Determination of Carotenoids in the Chinese Medical Herb Jiao-Gu-Lan (Gynostemma Pentaphyllum MAKINO) by Liquid Chromatography

Abstract

The amount and variety of carotenoids in Jiao-Gu-Lan (Gynostemma pentaphyllum MAKINO), a traditional Chinese medicinal herb which is currently sold in Taiwan and China as herbal tea, were determined by HPLC. Dried Jiao-Gu-Lan samples were ground into fine materials, and the carotenoids were extracted, saponified and subjected to HPLC analysis. A gradient mobile phase of methanol/isopropanol (99/1, v/v) (A) and methylene chloride (B) was used: 100% A and 0% B initially, maintained for 15 min, decreased to 70% A in 45 min, maintained for 15 min, and returned to 100% A in 65 min. A total of 25 carotenoids were resolved within 54 min by using a C-30 column with flow rate at 1.0 mL min⁻¹ and detection at 450 nm. For all the six cultivars of Jiao-Gu-Lan samples, all-trans-lutein was present in largest amount (72–376 μg g⁻¹), followed by cis isomers of lutein (0–72 μg g⁻¹), neochrome (13–65 μg g⁻¹), neoxanthin (0–41 μg g⁻¹), all-trans- α-carotene (0–27 μg g⁻¹), auroxanthin (7–23 μg g⁻¹), violaxanthin (3–22 μg g⁻¹), luteoxanthin (4–19 μg g⁻¹), all-trans-β-carotene (0–7.6 μg g⁻¹), β-cryptoxanthin (0–6.7 μg g⁻¹), and cis isomers of β-carotene (0–1.9 μg g⁻¹), on a dry weight basis.