Antimicrobial efficacy of extracts of Saudi Arabian desert Terfezia claveryi truffles

BACKGROUND: Terfezia claveryi truffles are known for their nutritional value and have been considered among traditional treatments for ophthalmic infections and ailments. OBJECTIVES: We sought to investigate the in vitro antimicrobial efficacy of several T. claveryi extracts from Saudi Arabia. Certain pathogenic fungi and gram-negative and gram-positive bacteria were included. METHODS: Dry extracts were prepared using methanol, ethyl acetate, and distilled water, while the latter was used for preparing fresh extracts. The extracts were microbiologically evaluated through the disc-diffusion agar method; the zones of inhibition of microbial growth were measured post-incubation. The minimum bactericidal concentration (MBC) and minimum inhibitory concentration (MIC) were determined in Müller-Hinton Broth through the microdilution susceptibility method. anti-biofilm activity was assessed for potent extracts. RESULTS: Dry extracts showed potent activity (>16-mm inhibition zones) against gram-positive (Bacillus subtilis IFO3007 and Staphylococcus aureus IFO3060) and gram-negative (Pseudomonas aeruginosa IFO3448 and Escherichia coli IFO3301) bacteria. The activity against fungi was moderate (12–16-mm inhibition zones) for both Aspergillus oryzae IFO4177 and Candida albicans IFO0583; there was no activity against Aspergillus niger IFO4414 growth. Methanolic extract had the lowest MIC and MBC, exhibiting remarkable activity against B. subtilis growth. Fresh extract showed moderate activity against bacterial growth and inactivity against fungal growth. Methanolic extract showed potent anti-biofilm activity (IC(50), 2.0 ± 0.18 mg/mL) against S. aureus. CONCLUSIONS: T. claveryi extracts showed antibacterial effects potentially suitable for clinical application, which warrants further in-depth analysis of their individual isolated compounds.