Antimicrobial activity of various extracts from some plants native to Alqassim Region,Saudi Arabia

摘要

Crude extracts of 21 plant species were screened for their antimicrobial activity. Described standard methods were used to prepare plant extracts and to determine their phytoconstituents (PCs). The antimicrobial activity was determined using agar discdiffusion and broth dilution methods. Microorganisms tested were ATCC strains: Pseudomonas aeruginosa, Klebsiella pneumoniae, Escherichia coli, Staphylococcus aureus, Candida albicans and Aspergillus brasiliensis. Commercial antibiotic discs were used as references. The PCs detected were phenolics and flavonoids, followed by saponins. Most active plants against bacteria were Artemisia herba-alba, Rhanterium epapposum and Achillea fragrantissima, while against A. brasiliensis was Deverra triradiata andagainst C. albicans were Moltkiopsis ciliata, D. triradiata and Echinops spinosus; minimum inhibitory concentration range was 0.153 - 0.937 mg/ml and zones of growth inhibition 7 - 22 mm (100 pg/disc). Diameters of all inhibition zones were less than those of reference antibiotics, except for methanolic extract of D. triradiata against A. brasiliensis, which performed better than nystatin. The presence of PCs was found moderately correlated with antimicrobial performance. These findings provide justification for searching antimicrobials in these plants, especially in D. triradiata against fungi.