Phytochemical Profiling of Sambucus nigra L. Flower and Leaf Extracts and Their Antimicrobial Potential against Almond Tree Pathogens

Abstract

Despite extensive research on the chemical composition of elderberries and their numerous uses in pharmaceutical, beverage, and food production, there is still a lack of knowledge about Sambucus nigra leaves and flowers’ antimicrobial activity against plant pathogens. In this study, the phytoconstituents of their aqueous ammonia extracts were first characterized by infrared spectroscopy and gas chromatography–mass spectrometry. The major phytocompounds identified in the flower extract were octyl 2-methylpropanoate; 3,5-dihydroxy-6-methyl-2,3-dihydropyran-4-one; propyl malonic acid; adenine; and 1-methyl-2-piperidinemethanol. Concerning the leaf extract, 1,6-anhydro-β-D-glucopyranose; oleic acid; 2,1,3-benzothiadiazole; 2,3-dihydro-benzofuran; and 4-((1E)-3-hydroxy-1-propenyl)-2-methoxyphenol and other phenol derivatives were the main constituents. The potential of the extracts to act as bioprotectants was then investigated against three almond tree pathogens: Diaporthe amygdali, Phytophthora megasperma, and Verticillium dahliae. In vitro tests showed higher activity of the flower extract, with EC90 values in the 241–984 μg·mL−1 range (depending on the pathogen) vs. 354–1322 μg·mL−1 for the leaf extract. In addition, the flower extract led to full protection against P. megasperma at a dose of 1875 μg·mL−1 in ex situ tests on artificially-infected excised almond stems. These inhibitory concentrations were lower than those of commercial fungicides. These findings suggest that S. nigra aerial organs may be susceptible to valorization as an alternative to synthetic fungicides for the protection of this important crop.

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.…”

“…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.)…”

Characterization, Antioxidant, and Antimicrobial Properties of Mulberry Lattices

“…aureus. In addition to the aforementioned secondary metabolites, there exists a reservoir of antimicrobial secondary metabolites present in the latex, including but not restricted to 1,6-anhydro-β- d -glucopyranose, hexadecanoic acid methyl ester, lupeol, lupeol acetate, and glutinol, which have also been documented to exhibit antimicrobial properties, as outlined in Table . − …”

Phytochemical Constituents and Antimicrobial Activity of Euphorbia serrata L. Extracts for Borago officinalis L. Crop Protection

“…It is also present in the extracts from Acalypha indica L., Ammannia baccifera L., Borassus flabellifer L., Camellia japonica L., Cocculus hirsutus (L.) Diels, C. sativus, Leucas aspera (Willd.) Link, Litchi chinensis Sonn., Marsilea quadrifolia L., Punica granatum L., Sambucus nigra L., and Rumex vesicarius L. [39][40][41]. Antibacterial activity has been demonstrated against Erwinia amylovora (Burrill 1882) Winslow et al, 1920) and Xylophilus ampelinus (Panagopoulos 1969) Willems et al, 1987 [39], and strong antifungal activity has been reported against Verticillium dahliae Kleb., Diaporthe amygdali (Delacr.)…”