Potential Antibacterial, Wound Healing and Anti-inflammatory Activities of Penicillium rubens, an Endophytic Fungus Isolated from the Leaves of Cucumis sativus L.

This study is the first to report the isolation and bioactivity of Penicillium rubens from Cucumis sativus L. leaves. Penicillium rubens was tested for its potential antibacterial, anti-inflammatory, and wound healing properties. The dried ethyl acetate extract of P. rubens (EPR) demonstrated antibacterial activity against Pseudomonas aeruginosa (ATCC 27853), showing a 24 mm inhibition zone in the agar disc diffusion method, where the disc was saturated with 1000 µg/mL of EPR in ethyl acetate. The minimum inhibitory concentration (MIC) of EPR against 20 clinical isolates of Pseudomonas aeruginosa ranged from 128 to 1024 µg/mL, as determined by the broth microdilution assay. Stimulation of WI38 cells with 20 µg/mL lipopolysaccharide (LPS) led to ~3.08-fold increase± 0.03 in the gene expression of the proinflammatory cytokine, TNF-α, as determined by qRT-PCR, while EPR treatment of LPS-stimulated cells led to a significant reduction in the expression of TNF-α to only ~1.09-fold increase± 0.02 (p<0.0001), providing insights into possible anti-inflammatory activity. The EPR effect on wound healing process was investigated in vitro where EPR treatment significantly increased the wound closure percentage (66.64% ± 5.61 and 99.94% ± 0.05) compared to the control cells (13.79% ± 3.98 and 83.37% ± 0.05) as indicated at 24 and 48 hours post-wound induction, respectively. Further studies may be needed to characterize the bioactive compounds responsible for the above-mentioned biological activities, which may help explore alternative therapeutically active compounds.