# Cell Wall Proteome of Candida albicans Reveals Proteins Associated with Tolerance to Antibiofilm Activity of a Lippia graveolens Kunth Stem Extract

## TL;DR

This study explores how a plant extract from Lippia graveolens affects Candida albicans biofilms and identifies cell wall proteins linked to resistance.

## Contribution

The study identifies cell wall proteins associated with tolerance to a natural extract's antibiofilm activity in Candida albicans.

## Key findings

- The Lippia graveolens extract inhibited biofilm formation in C. albicans by 77% at 1.6 mg/mL.
- 156 proteins were up-regulated and 94 down-regulated in the cell wall after extract exposure.
- 40 cell wall proteins were linked to biofilm formation, adhesion, and stress response.

## Abstract

Candida albicans is an opportunistic fungus capable of forming biofilms that are resistant to conventional antifungal treatments. This study evaluated the antibiofilm activity of an ethanolic extract from Mexican oregano (Lippia graveolens Kunth) stem and its impact on the protein composition of the C. albicans cell wall (CW). The proteomic analysis was restricted to the adherent cells that persisted after treatment, representing the more tolerant subpopulation. First, the biofilm-forming capacity of 18 clinical isolates was characterized. Subsequently, the effect of the Lippia graveolens Kunth stem extract on biofilm formation was assessed in clinical isolates of C. albicans with high and moderate biofilm-forming capacities. The results showed an MIC90 of 16 mg/mL against C. albicans isolates in planktonic growth. Furthermore, the extract exhibited an antibiofilm effect, showing a 77% inhibition in the highly biofilm-forming C. albicans 2400H strain at 1.6 mg/mL. To assess how the extract influences CW composition, we analyzed the CW proteome of the adherent biofilm cells of C. albicans that persisted after exposure to the stem extract. Mass spectrometry identified 1006 total proteins, where 156 were up-regulated, and 94 were down-regulated. Of the differentially expressed proteins, we identify 40 CW proteins (CWP’s) associated with dimorphic transition, adhesion, oxidative stress, and biofilm formation. These findings provide the potential of the L. graveolens Kunth stem as a natural antifungal agent against C. albicans biofilms. In addition, we identified CWP’s associated with tolerance to the extract’s antibiofilm activity, offering mechanistic insight into persistence and potential targets for improving antibiofilm interventions.