| | Reference | Tested sample | Assay procedures |
| | [19] | Erythrinastricta Roxb. fractions | Sample fraction (1 mL, 5–100 μg/mL), phosphate buffer (pH 7.5) (2.9 mL), xanthine oxidase (0.1 mL, 0.1 units/mL in phosphate buffer); preincubation 15 min (25°C); substrate solution (2 mL, 150 μM xanthine in buffer); incubation 30 min (25°C); HCl (1 mL, 1 M) |
| | [20] | Lanostanoids from Ganoderma tsugae | Test solution, 70 mM phosphate buffer (pH 7.5); enzyme solution (0.1 units/mL in 70 mM phosphate buffer (pH 7.5)); preincubation 25°C for 15 min; substrate (150 μM xanthine in the same buffer) |
| | [21] | Food extracts and components | Test sample, xanthine (0.8 mL, 150 μM), hydroxylamine (0.2 mM), and EDTA (0.1 mM), all in sodium phosphate buffer (0.2 M, pH 7.5); XO (0.2 mL, 23.42 mili, 0.2 M phosphate buffer); incubation 30 min (37°C); HCl (0.1 mL, 5 M) |
| | [22] | Malaysian medicinal plant | Sodium phosphate buffer (pH 7.5) (300 μL, 50 mM), 100 μL of sample solution in distilled water or DMSO, enzyme solution (100 μL, 0.2 units/mL of xanthine oxidase in phosphate buffer), 100 μL of distilled water; preincubation 15 min (37°C); xanthine (200 μL, 0.15 mM); incubation 30 min (37°C); 200 μL of 0.5 M HCl |
| | [23] | Edible plants of the Turkmen Sahra region | Plant extract (0.250 mL in 50 mM potassium phosphate buffer, pH = 7.4), xanthine (0.330 mL, 0.15 mM), potassium phosphate buffer (pH 7.4) (0.385 mL, 50 mM); XO (0.035 mL, in 50 mM potassium phosphate buffer) |
| | [24] | Anacardic acid | Sodium carbonate buffer containing 0.1 mM EDTA (pH 10.0) (2.76 mL, 40 mM), xanthine (0.06 mL, 10 mM), sample (0.06 mL in DMSO); xanthine oxidase (0.12 mL, 0.04 units) |
| | [25] | Czech medicinal plants | Phosphate buffer (pH 7.5) (400 μL, 120 mmol/L), xanthine (pH 7.5) (330 μL, 150 μmol/L), extract stock solution (250 μL), enzyme solution (20 μL 0.5 units/mL in buffer) |
| | [26] | Centaurium erythraea infusion | Xanthine (44 μM in 1 μM NaOH), XO (0.29 units/mL in 0.1 M EDTA), lyophilized infusion (5.2, 10.4, 20.8, 41.7, 83.3, and 166.7 µg/mL) |
| | [27] | Dried S. anacardiumseeds | 0.1 U/mL XO, 0.2 mL xanthine (0.26 M) in 50 mM phosphate buffer (pH = 7.4) |
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