Walaa Negm

Egypt

Antifungal activity of oily core PEGylated PLGA nanocapsules loaded with the endophytic fungus Penicillium oxalicum: in vitro, in vivo, and in silico

Engy Elekhnawy 1,* , Dalia H. Abdelkader 2, Duaa Eliwa 3, Sarah Ibrahim 4, Moataz A. Shaldam 5, Walaa A. Negm 3,*
1 Microbiology and Immunology Department, Faculty of Pharmacy, Tanta University, Tanta 31527, Egypt
2 Department of Pharmaceutical Technology, College of Pharmacy, Tanta University, Tanta, Egypt; Tanta 31527, Egypt
3 Department of Pharmacognosy, Faculty of Pharmacy, Tanta University, Tanta 31527, Egypt
4 Human Anatomy and Embryology Department, Faculty of Medicine, Tanta University, Tanta 31527, Egypt
5 Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Kafrelsheikh University, Kafr El-Sheikh 33516, Egypt

Abstract

Background

The rising incidence of difficult-to-treat fungal infections underscores the importance of developing new therapeutic approaches. Endophytic fungi represent a promising source of bioactive compounds with potential antifungal activity.

Methods

Endophytic fungi were isolated from Acalypha hispida leaves and identified molecularly using 18S rRNA gene sequencing, confirming the species as Penicillium oxalicum. The fungal extract was analyzed using LC-HRMS/MS. Oily core PEGylated PLGA nanocapsules (NCs) loaded with the P. oxalicum extract were prepared using a hybrid single-emulsion/nanoprecipitation technique. The NCs were characterized by particle size, size distribution, surface charge, and morphology. Antifungal activity was assessed using the agar well diffusion method, followed by evaluation of in vivo antifungal efficacy using a systemic infection model. Immunohistochemical analysis of TNF-α and COX-2 was conducted. In silico docking studies were performed against Candida albicans aspartic proteinases SAP4, SAP5, and SAP6.

Results

Increasing the concentration of m-PEG-PLGA resulted in a significant increase in particle size and zeta potential, and a substantial reduction in the polydispersity index. Transmission electron microscopy confirmed the spherical morphology of the formulated NCs. The PEGylated PLGA NCs loaded with the P. oxalicum extract exhibited antifungal activity with inhibition zones ranging from 10 to 14 mm. In vivo, treated animals showed marked improvement in kidney, liver, and spleen histology, accompanied by significant reductions in TNF-α and COX-2 immunostaining. In silico studies demonstrated strong predicted interactions of the major fungal metabolites with SAP4, SAP5, and SAP6.

Conclusions

Endophytic P. oxalicum extract encapsulated in PEGylated PLGA nanocapsules demonstrated potent in vitro, in vivo, and in silico antifungal activities. These findings highlight the potential of combining endophytic fungal metabolites with nanocarrier systems as a promising therapeutic strategy against difficult-to-treat fungal infections.