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Abstract Natural products, while valuable for drug discovery, encounter limitations like uncertainty in targets and toxicity. As an important active ingredient in traditional Chinese medicine, celastrol exhibits a wide range of biological activities, yet its mechanism remains unclear. In this study, they introduced an innovative “Degradation‐based protein profiling (DBPP)” strategy, which combined PROteolysis TArgeting Chimeras (PROTAC) technology with quantitative proteomics and Immunoprecipitation‐Mass Spectrometry (IP‐MS) techniques, to identify multiple targets of natural products using a toolbox of degraders. Taking celastrol as an example, they successfully identified its known targets, including inhibitor of nuclear factor kappa B kinase subunit beta (IKKβ), phosphatidylinositol‐4,5‐bisphosphate 3‐kinase catalytic subunit alpha (PI3Kα), and cellular inhibitor of PP2A (CIP2A), as well as potential new targets such as checkpoint kinase 1 (CHK1), O‐GlcNAcase (OGA), and DNA excision repair protein ERCC‐6‐like (ERCC6L). Furthermore, the first glycosidase degrader is developed in this work. Finally, by employing a mixed PROTAC toolbox in quantitative proteomics, they also achieved multi‐target identification of celastrol, significantly reducing costs while improving efficiency. Taken together, they believe that the DBPP strategy can complement existing target identification strategies, thereby facilitating the rapid advancement of the pharmaceutical field.

Abstract Candida albicans is an important human fungal pathogen. Our previous study disclosed that aryloxy‐phenylpiperazine skeleton was a promising molecule to suppress C. albicans virulence by inhibiting hypha formation and biofilm formation. In order to deeply understand the efficacy and mechanism of action of phenylpiperazine compounds, and obtain new derivatives with excellent activity against C. albicans, hence, we synthesized three series of (1‐heteroaryloxy‐2‐hydroxypropyl)‐phenylpiperazines and evaluated their inhibitory activity against C. albicans both in vitro and in vivo in this study. Compared with previously reported aryloxy‐phenylpiperazines, part of these heteroaryloxy derivatives improved their activities by strongly suppressing hypha formation and biofilm formation in C. albicans SC5314. Especially, (9H‐carbazol‐4‐yl)oxy derivatives 25, 26, 27 and 28 exhibited strong activity in reducing C. albicans virulence in both human cell lines in vitro and mouse infection models in vivo. The compound 27 attenuated the virulence of various clinical C. albicans strains, including clinical drug‐resistant C. albicans strains. Moreover, additive effects of the compound 27 with antifungal drugs against drug‐resistant C. albicans strains were also discussed. Furthermore, the compound 27 significantly improved the composition and richness of the faecal microbiota in mice infected by C. albicans. These findings indicate that these piperazine compounds have great potential to be developed as new therapeutic drugs against C. albicans infection.

Summary Candida albicans is a common human fungal pathogen. The previous study revealed that quinone compounds showed antimicrobial activity against C. albicans by inhibiting cell growth. However, it was unclear whether quinones have other antifungal effects against C. albicans in addition to fungicidal effects. In this study, we assessed the inhibitory activity of a total of 25 quinone compounds against C. albicans morphological transition, which is essential for the pathogenicity of C. albicans. Several quinones exhibited strong inhibition of mycelium formation by C. albicans SC5314. Three leading compounds, namely hypocrellins A, B and C, also exhibited marked attenuation of C. albicans SC5314 virulence in both human cell lines and mouse infection models. These three compounds significantly suppressed the proliferation of C. albicans SC5314 cells in a mouse mucosal infection model. Intriguingly, hypocrellins not only attenuated the cytotoxicity of a nystatin‐resistant C. albicans strain but also showed excellent synergistic effects with antifungal agents against both wild‐type C. albicans SC5314 and the drug‐resistant mutant strains. In addition, hypocrellins A, B and C interfered with the biological functions and virulence of various clinical Candida species, suggesting the promising potential of these compounds for development as new therapeutic agents against infections caused by Candida pathogens.