| Reference | Plant | Extract or compound | Inhibition effect IC50 or % of inhibition |
| [28] | Semecarpus anacardium | Fractionated methanolic extract by hexane, ethyl acetate, and butanol Isolated compound: tetrahydroamentoflavone (THA) | THA IC50 100 nM |
| [29] | Ajuga iva L. | Crude 85% methanol extract fractionated by chloroform (CE), ethyl acetate (EAE), and water (AE) | IC50 3.878–5835 μM/quercetin equivalent (QE) |
| [30] | Teucrium polium | Methanol (ME), chloroform (CE), and ethyl acetate (EAE) crude extracts | CE 0.79, ME 10.59, EAE 11.75 μM/QE |
| [21] | Food extracts | Various extracts and compounds | Hesperetin 35 μM/QE Theaflavin-3,3′-digallate 49 µM/QE Cranberry juice, purple grape juice, and black tea IC50 2.4–5.8% of extracts Sage, cinnamon, thyme, and rosemary infusions IC50 12.9–20.4% of infusion |
| [31] | Flavonoids | Genistein, apigenin, quercetin, rutin, and astilbin | In vitro: no significant inhibitory effect In vivo: quercetin, rutin, and astilbin-potent XOI |
| [20] | Ganoderma tsugae Murr. (Polyporaceae) | CE isolated compounds: new lanostanoids: sugaric acids A, B, and C, tsugarioside A, and four known compounds, 3β-hydroxy-5α-lanosta-8,24-dien-21-oic acid, 3-oxo-5α-lanosta-8,24-dien-21-oic acid, ergosta-7,22-dien-3β-ol, and 2β,3α,9α-trihydroxy-5α-ergosta-7,22-diene ME: two new lanostanoids, sugariosides B and C, and a mixture of the already known compounds 5α,8α-epidioxyergosta-6,22-dien-3β-ol and 5α,8α-epidioxyergosta-6,9(11),22-trien-3β-ol | Potent XOI |
| [25] | Plant species from Czech Republic | Different crude plant extracts | Methylene chloride, ME of Populus nigra and Betula pendula, with IC50 of 8.3 and 25.9 µg/mL, 80% EE of Caryophyllus aromaticus and Hypericum perforatum, 50 µg/mL |
| [19] | Erythrina stricta (Papilionaceae) distributed in India, China, Thailand, and Vietnam | Fractions of the hydromethanolic extract of leaves | Chloroform fraction (IC50 21.2 ± 1.6 µg/mL), pet. ether (IC50 30.2 ± 2.2 µg/mL), ethyl acetate (IC50 44.9 ± 1.4 µg/mL), and residual fraction (IC50 100 ± 3.3 µg/mL) |
| [26] | Centaurium erythraea (Gentianaceae) | C. erythraea flowering tops infusion Identified compound: several esters of hydroxycinnamic acids, namely, p-coumaric, ferulic, and sinapic acids | Noncompetitively inhibiting xanthine oxidase |
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