Anti-inflammatory effects of Huang-Lian-Jie-Du decoction, its two fractions and four typical compounds

Abstract

Huang-Lian-Jie-Du decoction (HLJDD) (Oren-gedoku-to in Japanese) as a famous traditional Chinese recipe is composed of Rhizoma coptidis, Radix scutellariae, Cortex phellodendri and Fructus gardeniae. It has been used to treat inflammation for nearly two thousand years. To explore the material base for the anti-inflammatory activity of formula HLJDD, its extract was fractionated on D101 macroporous resin to afford two fractions, HLJDD-1 and HLJDD-2. The whole formula, HLJDD-1 and HLJDD-2, and four typical component compounds were then evaluated for their effects on inflammation-related parameters using lipopolysaccharide (LPS)-induced RAW264.7 cells as a model system. The effect of HLJDD on carrageenan-induced mice paw edema was first evaluated. A series of inflammation-related parameters including malondialdehyde (MDA), nitric oxide (NO), superoxide dismutase (SOD), prostaglandin E(2) (PGE2), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and interleukin-10 (IL-10) were then measured in LPS-induced RAW264.7 cells treated with HLJDD, its two fractions, and four typical component compounds (geniposide, baicalin, berberine and baicalein). With the help of principal component analysis (PCA) technique, the data obtained revealed that the two fractions and the major group of compounds in HLJDD (iridoids, flavonoids and alkaloids) complement each other with particular emphasis to synergistically exert anti-inflammatory effects. This study demonstrated that HLJDD exhibited anti-inflammatory effect as a "whole", which justified the combined use of the four component herbs forming the compound prescription and suggested quality control of HLJDD based on its three types of components.