Study On The Chemical Constituents Of The Crude Saponins And Sapogenins From Phytolacca Esculenta Van Houtte

Radix Phytolaccae, a well-known traditional Chinese drug "Shanglu" collected in Chinese pharmacopeia, is the radix of Phytolacca esculenta Van Houtte(P. acinosa Roxb.) or P. americana L., which both belong to the family of Phytolaccaceae. According to Traditional Chinese Medicine, Shanglu is bitter in flavor and cold in nature, and attributive to the lung, kidney and large intestine meridians, used for treatment of edema, abdominal fullness, dysuria, abnormal defecation and external application for treatment of carbuncle and sore.According to "Compendium of Materia Medica", the plants of Shanglu grow in the mountain or valley in Xianyang of Shaanxi province, so Shaanxi province is the genuine place of Shanglu. In order to fully exploit the Shanglu resources in Shaanxi, on the basis of literatures, the author research the chemical constituents of the total saponins and genins of Shanglu. The dissertation is divided into three parts, as follows:In the first part, there are the reviews of Shanglu, including the herb, plant, chemical constituents and pharmacological aspects.In the second part, the author study the chemical constituents of the crude saponins, as follows:The major biological activity of Shanglu is due to its triterpenoid saponins,which were reported to have considerable activities. In this research, the freshradix of Phytolacca esculenta was collected, then washed, cut into pieces anddried. After that, the drug was immersed with 70% ethanol for several days,after removing the solvent, the ethanol extracts were dispersed into water, extracted with chloroform and n-BuOH saturated with water in sequence. The n-Bu OH extracts were condensed to get the saponins which were then subjected to silica gel column chromatograph, ODS column chromatograph and sephadex L H-20 column chromatograph to obtain five compounds.Through measuring their physical and chemical constants and spectroscopic analysis, their structures were elucidated as 3-O-β-D-xylopyranosyl phytolaccagenin (esculentoside B,compound II), 3-O-β-D-glucopyranosyl phytolaccagenin (esculentoside D, compound III), 3-O-[β-D-glucopyranosyl-(1→4)-β-D-xylopyranosyl] phytolaccagenin (esculentoside A, compound IV), 3-O-[β-D-glucopyranosyl-(1→4)-β-D-xylopyranosyl]-28-O-β-D-glucopyranosyl phytolaccagenin (esculentoside H, compound V), daucosterol (compound I).At the same time, the procedure of isolation saponins from Phytolacca esculenta was also investigated. Here, in order to efficiently obtain the saponins, the n-BuOH extraction strategy and macroporous resin enrichment followed by gradient elution strategy were compared. The results showed that the former strategy yielded more crude saponins, while the latter strategy got saponins with higher purity, which are more suitable for the successive separation and purification.Esculentoside A (EsA) is the major principle in crude saponins of Phytolacca esculenta, which have considerable activities similar to that of crude saponins. The method to determine the content of EsA in radix phytolaccae was mostly focus on thin layer scanning, because of lacking conjugated system in its structure, that make it difficult to be detected by UV detector. In this situation, ELSD was adopted, HPLC coupled with ELSD seems more powerful in detecting saponins constituent with weak UV absorption. Here, the contents of EsA in radix phytolaccae which collected from different places and different periods of a year were determined, as well as different parts of the plant were detected. It may serve as a basis research to add content determination issue to the radix phytolaccae quality control in future 2010 edition Chinese pharmacopeia.In the third part, the author study the chemical constituents of the genins from P. esculenta, as follows:In this part, the hydrolysis of saponins from Phytolacca esculenta was performed. Through acid hydrolysis, genins which were mainly phytolaccagenin were obtained. The pharmacological experiment showed it has significantly effects of relieving cough and eliminating phlegm, and was applied for an invention patent. Moreover, the active part was purified, and phytolaccagenin was separated. All this serve as the preliminary study for the new drug development. Considering acid hydrolysis may cause pollution, a further research was carried out in order to find an effective but unpolluted way to get genins. In this case, bioconversion was considered, so enzymatic hydrolysis was investigated, includingβ-glucosidase from aspergillus niger and amygdala amara, snailase and other enzymes. The results showed that enzymes from aspergillus niger, amygdala amara and snails can hydrolyze the glucose of EsA to get a secondary saponin EsB, but only snail enzymes can hydrolyze the whole saccharide chain to afford phytolaccagenin, however, the yield was low.