Studies On The Active Constituents Of Two Medicinal Plants

In this thesis,Stemona tuberosa?Stemonaceae,Stemona?and Melodinus axillaris?Apocynaceae,Melodinus?were chosen as the research object,and their active constituents were systematically studied.Firstly,the active constituents of the two plants were separated and purified by silica gel column chromatography,sephadex LH-20,reversed phase C₁₈column chromatography,high performance liquid chromatography,and high speed countercurrent chromatography;Secondly,the structures of these compounds were confirmed by modern spectral techniques,such as high resolution mass spectrometry?HR-MS?,1D and2D nuclear magnetic resonance?NMR?,infrared spectroscopy?IR?and circular dichroism?CD?,et al.;Finally,the cytotoxic activity of the alkaloids isolated from M.axillaris was evaluated by the MTT assay.Stemona is slightly mild in nature,bitter and sweet,with a little poison,and has the effects of moistening lungs and cough,killing insects and killing lice.It is mainly used for treating chronic cough,tuberculosis,body lice and ringworm.Modern pharmacological studies have shown that Stemona has a good killing effect on a variety of pathogenic bacteria and skin fungi,as well as a variety of parasites and insects,and also has central sedative and analgesic effects.17 non-alkaloids were isolated from the roots of S.tuberosa?Yiyuan County,Shandong Province?and identified as syringaresinol?1??ethyl 4-hydroxybenzoate?2??p-hydroxyl ethyl cinnamate?3??stemonone B?4??3,3'-bis?3,4-dihydro-4-hydroxy-6-methoxy-2H-1-benzopyran??5??7-hydroxy-4-?3-hydroxy-4-methoxyphenyl?-6-methoxy-3a,4,9,9a-tetr-ahy-dronaphtho[2,3-c]furan-1?3H?-one?6??prestegane B?7??stemtubester A?8??stemtubester B?9??3-hydroxy-2',5-dimethoxy-2-methylbibenzyl?10??stilbostemin O?11??stemostilbin B?12??isopimpinellin?13??3,5-dihydroxy-2'-methoxy-4-methvlbibenzyl?14??stemostilbin C?15??stemostilbin D?16?and stemostilbin A?17?,respectively.Compounds 8,9,12,15,16and 17 are new compounds.The plants of Melodinus genus have the effects of promoting blood circulation,removing wind and dampness,and replenishing lungs and eliminating accumulation.They are commonly used in the treatment of abdominal pain,hernia,dyspepsia,meningitis,orchitis,fractures and rheumatic heart disease.Modern pharmacological studies have shown that they have anti-tumor,anti-inflammatory and other biological activities.28 alkaloids were isolated from the leaves of M.axillaris?Puer City,Yunnan Province?and identified as?¹⁴-vincamine?18???¹⁴-vincine?19??16-epi-?¹⁴-vincine?20??16-epi-?¹⁴-vincamine?21??melodinine F?22??epoxy-14,15?-vincamine?23??14-chlorine-16-epi-?¹⁴-vincamine?24??melokhanine I?25??15?-hydroxy-vincadifformine?26??tabersonine?27??vincadifformine?28??melotenine A?29??14?,15?-dihydroxyvincadifformine?30??11-methoxytabersonine?31??3-methylol-tabersonine?32??lochnericine?33??6,7-epoxy-8-oxo-vincadifformine?34??3-oxotabersonine?35??14,15-?-epoxy-11-methoxytabersonine?36??3-oxo-11-methoxytabersonine?37??14?-methoxy-15?-hydroxyvincadifformine?38??melotenine B?39??melosine H?40??melosuavine I?41??3-oxo-5-hydroxy-11-methoxytabersonine?42??14-chlorinetabersonine?43??3?-aceto-nyltabersonine?44??melotenine C?45?,respectively.Compounds 24,25,29,30,32,38,39,42,43 and 45 are new compounds.Compounds 27,29,33,35 and 37 were evaluated for their cytotoxicities?A549,MDA-MB-231,K562,PC-3?against four human cancer cell lines using the MTT method with cisplatin as a positive control,the results show compound 29 showed stronger inhibitory effects than cisplatin against all cancer cell lines,with IC₅₀ values ranging from 0.6 to 1.5?M and the other four compounds exhibited moderate cytotoxicity against one or more of the cell lines,indicating that alkaloids with an acetonyl group at C-5 showed more significant cytotoxicity than those without the substitution.The research work and achievements of this subject on S.tuberosa and M.axillaris will provid certain technical support and theoretical basis for the development and utilization of the two kinds of plant resources.