Comparative Study of Bioactive Potential and Antifungal Susceptibility in H. undatus and H. polyrhizus Stem Extracts

Hylocereus species, an economically valuable crop cultivated in tropical and subtropical regions, are increasingly affected by fungal pathogens, leading to reduced yield. Understanding the phytochemical profile and bioactivity of Hylocereus stem extracts may support plant protection and therapeutic applications.

Stem extracts of Hylocereus undatus and Hylocereus polyrhizus were subjected to phytochemical screening and evaluated for antioxidant activity using 2,2-Diphenyl-1-picrylhydrazyl and hydrogen peroxide assays, anti-inflammatory activity by protein denaturation inhibition, and antimicrobial efficacy against bacterial and fungal pathogens. The agar well diffusion assay was conducted using Fluconazole and Itraconazole to determine antifungal effectiveness.

Phytochemical profiling revealed the presence of alkaloids, phenols, saponins, tannins, and terpenoids in both species. Hylocereus polyrhizus demonstrated markedly higher antioxidant and anti-inflammatory activity, with an IC50 value of 170.88 μg/mL, compared to Hylocereus undatus, which had an IC50 value of 257.72 μg/mL. Antibacterial assays showed significant inhibition against Neisseria meningitidis and Streptococcus pneumoniae. Agar well diffusion assay indicated dosedependent antifungal activity, with fluconazole exhibiting a maximum ZOI of 16.5 mm, which was higher than that of itraconazole.

The enhanced bioactivity of Hylocereus polyrhizus is linked to its richer phytochemical composition, indicating its potential as a natural source of multifunctional bioactive molecules. Although crude extracts lacked direct antifungal activity, the strong performance of commercial antifungals highlights the potential complementary application of plant-derived compounds in integrated disease management strategies.

This in vitro study presents the first comparative evaluation of Hylocereus undatus and Hylocereus polyrhizus stem extracts, confirming the superior therapeutic potential of Hylocereus polyrhizus and identifying fluconazole as the most effective antifungal agent for managing dragon fruit fungal infections against the tested species.