Magnolia Quality Evaluation, Based On The Analysis Of Water-soluble Ingredients

The stem bark of M. officinalis (magnoliae officinalis cortex) has been extensively used as a traditional Chinese medicine for the treatment of abdominal distention and pain, dyspepsia, and phlegm of cough with asthma. Previous chemical studies focused on its lipophilic ingredients, such as neolignans, alkaloids and volatile oil. Honokiol and magnolol were considered to be the major phenolic ingredients, and their contents were used as the index to evaluate the quality of magnoliae officinalis cortex. Traditionally, magnoliae officinalis cortex is boiled in water to extract active ingredients, hydrophilic ingredients were thus regarded to have more relation with their clinic effect. However, little work has been done on the hydrophilic ingredients. The paper deals with the isolation, structure elucidation, and activity of eleven hydrophilic ingredients. Meanwhile, the quality evaluation of magnoliae officinalis cortex was established on the basis of the hydrophilic ingredients.The dissertation includes four chapters:Chaper 1:Review on the research progress of magnoliae officinalis cortex.The correlative literature have been presented and analyzed, including plant resources, plant genetics, chemical components and pharmacological effects, etc.Chapter 2:Chemical studies on hydrophilic ingredients.Eleven compounds have been isolated using D101 macroporous resin, LH-20 and RP-C18. Their structures were identified by NMR, MS spectroscopy. They are magnoloside A (1), magnoloside D (2), magnoloside E (3), magnoloside B (4), magnoflorine (5), trans-syringin (6), methyl caffeate (7), syringaresinol-4,4'-O-bis-β-D-glucoside (8),1,1'-dibenzene-6',8',9'-trihydroxy-3-allyl-4-O-β-D-glucopyranoside (9), manglieside D (10) and saikolignanoside A (11). Among them, compounds 2 and 3 are new phenylethanoid glycosides, and the others were isolated from this plant for the first time except for compound 6.Chapter 3:Studies on pharmacological activities.The effects of six compounds on the contraction of isolated rat intestine in Ach and on the intestinal peristalsis in vivo were studied. Magnolol, honokiol, syringin, magnoloside B, and magnoloside A inhibited the muscle contraction of isolated rat intestine in a dose-dependent manner.The antioxidant activities of the eleven ingredients mentioned above were evaluated in ORAC and DPPH assays. The results show that, magnoloside A, magnoloside B, magnoloside D and magnoloside E display strong antioxidant effects. Magnoflorine, manglieside D, saikolignanoside A and compound 9, four of which display poor antioxidant effects in DPPH assay, exhibit the similar antioxidant effects to magnolol and honokiol in ORAC assay. The present results suggest that the antioxidant activities of compounds are relevant to the number of phenolic hydroxyl and pyrocatechol.Chapter 4:The quality evaluation based on the analysis of the hydrophilic ingredients.The method was established for the first time to simultaneously determine the four major ingredients, namely magnoflorine, syringin, magnoloside B, and magnoloside A. Seven peaks were detected in the HPLC fingerprint of 92 samples of magnoliae officinalis cortex. The results show that the content of 95% confidence interval of magnoflorine, syringin, magnoloside B and magnoloside A are 0.102-0.121%, 0.087-0.106%,1.041-1.279% and 0.922-1.112%, respectively. No difference was observed between the two species according to their contents of hydrophilic ingredients. There were significant differences in the contents of hydrophilic ingredients among habitats. The contents of the compounds in the branch bark are highest while in the root bark are lowest. The longer the storage time of magnoliae officinalis cortex, the lower content of the phenylpropanoid glycosides. Meanwhile, 29 samples collected from Bozhou and Anguo medicinal material market were analyzed. The result indicated that the contents of 95% confidence interval of magnoflorine, syringin, magnoloside B and magnoloside A are 0.034-0.048%,0.012-0.019%,0.065-0.148% and 0.086-0.159%, respectively. The contents of stem bark were higher than medicinal decoction pieces. To sum up, the major influencing factors of the quality of magnoliae officinalis cortex are processing and storage.