In vitro synergism of concentrated Allium sativum extract and amphotericin B against Cryptococcus neoformans

Allium sativum (garlic) derived preparations are used alone or with amphotericin B in Asia to treat human systemic fungal infections and cryptococcal meningitis. To evaluate the scientific merit of using allicin-derived compounds as an anti-fungal drug, we prepared a concentrated A. sativum extract that contained 34% allicin, 44% total thiosulfinates, and 20% vinyldithiins. We found that the concentrated extract possessed potent in vitro fungistatic and fungicidal activity against 3 different isolates of Cryptococcus neoformans. The minimum inhibitory concentration of the concentrated garlic extract against 1 x 10(5) organisms of C. neoformans ranged from 6 to 12 micrograms/ml. In addition, in vitro synergistic fungistatic activity with amphotericin B was demonstrated against all isolates of C. neoformans. This study lends laboratory support for the treatment of cryptococcal infections with concentrated garlic extracts.