Armeria maritima (Mill.) Willd. Flower Hydromethanolic Extract for Cucurbitaceae Fungal Diseases Control

Abstract

The cliff rose (Armeria maritima), like other halophytes, has a phenolics-based antioxidant system that allows it to grow in saline habitats. Provided that antioxidant properties are usually accompanied by antimicrobial activity, in this study we investigated the phytochemicals present in a hydromethanolic extract of A. maritima flowers and explored its antifungal potential. The main phytocompounds, identified by gas chromatography–mass spectrometry, were: hexadecanoic acid, octadecanoic acid, 9-octadecenoic acid, 3-(3,4-dihydroxy-phenyl)-acrylic acid ethyl ester, and benzeneacetaldehyde. The antifungal activity of the extract and its main constituents—alone and in combination with chitosan oligomers—was tested against six pathogenic taxa associated with soil-borne diseases of plant hosts in the family Cucurbitaceae: Fusarium equiseti, F. oxysporum f. sp. niveum, Macrophomina phaseolina, Neocosmospora falciformis, N. keratoplastica, and Sclerotinia sclerotiorum. In in vitro tests, EC90 effective concentrations in the 166−865 μg·mL−1 range were obtained for the chitosan oligomers–A. maritima extract conjugate complexes, lower than those obtained for fosetyl-Al and azoxystrobin synthetic fungicides tested for comparison purposes, and even outperforming mancozeb against F. equiseti. In ex situ tests against S. sclerotiorum conducted on artificially inoculated cucumber slices, full protection was achieved at a dose of 250 μg·mL−1. Thus, the reported results support the valorization of A. maritima as a source of biorationals for Cucurbitaceae pathogens protection, suitable for both organic and conventional agriculture.

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

“…and Perry, and Origanum syriacum L. (600 µg•mL −1 ) [78,79,82], and it is comparable to that of Silene uniflora Roth (1000 µg•mL −1 ) [73]. Against F. oxysporum spp., the activity is lower than those of Cestrum nocturnum L. ethyl acetate and methanol extracts (500 µg•mL −1 ) [89] and A. maritima extract (750 µg•mL −1 ) [44], and it is comparable to that of Cestrum nocturnum hexane and chloroform extracts (1000 µg•mL −1 ) [89]. As for S. sclerotiorum, higher activities have only been reported for A. maritima (375 µg•mL −1 ) [44] and for some C. nocturnum extracts (250-1000 µg•mL −1 ) [89], and a comparable activity has been reported for Zingiber officinale Roscoe essential oil (1000 µg•mL −1 ) [100].…”

“…When comparing the efficacy of E. serrata extract against other plant extracts tested against the four phytopathogens considered here (Table S1) [24,44,, it may be observed that the MIC values (750 µg•mL −1 against P. cichorii and 1000 µg•mL −1 against the three fungal taxa) are among the lowest reported to date. The antibacterial activity against P. cichorii is the highest among the plant extracts presented in Table S1, comparable to that of Ginkgo biloba L. [24].…”

“…Hexadecanoic acid (or palmitic acid), found as the major component in A. maritima [44], has been shown to be highly suitable for the integrated control of phytopathogens [49].…”

Chemical Constituents and Antimicrobial Activity of a Ganoderma lucidum (Curtis.) P. Karst. Aqueous Ammonia Extract

“…Willd. [ 28 ], Taxus baccata L. [ 29 ], and in small amounts in pomegranates, peas, cabbages [ 30 ], Foeniculum vulgare Mill. [ 31 ], and Landolphia owariensis Beauv.…”

Helichrysum stoechas (L.) Moench Inflorescence Extract for Tomato Disease Management

“…A more extensive comparison with the effectiveness of other tested plant extracts against the six fungi studied herein can be found in Table S1 [23,24,33,. However, caution should be exercised in comparing the results due to variations in isolates (or species, in the case of the genus Colletotrichum) across different studies.…”