Physicochemical Characterization of Crithmum maritimum L. and Daucus carota subsp. gummifer (Syme) Hook.fil. and Their Antimicrobial Activity against Apple Tree and Grapevine Phytopathogens

Abstract

Crithmum maritimum and Daucus carota subsp. gummifer are two species of the Apiaceae family that share multiple characteristics: both are halophitic, live on cliffs in the same geographic habitats, and are edible. While C. maritimum is rich in essential oils and flavonoids, D. carota is rich in terpenes and a gum producer. In the work presented herein, the biomass of these two wild plants and the bioactive compounds present in their extracts have been studied by elemental and thermal analysis, infrared spectroscopy, and gas chromatography-mass spectroscopy. To explore their bioactivities, both their hydroalcoholic extracts and their major constituents (apiole in C. maritimum and geranyl acetate in D. carota), either alone or in combination with chitosan oligomers, were assayed in vitro against bacterial and fungal pathogens that affect apple trees (Malus domestica) and grapevine (Vitis vinifera). Remarkable inhibition was observed against Erwinia amylovora, the causal agent of fire blight in apple; Xylophilus ampelinus [syn. Erwinia vitivora], the causal agent of bacterial blight of grapevine; and Diplodia seriata, a virulent pathogen of grapevines that also causes canker, leaf spot and fruit rot of apple. In view of their effectiveness against these three phytopathogens, a potential application of these two medicinal plants in organic farming may be envisaged.