peroxidase-linked spectrophotometric assay for the detection of monoamine oxidase inhibitors

To develop a new more accurate spectrophotometric method for detecting monoamine oxidase inhibitors from plant extracts, a series of amine substrates were selected and their ability to be oxidized by monoamine oxidase was evaluated by the HPLC method and a new substrate was used to develop a peroxidase-linked spectrophotometric assay. 4-[Trifluoromethyl] benzylamine [11] was proved to be an excellent substrate for peroxidase-linked spectrophotometric assay. Therefore, a new peroxidase-linked spectrophotometric assay was set up. The principle of the method is that the MAO converts 11 into aldehyde, ammonia and hydrogen peroxide. In the presence of peroxidase, the hydrogen peroxide will oxidize 4-aminoantipyrine into oxidised 4-aminoantipyrine which can condense with vanillic acid to give a red quinoneimine dye. The production of the quinoneimine dye was detected at 490 nm by a microplate reader. The delta[OD] value between the blank group and blank negative control group in this new method is twice as much as that in Holt's method, which enables the procedure to be more accurate and avoids the produce of false positive results. The new method will be helpful for researchers to screening monoamine oxidase inhibitors from deep-color plant extracts

Studies on chemical constituents of herbs of Oxytropis microphylla / 中国中药杂志

<p><b>OBJECTIVE</b>To study the chemical constituents of Oxytropis microphylla.</p><p><b>METHOD</b>The compounds were isolated and purified by various column chromatographic techniques and their structures were elucidated on the basis of spectral analysis (EI-MS, 1H-NMR, 13C-NMR).</p><p><b>RESULT</b>Eight compounds were isolated and identified as kaempferol (1), baicalein (2), 5-hydroxy-7, 8, 4'-trimethoxyflavone (3), stigmasterol (4), stigmast-4-en-3beta-ol (5), beta-sitosterol (6), lupenol (7), dehydrocostus lactone (8).</p><p><b>CONCLUSION</b>All compounds were isolated for the first time from this plant, compounds 2, 3, 5, and 8 were isolated for the first time from this genus.</p>

Isolation and identification of chemical constituents in Hemerocallis fulva (Ⅱ) / 中草药

Objective To study the chemical constituents in the roots of Hemerocallis fulva. MethodsCompounds were isolated from the CHCl3and n-butanol fraction of the EtOH extract by repeated column chromatography and their structures were identified by spectral analysis and physicochemical properties. Results From the CHCl3 and n-butanol fraction of the EtOH extract in the roots of H. fulva,ten compounds were isolated and identified as terresoxazine (Ⅰ),11-keto-?-boswellic acid (Ⅱ),hopane-6?,22-diol (Ⅲ),hecogenin (Ⅳ),stigmast-4-en-3?-ol (Ⅴ),stigmast-4-en-3-one (Ⅵ),?-feruloyloxy acid (Ⅶ),(E)-3,4-dihydroxyl cinnamic acid (Ⅷ),(E)-p-methyl cinnamic acid (Ⅸ),and vanillic acid (Ⅹ). Conclusion Compounds Ⅰ-Ⅳ,and Ⅶ are isolated and identified from the plants of Hemerocallis L. for the first time.

Isolation and structural elucidation of triterpenes from Cremanthodium potaninii C. Winkl / 中成药

AIM: To isolate and identify triterpenes from inflorescence of Cremanthodium potaninii C.Winkl,collected from Qinghai province.METHODS: The triterpenes were isolated by column chromatography and their structures were elucidated through NMR.RESULTS: Seven triterpenes were isolated and identified as ?-amyrin(I),Taraxast-20(30)-ene-3?,16?-diol-3-O-palmitate(II),olean-12-en-3?,16?-diol-3-O-palmitate(III),Olean-12-en-3?,11?,16?-triol-3-palmitate(IV),lup-3?,16?-diol-3-O-palmitate(V),lup-3?,16?,28-triol-3-O-palmitate(VI),16?-hydroxypseudo tarsxasterol-3-O-palmitate(VII).CONCLUSION: All these compounds are obtained from Cremanthodium potaninii C.Winkl for the first time.