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Bioactivity-guided fractionation of Australian native stingless bee (Tetragonula carbonaria) propolis extracts, based on in vitro free radical-scavenging and 5-lipoxygenase activities
Abstract   Peer reviewed

Bioactivity-guided fractionation of Australian native stingless bee (Tetragonula carbonaria) propolis extracts, based on in vitro free radical-scavenging and 5-lipoxygenase activities

Karina D Hamilton, Fraser D Russell and Peter R Brooks
2013 Australasian Society of Clinical and Experimental Pharmacologists and Toxicologists (ASCEPT) Annual Scientific Meeting Book of Abstracts, p.150
Australasian Society of Clinical and Experimental Pharmacologists and Toxicologists (ASCEPT) Annual Scientific Meeting: Breaking down the silos - academia, industry and the government collaboratively developing medicines, 2013 (Melbourne, Australia, 01-Dec-2013–04-Dec-2013)
2013
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http://www.asceptasm.com/wp-content/uploads/2013/06/ASCEPT-abstracts-403-493.pdfView
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Abstract

Pharmacology and Pharmaceutical Sciences
Introduction. Propolis, a resinous, plant-derived product of honeybees, exhibits anti-oxidant and anti-inflammatory properties (Búfalo et al, 2013). We found that a methanolic extract of Australian native stingless bee (Tetragonula carbonaria) propolis dose-dependently scavenged 2,2-diphenyl-1-picrylhydrazyl (DPPH) and inhibited 5- lipoxygenase activity in vitro. However, the active constituents of T. carbonaria propolis are yet to be elucidated. Aim. To identify fractions within T. carbonaria propolis that scavenge DPPH and inhibit 5-lipoxygenase activity. Methods. Propolis was collected from 40 T. carbonaria hives in South-East Queensland and extracted in 2:1 methanol:hexane. The crude methanolic extract was further separated into two hexane and one methanol-water subextract, which were evaporated to dryness and reconstituted in dimethyl sulfoxide. Sub-extracts (1-500 μg/mL) were tested for DPPH-scavenging activity (100 μmol/L; 30 min; 518 nm) and for inhibition of 5-lipoxygenase activity using colorimetry (Anthon et al, 2001). The methanol-water sub-extract was fractionated using preparative reversedphase HPLC, and 11 fractions were collected, dried and re-tested for bioactivity using the assays described above. Results. The polar, methanol-water sub-extract of T. carbonaria propolis was a more potent scavenger of DPPH than the hexane sub-extracts (EC50=31.1±1.6 μg/mL; n=3; P less than 0.05), and dose-dependently inhibited 5-lipoxygenase activity (IC50=42.8±4.6 μg/mL; n=3). Preparative fractions 1, 2 and 9 from the methanol-water sub-extract had greater DPPH-scavenging activity at 50 μg/mL than the other eight fractions (n=3; P less than 0.05). Fraction 1 also showed the greatest inhibition of 5-lipoxygenase activity at 100 μg/mL (n=5; P less than 0.05). Solvent controls were without effect. Discussion. Chemical analyses of fractions 1, 2 and 9 are currently underway to identify the constituents of T. arbonaria propolis that possess free radical-scavenging properties and inhibit 5-lipoxygenase activity in vitro.

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