Abstract: This study aimed to analyze the physicochemical properties and polyphenolic composition and to evaluate the antioxidant and anti-inflammatory activities of stingless bee honey (SBH) from Hainan, China. The polyphenolic compounds were analyzed by liquid chromatography-quadrupole time-of-flight mass spectrometry (LC-Q-TOF-MS). The contents of total phenolics and total flavonoids in SBH extract were determined by the Folin-Ciocalteu method and AlNO3 colorimetry, respectively. The antioxidant activity of SBH was assayed in vitro by using 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging, 2,2’-azinobis-(3-ethylbenzthiazoline-6-sulphonate radical) (ABTS+·) scavenging and reducing power methods. Its anti-inflammatory effect was investigated using lipopolysaccharide (LPS)-stimulated RAW 264.7 cells. Our results showed that SBH possessed the physicochemical properties: moisture content (26.3 ± 0.1)%, pH 3.7 ± 0.2, protein content (628.2 ± 9.0) mg/kg, amylase activity (19.6 ± 0.2) mL/(g·h), fructose content (21.0 ± 3.7)%, glucose content (24.9 ± 2.2)%, sucrose content (0.8 ± 0.1)%. The contents of total phenolics and total flavonoids in the extract were (96.6 ± 0.4) μg CAE/g and (16.1 ± 0.3) μg QE/g, respectively. The IC50 values of the extract for scavenging of DPPH and ABTS radicals were (435.1 ± 0.4) and (423.0 ± 0.3) μg/mL, respectively, and its ferric reducing power was (0.6 ± 0.02) μmol Trolox/g. SBH exhibited potent concentration-dependent anti-inflammatory effects by inhibiting nitric oxide (NO) release from LPS-stimulated RAW 264.7 cells, markedly decreasing the mRNA expression of iNOS, IL-1β, IL-6 and MCP-1, and significantly increasing the mRNA expression of HO-1. These results suggest that SBH was rich in nutrients, phenolic acids and flavonoids, and had potent antioxidant and anti-inflammatory properties, making it very promising.

Key words: stingless bee honey, food composition analysis, antioxidant, anti-inflammatory