Antimicrobial activity against pathogenic microorganisms by extracts from herbal Jordanian plants

The aim was to study antimicrobial activity of a group of herbal medicinal plants, including Achillea biebersteinii, Phlomis viscosa, Ainworthia trachycarpa, Solanum elaeagnifolium, Arum hygrophilum, Varthemia iphionoides, Crupina crupinastrum, Teucrium polium, Achillea santolina, Micromeria nervosa, Chenopodium murate, Ballota philistaea, Onosma roussaei, Fagonia mollis, Marrubium vulgare, Calotropis procera, Salvia hierosolymitana, Ballota undulata, Hallogeton alopecuroides, Scrophularia hierochuntica and Nonea melanocarpa, grown in Jordan. The tested medicinal plants showed different antimicrobial activity in different extract amounts (5, 10, 15, 20, 40, 60, 80 and 100 ppm) against the tested microorganisms. Minimum inhibition concentration (MIC) and the diameter of inhibition zone (DIZ) were determined by in vitro bioassays using hole-plate diffusion method against two bacterial species, Staphylococcus aureus and Pseudomonas aeruginosa, and one fungi, Candida albicans. Extracts of most tested plants, except Arum hygrophilum and Micromeria nervosa, showed antimicrobial activity against some of the tested microorganisms. The antimicrobial activity was highest in Crupina crupinastrum extract (5, 10, 15, 20, 40 and 60 ppm) which gave the largest inhibition zone (DIZ 24 mm) at 60 ppm followed by the extracts from Achillea biebersteinii with highest effect at 60 ppm (DIZ 18 mm). This study shed the light on the antimicrobial ability of extracts from Jordanian medicinal plants, which can be used as natural antimicrobial agents in pharmaceutical and food preservation systems.