不同采收期荔枝草中黄酮成分含量的动态变化研究

目的:为荔枝草的最佳采收期提供实验依据。方法:采用Lichrospher C18色谱柱(4.6mm×150mm,5μm);0.5%的甲酸水溶液-乙腈梯度洗脱,流速1.0mL/min,柱温:25℃,检测波长342nm。结果:高车前苷与假荆芥属苷分别在0.0472～0.472μg(r=0.9999)和0.0275～0.275μg(r=0.9999)范围内呈良好的线性关系。结论:该方法简单,结果准确可靠,重现性好。荔枝草在5月上旬未开花前黄酮含量积累达到最大,可参考作为荔枝草药材的最佳采收期。     

Redirection of flux through the phenylpropanoid pathway by increased glucosylation of soluble intermediates

The phenylpropanoid pathway is used in biosynthesis of a wide range of soluble secondary metabolites including hydroxycinnamic acid esters, flavonoids and the precursors of lignin and lignans. In Arabidopsis thaliana a small cluster of three closely related genes, UGT72E1-E3, encode glycosyltransferases (GTs) that glucosylate phenylpropanoids in vitro. This study explores the effect of constitutively over-expressing two of these GTs (UGT72E1 and E3) in planta using the CaMV-35S promoter to determine whether phenylpropanoid homeostasis can be altered in a similar manner to that achieved by over-expression of UGT72E2 as previously reported. The data show that impact of over-expressing UGT72E3 in leaves is highly similar to that of UGT72E2 in that the production of massive levels of coniferyl and sinapyl alcohol 4-O-glucosides and a substantial loss in sinapoyl malate. In contrast, the over-expression of UGT72E1 in leaves led only to minimal changes in coniferyl alcohol 4-O-glucoside and no effect was observed on sinapoyl malate levels. In roots, over-expression of both UGTs led to some increase in the accumulation of the two glucosides. The cell specificity expression of the whole UGT72E gene cluster was investigated and interestingly only UGT72E3 was found to be wound and touch responsive.     

Two phytoalexin glycosides from potato tubers infected with Phoma

Four coumarins and seven isoprenoid compounds have been identified in potato tubers infected with Phoma exigua var. foveata. Among these were the 7-O-β-D-glucopyranoside of 7-hydroxy-6,8-dimethoxycoumarin (isofraxidin) and the sesquiterpene 2-(11,12-dihydroxy-11-methylethyl)-6,10-dimethyl-spiro[4,5]dec-6-en-8-one and its 12-O-β-D-glucopyranoside, which apparently have not been previously identified in potato tubers. At least two diastereoisomers of the latter glucoside were present. Analysis of eight fluorescent compounds in different parts of infected potatoes was performed by an improved HPLC technique.     

A furan-2-carbonyl C-glucoside and an alkyl glucoside from the parasitic plant,Dendrophthoe pentandra

A new furan-2-carbonyl C-(6′-O-galloyl)-β-glucopyranoside (scleropentaside F, 1) and a new alkyl glucoside [butane-2,3-diol 2-(6′-O-galloyl)-O-β-glucopyranoside, 2] were isolated from the entire hemi-parasitic plant, Dendrophthoe pentandra growing on Tectona grandis together with ten known compounds including, benzyl-O-β-d-glucopyranoside (3), benzyl-O-α-l-rhamnopyranosyl-(1 → 6)-β-d-glucopyranoside (4), benzyl-O-β-d-apiofuranosyl-(1 → 6)-β-d-glucopyranoside (5), methyl gallate 3-O-β-d-glucopyranoside (6), methyl gallate 3-O-(6′-O-galloyl)-β-d-glucopyranoside (7), (+)-catechin (8), procyanidin B-1 (9) and procyanidin B-3 (10), bridelionoside A (11), and kiwiionoside (12). In addition, compounds 1, 3–9 were isolated from this species growing on the different host, Mangifera indica. The structure elucidations were based on physical data and spectroscopic evidence including 1D and 2D experiments.     

荔枝核的五个苷类成分

通过溶剂分部和多种色谱分离,从荔枝(Litchi chinensis Sonn.)核中得到5个苷类成分。经光谱分析及与文献数据对照,分别鉴定为(-)-松脂素4-O-β- D-吡喃葡萄糖苷 (1)、苯乙基β- D-吡喃葡萄糖苷 (2)、乙基β- D-吡喃葡萄糖苷 (3)、乙基α- D-吡喃葡萄糖苷 (4)和胞苷 (5)。它们均为首次从荔枝核中分离得到。     

A pyrone glycoside from Erigeron karwinskyanus

The aerial parts of Erigeron karwinskyanus yielded 3-hydroxy-4-pyrone 3-α-D-glucopyranoside, a new glycoside. The structure was elucidated from a combination of spectral data.     

Phenolic plant growth inhibitors from the flowers of Cucurbita pepo

Eleven compounds isolated from the growth inhibiting active fraction of male flowers of Cucurbita pepo, were identified as p-hydroxybenzaldehyde, anisyl alcohol, p-hydroxybenzyl methyl ether, p-hydroxybenzyl alcohol, veratryl alcohol, isovanillyl alcohol, p-coumaric acid, phloretic acid, benzyl-β-d-glucoside, 4-methoxybenzyl-β-d-glucoside and 3, 4-dimethoxybenzyl-β-d-glucoside. Each compound was assayed for growth inhibiting activity using lettuce seedlings; three showed strong activity, whereas the glucosides were inactive.     

Flavonoid glycosides from needles of Pinus massoniana

Seven flavonoids have been isolated from Pinus massoniana needles and identified as taxifolin and its 3′-O-β-D-glucopyranoside, (+)-catechin, naringenin-7-O-β-D-glucopyranoside and three new flavonoid glycosides, 6-C-methylaromadendrin 7-O-β-D-glucopyranoside, taxifolin 3′-O-β-D-(6″-O-phenylacetyl)-glucopyranoside and eriodictyol 3′-O-β-D-glucopyranoside.     

The enzymatic synthesis of amyrin glucoside

Label appeared in several cell fractions isolated from the cotyledons of pea seeds germinated for 48 hr with mevalonate-[2-¹⁴C]. The major radioactive metabolite in each fraction was amyrin. In a similar experiment, a fraction sedimenting between 1000 and 25 000 g and a microsomal pellet were labeled with 3H from mevalonate-[2-³H]. Each of these tritiated fractions on incubation with UDP-glucose-[U-¹⁴C] yielded CHCl₃-MeOH-soluble material bearing ¹⁴C and ³H. TLC of the extracts gave a compound chromatographically identical with a glucoside and bearing the two isotopes. Acid hydrolysis of this compound gave an ether-soluble material carrying ³H alone. On TLC it co-chromatographed with amyrin. Of the two tritiated cotyledon fractions, the microsomal pellet had the lower glucosyltransferase activity. The labeled amyrin residing in this fraction served as an acceptor for glucose from UDP-glucose in the presence of a glucosyltransferase from pea seedling axis tissue. In such a mixed preparation, the axis tissue transferase suffers a marked inhibition by the cotyledon preparation.     

Holocalin: Ein neues cyanogenes glykosid aus Holocalyx balansae

From seeds of Holocalyx balansae Mich. holocaline, a new cyanogenetic glycoside, has been isolated by chromatography on silica gel. Holocaline is enzymatically split by emulsin into glucose, HCN and m-hydroxybenzaldehyde. According to its optical rotation, it represents the hitherto unknown diastereomer of zierine.     

Two New Sesquiterpenoid Glucosides from the Aerial Parts of Saussurea involucrate

Two new sesqulterpenoid glucosides, namely α-hydroxycostic acid 6-β-D-glucopyranoside （compound 1） and 11 βH-11,13-dlhydrodehydrocostuslactone 8α-O-（6＇-acetyl）-β-D-glucopyranoside （compound 2）, along with 11 known sesqulterpenoids （compounds 3-13） were isolated from the aerial parts of Saussurea involucrate （Kar. et Kir.） Sch.- BIp. The structures of the new sesquiterpenoid glucosides were established by one- and two-dimensional nuclear magnetic resonance and mass spectrometry analysis.     

Tobacco Salicylic Acid Glucosyltransferase Is Active toward Tuberonic Acid (12-Hydroxyjasmonic Acid) and Is Induced by Mechanical Wounding Stress

Recently we reported that rice salicylic acid (SA) glucosyltransferase (OsSGT) is active toward 12-hydroxyjasmonic acid (tuberonic acid, TA) and that OsSGT gene expression is induced by wounding stress. Here we report that tobacco SA glucosyltransferase (NtSGT), which is thought to be an ortholog of OsSGT, is also active toward TA. Although NtSGT expression is known to be induced by biotrophic stress, it was also induced by wounding stress in the same manner as OsSGT. These results indicate that this glucosyltransferase is important not only in biotrophic stress but also for wounding stress. It was found that this enzyme is dually functional, with activity both toward TA and SA.     

Chlorine-containing iridoid and iridoid glucoside, and other glucosides from leaves of Myoporum bontioides

Sixteen compounds were isolated from the MeOH extract of leaves of Myoporum bontioides. The five compounds hitherto unknown, were elucidated to be a chlorine-containing iridoid, named myopochlorin, and an iridoid glucoside, an acylated iridoid glucoside, a linear acetogenin glucoside, and an acyclic monoterpene glucoside, named myobontiosides A-D, respectively, by means of spectroscopic analyses.     

黑蒴中的单萜甙类化合物

自黑蒴(Melasma arvense[Benth.]H.-M.)根中分离鉴定了羟基-β-紫罗兰酮葡萄醣甙(hydroxy-β-ionone glucosid 1)和一新的环烯醚萜甙—桃叶珊瑚甙元-1-O-β-龙胆双醣甙(aucubigenin-1-O-β-gentiobioside 2)。     

棒柄花的化学成分研究

从棒柄花(Cleidion brevipetiolatum)的乙醇提取物中分离得到6个化合物,经波谱分析确定其结构为：benzyl-1-O-β-D-glumpyranoside(1),chavicol-1-O-β-D-glumpyranoside(2),3,4,5-trimethoxyphenol(3),3,4,5-trimethoxyphenol-1-O-β-D-glucopyranoside(4),β-sitosterol(5),daumsterol(6),以上化合物均为首次从该植物中分离得到。