Abstract: Noni (Morinda citrifolia) powders are botanical dietary supplement providing purported health benefits, such as scavenging free radicals, anti-cancer activity, and anti-inflammatory effect. This study aimed to optimize the ultrasonic extraction condition and to determine the contents of scopoletin, rutin, and quercetin in noni powders by high performance liquid chromatography (HPLC). The optimized extraction parameters that provided the maximum extraction efficiency were determined as follows: a mixture of methanol and water as extraction solvent, 80%; extraction time, 30 min; temperature, 20 ℃ and ultrasonic frequency, 45 kHz. With an Elite Hypersil ODS column (4.6 mm × 250 mm，5 μm), the HPLC separation was achieved by a gradient mobile phase composed of acetonitrile, methanol, and H2O with a flow rate of 1.0 mL/min at a column temperature of 25 ℃. The quantitative analysis of scopletin, rutin, and quercetin exhibited a good linear relationship, r2≥0.999 8, low detection limit (≤ 1.30 μg/L), high recovery (90.67%–113.00%), and good repeatability (RSD ≤ 1.46%, n = 8). The method proved to be accurate reliable, and suitable for the determination of scopletin, rutin and quercetin in noni powders.

Key words: ultrasonic extraction, scopoletin, rutin, quercetin, noni powder