紫芝和赤芝多糖化学与生物活性的比较研究

赤芝Ganoderma lucidum和紫芝G. sinense同作灵芝使用。一直以来,因为灵芝酸类化合物对癌细胞具有细胞毒作用，所以被普遍认为是其有效成分，也是有关质控研究的焦点。但是最近的研究表明，只有赤芝含有灵芝酸，而紫芝却没有。由此，这一常用中药的质量控制面临着紧迫而严峻的挑战。另一方面，作为主要成分，紫芝和赤芝多糖均有明显的免疫调节作用，并能显著抑制肿瘤生长，理应成为质控的重点。然而目前的研究多集中在粗多糖的层面，仅偶有赤芝纯化多糖的报道,对紫芝多糖更是知之甚少，整体研究缺乏系统性，作用机理也不甚清楚。本项目旨在使用系统的提取分离结构解析手段，以及抗肿瘤、免疫调节、心肌细胞保护等多个活性研究平台，对紫芝和赤芝多糖（分总多糖、中性/酸性组分和纯化多糖）的化学结构、生物活性及其分子靶点进行多层次、多方面的比较研究，从而揭示二芝共有的活性物质基础，为其质量控制和研发提供科学依据。

The quality assessment of Lingzhi is challenging. Lingzhi is a popularly used anticancer fungus. According to Chinese Pharmacopeia, it includes two species: G. lucidum and G. sinense. Its anti-cancer ingredients are commonly thought to be ganoderic acids (GAs), however, only G. lucidum contains GAs. If this is true, G. sinense should not be certified as Lingzhi. Instead, the anticancer components may be polysaccharides, as indicated by a number of publications and our own work. In order to solve this problem, the chemical nature of these two species, and the active anticancer components need to be determined and compared. People think GAs are the active components because they are bioavailable; however, GAs are not water soluble and the two species have different GA profiles. On the other hand, both species are rich in polysaccharides; polysaccharides are water-soluble, hence abundant in the decoctions-which is the usual form in which they are consumed. However, these polysaccharides appear to be poorly bioavailable. In collaboration with pharmacologists, we have proven that oral feeding with the crude polysaccharide of both Lingzhi species signicantly suppressed the growth of different tumors in mice. And decoctions of both speices showed identical molecular distribution patterns in HPGPC (high performance gel permeation chromatography) examination. We hypothesize that the polysaccharides of two Ganoderma species are biologically and chemically equivalent. Further separation has yielded 20+ purified polysaccharides. Some have been tested and exhibit significant inducing effects on the cytokine secretion of PBMCs (peripheral blood mononuclear cells), macrophages, and DCs (dendric cells), especially inducing the maturation of DCs via TLR-4 pathway. It is hypothesized that these polysaccharides, without entering blood, might work as immunotherapy agents to sensitize the DCs in the intestine which is known as trigger to activate cytoxotic T lymphocytes against cancer cells. This project will provide substantial scientific evidences to determine the Ganoderma chem-/bio-equivalence by 1) qualitative and quantitative analysis of their polysaccharide profiles using innovative recycling HPGPC and purified/characterized polysaccharide markers and by 2) evaluation of the bio-equivalence of these polysaccharides' bioacvities using various animal/cell models in three aspects: a. in vivo/in vitro anticancer effects; b. immunomodulating effects on macrophages and Dendritic cells; c. interaction with TLRs. This project will offer a successful example for polysaccharide-based quality control of many Lingzhi-like Chinese medicines that are rich in saccharides and traditionally used in the form of decoction.