In Vitro Antifungal Activity of Chitosan-Polyphenol Conjugates against Phytophthora cinnamomi

Abstract

Phytophthora cinnamomi is responsible for radical rot in a wide range of hosts, resulting in large economic and ecological losses worldwide. In Spain, it is responsible for diseases such as the oak decline or the chestnut blight. In this study, different polyphenol-stevioside inclusion compounds dispersed in a hydroalcoholic solution of chitosan oligomers have been investigated, with a view to their application as natural bioactive complexes to replace conventional systemic fungicides against this fungus. The polyphenols tested in vitro were curcumin, ferulic acid, gallic acid and silymarin. Three concentrations (125, 250 and 500 µg·mL −1 ) were assayed, with and without silver nanoparticles (AgNPs), and notable differences were found in the inhibition of mycelium growth, with EC 50 and EC 90 values ranging from 171 to 373.6 µg·mL −1 , and from 446.2 to 963.7 µg·mL −1 , respectively. The results obtained showed that the addition of AgNPs, despite their antimicrobial activity, did not always lead to synergies. In the case of P. cinnamomi, an unexpected antagonistic behavior was found for two of the polyphenols (curcumin and silymarin), while an additive behavior for ferulic acid and a synergistic behavior for gallic acid were attained. In view of their inhibitory power, the preparations based on ferulic acid with AgNPs and on silymarin without AgNPs are proposed for applications in crop and forests protection against P. cinnamomi.

Antifungal Activity against Botryosphaeriaceae Fungi of the Hydro-Methanolic Extract of Silybum marianum Capitula Conjugated with Stevioside

“…In the former case, composites based on stevioside:ferulic acid inclusion compounds (in a 5:1 molar ratio), combined with chitosan oligomers in hydroalcoholic solution or in choline chloride:urea deep eutectic solvent media, led to EC 90 values in the 377–713 µg·mL −1 range against F. culmorum [ 72 ], depending on the dispersion medium. In the case of P. cinnamomi , inclusion compounds from stevioside and ferulic acid in 6:1 ratio, dispersed in a hydroalcoholic solution of chitosan oligomers, resulted in EC 90 values of 446–450 µg·mL −1 (depending on the presence/absence of silver nanoparticles) [ 73 , 74 ].…”

Rutin-stevioside and related conjugates for potential control of grapevine trunk diseases

“…Composites based on stevioside:ferulic acid inclusion compounds (in a 5:1 molar ratio), combined with chitosan oligomers in hydroalcoholic solution or in choline chloride:urea deep eutectic solvent media, were assayed against F. culmorum by Matei et al (2018a), obtaining EC 50 s ranging from 175 to 292 µg•mL −1 and EC 90 s in the 377 to 713 µg•mL −1 interval, depending on the dispersion medium. Inclusion compounds from stevioside and ferulic acid in 6:1 ratio, dispersed in a hydroalcoholic solution of chitosan oligomers, were also assayed against P. cinnamomi by Matei et al (2018b) and Matei et al (2020), obtaining EC 50 s of 171 to 229 µg•mL −1 and EC 90 s of 446 to 450 µg•mL −1 , depending on the presence or absence of silver nanoparticles.…”

Callus induction and phytochemical profiling of Yucca carnerosana (Trel.) McKelvey obtained from in vitro cultures

“…Similarly, compound 40 occurred in callus tissue and in vitro plants, and it was assigned as a ferulic acid derivative (Cabañas-García et al, 2019). It has been proposed that ferulic acid inhibits the growth of Phytophthora cinnamomi, a fungus responsible for root rot in a wide range of hosts, producing significant economic and ecological losses worldwide (Matei et al, 2020). Thus, this derivative may be interesting for further studies.…”