Identification and quantitative determination of d-arabino-hexulosonic acid in Cyttaria species

d-arabino-hexulosonic acid has been identified by GLC in an aqueous extract from Cyttaria harioti and Cyttaria johowii and the amount present (1 and 0.05% respectively) determined.     

Chemical composition of the cell wall of the tree fungusCyttaria harioti Fischer

Isolated cell walls of stromata ofCyttaria harioti Fischer, collected in the field, accounted for ca. 67% of the fungus dry weight and were composed of neutral sugars (81%), 2-amino-2-deoxyglucose (0.2%), aminoacids (3.4%), and lipids (6.8%). Alkaline treatment gave a major soluble β-(1 → 3)-glucan and a minor insoluble one, structurally related, which in total accounted for 89% of the cell wall preparation. The absence of chitin is a remarkable feature since it is present in almost all the Ascomycetes previously studied.     

Properties and nature of inhibitors of potato virus X in four medicinal plant extracts

The inhibitors present in the extracts ofCinchoma ledgeriana, Emblica officinalis, Chrysobalanus C. icaco andTerminalia chebula were heat-stable, resistant to autoclaving, aging and desiccation for a week. However, they did not withstand dialysis for 48 hrs (exceptT. chebula extract.) These four extracts markedly inhibited the virus even on dilution in the ratio of 1?1 but viral infectivity was sharply reduced at higher dilutions in each case. Moreover, the inhibitors in the stem bark extract ofC. ledgeriana, fruit pericarp extract ofE. officinalis andT. chebula were highly inhibitory even at pH 10·0, whereas inhibition of the virus by leaf extract ofC. icaco was reduced to 24 per cent only at the same pH. The inhibitors in these four extracts were found to be probably not proteinaceous in nature, when precipitated with ammonium sulphate and ethanol.     

Toxicity of mycotoxins produced by four Alternaria species toArtemia salina larvae

22 isolates ofAlternaria alternata, A raphani, A consortiale, andA chartarum were examined for the production of alternariol (AOH), alternariol methyl ether (AME), altenuene (ALT), altertoxin I (ATX I), and tenuazonic acid (TA) on wheat grain and for toxicity of culture extracts toArtemia salina larvae. The total amount of 5 toxins produced under laboratory conditions ranged from 5 mg/kg to 11.112mg/kg. The toxic extracts showed EC50 values in the range of 3.3 to 144.5 mg/mL. There was no correlation between toxicity of extracts toArtemia salina and the amount of mentioned mycotoxins in culture.     

The structure of an α-D-glucan from Cyttaria harioti Fischer

A homogeneous glucan has been isolated from the fruiting bodies of Cyttaria harioti Fischer. Partial acid hydrolysis produced major amounts of isomaltose, whereas acetolysis gave maltose and maltotriose. Enzymic hydrolysis with amylo-glucosidase and pullulanase indicated a structure based on maltotriose residues connected by (1→6)-α-D linkages. This conclusion was supported by periodate-oxidation data which also showed that 3–7% of the glucose resisted oxidation. Methylation analysis confirmed the presence of (1→6) and (1→4) linkages in the ratio 1:2.4.     

A gel-forming (1→3)-β-D-glucan isolated from cyttaria harioti fischer

An alkali-soluble glucan, [α]_D + 11° (M potassium hydroxide) having a degree of polymerization of 220, has been isolated from the fruit bodies of the tree fungus Cyttaria harioti Fischer. Periodate oxidation and methylation analysis show that it consists of a highly branched β-D-(1→3)-linked backbone. Hydrolysis of the methylated polysaccharide yielded 2,3,4,6-tetra-O-methyl- (24.5 mol%), 2,4,6-tri-O-methyl-(39.4 mol%), 2,3,4-tri-O-methyl- (8.6 mol%), and 2,4-di-O-methyl-D-glucose (27.5 mol%). Periodate-oxidation results substantiate the methylation studies. The general structural features of the glucan are discussed.     

Natural insecticides fromHippocratea excelsa andHippocratea celastroides

Hippocratea excelsa andHippocratea celastroides have therapeutic and insecticide applications in Mexican traditional medicine. The toxicity ofH. excelsa root cortex has been previously demonstrated against the stored grain pest Sitophilus zeamais. To identify the active compounds, several extracts (petroleum ether, CH₂Cl₂, acetone, methanol, and water) and compounds were obtained from the roots, and tested (1% w/w) with a force-feeding assay againstS. zeamais. AllH. excelsa extracts showed high antifeedant activity, and elicited moderate mortality. The triterpenoid pristimerin and a mixture of sesquiterpene evoninoate alkaloids, isolated from the hexane and methanol extracts, respectively, strongly reduced the insect feeding capacity. Other triterpenoids (friedelin, β-sitosterol, canophyllol) isolated from the hexane extract, and the alditol galactitol obtained from the water extract, were innocuous or its activity was not statistically significant. The organic extracts fromH. celastroides only showed moderate antifeedant activity, while the water extract was innocuous. Galactitol was also obtained from this extract.     

Antioxidant and antimicrobial properties of ethanolic extract fromLepista nuda (Bull.) Cooke

Antioxidant capacity and antimicrobial activities ofLepista nuda (Bull.) Cooke extracts obtained with ethanol were investigated. Four complementary test systems, namely DPPH free radical scavenging, β-carotene/linoleic acid systems, total phenolic compounds and total flavonoid concentration, have been used. Linoleic, acid inhibition values ofL. nuda ethanolic extract, BHA and α-to copherol standards were found to be 84.3% 98.9% and 99.2% respectively in the concentration of 160μg/ml. Total flavonoid amount was 8.21 ± 0.56 μg mg^?1 quercetin equivalent while the phenolic compound amount was 48.01 ± 0.29 μg mg^?1 pyrocatechol equivalent in the extract. The antimicrobial activity ofL. nuda extract was testedin vitro by using the agar-well diffusion method. TheL. nuda extract showed antibacterial activity againstMicrococcus flavus, Micrococcus luteus, Bacillus cereus, Yersinia enterocolitica, Staphylococcus aureus, Salmonella enteritidis andEscherichia coli. TheL. nuda extract did not exhibit antican didal activity againstCandida albicans. The extracts could be suitable as antimicrobial and antioxidativeagents in the food industry.     

Effects of beauvericin to mammalian tissue and its production by Austrian isolates ofFusarium proliferatum and Fusarium subglutinans

Austrian isolates ofFusarium subglutinans andFusarium proliferatum were studied for their ability to produce beauvericin, moniliformin and fumonisin B₁ and B₂ under laboratory conditions. Analytical methodology for beauvericin was specially adapted for this task. Our analyses showed that the strains produced beauvericin up to 687 mg /kg maize and moniliformin up to 70 mg/kg. The culture ofF. proliferatum in addition produced fumonisin B₁ and B₂ at levels of 106 and 61 mg/kg,respectively. The preliminary toxicity experiments performed in this study clearly indicated a toxic effect of beauvericin on the contractility of mammalian smooth muscle and thus on mammalian cells.     

Influence of fungicides on mycotoxin production by Alternaria mali

Extracts of fungicide induced variants ofAlternaria mali were tested with mice and bacteria. Both the living fungi and their crude chloroform extracts inhibited growth ofStaphylococcus aureaus, Sarcina lutea, Bacillus mycoides, andB. subtilis. B. megaterium was not sensitive to most of the extracts and was only slightly so to the remainder. The LD₅₀ in mice when injected intraperitoneally ranged from 300 mg/kg to 2400 mg/kg; however, in some cases there were no lethal effects. The toxicity of the wild type was greatly reduced when grown in the presence of fungicide decomposition products. Altenuene, alternariol, and alternariol monomethyl ether were not found in any of the extracts.     

Effect of some plant extracts on two coccinellid predators of the cowpea aphid,Aphis craccivora (Hom.: Aphididae)

This study was conducted to examine the effects of some aphicidal biologically active plant compounds on the natural enemies of the cowpea aphid,Aphis craccivora Koch. In the laboratory, acetone extracts ofCymbopogon citratus (DC) Stapf.,Momordica charantia L.,Zingiber officinale Rose andAframomum melegueta (Rose) K. Schum, were tested for toxicity to two coccinellid species,Cheilomenes lunata (Fabricius) andCheilomenes vicina (Mulsant) predaceous on the aphid. All the extracts were highly ovicidal to eggs of the two coccinellid predators. None of the extracts caused mortality of eitherC. lunata orC. vicina fourth-instar larvae after 24 h. Larvae treated with the extracts consumed fewer aphids in 24 h than untreated larvae. Ability to pupate was also significantly reduced in larvae treated with the extracts. No morphological deformities were observed in adults emerging from treated larvae.     

Biocontrol evaluation of extracts and a major component,clusianone, from Clusia fluminensis Planch. & Triana against Aedes aegypti

Studies evaluated the effects of hexanic extracts from the fruits and flowers ofClusia fluminensis and the main component of the flower extract, a purified benzophenone (clusianone), against Aedes aegypti. The treatment of larvae with the crude fruit or flower extracts from C. fluminensis did not affect the survival ofAe. aegypti (50 mg/L), however, the flower extracts significantly delayed development of Ae. aegypti. In contrast, the clusianone (50 mg/L) isolate from the flower extract, representing 54.85% of this sample composition, showed a highly significant inhibition of survival, killing 93.3% of the larvae and completely blocking development of Ae. aegypti. The results showed, for the first time, high activity of clusianone against Ae. aegypti that both killed and inhibited mosquito development. Therefore, clusianone has potential for development as a biopesticide for controlling insect vectors of tropical diseases. Future work will elucidate the mode of action of clusianone isolated from C. fluminensis.     

Fusarium species associated with banana fruit rot and their potential toxigenicity

Banana fruits exhibiting signs of decay were collected from markets in the United States and Italy. Fungi isolated from the lesions on the banana fruits wereFusarium moniliforme, F subglutinans, andF. semitectum var.majus. When the fungal strains were cultivated on maize kernels, the cultures did not produce zearalenone (ZON), zearalenols (á-, â-ZOH), and trichothecenes [deoxynivalenol (DON), 3-acetyldeoxynivalenol (3-AcDON), T-2 toxin (T-2), diacetoxyscirpenol (DAS)]. Fumonisins and fusarin C (FUS-C) were not detected naturally nor in bananas purchased in the U.S. and artificially infected withFusarium. Moniliformin (M) (up to 267 mg/kg) was detected in maize kernel cultures ofF. subglutinans from bananas. No mycotoxins were detected in naturally infected fruits. Although no mycotoxins were detected in the extracts from corn cultures ofF. semitectum var.majus, the extracts were toxic to brine shrimp and mice.     

Aspidosperma (Apocynaceae) plant cytotoxicity and activity towards malaria parasites. Part II: experimental studies with Aspidosperma ramiflorum in vivo and in vitro

Several species of Aspidosperma plants are used to treat diseases in the tropics, including Aspidosperma ramiflorum, which acts against leishmaniasis, an activity that is experimentally confirmed. The species, known as guatambu-yellow, yellow peroba, coffee-peroba andmatiambu, grows in the Atlantic Forest of Brazil in the South to the Southeast regions. Through a guided biofractionation of A. ramiflorum extracts, the plant activity against Plasmodium falciparum was evaluated in vitro for toxicity towards human hepatoma G2 cells, normal monkey kidney cells and nonimmortalised human monocytes isolated from peripheral blood. Six of the seven extracts tested were active at low doses (half-maximal drug inhibitory concentration < 3.8 µg/mL); the aqueous extract was inactive. Overall, the plant extracts and the purified compounds displayed low toxicity in vitro. A nonsoluble extract fraction and one purified alkaloid isositsirikine (compound 5) displayed high selectivity indexes (SI) (= 56 and 113, respectively), whereas compounds 2 and 3 were toxic (SI < 10). The structure, activity and low toxicity of isositsirikine in vitro are described here for the first time in A. ramiflorum, but only the neutral and precipitate plant fractions were tested for activity, which caused up to 53% parasitaemia inhibition of Plasmodium berghei in mice with blood-induced malaria. This plant species is likely to be useful in the further development of an antimalarial drug, but its pharmacological evaluation is still required.     

Ethnobotany of the genusCyphomandra (Solanaceae)

Plants of the genusCyphomandra (Solanaceae) have long been utilized for their edible fruits in their native Latin America. The best-known species is the domesticated tree tomato or tamarillo,Cyphomandra betacea. This species, popular as a raw or cooked fruit, is widely cultivated in Andean South America and is now dispersed worldwide in subtropical areas. Its origin and wild relatives are still unknown, but there are tentative reports of wild populations ofC. betacea in southern Bolivia and northwestern Argentina. Wild species ofCyphomandra such asC. hartwegii, C. sibundoyensis, andC. cajanumensis also produce edible fruits. Other species ofCyphomandra are used in medicinal preparations and as dyes. This group of plants is of increasing economic importance and may have considerable potential for future exploitation.     

Structural studies on a glycopeptide from the tree fungus Cyttaria harioti Fischer

A glycopeptide (In₁) was isolated by phenol-water extraction from Cyttaria harioti Fischer, parasite of Nothofagus sps. Neutral sugars account for 89% of In₁ and were characterized as glucose, mannose, and galactose. Glucosamine, identified by g.l.c., was colorimetrically estimated (5.8%). The molar ratio of Glc:Man:Gal:GlcNAc was 17:11:3:2. The linkages between the various monosaccharide residues were established through methylation analysis and periodate oxidation studies. The anomeric configurations of the various glycosyl groups were determined by chromium trioxide oxidation of the acetylated polysaccharide. The results were confirmed by ¹³C-n.m.r. spectroscopy. The sugar chain is N-glycosyl-linked to the peptide. Structural features of the carbohydrate moiety of glycopeptide In₁ are described.     

Anti-urolithiatic,antibacterial, anti-inflammatory and analgesic effects of Erica arborea flowers and leaves hydromethanolic extracts: An ethnopharmacological study

Erica arborea L. is a medicinal plant vastly used in therapeutic purposes in several parts of the world for antimicrobial, anti-inflammatory, and diuretic purposes, and in treating urinary infections and kidney stones. The current investigation aimed to evaluate the medicinal use of E. arborea in Algeria's Bejaia region, and to examine the anti-urolithiatic, antibacterial, anti-inflammatory (in vivo), analgesic, and toxicity effects of E. arborea hydromethanolic extracts from leaves (EALE) and flowers (EALE) to give a justification for its use in the traditional medicine. The in vitro anti-urolithiathic activity of E. arborea leaf and flower hydromethanolic extracts nucleation and aggregation of crystals were measured using spectrophotometric methods. The agar disk diffusion assay and minimum inhibitory concentration (MIC) determination were employed to estimate the antibacterial effect of EAME against three Gram-positive and three Gram-negative bacterial strains in vitro. In addition, the xylene and croton oil-induced ear edema methods in mice were used to examine the topical and oral anti-inflammatory potential of the extracts. Similarly, the analgesic effect of the extract was assessed via the acetic acid-induced abdominal constriction in mice, whereas the acute toxicity of EAME was conducted following OECD guidelines. An ethnobotanical survey was conducted among 171 informants with 212 questionnaire cards. Results indicated that 28.04 % of people in the studied region used E. arborea in traditional folk medicine. Additionally, results revealed the presence of epicatechin, palmitic acid, and kaempferol-3-O-glucoside in the plant extracts. Results also showed that EAME exhibits significant and dose-dependent anti-urolithiatic activity in nucleation and aggregation assays. Furthermore, results revealed that the extracts exhibit significant antibacterial activity. The E. arborea flower extract (EAFE) showed maximum antibacterial activity, especially against P. aeruginosa, E. coli, S. gallinarum, and B. cereus. In addition, a greater minimum inhibitory concentration (MIC) in this extract was found at 1.60 mg/mL against M. luteus strain compared to the positive control. Moreover, the EAME caused a significant inhibition influence in the xylene and croton oil-induced edematous in mice. In contrast, the topical anti-inflammatory potential showed that extracts exhibit a considerable anti-edematogenic effect in both animal models. In the writhing reaction induced by the acetic acid model, the two extracts significantly reduced abdominal contractions. Finally, results of the toxicity assay showed that EAME is safe and no deaths or changes in mice behavior were observed even when doses as high as 5 g/kg DW were used. From the ethnopharmacological studies, our consequences endorse the benefit of E. arborea in folk medicine. Results of this investigation suggest that the leaf and flower extracts of E. arborea exhibit notable anti-urolithiatic, anti-inflammatory, analgesic, and antibacterial activities and are safe as a natural source of drugs with the above effects.     

The selective allelopathic interaction of a pasture-forest intercropping in Taiwan

An allelopathic interaction of a pasture-forest intercropping system was evaluated by field and greenhouse experiments and by laboratory assays. A study site was situated in the farm of Hoshe Forestry Experiment Station at Nantou County, Taiwan. After deforestation of Chinese fir (Cunninghamia lanceolata), a split plot design of 8 treatments was set up: open ground without planting as control, planted with kikuyu grass, planted with kikuyu grass andAlnus formosana, planted with kikuyu grass andZelkova formosana, planted with kikuyu grass andCinnamomum camphora, planted withA. formosana, planted withZ. formosana, and planted withC. camphora. Field measurements showed that weeds grew luxuriantly six months after treatment in plots which had not been planted with kikuyu grass. However, the growth of weeds was significantly retarded but that of woody plants was not affected when the plots were planted with kikuyu grass. As compared with the tap water control, the aqueous leachate of kikuyu grass stimulated the seedling growth ofC. camphora andA. formosana, but the extract stimulated the growth ofC. camphora and inhibited that ofA. formosana. In contrast, the aqueous extracts of three hardwood plants exhibited variable inhibition on the root initiation of kikuyu grass, and the extract ofZ. formosana revealed the highest phytotoxic effect. The aforementioned extracts and leachates were bioassayed against seed germination and radicle growth of four test plants, namely annual rye grass, perennial rye gras, tall fescue, and Chinese cabbage and against seedling growth ofMiscanthus floridulus. The extract ofZ. formosana revealed the highest phytotoxic effect on the test species while that of kikuyu grass showed the least effect. By means of paper chromatography and high performance liquid chromatography, phytotoxic phenolics were identified and the amount of phytotoxins present was highest in the extract ofZ. formosana but was lowest in that of kikuyu grass. The degree of phytotoxicity and amount of phytotoxins was in good correlation, indicating that a selective allelopathic effect was involved. The findings suggest that allelopathy may contribute benefits in the intercropping system to reduce the need for herbicides and to lessen the labour cost for weed control.Paper No. 346 of the Scientific Journal Series of the Institute of Botany, Academia Sinica, Taipei, Taiwan, Republic of China. This study was supported in part by grants of Academia Sinica, Taipei, and Council of Agriculture, Executive Yuan of the Republic of China.     

Assembly of nucleosomal DNA in a cell-free extract from wild-type and top1− strains ofUstilago maydis

An in vitro nucleosome assembly system has been established from cell-free extracts of the fungusUstilago maydis. The extract catalyzed DNA supercoiling in the absence of exogenously added co-factors such as ATP and MgCl₂ and was inhibited by moderate concentrations (200 mM) of KCl or NaCl. DNA supercoiling occurs via the formation of nucleosomes. Similar extracts, displaying the same activity, were prepared fromSaccharomyces cerevisiae andCandida albicans, suggesting that the extract preparation protocol may be useful for many lower eukaryotic systems. An extract prepared from a strain ofU. maydis lacking topoisomerase I failed to catalyze nucleosome assembly, clearly implicating this enzyme in this process. Addition of purified topoisomerase I, and, to a lesser extent, topoisomerase II, to the top1^? extract regenerated the supercoiling activity. Our results provide a method for preparing assembly extracts from organisms, that are particularly amenable to genetic manipulation.     

Toxicity,of extracts of barley kernels inoculated withFusarium spp. toArtemia salina

Toxicity toA. salina, of the Fusarium metabolites: deoxynivalenol (DON), its acetylated derivatives (3- and 15-AcDON), zearalenone (ZON), neosolaniol (NEO), nivalenol (NIV), T-2, HT-2 toxins, has been examined and compared with toxicity of extracts of barley kernels (8 cultivars and 4 lines) inoculated withFusarium culmorum, F. graminearum andF. sporotrichioides respectively. Estimated LC₅₀ values were expressed as relative toxicity (RT) in mg DON/kg for samples inoculated withF. culmorum, F. graminearum or in mg T-2/kg forF. sporotrichioides inoculations. Toxicity of extracts of the same genotype/line kernels was compared among different pathogens used for inoculation and differences in Fusarium head blight susceptibility of different genotypes/lines inoculated with the sameFusarium strain were found. Significant correlation between toxicity of extracts (LC₅₀, RT) and toxic metabolites concentration was found ( $\bar r = 0.82$ ; P = 0.01). Bioassays withA. Salina offer a fast, easy and inexpensive method to examine cereal genotypes susceptibility to Fusarium head blight and mycotoxins accumulation in kernels.