The Water-Soluble Chitosan Derivative, N-Methylene Phosphonic Chitosan, Is an Effective Fungicide against the Phytopathogen Fusarium eumartii

Antifungal Chitosan Nanocomposites-A New Perspective for Extending Food Storage

Chitosan, a biopolymer derived from chitin, exhibits significant antifungal properties, making it a valuable compound for various applications in agriculture food preservation, and biomedicine. The present study aimed to assess the antifungal properties of chitosan-modified films using sol-gel derivatives (CS:ZnO) or graphene-filled chitosan, (CS:GO and CS:rGO) against two strains of fungi that are the most common cause of food spoilage: Aspergillus flavus ATCC 9643 and Penicillium expansum DSM 1282. The results indicate important differences in the antifungal activity of native chitosan films and zinc oxide-modified chitosan films. CS:ZnO nanocomposites (2:1 and 5:1) completely inhibited spore germination of the two tested fungal strains. Furthermore, a decrease in spore viability was observed after exposure to CS:Zn films. Significant differences in the permeability of cell envelopes were observed in the A. flavus. Moreover, the genotoxicity of the materials against two cell lines, human BJ fibroblasts and human KERTr keratinocytes, was investigated. Our studies showed that the tested nanocomposites did not exhibit genotoxicity towards human skin fibroblasts, and significant damage in the DNA of keratinocytes treated with CS:ZnO composites. Nanocomposites based on chitosan may help reduce synthetic fungicides and contribute to sustainable food production and food preservation practices.

Rumex japonicus Houtt. leaves: the chemical composition and anti-fungal activity

BACKGROUND

Candida albicans is a pathogenic commensal fungus. Trichophyton mentagrophytes and Trichophyton rubrum are the leading pathogens of dermatophysis. Rumex japonicus Houtt. has a miraculous effect on the treatment of tinea skin disease, but its mechanism has not been clarified.

PURPOSE

This paper investigated the anti-fungal ingredients of the leaves of Rumex japonicus Houtt. (RJH-L) and the mechanism of the anti-fungal (Trichophyton mentagrophytes, Trichophyton rubrum and Candida albicans).

METHOD

First, the chemical composition analysis of RJH-L was conducted by acid extraction and alcohol precipitation, high performance liquid chromatography (HPLC) and nuclear magnetic resonance spectroscopy (NMR); in vitro anti-fungal experiments were carried out, including the minimum inhibitory concentration (MIC) and the minimum fungicidal concentration (MFC) spore germination rate, germ tube production rate, nucleic acid and protein leakage rate, biofilm structure, PCR, etc., to study the mechanism of action of RJH-L anti-fungal and anti-biofilm activity.

RESULT

Seven monomer compounds were obtained: anthraquinones (rhein, emodin and aloe-emodin); polyphenols (ferulic acid, p-coumaric acid), and flavonoids (rutin and quercetin). The results of in vitro anti-fungal experiments showed that the extracts of RJH-L had strong inhibitory effect on both fungi (MIC: 1.96 µg/mL-62.50 µg/mL), of which emodin had the strongest effect on Trichophyton mentagrophytes; and rhein had the strongest effect on Candida albicans and Trichophyton rubrum. The above active components can inhibit the germination of fungal spores and germ tube, change cell membrane permeability, prevent hyphal growth, destroy the biofilm structure, and down-regulate the expression of agglutinin-like sequencefamily1 of biofilm growth.

CONCLUSION

This study shows that RJH-L are rich in polyphenols, flavonoids, and anthraquinones, and play a fungicidal role.

Deciphering physical and functional properties of chitosan-based particles for agriculture applications

Traditional methods for controlling plant pathogens rely on toxic chemicals, posing environmental and health risks. Developing sustainable, eco-friendly alternatives is crucial. Chitosan (CS)-based materials offer promising solutions for sustainable agriculture. We aimed to synthesize and characterize CS-based microparticles with varying properties and assess their antimicrobial performance to establish correlations between variations in physicochemical characteristics and their impact on performance within biological systems. We adjusted the synthesis parameters, producing particles labeled P1, P2, and P3, which have sizes of 0.19 ± 0.07 μm, 0.45 ± 0.32 μm, and 1.22 ± 0.32 μm, and zeta potentials of +7.6 ± 4.25 mV, +22 ± 3.51 mV, and + 12.9 ± 4.54 mV, respectively. Extensive toxicological screenings showed that these CS-based microparticles were non-toxic across cell cultures, mouse red blood cells, soil microbiota, nitrogen-cycling bacteria, and plant toxicity assays. Encouraged by these results, we evaluated their antimicrobial potential against economically important crop pathogens. The CS-based microparticles exhibited antimicrobial effects against the bacterium Pseudomonas syringae pv. tomato DC3000 and the fungus Fusarium solani f. sp. eumartii. Higher zeta potentials correlated with greater antimicrobial efficacy, evidenced by lower IC50 and minimum inhibitory concentration (MIC) values. These findings indicate that all three microparticles analyzed displayed antimicrobial activity against two economically significant crop pathogens, with P2 showing solid performance attributed to its physicochemical characteristics. Therefore, CS-based microparticles represent a promising, nontoxic, and environmentally friendly alternative for modern agriculture, with their biological activities potentially predictable through careful selection of physicochemical properties before the synthesis process.

Chitosan derivatives act as a bio-stimulants in plants: A review

Chitosan has been considered an eco-friendly biopolymer. Chitosan is a natural polycationic linear polysaccharide composed of D-glucosamine and N-acetyl-D-glucosamine linked by β-1,4-glycosidic bonds. Chitosan has been used as an eco-friendly biopolymer for so many agricultural applications. Unfortunately, the relatively poor solubility and poor antimicrobial properties limit its widespread applications in agriculture sciences. Hence, chitosan derivatives are produced via various chemical approaches such as cross-linking, carboxylation, ionic binding, and so on. As an alternative to chemical fertilizers, chitosan derivatives, chitosan conjugates, nanostructures, semisynthetic derivatives, oligo mixes, chitosan nanoparticles, and chitosan nano-carriers are synthesized for various agricultural applications. Its several chemical and physical properties such as biocompatibility, biodegradability, permeability, cost-effectiveness, low toxicity, and environmental friendliness make it useful for many agricultural applications. Hence, popularizing its use as an elicitor molecule for different host-pathogen interaction studies. Thus, the versatile and plethora of chitosan derivatives are gaining momentum in agricultural sciences. Bio-stimulant properties and multifunctional benefits are associated with further prospective research. Therefore, in the present review, we decipher the potential pros and cons of chitosan derivatives in plants.

Antifungal and antibacterial activities of Cannabis sativa L. resins

ETHNOPHARMACOLOGICAL RELEVANCE

Cannabis sativa L. (Cannabaceae) is a plant native to Eastern Asia spread throughout the world because of its medicinal properties. Despite being used for thousands of years as a palliative therapeutic agent for many pathologies, in many countries research on its effects and properties could only be carried out in recent years, after its legalization.

AIMS OF THE STUDY

Increasing resistance to traditional antimicrobial agents demands finding new strategies to fight against microbial infections in medical therapy and agricultural activities. Upon legalization in many countries, Cannabis sativa is gaining attention as a new source of active components, and the evidence for new applications of these compounds is constantly increasing.

METHODS

Extracts from five different varieties ofCannabis sativa were performed and their cannabinoids and terpenes profiles were determined by liquid and gas chromatography. Antimicrobial and antifungal activities against Gram (+) and Gram (-) bacteria, yeast and phytopathogen fungus were measured. To analyze a possible action mechanism, cell viability of bacteria and yeast was assessed by propidium iodide stain.

RESULTS

Cannabis varieties were grouped into chemotype I and II as a consequence of their cannabidiol (CBD) or tetrahydrocannabinol (THC) content. The terpenes profile was different in quantity and quality among varieties, with (-)b-pinene, b-myrcene, p-cymene and b-caryophyllene being present in all plants. All cannabis varieties were effective to different degree against Gram (+) and Gram (-) bacteria as well as on spore germination and vegetative development of phytopathogenic fungi. These effects were not correlated to the content of major cannabinoids such as CBD or THC, but with the presence of a complex terpenes profile. The effectiveness of the extracts allowed to reduce the necessary doses of a widely used commercial antifungal to prevent the development of fungal spores.

CONCLUSION

All the extracts of the analysed cannabis varieties showed antibacterial and antifungal activities. In addition, plants belonging to the same chemotype showed different antimicrobial activity, demonstrating that the classification of cannabis strains based solely on THC and CBD content is not sufficient to justify their biological activities and that other compounds present in the extracts are involved in their action against pathogens. Cannabis extracts act in synergy with chemical fungicides, allowing to reduce its doses.