Quantitative Determination of Phenolic Acids in Lonicera japonica Thunb. by High Performance Thin Layer Chromatography

Lonicera japonica Thunb. is the one of the most commonly used traditional Chinese medicinal plants and is mainly used for its anti-inflammatory activity. It also used for the treatment of variety diseases including arthritis, diabetes mellitus, fever, infections, sores, and swelling [1, 2]. Recent studies indicated that the flowers of L. japonica also exhibited good antioxidant activities [3]. Phenolic acids are believed to be one of the beneficial components responsible for its antioxidant activity, therefore were selected as the target compounds for this study.

A simple, precise and rapid high performance liquid chromatography (HPTLC) method was developed for the simultaneous quantitative determination of three phenolic acids, namely, 4,5-O-dicaffeoylquinic acid (1), 3,4-O-dicaffeoylquinic acid (2) and chlorogenic acid (3) from the flower buds of Lonicera japonica. The separation of these compounds was carried out on silica gel ⁶⁰F₂₅₄ elution with ethyl acetate: chloroform: methanol: formic acid: water (6: 2.5: 1.5: 0.6: 0.1 v/v/v/v) and a detection wavelength of 330nm. The developed method gave a good linear regression relationship between peak area and concentration was obtained over the range of 200–1200ng/ml for the three major compounds mentioned above. The mean percent content of compounds 1–3 were 2.07, 0.6, 3.7% for sample LJ-1; 1.69, 0.89, 3.0% for sample LJ-2 and 1.69, 0.55, 2.62% for sample LJ-3, respectively.

Fig.1: HPTLC chromatogram of (1) LJ-1; (2) Std mix; (3) LJ-2; and (4) LJ-4 Fig.2: Densitogram of (1) LJ-1; (2) Std mix; (3) LJ-2; and (4) LJ-4at 330nm

Acknowledgements: This research is supported in part by Science Based Authentication of Dietary Supplements and Botanical Dietary Supplement Research funded by the Food and Drug Administration grant numbers 5U01FD002071–09 and 1U01FD003871–01, and the United States Department of Agriculture, Agricultural Research Service, Specific Cooperative Agreement No. 58–6408–2-0009. References: [1] Qian ZM, Li HJ, et al. (2007) Chem Pharm Bull 55: 1073–1076. [2] Song W, Li S, et al. (2008)J Nat Prod 71: 922–925. [3] Tang D, Li HJ, et al. (2008)J Sep Sci 31: 3519–3526.