Ecofriendly synthesis of halogenated flavonoids and evaluation of their antifungal activity

Abstract

Brominated and chlorinated flavonoids belonging to different classes (flavanones, flavones and catechins) were prepared from the corresponding flavonoids by a simple and ecofriendly procedure based on the use of sodium halides, aqueous hydrogen peroxide and acetic acid. Pure samples of substrates and products were tested against Trichoderma koningii, Fusarium oxysporum and Cladosporium cladosporioides, common saprotrophic soil and seed fungi, potential pathogens for humans and their activity was expressed as linear mycelial growth inhibition (%). Among them, 8-chloro-5,7,3 0 ,4 0tetramethoxyepicatechin 29, a novel catechin derivative, exhibited a remarkable effect against all tested fungi also at low concentrations.

Dibromopinocembrin and Dibromopinostrobin Are Potential Anti-Dengue Leads with Mild Animal Toxicity

“…The bromination and iodination of pinostrobin ( TH019 ) and pinocembrin ( TH022 ) were adapted from the protocol previously described [ 15 ] ( Figure 1 ). Following the reactions, 6,8-dibromopinostrobin ( TH002 ), 6,8-dibromopinocembrin ( TH011 ), 6,8-diiodopinocembrin ( TH012 ), and 6-iodopinostrobin ( TH018 ) were isolated using silica gel chromatography, yielding 96%, 93%, 73%, and 10%, respectively.…”

“…They are plant-derived secondary metabolites originated from chalcones in the flavonoid biosynthetic pathway, and still highly reactive for further structural modifications, such as dehydrogenation, glycosylation, hydroxylation, etc. They are key mediators of various biological processes in plants, such as nitrogen fixation, photosynthesis, energy transfer, and anti-oxidation [ 15 ]. Moreover, their activities extended towards anti-cancer, antivirals [ 10 , 12 , 17 ], and anti-inflammation [ 29 , 30 ].…”

Lichen Xanthones as Models for New Antifungal Agents

“…On the other hand, in the last years, a number of green procedures based on the generation of the electrophilic reagent Cl + by an ecofriendly oxidation of chlorine ions was also reported in the literature. These include the use of benign oxidants like dimethyldioxirane (DMD), potassium peroxymono-sulfate (Oxones ® ) or NaCl, aqueous H 2 O 2 and acetic acid [ 18 ]. Other methods use harsh conditions like neat thionyl chloride [ 19 ] or sulfuryl chloride in tetrahydrofuran [ 11 ].…”

Design, Synthesis and Antifungal Activity of Coumarin Ring-Opening Derivatives

“…Many experimental protocols for antifungal tests are reported in the literature [22,23].In this study, the antifungal activities of all the synthesized target compounds were carried out at the concentration of 50 µM using mycelia growth inhibitory rate methods, with Azoxystrobin used as the positive control. For the detailed procedure of experimental methods for the antifungal activity, refer to the paper from Department of Plant Pathology, Nanjing Agriculture University [24].…”