A survey of Chinese herbal ingredients with liver protection activities

Abstract

A literature survey was conducted on herbs, their preparations and ingredients with reported liver protection activities, in which a total of 274 different species and hundreds of active ingredients have been examined. These ingredients can be roughly classified into two categories according to their activities: (1) the main ingredients, such as silybin, osthole, coumarin, glycyrrhizin, saikosaponin A, schisandrin A, flavonoids; and (2) supporting substances, such as sugars, amino acids, resins, tannins and volatile oil. Among them, some active ingredients have hepatoprotective activities (e.g. anti-inflammatory, anticancer, antioxidant, immunomodulating and liver cirrhosis-regulating effects). Calculation of physicochemical parameters indicates that the main ingredients with negative and positive E(lumo) values possibly display their hepatoprotective effects through different mechanisms, such as antioxidative, anti-inflammatory and immunomodulating effects. As the combination of herbs may achieve some treatment effects synergistically and/or additively, it is common in Chinese medicine to use mixtures of various medicinal herbs with pharmacologically active compounds to have synergistic and/or additive effects, or to reduce harmful effects of some pharmacologically active compounds. In particular, the active compounds with Clog P around 2 are suitable for passive transport across membranes and accessible to the target sites. Thus, E(lumo) and Clog P values are good indicators among the calculated parameters. Seven different physicochemical parameters (MW, Clog P, CMR, mu, E(lumo), E(lumo) and H(f)) and four major biological activities (antioxidant, anti-inflammatory, antiviral/antitumor and immunomodulating) are discussed in this review. It is hoped that the discussion may provide some leads in the development of new hepatoprotective drugs.

Figure 1

Structures of the four isomers in silymarin.

Figure 2

Metabolism of glycyrrhizin catalyzed by β-D-glucuronidase in human liver and intestines.

Figure 3

Structures of the dibenzocyclooctadiene compounds and osthole.

Figure 4

Structures of the saikosaponin and ginsenoside compounds.

Figure 5

Damaging effects of oxyradical on biological systems and sites of blockades () by antioxidants/free radical scavengers (adapted and expanded from reference [61]).