Eudesmane Sesquiterpenes from Verbesina lanata with Inhibitory Activity against Grapevine Downy Mildew

Abstract

An in-house library of more than 3000 extracts of plant and fungal origin was screened against some major plant pathogens. As one of the hits, an ethyl acetate extract from inflorescences of Verbesina lanata showed significant inhibitory activity in vitro against grapevine downy mildew (Plasmopara viticola), with a MIC value of 35 μg/mL. An emulsifiable concentrate formulation with 50 mg/g of the extract was developed for in vivo evaluation. A suspension of the formulation containing 1 mg/mL of extract lowered leaf surface infection of grapevine seedling by 82% compared to the nontreated control. With the aid of HPLC-based activity profiling, the antifungal activity was correlated with a series of lipophilic compounds. Preparative isolation by a combination of chromatographic techniques afforded 16 eudesmane sesquiterpenes including eight new congeners. Nine compounds were obtained in sufficient quantities to be tested in vitro and were found to inhibit the zoospore activity of P. viticola with MIC values ranging from 4 to 50 μg/mL. The two major compounds, 6β-cinnamoyloxy-4β,9β,15-trihydroxyeudesmane (9) and 6β-cinnamoyloxy-1β,15-dihydroxyeudesm-4-en-3-one (13), showed MIC values of 5 and 31 μg/mL, respectively.

Composition, Antioxidant Potential, and Antimicrobial Activity of Helichrysum plicatum DC. Various Extracts

“…Compound Class/Name EE DCME ACNE helichrysoside [51] + quercetin [40] + + tiliroside [52] + tiliroside analog [52] + kaempferol [41] + chalcone arenariumoside V [53], arenariumoside VI [53], arenariumoside VII [53] + tomoroside A [53] + isosalipurposide [40] + helilupolone [54] + Terpenoid sesquiterpenoid sesquiterpene derivative [55][56][57] + sesquiterpene derivative [55][56][57] + sesquiterpene derivative [58][59][60] + sesquiterpene derivative [61,62] + sesquiterpene derivative [62][63][64] + eudesmane derivative [65] + sesquiterpene derivative [66][67][68] + sesquiterpene derivative [66][67][68] + ainsliaside E [69] + cinnamoyloxy-hydroxyeudesmane [70] + athrolide C [71] + + athrolide D [71] + diterpenoid diterpene derivative [30,72] + 8-(acetyloxy)-3-ethenyloctahydro-10-hydroxy-3,4a,7,7,10a-pentamethyl-1H-naphtho[2,1-b]pyran-2,5(3H,4aH)-dione [72] + (7-ethenyl-1,2,3,4,4a,4b,5,6,7,8,10,10a-dodecahydro-1,4a,7-trimethyl-1-phenanthrenyl)methyl-butanedioic acid methyl ester [72] + ent-kaurane derivative [73] + gymnospermin …”

Suppressive Activity of Glechoma hederacea Extracts against the Phytopathogenic Oomycete Plasmopara viticola, and First Screening of the Active Metabolites

“…Other studies highlighted disease severity reduction above 90% on leaf discs with plant extracts and essential oils obtained from different species such as Artemisia absinthium, Equisetum arvense, Frangula alnus, Glycyrrhiza glabra, Melaleuca alternifolia, Picea abies, Quillaia saponaria, Rheum palmatum, Salix alba and Yucca schidigera [14][15][16][17][18][19][20]. Moreover, Inga sapindoides, Juncus effusus, Larix sibirica, Oreganum vulgare, Pinus sylvestris, Solidago canadensis and Verbesina lanata plant extracts have been successfully tested in greenhouse-cultivated seedlings, with plant protection efficacy above 80% [21][22][23][24][25].…”

Assessment of different strategies to reduce environmental fungicide contamination in vineyards

“…The majority (48.6%) were other products, such as botanical extracts (Dagostin et al, 2010;Ramseyer et al, 2017;Thuerig et al, 2016;Thuerig, James, et al, 2018;Thuerig, Ramseyer, et al, 2018). Many of the respondents (48.0%) thought that the composition and dosage information on biopesticide labels was insufficient for proper use.…”