Protoporphyrin IX–Chitosan Oligosaccharide Conjugate with Potent Antifungal Photodynamic Activity

Abstract

A new chemical conjugate between protoporphyrin IX (PPIX) and chitosan oligosaccharides (CH) was prepared and evaluated in vitro as an antifungal agent against Penicillium digitatum. Chemical characterization and photophysical/photochemical studies were conducted. The antifungal effect of the CH–PPIX conjugate was compared to its components (PPIX and CH) and a physical mixture of both, under dark and illuminated conditions. The CH–PPIX conjugate was photostable and inhibited fungal growth with 100% efficiency at a dose of 0.005% w/v under visible light irradiation, while no antifungal activity was observed in the dark. Under the same conditions, CH and PPIX did not display any fungicidal activity, demonstrating the improved properties of the conjugate. Insights into the mechanism of fungal inactivation revealed an efficient spore uptake and photoinduced membrane damage through singlet oxygen generation. This new bioconjugate, which is based on natural components, represents a promising agent for fungicidal formulations based on antimicrobial photodynamic therapy.

Synthesis and Characterization of Slow-Release Chitosan Oligosaccharide Pyridine Schiff Base Copper Complexes with Antifungal Activity

“…The antifungal activity of COS has been studied against various fungi, and the modification of COS improves its biological activity. − Herein, four phytopathogenic fungi, namely, B. cinerea , Alternaria , P. vexans , and Ph. capsici , were selected.…”

A pectin-based photoactivated bactericide nanosystem for achieving an improved utilization rate, photostability and targeted delivery of hematoporphyrin

“…To improve the photostability and the targeting ability, recently, a chitosan oligosaccharide-protoporphyrin IX (CH-PpIX) conjugate was prepared, whose polycationic properties make it more readily taken up by fungi with a negatively charged external structure, enhancing the antifungal activity. 15 In addition, our group designed a GSH-responsive alginate oligosaccharide-protoporphyrin IX (AOS-ss-PpIX) nanosystem to improve the water solubility, photostability and targeted release of PpIX. The research shows that this system can not only significantly reduce the photodegradation of PpIX, but also trigger the release of PpIX in response to overexpressed GSH stimulation at plant infection sites, thus promoting the targeting ability.…”

Development of New Photoinactivation Strategies for Microbial Decontamination in Fruits and Packaging

“…In PDI applications, CS interacts with the external surface of bacteria, destabilizing the cell envelope that allows the penetration of PS. , This effect results in an increase in the efficiency of photodynamic processes. In addition, PSs covalently linked to CS were effective antimicrobial photodynamic agents. − In addition, a conjugate of PPIX to CS was previously evaluated as an effective antifungal agent . In this study, the spectroscopic and photodynamic properties of CS–PPIX were assessed in a homogenic solution by employing various substrates to identify the formation of ROS.…”

“…35−37 In addition, a conjugate of PPIX to CS was previously evaluated as an effective antifungal agent. 38 In this study, the spectroscopic and photodynamic properties of CS−PPIX were assessed in a homogenic solution by employing various substrates to identify the formation of ROS. The photokilling capacity of this conjugate was first evaluated against S. aureus cells suspended in aqueous media and in cells deposited on agar surfaces.…”