Antifungal Polyamides of Hydroxycinnamic Acids from Sunflower Bee Pollen

Abstract

The aim of the bioassay-guided fractionation was the selection of the most potent group of compounds responsible for the protection of sunflower bee pollen grains. Synthesis of prospective antifungal polyamides of hydroxycinnamic acids was based on previous structural elucidation of ethanol soluble fraction by 1H,1H-PFG-COSY, 1H,13C-HSQC, FT-IR, FT-Raman, and LC–MS experiments. The main compounds found were tri-p-coumaroylspermidines accompanied by other HCAA of spermidine and putrescine. Several model HCAA derivatives were prepared to test their antifungal activity against widespread spoilage fungi (A. niger 42 CCM 8189, F. culmorum DMF 0103, and P. verrucosum DMF 0023). A. niger CCM 8189 and F. culmorum DMF 0103 exhibited higher resistance to the antifungal effects of hydroxycinnamic acid amides, whereas P. verrucosum DMF 0023 was the most sensitive strain. It has been discovered the effect of HCAA polarity on the role of secondary metabolites in the microbial protection of pollen grains. The combination of bioassay-guided fractionation, structural elucidation, selection of prospective compounds, and their synthesis to determine their antifungal properties could be considered as an original approach.

Phenolamides in plants: an update on their function, regulation, and origin of their biosynthetic enzymes

“…Experiments done in vitro with phenolamides extracted and partially purified from bee pollen evidenced the putative role of these molecules in oxidative stress protection (Zhang et al, 2020). Additionally, some antifungal properties were also reported for phenolamides accumulated at the surface of sunflower pollen (Kyselka et al, 2018). In addition, by comparison to phenolamides accumulated in other parts of the plant (see below), multiple roles have been tentatively assigned to their accumulation in the pollen coat, such as protection against abiotic or biotic stress (desiccation resistance, antifungal activity, insect interaction, antimicrobial activity), function in the stigma-pollen interaction, and pollen germination (Grienenberger et al, 2009;Elejalde-Palmett et al, 2015;Fellenberg and Vogt, 2015;Delporte et al, 2018;Vogt, 2018).…”

“…Consequently, most obtained accessions might be false positives, and conclusions on a wide distribution of HvACT clusters outside Monocotyledons are speculative. Since putrescine based phenolamides were reported outside Solanaceae, among Eudicotyledons (Martintanguy et al, 1978;Negrel, 1989;Kyselka et al, 2018;Elejalde-Palmett et al, 2015), their synthesis could also involve HvACT orthologues or any other Nhydroxycinnamoyltransferase clusters, such as NaDH29, AtSDT, Os12g27220, or one that is still unidentified.…”

Clovamide, a Hydroxycinnamic Acid Amide, Is a Resistance Factor Against Phytophthora spp. in Theobroma cacao

“…HCAAs typically form via the amide condensation of hydroxycinnamoyl-CoA thioesters and amines (Bontpart et al, 2015;Petersen, 2016). They contribute to stress tolerance in numerous plant species due to their high antioxidant activity (Zacares et al, 2007), cell wall reinforcing properties (Gunnaiah et al, 2012), or direct antimicrobial activity (Newman et al, 2001;Kyselka et al, 2018). The role of HCAAs in defense is supported by in vivo evidence.…”

Bee breads from two regions of Eastern Ukraine: composition, physical properties and biological activities

“…In the case of FT MIR, the KBr tablets containing bee bread samples made using hand press (Pike, USA) were prepared for the measurements; 64 scans were accumulated with a spectral resolution of 2 cm -1 . In the case of FT NIR, the measurement was made in glass cuvettes using rotation equipment; 100 scans were accumulated with a spectral resolution of 4 cm -1 (Kyselka et al 2018). FT Raman spectra (4000-100 cm -1 , λ ex 1064 nm) of the samples were recorded on Nicolet iS50 spectrometer with FT Raman module (Thermo Scientific, USA) using Omnic 9.0 software (ThermoScientific, USA); 100 scans were accumulated with a spectral resolution of 4 cm -1 .…”