*3.5. HPLC Conditions*

For the RP-HPLC analysis, the column was thermostated at 35 ◦C, and the autosampler was thermostated to 4 ◦C. Sample concentration was 4 mg/mL, and injection volume was 5.0 μL. UV detection was used at 220 nm, and gradient elution was used at flow rate of 1.6 mL/min according to the following procedure. Eluent mixture: Water + 0.085% phosphoric acid (A), acetonitrile + 0.085% phosphoric acid (B). Gradient elution: 70% of B up to 3 min, 85% of B to 7 min, 95% of B to 7.01 up to 8.00 min, and 70% of B up to 10 min. The eluent mixture was previously filtered with a Millipore system equipped with a 0.2 μm nylon filter.
