HPLC Analysis of Bioactive Diterpenoids from the Root Bark of Pseudolarix kaempferi

CHUN-FENG QIAO, QUAN-BIN HAN, JING-ZHENG SONG, SHI-FU MO, CHUN TAI AND HONG-XI XU*

(Received: April 13, 2006; Accepted: August 1, 2006)

   The root bark of Pseudolarix kaempferi, a famous traditional Chinese medicine, has been commonly used in China to treat skin diseases caused by fungal infections.  To evaluate its pharmatherapeutic quality, a sensitive, simple and accurate high-performance liquid chromatography (HPLC) method was developed for the quantitative analysis of three major bioactive diterpenoids, pseudolaric acids A-C in P. kaempferi.  A Zorbax XDB RP-C18 (4.6 mm × 250 mm, 5 μm) was used in this HPLC system, with UV detection at 260 nm.  A gradient elution was effected by a mobile phase composed of acetonitrile and 1% aqueous acetic acid, where acetonitrile concentration was changed from 30% to 60% in 30 min.  These three constituents were well resolved by this method with good linear relationships in the range of 0.982-98.2 μg/mL for pseudolaric acid A, 0.618-61.8 μg/mL for pseudolaric acid B, and 1.052-105.2 μg/mL for pseudolaric acid C, respectively.  The correlation coefficients of the calibration curves were all over 0.999.  In addition, these three compounds in six batches of the root barks of P. kaempferi were quantitatively determined to evaluate the effectiveness of this method.

Key words: Pseudolarix kaempferi, pseudolaric acid A, pseudolaric acid B, pseudolaric acid C, HPLC, determination