Physicochemical analyses, antioxidant, antibacterial, and toxicity of propolis particles produced by stingless bee Heterotrigona itama found in Brunei Darussalam

Nurul Aliah Abdullah; Fairuzeta Ja'afar; Hartini M Yasin; Hussein Taha; Mark I R Petalcorin; Mitasby H Mamit; Eny Kusrini; Anwar Usman

doi:10.1016/j.heliyon.2019.e02476

Physicochemical analyses, antioxidant, antibacterial, and toxicity of propolis particles produced by stingless bee Heterotrigona itama found in Brunei Darussalam

Heliyon. 2019 Sep 14;5(9):e02476. doi: 10.1016/j.heliyon.2019.e02476. eCollection 2019 Sep.

Authors

Nurul Aliah Abdullah¹, Fairuzeta Ja'afar¹, Hartini M Yasin¹, Hussein Taha², Mark I R Petalcorin³, Mitasby H Mamit⁴, Eny Kusrini⁵, Anwar Usman¹

Affiliations

¹ Department of Chemistry, Faculty of Science, Universiti Brunei Darussalam, Jalan Tungku Link, Gadong BE1410, Brunei Darussalam.
² Environmental and Life Sciences Programme, Faculty of Science, Universiti Brunei Darussalam, Jalan Tungku Link, Gadong BE1410, Brunei Darussalam.
³ PAPRSB Institute of Health Sciences, Universiti Brunei Darussalam, Jalan Tungku Link, Gadong BE1410, Brunei Darussalam.
⁴ Tasbee Meliponiculture Farm, Jalan Bukit Nanas, Kg Sungai Kelugos, Tutong, Brunei Darussalam.
⁵ Department of Chemical Engineering, Faculty of Engineering, Universitas Indonesia, Kampus Baru UI, Depok, 16424, Indonesia.

Abstract

In this study, the physicochemical, antioxidant, antibacterial properties, and the toxicity of propolis particles produced by stingless bee Heterotrigona itama found in Brunei Darussalam were investigated. Propolis particles of different sizes were extracted from raw propolis using various volume fractions of ethanol in water. Spectroscopic analyses were utilized to characterize the chemical structures, functional groups, as well as absorbance and fluorescence properties. The total antioxidant capacity of propolis particles, which was assessed using DPPH (2,2-diphenyl-1-picrylhydrazyl) assay, was found to increase with volume fraction of ethanol. The maximum antioxidant capacity was as high as 317.65 mg ascorbic acid equivalent per gram of propolis particles. All of the propolis particles showed antibacterial activity against Gram-positive (Bacillus subtilis and Staphylococcus aureus) and Gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa). The diameters of the inhibition zone were either significantly higher or equivalent to those of two standard antibiotics (rifampicin and streptomycin), suggesting strong antibacterial activity. The toxicity studies of propolis particles against Caenorhabditis elegans revealed that they are non-toxic after 24 h exposure. Overall findings suggest that H. itama propolis particles are not only an important source of natural antioxidants that could be beneficial for human health, but they have potentials as antimicrobial against bacteria.

Keywords: Analytical chemistry in food science; Antibacteria; Antimicrobial; Antioxidant; Chemical characterization of food; Chemical food analysis; Food chemistry; Food science; Heterotrigona itama; Material science of foods; Propolis particles; Stingless bee propolis; Toxicity; Toxicology.