RESUMO
Polygala tenuifolia Willd. is a traditional Chinese herbal medicine that is widely used in treating nervous system disorders. Triterpene saponins in P. tenuifolia (polygala saponins) have excellent biological activity. As a precursor for the synthesis of presenegin, oleanolic acid (OA) plays an important role in the biosynthesis of polygala saponins. However, the mechanism behind the biosynthesis of polygala saponins remains to be elucidated. In this study, we found that CYP716A249 (GenBank: ASB17946) oxidized the C-28 position of ß-amyrin to produce OA. Using quantitative real-time PCR, we observed that CYP716A249 had the highest expression in the roots of 2-year-old P. tenuifolia, which provided a basis for the selection of samples for gene cloning. To identify the function of CYP716A249, the strain R-BE-20 was constructed by expressing ß-amyrin synthase in yeast. Then, CYP716A249 was co-expressed with ß-amyrin synthase to construct the strain R-BPE-20 by using the lithium acetate method. Finally, we detected ß-amyrin and OA by ultra-HPLC-Q Exactive hybrid quadrupole-Orbitrap high-resolution accurate mass spectrometry and GC-MS. The results of this study provide insights into the biosynthesis pathway of polygala saponins.
Assuntos
Clonagem Molecular/métodos , Polygala/genética , Polygala/metabolismo , Proteínas de Saccharomyces cerevisiae/biossíntese , Proteínas de Saccharomyces cerevisiae/genética , Triterpenos/metabolismo , Proteínas de Arabidopsis/biossíntese , Proteínas de Arabidopsis/genética , Sistema Enzimático do Citocromo P-450/biossíntese , Sistema Enzimático do Citocromo P-450/genética , Regulação da Expressão Gênica de Plantas , Ácido Oleanólico/análogos & derivados , Ácido Oleanólico/genética , Ácido Oleanólico/metabolismo , Filogenia , Saccharomyces cerevisiae , Saponinas/biossíntese , Saponinas/genéticaRESUMO
In this paper, the RP-HPLC specific chromatography was adopted, with DIKMA-C18 (4.6 mm x 250 mm, 5 µm) as the chromatographic column, with a gradient elution compose of acetonitrile and 0.1% phosphoric acid at flow rate of 0.8 mL · min(-1), the detection wavelength was 220 nm. The difference of the HPLC specific chromatograms between the Lu Dangshen and other different base sources and different producing area of Codonopsis Radix was compared, involved in the similarities and differences of the number and the relative peak area of characteristic peaks in the HPLC specific chromatograms. The HPLC specific chromatograms of Lu Dangshen was established and the relative retention times of seven peaks was determined, and the peaks of codonopyrrolidium B, syringin, lobetyolin, tangshenoside I and atractylenoide III were identified; The HPLC specific chromatograms of Lu Dangshen provided a method for scientific evaluation and effective control the quality of Lu Dangshen from Shanxi famous-region.
