Microwave ave-assisted extraction (MAE) of propolis from tetragonula biroi (Philippine Kiwot Bee) hives (Manila: PLM, 2024)
ABSTRACT: Propolis is a sticky, resinous substance produced by bees that contains pharmacological properties due to flavonoid content and other polyphenolic compounds. A distinct type of propolis may be derived from the Philippine kiwot bees (teragonula biroi), a native species of singles bees from the Philippines. In the present study, microwave-assisted extraction of propolis (MAE) from Philippine kiwot bees was accomplished with ethanol as the solvent and with varying extraction parameters, such as solvent-to-sample ratio (5 mL/g, and 15 mL/g), solvent concentration (35% v/v, 65% v/v, and 95% v/v), and extraction time (60 s, 180 s, and 300 s), to determine their effects on the yield and the phenolic and flavonoid contents. In this study, propolis was extracted using MAE, then concentrated using a rotary evaporator, and freeze dried. Afterwards, the phenolic content was determined through the Folin-Ciocalteu method, while the flavonoid content was identified through the formation of complexes with aluminum chloride in a methanol solution. Interactions between solvent-to-sample ratio and solvent concentration was determined to significantly affect the propolis extract yield, while the extraction time has no significant effect on the yield. Results show that using M.A.E with ethanol as solvent successfully extracted propolis. It was found that lower solvent-to-sample ratios with increasing solvent concentration resulted in higher yields. On the other hand, high solvent concentrations with increasing solvent-to-sample ratio decreases the yield. The highest yield (0.144 g/g) was obtained with 5 mL/g solvent-to-sample ratio, 95% v/v solvent concentration, and 300 s extraction time, while the highest phenolic content (180.145 mg GAE/g propolis) was observed with 5 mL/g solvent-to-sample ratio, 95% v/v solvent concentration, and 60 s extraction time. In comparison, the highest flavonoid content (124.190 mg QE/g propolis) was determined with a 10 mL/g solvent-to-sample ratio, 35% v/v solvent concentration, and 180 s extraction time.
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