Kinetic changes and antihypertensive effect of aqueous extract of Danggui (Angelica sinensis radix) after stir-fry processing

Danggui (Angelica sinensis Radix) in East Asia for its unique pleasant flavor is usually cooked before utilizing to enhance its tonic effect. To evaluate the quality and bioactivity changes, heat treatments were carried out at 250°C for 0–45 min. 5-Hydroxymaltol, 5-hydroxymethylfurfural, Z-ligustilide, and ferulic acid in aqueous extract of processed danggui (APD) were determined by HPLC while antihypertensive effects were studied after oral administration of APD (50 and 100 mg/kg) for 3 days in spontaneously hypertensive rats (SHR). Compared with aqueous extract of danggui (AD), contents of ferulic acid and Z-ligustilide in APD were significantly decreased but 5-hydroxymaltol and 5-hydroxymethylfurfural were increased. APD could lower blood pressures, plasma renin activities, and angiotensin II levels of SHR, but AD failed to do those. APD exhibited hypotensive effects by regulating renin-angiotensin system and may warrant further evaluation as a potential antihypertensive agent.