Akebia saponin D, a saponin component from Dipsacus asper Wall, protects PC 12 cells against amyloid-β induced cytotoxicity

According to Traditional Chinese Medicine, Alzheimer's disease (AD) is regarded as senile dementia, and the etiopathogenesis lies in kidney deficiency during aging. Dipsacus asper Wall (DAW), a well-known traditional Chinese medicine for enhancing kidney activity, may possess the therapeutic effects against AD. Our objectives were to investigate the protective effects of DAW against the amyloid-β peptide (Aβ)-induced cytotoxicity and explore its major active components. Injury of PC 12 cells mediated by Aβ_25–35 was adopted to assess the cytoprotective effects of DAW aqueous extract and various fractions. Salvianolic acid B, a polyphenol compound isolated from Salvia miltiorrhiza, was employed as a positive control agent due to its markedly protective effect against neurotoxicity of amyloid β. Five chemical fractions (i.e. alkaloids, essential oil, saponins, iridoid glucoside and polysaccharides) were prepared for activity test and analyzed by HPLC for active components identification. In addition, Akebia saponin D (the most important compound in DAW saponins) and hederagenin (the mother nucleus of akebia saponin D) were prepared for testing of their activity. DAW water extract, saponins fraction and akebia saponin D had the neuroprotective capacity to antagonize Aβ_25–35-induced cytotoxicity in PC 12 cells. In contrast, other fractions and hederagenin had no cytoprotective action. This research suggests that DAW may represent a potential treatment strategy for AD and akebia saponin D is one of its active components.     

Triterpenoid saponins with antifeedant activities from stem bark of Catunaregam spinosa (Rubiaceae) against Plutella xylostella (Plutellidae)

Seven triterpenoid saponins, including four new compounds, catunarosides A–D (1–4), and three known compounds, swartziatrioside (5), aralia-saponin V (6), araliasaponin IV (7) were isolated from the stem bark of Catunaregam spinosa, a Chinese mangrove associate. Their structures were elucidated on the basis of their spectral data and hydrolysis experiments. The antifeedant activities of compounds 1–7 against Plutella xylostella were also evaluated.     

Utility of coupled-HSQC experiments in the intact structural elucidation of three complex saponins from Blighia sapida

The structures of three complex saponins from the fruit pods of Blighia sapida have been elucidated and their ¹H and ¹³C NMR spectra assigned employing a variety of one- and two-dimensional NMR techniques without degradative chemistry. The saponins have either four or six monosaccharide units linked to a triterpene aglycone. High-resolution, proton-coupled-HSQC spectra were important for determining both the identities of the intact monosaccharide units and coupling constants in strongly coupled proton spin systems. These NMR experiments will prove crucial as the complexity of saponin structures reaches the limit that can be determined solely by NMR.     

Coumarins from the heartwoods of Mansonia gagei Drumm.

Three coumarins and three known mansonones were isolated from the heartwood of Mansonia gagei Drumm. The structures of the three coumarins were elucidated as 3,8-dimethyl-5-isopropyl-6-methoxycoumarin (mansonrin A) 3,8-dimethyl-5-isopropyl-6-hydroxycoumarin (mansorin B) and 2,3-dihydro-3,6,9-trimethyl naphtho[1,8-bc]pyran-7-oxa-8-one (mansorin C) by analyses of physical properties and spectroscopic data. The cytotoxicity of the isolated compounds against brine shrimp Artemia salina Linn. was also evaluated.     

Two new steroidal saponins from Dioscorea panthaica

Two new furostanol saponins, 3-O-[α-l-rhamnopyranosyl-(1→4)-β-d-glucopyranosyl]-26-O-β-d-glucopyranosyl-25(R)-furosta-5,22(23)-dien-3β,20α,26-triol (1), 3-O-[β-d-glucopyranosyl-(1→3)-O-α-l-rhamnopyranosyl-(1→2)-β-d-glucopyranosyl]-26-O-β-d-glucopyranosyl-20(R)-methoxyl-25(R)-furosta-5,22(23)-dien-3β,26-diol (2) were isolated from the Dioscorea panthaica along with five known steroidal saponins (3–7). The structures of the new saponins were determined by detailed analysis of spectral data (including 2D NMR spectroscopy). The inhibitory activities of the saponins against α-glucosidase were investigated, gracillin (4) and 3-O-[α-l-rhamnopyranosyl-(1→2)-β-d-glucopyranosyl]-26-O-β-d-glucopyranosyl-25(R)-furosta-5,20(22)-dien-3β,26-diol (5) were found to exhibit potent activities with IC₅₀ values of 0.11 ± 0.04 mM and 0.09 ± 0.01 mM.     

Diversity of nodule-endophytic agrobacteria-like strains associated with different grain legumes in Tunisia

This study represents the first report describing the genetic diversity of nodule-endophytic agrobacteria isolated from diverse legumes and their phylogenetic relationships with the valid species of agrobacteria, as well as the non-recognized genomospecies of the former Agrobacterium tumefaciens (Rhizobium radiobacter). The genetic diversity of a collection of 18 non-nodulating agrobacteria-like strains, previously isolated from root nodules of Vicia faba, Cicer arietinum and Phaseolus vulgaris from different geographical regions of Tunisia, was studied by REP-PCR and PCR-RFLP of the 16S-23S rDNA IGS, as well as by sequence analysis of the 16S rDNA and the housekeeping genes recA and atpD. The aim of the work was to study the genetic diversity of the different isolates and to check for any host-specificity. The results from the different techniques were congruent and suggested a specific interaction for P. vulgaris, whereas no specific endophytic interaction was observed for V. faba and C. arietinum. The phylogenetic analysis clearly indicated that some isolates were affiliated to R. radiobacter or to its non-recognized genomic species (genomovars G2, G4 and G9). However, the other isolates probably constitute new species within Rhizobium (Agrobacterium) and Shinella.     

Differences in susceptibility of introduced and native white grub species to entomopathogenic nematodes from various geographic localities

Invasive, non-native, white grubs (Coleoptera: Scarabaeidae) cause significant damage in urban landscapes. Although the lack of natural enemies in their new home is often suggested as an important factor in the establishment and spread of invasive species, the potential of incumbent generalist parasites and pathogens to delay their establishment and spread has not been explored. We compared the susceptibility of the introduced Popillia japonica and the native Cyclocephala borealis to 16 species and strains of entomopathogenic nematodes isolated from within or outside the geographic ranges of the two scarabs. We found large variation in the virulence of the species/strains of nematodes with over 50% mortality of P. japonica produced by Heterorhabditis zealandica strain X1 and H. bacteriophora strain GPS11 and of C. borealis by H. zealandica and H. bacteriophora strains KMD10 and NC1. Heterorhabditis indica and H. marelatus caused less than 20% mortality of both scarab species. When considered as a group the nematode species and strains from within and outside the geographic ranges of either P. japonica or C. borealis did not differ in virulence towards either scarab species. Dose response studies with selected nematode species and strains against P. japonica and two additional non-native species Anomala (Exomala) orientalis and Rhizotrogus majalis and the native C. borealis indicated that R. majalis was the least susceptible and P. japonica and A. orientalis were as susceptible as the native C. borealis. Heterorhabditis zealandica was significantly more virulent than any other species or strain against P. japonica with a LC₅₀ of 272 IJs/grub. The LC₃₀ and LC₅₀ values for H. zealandica were also the lowest among the four nematode species/strains tested against A. orientalis and C. borealis. The LC₅₀ values for H. zealandica and H. megidis (UK strain) were significantly lower for the native C. borealis than the introduced A. orientalis. H. zealandica also showed the highest penetration efficiency and the lowest encapsulation in P. japonica and C. borealis grubs. Results suggest that the introduction of the exotic H. zealandica into the front-line states with respect to the movement of P. japonica and A. orientalis should be explored as a tactic to delay their establishment and spread. The results also suggest that the manipulation of the indigenous H. bacteriophora populations may help in delaying spread and mitigating losses caused by the invasive grub species.     

Cytotoxic ent-kaurane diterpenoids from Isodon sinuolata

Five (1–5) ent-kaurane diterpenoids and 17 other known ones, were isolated from the leaves and stems of Isodon sinuolata. Their structures were determined on the basis of spectroscopic methods including 1D and 2D NMR spectroscopic analysis. All compounds were evaluated for cytotoxicity against a small panel of cell lines. Some compounds exhibited significant cytotoxicity.     

New triterpenoid saponins from the roots of Gypsophila perfoliata Linn

Nine new triterpenoid saponins (1–9) have been isolated from the roots of Gypsophila perfoliata Linn. Their structures were established on the basis of extensive NMR (¹H, ¹³C, HSQC and HMBC) and ESIMS studies.     

Evaluation of Beauveria bassiana and B. brongniartii strains and four wild-type fungal species against adults of Bactrocera oleae and Ceratitis capitata

The virulence of two isolates of the hyphomycete fungi, Beauveria bassianaand B. brongniartii, and additional fungal species isolated from diseased Bactrocera oleae pupae and Sesamia nonagrioideslarvae were assessed against adults of the olive fruit fly B. oleae and the Mediterranean fruit fly Ceratitis capitata (Diptera: Tephritidae). Contact and oral bioassays revealed that moderate to high mortality rates for the olive fruit fly occurred when the adults were exposed to conidia of Mucor hiemalis, Penicillium aurantiogriseum, P. chrysogenum and B. bassianaisolates. A strain of M. hiemalis isolated from S. nonagrioides larvae was the most toxic resulting in 85.2% mortality to the olive fruit fly adults. B. brongniartiiand B. bassiana were the most pathogenic to the C. capitataadults causing 97.4 and 85.6% mortality. Metabolites collected from the M. hiemalis and P. chrysogenum isolates were toxic to adults of both species.     

Biosynthesis of oleanolic acid glycosides in protoplasts isolated from Calendula officinalis L. roots

Many medicinal plants contain oleanane saponins in roots, however, only scarce data on their biosynthesis in this organ are available so far, including our previous results concerning Calendula officinalis plant. Thus, the purpose of the present work was to confirm the presumable biosynthetic pathway of oleanolic acid glycosides in roots of young C. officinalis plants. First of all, the effective method of isolation of protoplasts from C. officinalis roots was established. Then, isolated root protoplasts were supplied with radioactive precursors, [2-¹⁴C] mevalonate (MVA) and [3-³H] oleanolic acid (OL) and their transformations were studied with comparison to results obtained with excised roots. The penetration of both precursors into protoplasts was more rapid and effective than in the case of excised roots. The labeling of sterols and OL during the incubation with MVA showed that the isoprenoid pathway leading to triterpenoids was operative in excised roots as well as isolated root protoplasts. Moreover, the transformations of OL into two series of its glycosides, i.e. glucosides and glucuronides were investigated. It has been shown that both series of OL glycosides are synthesized in isolated root protoplasts in the same way as in excised roots of young marigold plants.     

Isolation and metabolite production by Penicillium roqueforti,P. paneum and P. crustosum isolated in Canada

Penicillium roqueforti, P. crustosum and P. paneum grow on ensiled grain and recycled feed unless properly treated. The former two species occur also on cut lumber in Canada. These are known to produce a number of secondary metabolites including roquefortine. In cooler dairy production areas, including Scandinavia and North America, cattle toxicosis has been associated with silage contaminated by these fungi. We collected strains associated with cow or cattle toxicoses. The principal metabolites were determined making use of a new extraction method and analysis combining HPLC, LC/MS/MS, and LC/NMR. Penicillium roqueforti and P. crustosum required amino acid nitrogen for metabolite formation and their toxins were formed under conditions of low oxygen (20–30% saturation). Production of roquefortine C occurred on depletion of the available nitrogen and penitrem A on depletion of carbon source. Yield was reduced by excess carbon. Medium osmotic tension (a_w) affected metabolite production by the two species differently. Penicillium paneum was associated with ill-thrift of dairy cows and P. roqueforti was associated with more serious symptoms. Our data suggest a physiological basis for the common occurrence of roquefortine C in silage without serious consequences and the alternative, the presence of roquefortine C and toxicoses. The strain isolated from lumber was the best producer of the toxins studied. This is the first report of the toxigenic potential of P. roqueforti and P. paneum from Canada.     

南方红豆杉内生及根际放线菌多样性及其生物活性

【目的】研究药用植物南方红豆杉内生及根际土壤放线菌的多样性及其抑菌、抗肿瘤等重要生物活性并获得一些具有强抑制植物病原真菌以及抗肿瘤等重要生物活性的菌株。【方法】选择7种培养基从南方红豆杉及其根际土壤中分离放线菌,对链霉菌进行形态学分类,去重复后对其进行抑制植物病原真菌以及抗肿瘤活性的筛选并对高活性菌株进行初步鉴定。对部分菌株进行16S rRNA基因测序分析研究其多样性。【结果】研究共分离得到277株放线菌,经去重复后剩余111株放线菌,可归类到6个亚目、7个科、8个属。其中链霉菌可分为10个类群。生物活性研究结果显示:30.9%的菌株具有抑制植物病原真菌活性,其中6株放线菌对多种植物病原真菌显示了强的抑菌活性。分别有44.1%和33.3%的菌株对胃癌肿瘤细胞株SGC-7901和肺癌肿瘤细胞株NCI-H460的抑制率在40%以上。【结论】药用植物南方红豆杉及其根际土壤蕴含种类丰富的放线菌资源,具有良好的生物学活性。菌株KLBMP 2170具有显著的抑菌以及抗肿瘤活性,值得我们去进一步研究。     

高致病性美人鱼发光杆菌美人鱼亚种胞外产物的毒力特性分析

【目的】美人鱼发光杆菌美人鱼亚种(Photobacterium damselae subsp. damselae,PDD)是一种可导致多种海洋生物患病的重要病原菌。本研究以从我国海水养殖环境中分离的具有强磷脂酶活性、强溶血性表型且具有高致病性的2株PDD菌株为研究对象,分析PDD菌株胞外产物(extracellularproducts,ECP)的致病性及细胞毒性,及其与菌株致病性表型的相关性。【方法】利用培养基平板法测定菌株PDD1605、PDD1608的ECP体外磷脂酶活性和溶血性;通过人工感染实验测定PDD1605和PDD1608活菌株及其ECP对许氏平鲉的致病性,并进行组织病理切片观察组织的病理损伤;通过向人胚肾细胞系HEK293T和小鼠成纤维细胞系MCFS等2种培养细胞中添加菌株PDD1605和PDD1608的ECP测定其对哺乳动物的细胞毒性。【结果】人工感染PDD1605和PDD1608活菌株对许氏平鲉均表现为高致病性,5×108CFU/mL的菌液浓度24h内受试鱼全部死亡;菌株PDD1605和PDD1608的ECP对许氏平鲉同样表现为高致病性,受试鱼的死亡曲线与感染活菌株的...     

Bioactive Saponins from Allium and Aster Plants

Plants belonging to the genera Allium and Aster are widely distributed in nature and have been used as food and/or medicine. Their wide use was mainly due to the medicinal properties attributed to these plants since ancient times, recently supported by epidemiological and laboratory studies. Saponin compounds, responsible for many pharmacological activities, are quite abundant in these plants. Thus, a deep knowledge about the saponin composition of these vegetables appears to be essential and could promote the discovery of new potential leads. As part of our continuing research aimed at the identification of bioactive metabolites, we have addressed our attention to several Allium and Aster species. The study resulted in the isolation of over fifty saponins of furostane, spirostane, cholestane, and oleane-type structures. Some of the isolated compounds exhibited promising antiproliferative, antifungal, and antispasmodic activities. Their structure, distribution and bioactivity will be reported here together with a brief overview of the literature on Allium and Aster saponins.     

Cytotoxic and antioxidant triterpene saponins from Butyrospermum parkii (Sapotaceae)

Three new triterpenoid saponins, elucidated as 3-O-β-d-glucopyranosyloleanolic acid 28-O-β-d-xylopyranosyl-(1→4)-α-l-rhamnopyranosyl-(1→2)-β-d-xylopyranoside (parkioside A, 1), 3-O-[β-d-apifuranosyl-(1→3)-β-d-glucopyranosyl]oleanolic acid 28-O-[β-d-apifuranosyl-(1→3)-β-d-xylopyranosyl-(1→4)-[α-l-rhamnopyranosyl-(1→3)]-α-l-rhamnopyranosyl-(1→2)β-d-xylopyranoside (parkioside B, 2) and 3-O-β-d-glucuronopyranosyl-16α-hydroxyprotobassic acid 28-O-α-l-rhamnopyranosyl-(1→3)-β-d-xylopyranosyl-(1→4)-α-l-rhamnopyranosyl-(1→2)-β-d-xylopyranoside (parkioside C, 3), were isolated from the n-BuOH extract of the root bark of Butyrospermum parkii, along with the known 3-O-β-d-glucopyranosyloleanolic acid (androseptoside A). The structures of the isolated compounds were established on the basis of chemical and spectroscopic methods, mainly 1D and 2D NMR data and mass spectrometry. The new compounds were tested for both radical scavenging and cytotoxic activities. Compound 2 showed cytotoxic activity against A375 and T98G cell lines, with IC₅₀ values of 2.74 and 2.93 μM, respectively. Furthermore, it showed an antioxidant activity comparable to that of Trolox or butylated hydroxytoluene (BHT), used as controls, against 2,2-diphenyl-1-picryl hydrazyl (DPPH), 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), oxygen and nitric oxide radicals.     

Rhodothermus marinus: physiology and molecular biology

Rhodothermus marinus has been the subject of many studies in recent years. It is a thermohalophilic bacterium and is the only validly described species in the genus Rhodothermus. It is not closely related to other well-known thermophiles and is the only thermophile within the family Crenotrichaceae. R. marinus has been isolated from several similar but distantly located geothermal habitats, many of which are subject to large fluctuations in environmental conditions. This presumably affects the physiology of R. marinus. Many of its enzymes show optimum activity at temperatures considerably higher than 65°C, the optimum for growth, and some are active over a broad temperature range. Studies have found distinguishing components in the R. marinus electron transport chain as well as in its pool of intracellular solutes, which accumulate during osmotic stress. The species hosts both bacteriophages and plasmids and a functional intein has been isolated from its chromosome. Despite these interesting features and its unknown genetics, interest in R. marinus has been mostly stimulated by its thermostable enzymes, particularly polysaccharide hydrolysing enzymes and enzymes of DNA synthesis which may be useful in industry and in the laboratory. R. marinus has not been amenable to genetic analysis until recently when a system for gene transfer was established. Here, we review the current literature on R. marinus.     

Phytophthora quercetorum sp. nov., a novel species isolated from eastern and north-central USA oak forest soils

Isolates belonging to an undescribed Phytophthora species were frequently recovered during an oak forest soil survey of Phytophthora species in eastern and north-central USA in 2004. The species was isolated using an oak leaf baiting method from rhizosphere soil samples collected from Quercus rubra, Q. macrocarpa, and Q. phellos. This species is formally described as P. quercetorum. It is homothallic and has aplerotic oogonia and paragynous antheridia. It produces papillate sporangia (occasionally bipapillate) of ovoid-elongated shapes. Its temperature optimum for growth is ca 22.5 °C with the upper limit of ca 32.5 °C. P. quercetorum differs from the morphologically related P. quercina in producing distinct submerged colony-patterns, different growth-temperature requirements, and oogonial shapes and sizes. Phylogenetic analyses using seven nuclear loci supported P. quercetorum as a novel species within clade 4, closely related to P. arecae, P. palmivora, P. megakarya, and P. quercina.