Novel acylated lipo-oligosaccharides from the tubers of Ipomoea batatas

Nine new lipo-oligosaccharides, batatosides H-P, were isolated from the tubers of Ipomoea batatas (Convolvulaceae). Spectral and chemical methods allowed to characterize them as tetra- or penta-saccharides that form a macrolactone with the aglycone, (11S)-hydroxyhexadecanoic acid (jalapinolic acid), the absolute configuration of which was established by Mosher’s method. Batatosides L and O showed a weak inhibitory effect on the growth of Hep-2 cells, while the others proved to be inactive.     

Bacterial resistance modifying tetrasaccharide agents from Ipomoea murucoides

As part of an ongoing project to identify oligosaccharides which modulate bacterial multidrug resistance, the CHCl₃-soluble extract from flowers of a Mexican arborescent morning glory, Ipomoea murucoides, through preparative-scale recycling HPLC, yielded five lipophilic tetrasaccharide inhibitors of Staphylococcusaureus multidrug efflux pumps, murucoidins XII-XVI (1-5). The macrocyclic lactone-type structures for these linear hetero-tetraglycoside derivatives of jalapinolic acid were established by spectroscopic methods. These compounds were tested for in vitro antibacterial and resistance modifying activity against strains of Staphylococcus aureus possessing multidrug resistance efflux mechanisms. Only murucoidin XIV (3) displayed antimicrobial activity against SA-1199B (MIC 32 μg/ml), a norfloxacin-resistant strain that over-expresses the NorA MDR efflux pump. The four microbiologically inactive (MIC > 512 μg/ml) tetrasaccharides increased norfloxacin susceptibility of this strain by 4-fold (8 μg/ml from 32 μg/ml) at concentrations of 25 μg/ml, while murucoidin XIV (3) exerted the same potentiation effect at a concentration of 5 μg/ml.     

Acylated peonidin glycosides from duskish mutant flowers of Ipomoea nil

Five acylated peonidin glycosides were isolated from the pale gray-purple flowers of a duskish mutant in the Japanese morning glory (Ipomoea nil or Pharbitis nil) as major pigments, along with a known anthocyanin, Heavenly Blue Anthocyanin (HBA). Three of these were based on peonidin 3-sophoroside and two on peonidin 3-sophoroside-5-glucoside as their deacylanthocyanins; both deacylanthocyanins were acylated with caffeic acid and/or glucosylcaffeic acids. By spectroscopic and chemical methods, the structures of the former three pigments were determined to be 3-O-[2-O-(6-O-(trans-caffeoyl)-beta-D-glucopyranosyl)-beta-D-glucopyranoside], 3-O-[2-O-(6-O-(3-O-(beta-D-glucopyranosyl)-trans-caffeoyl)-beta-D-glucopyranosyl)-6-O-(4-O-(6-O-(3-O-(beta-D-glucopyranosyl)-trans-caffeoyl)-beta-D-glucopyranosyl)-trans-caffeoyl)-beta-glucopyranoside], and 3-O-[2-O-(6-O-(trans-caffeoyl)-beta-D-glucopyranosyl)-6-O-(4-O-(6-O-(3-O-(beta-D-glucopyranosyl)-trans-caffeoyl)-beta-D-glucopyranosyl)-trans-caffeoyl)-beta-D-glucopyranoside] of peonidin. The structures of the latter two pigments were also confirmed as 3-O-[2-O-(6-O-(trans-caffeoyl)-beta-D-glucopyranosyl)-beta-D-glucopyranoside]-5-O-beta-D-glucopyranoside, and 3-O-[2-O-(6-O-(trans-caffeoyl)-beta-D-glucopyranosyl)-6-O-(4-O-(6-O-(3-O-(beta-D-glucopyranosyl)-trans-caffeoyl)-beta-D-glucopyranosyl)-trans-caffeoyl)-beta-D-glucopyranoside]-5-O-beta-D-glucopyranoside of peonidin. The mutation affecting glycosylation and acylation in anthocyanin biosynthesis of Japanese morning glory was discussed.     

五爪金龙中香豆素类物质含量及其对福寿螺、水稻和稗草的影响

在不同季节采集并测定了入侵植物五爪金龙不同器官中伞形花内酯(Umbelliferone(UMB))和东莨菪亭内酯(Scopoletin(SCO))的含量、同时室内分析了这两种物质的杀螺效果及其对水稻和稗草生长的影响、并研究了这两种物质在土壤中的降解情况。结果表明:五爪金龙植株中SCO含量高于UMB含量,两物质均是夏季含量最高,春季次之,秋冬季低,SCO夏季在茎中含量最大,秋冬季幼茎和幼叶中含量较高;UMB对福寿螺的毒杀力强于SCO,UMB浓度为C2(200μg/mL)时处理24 h对福寿螺的致死率达100%,而SCO浓度为C2时处理24 h对福寿螺的致死率仅为8%;SCO对水稻和稗草苗生长的影响较UMB强,在C0(50μg/mL),C1(100μg/mL)、C2浓度下均促进水稻及稗草苗的生长,而C3(400μg/mL)浓度下则抑制水稻和稗草苗的生长。UMB和SCO混合溶液比单一物质在相同浓度的杀螺效果及对水稻和稗草的生长影响要强;UMB和SCO在土壤中10 d内完全降解。入侵植物五爪金龙中的次生物质UMB和SCO在稻田中的生态效应值得进一步研究。     

Two triacylated and tetraglucosylated anthocyanins from Ipomoea asarifolia flowers

Two triacylated and tetraglucosylated anthocyanins derived from cyanidin were isolated from the flowers of Ipomoea asarifolia and their structures elucidated using chemical, GC, MS and NMR methods (1H and 13C, TOCSY-1D, DQF-COSY, DIFFNOE and HMBC). These complex pigments were found to consist of cyanidin 3-O-[2-O-(6-O-E-caffeoyl-beta-D-glucopyranosyl)]-[6-O-[4-O-(6-O-E-3,5-dihydroxycinnamoyl-beta-D-glucopyranosyl)-E-caffeoyl]-beta-D-glucopyranosyl]-5-O-beta-D-glucopyranoside and cyanidin 3-O-[2-O-(6-O-E-p-coumaroyl-beta-D-glucopyranosyl)]-[6-O-[4-O-(6-O-E-p-coumaroyl-beta-D-glucopyranosyl)-E-caffeoyl]-beta-D-glucopyranosyl]-5-O-beta-D-glucopyranoside.     

Cryopreservation of sweetpotato (Ipomoea batatas) and its pathogen eradication by cryotherapy

Sweetpotato (Ipomoea batatas) ranks as the seventh most important staple crop in the world and the fifth in developing countries after rice, wheat, maize and cassava. Sweetpotato is mainly grown in developing countries, which account for more than 95% of total production of the whole world. Genetic resources, including cultivated varieties and wild species, are a prerequisite for novel sweetpotato breeding in both conventional and genetic engineering programs. Various cryopreservation protocols have been developed for shoot tips and embryogenic tissues. The former explants are preferred for long-term conservation of sweetpotato genetic resources, while the latter are valuable for sweetpotato genetic improvement. This review provides update comprehensive information on cryopreservation of sweetpotato shoot tips and embryogenic tissues.Plant pathogens such as viruses and phytoplasma severely hamper high yield and high quality production of sweetpotato. Thus, usage of pathogen-free planting materials is pivotal for sustainable sweetpotato production. Cryotherapy of shoot tips can efficiently eradicate sweetpotato pathogens such as viruses and phytoplasma. The mechanism behind pathogen eradication by cryotherapy of shoot tips has been elucidated. Pathogen eradication by cryotherapy provides an alternative, efficient strategy for production of pathogen-free plants. In addition, cryopreserved tissues may also be considered to be safer for exchange of germplasm between countries and regions.     

Dimeric anthocyanins from strawberry (Fragaria ananassa) consisting of pelargonidin 3-glucoside covalently linked to four flavan-3-ols

Flavanol-anthocyanin complexes were isolated by successive use of Amberlite XAD-7 chromatography, Sephadex LH-20 gel filtration and preparative HPLC from acidified, methanolic extract of strawberries (Fragaria ananassa Dutch.). These purple minor pigments were characterized by UV-Vis spectroscopy, 1D and 2D NMR techniques, and electrospray mass spectrometry to be catechin(4alpha --> 8)pelargonidin 3-O-beta-glucopyranoside (1), epicatechin(4alpha --> 8)pelargonidin 3-O-beta-glucopyranoside (2), afzelechin(4alpha --> 8)pelargonidin 3-O-beta-glucopyranoside (3) and epiafzelechin(4alpha --> 8)pelargonidin 3-O-beta-glucopyranoside (4). The stereochemistry at the 3- and 4-positions of the flavan-3-ol units was based on assumption of R-configuration at C-2. Each of the four pigments occurred in the NMR solvent as a pair of rotamers. Proved by cross-peaks in the 1H-1H NOESY NMR spectra of 1, 2 and 4, the two conformations within each rotameric pair were in equilibrium with each other. Even though 1 and 2 are based on a different aglycone, their structures may be similar to tentatively identified pigments, which have been assumed to contribute to the colour of red wines.     

Peroxidase from Ipomoea batatas seedlings: Purification and properties

A peroxidase has been purified to homogeneity from Ipomoea batatas seedlings using ammonium sulphate precipitation and chromatography on DEAE-cellulose and SP-Sephadex columns. The pH optimum of the enzyme was found to be dependent on the buffer and substrate used. The isoelectric point is 7.3. The activation energy was estimated to be 14 kcal/mole. The prosthetic group was shown to be ferriprotoporphyrin IX. Gel chromatography and PAGE indicate that the purified protein is composed of a single polypeptide of MW 42 000. The amino acid composition appears to be similar to those reported for other plant peroxidases.     

浮床空心菜对氮循环细菌数量与分布和氮素净化效果的影响

通过在塑料水箱中水培空心菜(Ipomoea aquatica),研究浮床空心菜对氮循环细菌数量、分布和氮素净化效果的影响。研究结果表明,浮床空心菜氮循环细菌总数、氨化菌、亚硝化菌、硝化菌数量极显著高于空白对照(P<0.01),浮床空心菜反硝化菌数量与空白对照差异不显著(P>0.05);氨化菌在根内、根面、水体中的分布差异不大,亚硝化菌主要分布在根内和根面,硝化菌主要分布在根面,反硝化菌主要分布在水体中;试验结束时,浮床空心菜系统和空白对照对氨氮的去除率分别为91.8%和88.5%,对总氮的去除率分别为48.2%和62.1%。通过浮床空心菜各种氮循环细菌数量、分布与氮素浓度的相关性分析,发现浮床空心菜系统中氮素的去除是植物吸收,根系表面的氨化作用,以及水体中硝化、反硝化共同作用的结果,而空白对照系统中氮素的主要去除途径是微生物的硝化/反硝化作用以及氨挥发。     

A new β-d-quinovoside from commercial Ipomoea purga

Treatment of convolvulin (the ether insoluble portion of purified jalap resin) with sodium methoxide in methanol has yielded a new β-d-quinovoside. Periodate oxidation and methylation studies together with chemical and spectroscopic analyses have shown this fragment to consist of one molecule of d-quinovose glycosidically linked to a molecule of methyl 11-hydroxytetradecanoate.     

Acylated anthocyanins from the violet-blue flowers of Orychophragonus violaceus

Three acylated cyanidin 3-sambubioside-5-glucosides (1-3) were isolated from the violet-blue flowers of Orychophragonus violaceus, and their structures were determined by chemical and spectroscopic methods. Two of those acylated anthocyanins (1 and 3) were cyanidin 3-O-[2-O-(2-O-(4-O-(6-O-(4-O-(beta-D-glucopyranosyl)-trans-caffeoyl)-beta-D-glucopyranosyl)-trans-caffeoyl)-beta-D-xylopyranosyl)-6-O-(4-O-(beta-D-glucopyranosyl)-trans-acyl)-beta-D-glucopyranoside]-5-O-(6-O-malonyl-beta-D-glucopyranoside)s, in which the acyl groups were p-coumaric acid for 1, and sinapic acid for 3, respectively. The last anthocyanin 2 was cyanidin 3-O-[2-O-(2-O-(4-O-(6-O-(4-O-(beta-D-glucopyranosyl)-trans-caffeoyl)-beta-D-glucopyranosyl)-trans-caffeoyl)-beta-D-xylopyranosyl)-6-O-(4-O-(beta-D-glucopyranosyl)-trans-feruloyl)-beta-D-glucopyranoside]-5-O-beta-D-glucopyranoside. In these flowers, the anthocyanins 2 and 3 were present as dominant pigments, and 1 was obtained in rather small amounts.     

Chemical compositions,antimicrobial and herbicidal effects of essential oils isolated from Turkish Tanacetum aucheranum and Tanacetum chiliophyllum var. chiliophyllum

The chemical composition of essential oils isolated from the aerial parts by hydrodistillation of Turkish Tanacetum aucheranum and Tanacetum chiliophyllum var. chiliophyllum were analyzed by GC–MS. The oils contain similar major components. The major components of T. aucheranum oil were 1,8-cineole (23.8%), camphor (11.6%), terpinen-4-ol (7.2%), α-terpineol (6.5%), borneol (3.8%), (E)-thujone (3.2%), epi-α-cadinol (3.1%), and artemisia ketone (3.0%). Camphor (17.9%), 1,8-cineole (16.6%) and borneol (15.4%) were found to be predominant constituents in the oil of T. chiliophyllum. It is interesting to find that ester derivatives of dihydro-α-cyclogeranic acid (2,2,6-trimethylcyclohexylcarboxylate), dihydro-α-cyclogeranyl hexanoate (10.1%), dihydro-α-cyclogeranyl pentanoate (3.0%), dihydro-α-cyclogeranyl butanoate (2.1%) and dihydro-α-cyclogeranyl propionate (1.2%) are firstly found as chemotaxonomically important components in T. chiliophyllum oil. From these, dihydro-α-cyclogeranyl hexanoate was isolated on silica gel column chromatography and its structure was confirmed by spectroscopic methods. This is the first report on the occurrence of ester derivatives of dihydro-α-cyclogeranic acid in essential oils of Tanacetum species. The oils were also characterized to have relatively high amounts of oxygenated monoterpenes. Results of the antifungal testing by microbial growth inhibition assays showed that the oils completely inhibit the growth of 30 phytopathogenic fungi. However, their growth inhibition effects were lower than commercial benomyl. The oils tested for antibacterial activity against 33 bacterial strains showed a considerable antibacterial activity over a wide spectrum. Herbicidal effects of the oils on seed germination of Amaranthus retroflexus, Chenopodium album and Rumex crispus were also determined and the oils completely inhibited the seed germination and seedling growth of the plants.     

入侵杂草五爪金龙在切割处理下的再生能力

对五爪金龙(Ipomoea cairica (Linn.) Sweet)进行切割试验,对其在不同光环境及不同季节的萌芽率、成活率、主茎长度和生物量等进行研究。结果表明:五爪金龙切条越短其萌芽越迟,其成活率、主茎长度和生物量下降;五爪金龙在光下和林下的成活率无显著差异,但林下生物量较低;切条越短,林下条件越不利于主茎的伸长;冬季五爪金龙的主茎长度和生物量最低;夏季在光下和林下不能再生的最长切条长度均为4 cm;秋季均为1 cm;而冬季光下为1 cm,林下为3 cm;春季光下则为4 cm,林下为5 cm。春季时将五爪金龙切割为5 cm并置于林下是最经济的防除方法;如果不考虑季节性及光条件,应将其切割至1 cm以下的片段,可以有效防止五爪金龙再生。     

Effects of chlorogenic and caffeic acids on IAA oxidase preparations from sweet potato roots

IAA oxidase preparations from sweet potato (Ipomoea batatas) roots oxidised IAA in the absence of added phenolics. Activity was optimal around pH 6·8 and a minor pH optimum occurred around pH 4·3. Both chlorogenic and caffeic acids inhibited IAA oxidase activity at high concentrations (0·6–5·7 nmol/ml) but stimulated enzyme activity at low concentrations (0·10-0·55 nmol/ml); these effects were dependent on IAA and enzyme concentration and on pH. The activities of both substances are compared with those of other phenolics known to stimulate and inhibit plant IAA oxidases.     

Chemical markers in Veronica sect. Hebe. II

In a continued chemosystematic investigation of the water-soluble compounds in Veronica sect. Hebe, four additional species were investigated. In comparison to other, Northern Hemisphere (NH) species of Veronica, those belonging to the New Zealand species in sect. Hebe are apparently more variable in chemical content. In addition to the compounds characteristic for NH Veronica, namely mannitol, aucubin, catalpol and 6-O-esters of catalpol as well as some caffeoyl phenylethanoid glucosides (CGPs), Veronica topiaria (syn. Hebe topiaria) also gave an unusual 6-O-ester of aucubin named topiarioside. The former Hebe species Veronica cupressoides and Veronica stenophylla each provided one of the two previously undescribed disaccharide esters named hebitol I and II, respectively, and the former plant also provided a CPG named cuproside, a 6-O-β-glucopyranosyl derivative of the known hebeoside. The last species, namely Veronica hulkeana (syn. Heliohebe hulkeana) only contained compounds common to other species of Veronica. The taxonomic results are discussed and it is concluded that carbohydrate esters are common in sect. Hebe. The data so far obtained indicate that the occurrences of esters of 6-O-rhamnopyranosylcatalpol are confined to the most derived species in the section.