Truffles are consumed worldwide as a type of precious food. Desert truffles are characterized by their growth under extreme soil and climate conditions. They have numerous nutritional and medicinal applications. Desert truffles have been shown to exhibit various biological activities. During the present work, we identified two truffle types collected from Riyadh Province, Kingdom of Saudi Arabia, as Tirmania nivea and Terfezia claveryi. Their extracts showed significant antimicrobial activity against Bacillus subtilis, while the activity was less obvious against Escherichia coli. Hexane and ethyl acetate extracts of both types showed a dose-dependent effect against MCF-7 cancer cells, where their highest toxicities ranged from 91-93%. The lowest effective IC 50 values were 378.9±0.96 and 215.8±0.92 μg/mL for T. nivea and T. claveryi, respectively
