₁). The AFB₂ production was completely inhibited at 0.25 µL mL^{- 1} by O. tenuiflorum EO, while O. basilicum and O. gratissimum EOs showed inhibition against AFB₂ at 0.50 µL mL^{- 1}, and 1.0 µL mL^{- 1}, respectively. The present study suggests that EOs of basil herbs could be a potential natural alternative of synthetic fungicides to inhibit the fungal growth and aflatoxin production.