# A Comprehensive Review of Stingless Bee Products:
## 2 Stingless Bee Honey
### Antioxidant Properties
#### 2.1.4 Antioxidant Capacity  
According to [PERSON] and [PERSON] [44], each method of determining antioxidant capacity will have a different result. This is due to antioxidants responding differently to different radical or oxidant stress, and no method can precisely reveal all radical sources or antioxidants in a compound. [PERSON] et al. [41] used a 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay to evaluate honey antioxidant capacity, for which the result ranged from 2.77% to 44.05%. The study showed a significant correlation of DPPH activity with the phenolic compounds of stingless bee honey, for which the high phenolic content resulted in low DPPH activity. [PERSON] et al. [37] used a DPPH assay to investigate stingless bee honey and European honeybee honey. The antioxidant capacity of stingless bee honey via the DPPH assay was 42.23 mmol TE/100 g, whereas for European honeybee honey it was 31.06 mmol TE/100 g. The author stated that the chemical composition of honey is attributed to bee species and floral and geographical origin. [PERSON] et al. [36] used a ferric reducing antioxidant power (FRAP) assay to assess the reduction capacity of Brazilian stingless bee honey, for which the value ranged from 67.5 to 734.5 mmol Fe\({}^{+2}\) 100/g. The author used eight different honey samples, which were produced by _Scapttrigona bipunctata_, _Melipona marginata_, _Tetragonisca angustula_, _Trigona hypogea_, _Melipona quadrificaata_, and _Tetragonic clavipes_, and the highest FRAP value was from _Tetragonisca angustula_ honey. [PERSON] et al. [30] also used a FRAP assay in determining the antioxidant capacity of honey. The study investigated three species of bees, _Genitorigona thoracica_, _Heterotrigona itama_, and _Heterotrigona erythrogastra_, for which the results showed that the antioxidant capacity of the stingless bee honey ranged from 25.78 to 50.66 mM of Fe\({}^{2+}\)/100 g, with _Heterotrigona itama_ being associated with the highest value. [PERSON] et al. [45] found that the antioxidant activity assessed using a FRAP assay by _Heterotrigona itama_ was twice as high as that of European honeybee honey, which ranged from 19.05 to 23.34 mg AAE/100 g.  
Generally, the concept of a 2,2\({}^{\prime}\)-azino-bis(3-ethylbenzothazoline-6-sulphonic acid (ABTS) scavenging assay is similar to the DPPH scavenging assay, which involves the affinity activity of free radicals. Antioxidant activity is determined by the capability of the test sample to transfer an electron to the ABTS radical cation through the decolourisation of the radical cation [31]. The author also used an ABTS scavenging assay to determinethe antioxidant content of unifloral and multifiloral stingless bee honey in which the ABTS inhibition ranged from 15.61% to 65.77%. The study showed that unifloral honey types hold higher antioxidant content than multifiloral honey types and concluded that the antioxidant content of honey is attributed to the plant source, geographical origins, climate, and methods of processing [31]. In addition, [PERSON] et al. [46] also used an ABTS assay to determine honey antioxidant content. Stingless bee honey was collected from three different locations across Malaysia for which the antioxidant levels ranged from 216.18 to 2006.87 \(\upmu\)g TEAC/g. The study also showed a positive correlation of antioxidant levels with the phenolic compounds of stingless bee honey. A study by [PERSON] et al. [43] investigated the antioxidant capacity of stingless bee honey from _Trigona_ sp. and European honeybee honey using the oxygen radical absorbance capacity (ORAC) assay, and revealed that stingless bee honey has a higher antioxidant capacity than European honeybee honey, at 29.56 to 89.44 \(\upmu\)m TE/g and 22.28 to 75.47 \(\upmu\)m TE/g, respectively. The study showed a significant correlation of polyphenol content with antioxidant capacity, as high polyphenol content was detected in the stingless bee honey and attributed to high antioxidant potential. Finally, a study by [PERSON] et al.