ANTIFUNGAL ACTIVITY OF GEOPROPOLIS EXTRACTS FROM Melipona quadrifasciata anthidioides AGAINST POSTHARVEST FUNGI

Abstract- Geopropolis is a product made by stingless bees from resins, other plant-

derived materials, wax, and soil components, playing structural and protective roles

within the colony. Its chemical composition may vary according to geographical region,

local flora, bee species, and seasonality. Due to its complex composition, geopropolis

has attracted scientific interest because of the presence of bioactive compounds

associated with different biological activities. This study aimed to evaluate the in vitro

antifungal activity of aqueous and hydroalcoholic extracts of geopropolis produced by

Melipona quadrifasciata anthidioides (mandaçaia). The material was obtained from an

apiary in Teresópolis-RJ, and extracted at a ratio of 1g of sample to 10 mL of solvent.

The aqueous extract was obtained by infusion at 95°C for 2h, whereas the

hydroalcoholic extract, using 70% ethanol, was prepared by ultrasound-assisted

extraction for 30 min. After extraction, both extracts were filtered. Four fungal isolates

obtained from plant matrices purchased from a local fruit and vegetable market were

evaluated: Corynespora sp., isolated from papaya; two isolates of Aspergillus section

Nigri, obtained from ginger and orange; and Fusarium sp., isolated from tomato. These

genera are frequently associated with spoilage and postharvest diseases. Antifungal

activity was determined based on the inhibition of mycelial growth in culture medium

containing the extracts at concentrations of 1% and 2%, using distilled water and 70%

ethanol as the respective controls. The assays were performed in duplicate. After

inoculation with mycelial discs, the plates were incubated at 33 ± 2 °C for seven days.

Colony diameters were measured, and the percentage of inhibition was calculated

relative to the respective controls. The aqueous extract showed low or no antifungal

activity, with inhibition rates of 16.98% and 0.00% against Fusarium sp.; 1.25% and

6.25% against the Aspergillus section Nigri isolate from orange; 0.00% at both

concentrations against the isolate from ginger; and 12.50% and 11.25% against

Corynespora sp., at concentrations of 1% and 2%, respectively. In contrast, the

hydroalcoholic extract exhibited high antifungal activity, predominantly achieving 100%

inhibition of mycelial growth at both concentrations evaluated. The difference observed

between the extracts suggests that the solvent and extraction method influence the

recovery of constituents with antifungal activity. Under the experimental conditions

evaluated, the hydroalcoholic extract of geopropolis produced by M. quadrifasciata

anthidioides provides further evidence of antifungal potential against filamentous fungi

isolated from plant matrices, supporting further investigations aimed at characterizing

the bioactive compounds and determining the minimum inhibitory concentration.

Acknowledgments: The authors acknowledge the Technical Support Program for

Teaching, Research, and Extension Activities (PROATEC/Uerj) for the scholarship, and

the Natural Products Technology Laboratory and the Biotechnology Teaching

Laboratory at Uerj Campus Zona Oeste for the technical support and infrastructure

provided for the experimental activities.