The total flavonoid TF contents of betel leaves extracted from different solvents and different concentrations are presented in Table 1. The TF contents of the ethanol extract of betel leaves ranged from 12.13 to 78.8 mg CE/g. The TF contents of methanol-, acetone-, and ethyl acetate-extracted samples ranged from 12.25 to 80.59 mg CE/g, from 12.10 to 82.55 mg CE/g, and from 10.97 to 42.05 mg CE/g, respectively. In water-extracted samples, the TF content was 30.88 mg CE/g.