Phytochemical Screening and Antibacterial Activity of Taxus baccata L. against Pectobacterium spp. and Dickeya chrysanthemi

Abstract

The yew tree (Taxus baccata L.) is considered in folklore a symbol of immortality due to its qualities of longevity and regeneration. Despite its poisonous reputation, the yew tree has a long history of medicinal use, particularly in the form of extracts from its leaves and bark. In the work presented herein, gas chromatography–mass spectrometry (GC–MS) chemical profiling was applied to the aqueous ammonia/hydromethanolic extracts of several plant organs of T. baccata, leading to the identification of different bioactive compounds than those previously characterized by high-performance liquid chromatography with tandem mass spectrometry (HPLC–MS/MS) in other extraction media. The leaf aqueous ammonia extract was rich in 2-hexylthiophene and 3-O-methyl-d-fructose; 9-octadecenoic and hexadecanoic acid were the main constituents of the bark aqueous ammonia extract; and the fruit hydromethanolic extract contained methyl 2-O-methyl-α-d-xylofuranoside, 1,3-dioxolane derivatives, and erysimoside. The antimicrobial activity of the extracts was assayed against four bacterial pathogens responsible for the soft rot and blackleg diseases of potatoes, viz. Pectobacterium carotovorum subsp. carotovorum, Pectobacterium atrosepticum, Pectobacterium parmentieri, and Dickeya chrysanthemi, resulting in minimum inhibitory concentration (MIC) values as low as 187 μg·mL−1. Bioassays on potato slices confirmed the efficacy of the leaf extract at this dose when applied as a preventive treatment before artificial inoculation with P. carotovorum subsp. carotovorum. In view of this high activity, these extracts may find application in the integrated pest management of soft rot Pectobacteriaceae (SRP) diseases.

Antibacterial Activity of Ginkgo biloba Extracts against Clavibacter michiganensis subsp. michiganensis, Pseudomonas spp., and Xanthomonas vesicatoria

“…The presence of catechol should be attributed to the rupture of catechin (a constituent identified by Lin et al [6] in the G. biloba leaves aqueous methanol extract) (Figure 2). Catechol had previously been identified in the extracts of Taxus baccata L. [31], Allium sativum L. [32], Sambucus nigra L. [33], and Quercus ilex L. [34], with concentrations ranging from 1.6 to 6.4% (compared to 3.3−7.9% in the extracts reported herein). Catechol oxidizes to melanoid pigments that are derivatives of benzoquinone, which is reported to have antimicrobial properties, slowing the decay of damaged fruits and other parts of plants.…”

“…[50]; and 2-O-methyl-α-D-xylofuranoside has been reported in Alternanthera sessilis (L.) DC. [51] and T. baccata [31]. Additionally, 3-methylmannoside has been found in Psidium guajava L. [52].…”

“…1-hydroxy-2-propanone is an alpha-hydroxy ketone found, for instance, in T. baccata leaf aqueous ammonia extracts [31]. Hydroxyacetone has also been detected, but not quantified, in several different edible plants, such as black cabbages, pulses, mentha, onion family vegetables, and rape.…”

“…2,3-dihydro-3,5-dihydroxy-6-methyl-4H-pyran-4-one was identified in Hibiscus syriacus L. [39], S. nigra [33], Punica granatum L. [40], and T. baccata [31]. In terms of antifungal activity, it is effective against Phytophthora megasperma Drechsler, Verticillium dahliae Kleb., and Diaporthe amygdali (Delacr.)…”

“…3-O-methyl-D-fructose has been found to be present in Ichnocarpus frutescens (L.) W.T.Aiton [48] and in T. baccata [31], and reports have indicated its antibacterial activity [49]; 4,6-di-methyl-α-D-galactose has been found in the Siberian ginseng Eleutherococcus senticosus (Rupr. & Maxim.)…”