Abstract

Resistance to current antibacterial drugs and the rise of opportunistic fungal infections are growing global concerns. Traditional medicine is a potential source of new antibacterials and antifungals. Citrullus colocynthis Schrad (Cucurbitaceae) endemic in Southern Iran is used in folk medicine against dermatological, gynaecological and pulmonary infections. To assess in vitro antibacterial and anticandidal activity of aqueous and diluted acetone extracts of C. colocynthisSchrad. MIC and MBC/MFC were determined for plant organs at different maturation stages. C. colocynthis Schrad. was harvested and its identification was verified. Aqueous and diluted acetone extracts (from the plant’s roots, stems, leaves and three maturation stages of its fruit and seeds) were screened for activity against Gram-negative and Gram-positive bacteria (Escherichia coli,Pseudomonas aeruginosa, Staphylococcus aureus and Enterococcus faecalis) and various Candida spp. (Candida glabrata, Candida albicans, Candida parapsilosis and Candida kreusei). All extracts showed activity against all strains. The highest MICs and MBCs/MFCs were obtained from the fruit aqueous extracts (MIC 0.10 mg/ml against C. albicans and C. glabrata, 0.20 mg/ml against E. coliand P. aeruginosa), lowest activity from the root extracts. C. colocynthis Schrad shows antibacterial and anticandidal properties. The folk medicinal use as a broad-spectrum antimicrobial agent is validated.

Key words: Citrullus colocynthis Schrad, aqueous extract, acetone extract, antibacterial, anticandidal, Iran.