Phytochemical Screening and In Vitro Antifungal Activity of Several Moroccan Medicinal Plants against Penicillium italicum, the Causal Agent of Citrus Blue Mold

The aim of this study was to evaluate the antifungal activity of 50 plant species, harvested in different regions of southern Morocco, against Penicillium italicum, the causal agent of citrus blue mold. The in vitro antifungal activity of plant tissue powder was determined using the agar plate method. Our results showed that among the 50 plants tested, the tissue powder of Anvillea radiata and Thymus leptobotrys plants completely inhibited mycelial growth of P. italicum at a concentration of 10% (w/v). Furthermore, the tissue powder of Asteriscus graveolens, Bubonium odorum, Ighermia pinifolia, Inula viscosa, Halimium umbellatum, Hammada scoparia, Rubus ulmifolius, Sanguisorba minor and Ceratonia siliqua plants were also effective against P. italicum with more than 75% inhibition of the mycelial growth. The effect of plant aqueous extracts on spore germination and germ tube elongation varied significantly (P<0.05) between tested plants. Aqueous extracts from A. graveolens, B. odorum and H. umbellatum totally inhibited germination and germ tube elongation of P. italicum conidia at a concentration of 10 mg/ml. Phytochemical analysis of plants with more than 75% inhibitory effect showed the presence of antimicrobial active compounds such as alkaloids, flavonoids, terpenoids, coumarins, tannins and saponosids. These results indicate that these plants contained compounds with antifungal potential against P. italicum. These natural products represent a sustainable alternative to the use of chemical pesticides.