地钱中总黄酮含量的测定

采用改进的铝盐显色分光光度法 ,在 5 2 5 nm波长下 ,Na NO2 - Al Cl3 - Na OH为显色剂 ,常温显色 ,15 min内测定地钱黄酮提取物中总黄酮的含量。在 4 0— 4 0 0 μg/ m L范围内线性关系良好 ,回归方程为 A=0 .0 30 0 C- 0 .0 15 3,RSD=0 .16 % ,相关系数为 0 .9997,加标回收率在 97.6 1%— 10 1.5 9%范围内。本法用于地钱中总黄酮含量的测定 ,方法准确、可靠 ,结果令人满意     

Molecular evolution of mitochondrial introns in the liverwort Marchantia polymorpha

We here describe in detail the characterization and molecular evolution of group II introns in the mitochondrial genome of the liverwort Marchantia polymorpha. We find that 18 introns of the 25 group II introns can be assigned by their similarities to six clusters, indicating an intra-genomic propagation of one ancestral intron each into the respective clusters in the liverwort mitochondrial genome. Interestingly, the intra-genomic propagation of some of these introns occurred only after the evolutionary separation of the bryophytes from the other clades of plants. Finally we report that the maturase-like sequences in the liverwort group II introns have further evolved by horizontal and independent transposition and substitution by analogous sequences from other fungal introns.     

Water‐Soluble Constituents from the Liverwort Marchantia polymorpha

Four new glycosides, the bibenzyl glycoside α,β‐dihydrostilbene‐2,4′,5‐triol 2,5‐di‐(β‐D ‐glucopyranoside) ( 1 ), the shikimic acid glycoside shikimic acid 4‐(β‐D ‐xylopyranoside) ( 2 ), and two phenylethanoid glycosides 2‐(3,4‐dihydroxyphenyl)ethyl O‐α‐L ‐rhamnopyranosyl‐(1→2)‐β‐D ‐allopyranoside ( 3 ) and 2‐(3,4‐dihydroxyphenyl)ethyl O‐β‐D ‐xylopyranosyl‐(1→6)‐β‐D ‐allopyranoside ( 4 ), together with three known aromatic glycosides were isolated from the H₂O‐soluble fraction of the EtOH extract of the liverwort Marchantia polymorpha. Their structures were elucidated on the basis of chemical and spectroscopic evidences.     

Stereochemical Investigation of Macrocyclic Bisbibenzyls with a Stereogenic Center at One of the Ethylene Bridges

7′‐Hydroxyriccardin C ( 1 ) and marchantin E ( 2 ), two macrocyclic bisbibenzyls with a stereogenic center at the ethylene bridge from Chinese liverworts, were investigated stereochemically. Compound 1 was found to be optically active and occurred as a pair of dynamically interchangeable atropisomers at room temperature due to the low barrier of rotation around the biaryl bond, while 2 was a racemic mixture, which was successfully resolved by chiral HPLC into two enantiomers. Their absolute configurations were unequivocally assigned by analysis of temperature‐dependent NMR spectra, X‐ray crystallographic diffraction, and comparison of experimental and calculated ECD data.     

Three New Bibenzyl Derivatives from the Chinese Liverwort Marchantia polymorpha L.

From the Et₂O extract of the Chinese liverwort Marchantia polymorpha L., three new bibenzyl (=1,1′‐(ethane‐1,2‐diyl)bisbenzene) derivatives, compounds 1 – 3 , were obtained, together with the two known compounds marchantin J and perrottetin E. Their structures were established by NMR and HR‐EI‐MS analyses. Polymorphatin A ( 1 ) represents a new type of bis[bibenzyl] skeleton, and compound 3 is the first example of a bibenzyl oxidatively coupled to a phenylmethanol.     

反相高效液相色谱法用于地钱中黄酮类化合物的分离与测定

采用反相高效液相色谱,在RP—C18柱上以乙酸-甲醇-乙腈-磷酸-水为多元流动相,等度洗脱,在30min内对地钱的黄酮提取物进行分离与测定,检测波长350nm,流速0．60mL／min,采用校准曲线法对实际样品中的芹菜素、槲皮素和木犀草素进行定量分析。结果表明：平均加标回收率96．79％～101．13％．相对标准偏差0．66％～1．52％．