# Phytochemical characterization and pharmacological evaluation of aerial and root parts of Dalea pazensis Rusby [Fabaceae]

## TL;DR

This study explores the chemical and biological properties of Dalea pazensis, revealing its potential as a natural antifungal and skin treatment.

## Contribution

The first chemical report of essential oil and prenylflavonoid content in Dalea pazensis, highlighting dual antifungal and anti-tyrosinase activity.

## Key findings

- Chloroform extract of D. pazensis showed potent antifungal activity against azole-resistant Candida albicans.
- The extract also exhibited strong tyrosinase inhibition, relevant for dermatological applications.

## Abstract

The Dalea genus [Fabaceae] is rich in bioactive flavonoids and contains underexplored species, such as Dalea pazensis Rusby, with potential for antifungal and dermatological applications.

Considering the limited knowledge available on D. pazensis, this study aims to expand the current understanding of its chemical and biological potential.

Sequential extraction of D. pazensis roots was performed using solvents of increasing polarity. Additionally, essential oil (EO) was obtained from the aerial parts. Extracts and EO were chemically characterized by ultra-performance liquid chromatography–tandem mass spectrometry (UPLC-MS/MS) and gas chromatography/mass spectrometry (GC-MS), respectively. Antifungal activity was evaluated against azole-sensitive and azole-resistant Candida albicans strains, while tyrosinase inhibition was assessed in the different extracts using an in vitro enzymatic assay.

The chloroform extract (CDp) exhibited the most potent antifungal activity (minimum inhibitory concentration, MIC = 125 μg/mL), a relevant value considering that the reference drug fluconazole shows an MIC of 32 μg/mL in this resistant strain, underscoring the extract’s significant activity despite azole resistance. CDp showed significant tyrosinase inhibition (half-maximal inhibitory concentration, IC50 = 1.27 μg/mL). UPLC-MS/MS analysis identified (2S)-5,7,2′,4′-tetrahydroxy-5′-(1‴,1‴-dimethylallyl)-8-prenylflavanone (compound 1) as the major constituent, previously linked to antifungal activity and efflux pump inhibition. EO analysis revealed β-caryophyllene (41.1%) as the main component, suggesting a distinct chemotype within the species.

This is the first chemical report of the EO and the deepening of prenylflavonoid content in different extracts of D. pazensis, highlighting the pharmacological relevance of its dual antifungal and antityrosinase profile, a combination of interest for dermatological formulations targeting fungal infections, hyperpigmentation, or post-infectious dyschromias. The findings underscore this species as a promising source of prenylated flavanones with dual antifungal and anti-tyrosinase activity, as well as bioactive volatiles with antifungal activity. The results support its use in developing natural antifungal therapies, particularly against MDR pathogens.