Larvicidal activity of essential oils from Brazilian plants against Aedes aegypti L

Aedes aegypti L. is the major vector of dengue fever, an endemic disease in Brazil. In an effort to find effective and affordable ways to control this mosquito, the larvicidal activities of essential oils from nine plants widely found in the Northeast of Brazil were analyzed by measurement of their LC50. The essential oils were extracted by steam distillation and their chemical composition determined by GL-chromatography coupled to mass spectroscopy. The essential oils from Cymbopogon citratus and Lippia sidoides, reported in the literature to have larvicidal properties against A. aegypti, were used for activity comparison. The results show that Ocimum americanum and Ocimum gratissimum have LC50 of 67 ppm and 60 ppm respectively, compared to 63 ppm for L. sidoides and 69 ppm for C. citratus. These results suggest a potential utilization of the essential oil of these two Ocimum species for the control of A. aegypti.     

Larvicidal activity of saponins from Balanites aegyptiaca callus against Aedes aegypti mosquito

Seeking an alternative approach for producing a larvicidal product from Balanites aegyptiaca plants, callus was produced from in vitro cultures of root explants and its larvicidal activity against Aedes aegypti mosquito larvae was evaluated. Concentrations of 0, 50, 100, 500, 1000, and 1500 ppm of saponins from the root-derived callus of B. aegyptiaca were used to determine larvicidal effects and consequent effect on adult emergence. A dose-dependent effect was observed. In a chronic mortality assessment (after 7 days of exposure), concentrations of 500 ppm or greater killed 100% of the test larvae population. Fifty parts per million showed no difference in larval mortality compared to the control (0 ppm); however, this concentration allowed one-fourth of the adult emergence of the control treatment. These results suggest that saponins from in vitro cultures of the root explant of B. aegyptiaca can be used as a larvicidal agent against A. aegypti larvae.     

Antifungal activity of altenusin isolated from the endophytic fungus Alternaria sp. against the pathogenic fungus Paracoccidioides brasiliensis

BackgroundAltenusin is a biphenyl derivative isolated from different species of fungi, which presents several biological activities.AimsWe report the antifungal activity of the altenusin isolated from the endophytic fungus Alternaria sp., against clinical isolates of Paracoccidioides brasiliensis, and its action on cell walls of P. brasiliensis and the nonpathogenic yeast Schizosaccharomyces pombe.MethodsIn vitro antifungal activity of altenusin was evaluated using the broth microdilution method against 11 strains of P. brasiliensis and one strain of S. pombe. The effects of the altenusin on the cell wall were estimated using the sorbitol protection assay.ResultsThe altenusin presented strong activity against P. brasiliensis with MIC values ranging between 1.9 and 31.2 μg/ml, and 62.5 μg/ml for S. pombe. Our results demonstrated that the MIC values for altenusin were increased for P. brasiliensis Pb18 and for S. pombe when the medium was supplemented with sorbitol. Additionally, S. pombe cells treated with altenusin were more rounded in shape than untreated cells.ConclusionsAltenusin showed activity against clinical strains of P. brasiliensis at the concentration tested, and this compound probably affects fungal cell walls. These findings suggest that altenusin could act through the inhibition of cell wall synthesis or assembly in P. brasiliensis and S. pombe, and could be considered as a lead compound for the design of new antifungals.     

Development and characterization of microsatellite markers for the Brazil nut tree Bertholletia excelsa Humb. & Bonpl. (Lecythidaceae)

Twelve polymorphic microsatellite markers were developed for the Brazil nut (Bertholletia excelsa), one of the most valuable non‐timber forest products from the Amazon, based on enrichment protocol. Six to 18 (mean 10.4) alleles per locus were identified and the expected heterozygosity ranged from 0.663 to 0.923 based on a screen of 40 individuals from one population of B. excelsa. The combined probabilities of genetic identity (8.39 × 10^?17) and paternity exclusion (0.999999) indicated that multilocus genotypes are likely to be unique allowing precise analyses of genetic structure, gene flow, and mating system of this economically important species.     

Antimicrobial activity and molecular characterization of an endophytic fungus, Quambalaria sp. isolated from Ipomoea carnea

An endophytic fungus displaying considerable antimicrobial activity was isolated from stem tissue of an invasive plant species, Ipomoea carnea. The fungus was identified as Quambalaria sp. and confirmed by ITS rDNA sequence analysis. A BLAST search result of the sequence indicated 97 % homology with Quambalaria cyanescens. Crude metabolites of the fungus showed considerable antimicrobial activity against a panel of clinically significant microorganisms. The metabolites showed highest in vitro activity against Shigella dysenteriae followed by Escherichia coli and Candida albicans. Optimum metabolites production required neutral pH and a 15-day incubation period. Bark extracts amended with fungal media demonstrated higher antimicrobial activity. Optimum metabolites activity was recorded in Czapek Dox broth amended with leaf extracts (CDB + LE) of the host plant. The metabolites showed UV λ-max in ethyl acetate at 284.6 nm with an absorbance value of 1.093. Phylogenetic tree generated by the Maximum Parsimony method showed clustering of our isolate with Q. cyanescens with supported bootstrap of 65 %. Species of Quambalaria are pathogens to Eucalyptus and occurrence of this fungus as endophytes support it to be a latent pathogen. Sequence base analysis and RNA secondary structure study also confirmed such a relationship. Secondary structural features like two hinges and a 5’ dangling end were found to be unique to our isolate. These structural features can also be used as potential barcodes for this fungus. The findings indicate that invasive plant species can be a reliable source of novel endophytes with rich antimicrobial metabolites. The study also validates the assumption that endophytes can become parasites and share a close affinity.     

New p-terphenyls from the endophytic fungus Aspergillus sp. YXf3

Five new p-terphenyls named prenylterphenyllin D (1), prenylterphenyllin E (2), 2′-O-methylprenylterphenyllin (3), 4-O-methylprenylterphenyllin (4) and 3′-O-methylterphenyllin (5) together with seven known compounds (6–12), were isolated from cultures of Aspergillus sp. YXf3. The structures of the new compounds were elucidated by extensive MS and NMR analyses. The NMR and MS data of 5 is reported for the first time, as its structure was listed in SciFinder Scholar with no associated reference. Compounds 6 and 7 were distinguished from each other on the basis of 2D NMR experiments. Compounds 1, 2, 3 and 8 showed antibacterial activities against X. oryzae pv. oryzicola Swings and E. amylovora with the same MIC values of 20 μg/mL while 10 exhibited activities against E. amylovora with an MIC value of 10 μg/mL.     

Larvicidal activity of major essential oils from stems of Allium monanthum Maxim. against Aedes aegypti L

The stems of Allium monanthum were extracted, and the major essential oil composition and larvicidal effects were studied. The analyses were conducted by gas chromatography and mass spectroscopy revealed that the essential oils of A. monanthum stems. The A. monanthum essential oil yield was 4.25%, and gas chromatography and mass spectroscopy analysis revealed that its major constituents were dimethyl trisulfide (23.21%), dimethyl tetrasulfide (11.24%) and methlyl propyl trisulfide (8.21%). The essential oil had a significant toxic effect against early fourth-stage larvae of Aedes aegypti L with an LC(50) value of 23.14 ppm and an LC(90) value of 36.31 ppm. Also, dimethyl trisulfide (≥95.0%), dimethyl tetrasulfide (≥95.0%) and methlyl propyl trisulfide (≥95.0%) were tested against the F(21) laboratory strain of A. aegypti. Methlyl propyl trisulfide (≥95.0%) has good activity with an LC(50) value of 19.38 ppm. Also, the above indicates that other major compounds may play a more important role in the toxicity of essential oil.     

Larvicidal activity of the essential oil from Lippia sidoides Cham. Against Aedes aegypti linn

The aim of this work was to study the larvicidal activity of Lippia sidoides essential oil against Aedes aegypti larvae. The essential oil and its hydrolate (saturated solution of essential oil in water) were obtained by vapor extraction and their chemical composition determined by GL-chromatography coupled to mass spectroscopy. Bioassays were run with the essential oil, pure and diluted hydrolate and with their main constituents thymol and carvacrol. The results obtained showed that L. sidoides essential oil and its hydrolate have larvicidal action against the mosquito A. aegypti, causing an almost instantaneous mortality. Thymol, an alkylated phenol derivative and one of the major components of L. sidoides essential oil, was identified as the active principle responsible for the larvicidal action, causing 100% larval mortality at the lowest tested concentration of 0.017% (w/v). These results suggest that the essential oil of L. sidoides is promising as larvicide against A. aegypti and could be useful in the search of newer, more selective, and biodegradable larvicidal natural compounds to be used in official combat programs and at home.     

Transcriptomic analysis and molecular docking reveal genes involved in the response of Aedes aegypti larvae to an essential oil extracted from Eucalyptus

BackgroundAedes aegypti (L.) is an urban mosquito, vector of several arboviruses that cause severe diseases in hundreds of million people each year. The resistance to synthetic insecticides developed by Ae. aegypti populations worldwide has contributed to failures in vector control campaigns, increasing the impact of arbovirus diseases. In this context, plant-derived essential oils with larvicidal activity could be an attractive alternative for vector control. However, the mode of action and the detoxificant response of mosquitoes to plant derived compounds have not been established, impairing the optimization of their use.Methods and findingsHere we compare gene expression in Ae. aegypti larvae after 14 hrs of exposure to Eucalyptus camaldulensis essential oil with a control group exposed to vehicle (acetone) for the same lapse, by using RNA-Seq. We found differentially expressed genes encoding for cuticle proteins, fatty-acid synthesis, membrane transporters and detoxificant related gene families (i.e. heat shock proteins, cytochromes P450, glutathione transferases, UDP-glycosyltransferases and ABC transporters). Finally, our RNA-Seq and molecular docking results provide evidence pointing to a central involvement of chemosensory proteins in the detoxificant response in mosquitoes.Conclusions and significanceOur work contributes to the understanding of the physiological response of Ae. aegypti larvae to an intoxication with a natural toxic distilled from Eucalyptus leafs. The results suggest an involvement of most of the gene families associated to detoxification of xenobiotics in insects. Noteworthy, this work provides important information regarding the implication of chemosensory proteins in the detoxification of a natural larvicide. Understanding the mode of detoxification of Eucalyptus distilled compounds could contribute to their implementation as a tool in mosquito control.     

Bioactive metabolites from the endophytic fungus Ampelomyces sp. isolated from the medicinal plant Urospermum picroides

Extracts of cultures grown in liquid or on solid rice media of the fungal endophyte Ampelomyces sp. isolated from the medicinal plant Urospermum picroides exhibited considerable cytotoxic activity when tested in vitro against L5178Y cells. Chromatographic separation yielded 14 natural products that were unequivocally identified based on their ¹H and ¹³C NMR as well as mass spectra and comparison with previously published data. Six compounds (2, 4, 5, 7, 9 and 11) were natural products. Both fungal extracts differed considerably in their secondary metabolites. The extract obtained from liquid cultures afforded a pyrone (2) and sulfated anthraquinones (7 and 9) along with the known compounds 1, 3, 6 and 8. When grown on solid rice medium the fungus yielded three compounds 4, 5 and 11 in addition to several known metabolites including 6, 8, 10, 12, 13 and 14. Compounds 4, 8 and 10 showed the strongest cytotoxic activity against L5178Y cells with EC₅₀ values ranging from 0.2–7.3 μg/ml. Furthermore, 8 and 10 displayed antimicrobial activity against the Gram-positive pathogens, Staphylococcus aureus, S. epidermidis and Enterococcus faecalis at minimal inhibitory concentrations (MIC) of 12.5 μg/ml and 12.5–25 μg/ml, respectively. Interestingly, 6 and 8 were also identified as constituents of an extract derived from a healthy plant sample of the host plant U. picroides thereby indicating that the production of bioactive natural products by the endophyte proceeds also under in situ conditions within the host plant.     

Antiproliferative metabolites from the endophytic fungus Penicillium sp. FJ-1 isolated from a mangrove Avicennia marina

Two new compounds, named as 4-(2′,3′-dihydroxy-3′-methyl-butanoxy)-phenethanol (1), and 15-hydroxy-6α,12-epoxy-7β,10αH,11βH-spiroax-4-ene-12-one (2), were isolated from the endophytic fungus Penicillium sp.FJ-1 of Avicennia marina. Their structures were elucidated on the basis of spectroscopic analysis. Additionally, compounds 1 and 2 exhibited antiproliferative activities, and compound 2 significantly inhibited the tumor growth of human xenograft osteosarcoma in nude mice.     

NF kappa B inhibitors and antitrypanosomal metabolites from endophytic fungus Penicillium sp. isolated from Limonium tubiflorum

Chemical investigation of the endophytic fungus Penicillium sp. isolated from Limonium tubiflorum growing in Egypt afforded four new compounds of polyketide origin, including two macrolides, penilactone (1) and 10,11-epoxycurvularin (2), a dianthrone, neobulgarone G (7), and a sulfinylcoumarin, sulfimarin (14), along with twelve known metabolites (3-6, 8-13, 15 and 16). The structures of all compounds were assigned by comprehensive spectral analysis (1D and 2D NMR) and mass spectrometry. Compounds 3, 4, 13 and 16 showed pronounced antitrypanosomal activity with mean MIC values ranging from 4.96 to 9.75 ??M. Moreover, when tested against a panel of three human tumor cell lines compounds 3, 4, 6 and 12 showed selective growth inhibition against Jurkat and U937 cell lines with IC₅₀ values ranging from 1.8 to 13.3 ??M. The latter compounds also inhibited TNF??-induced NF-??B activity in K562 cells with IC₅₀ values ranging from 1.6 to 10.1 ??M, respectively.     

New bisabolane sesquiterpenoids from a marine-derived fungus Aspergillus sp. isolated from the sponge Xestospongia testudinaria

Three new phenolic bisabolane sesquiterpenoid dimers, disydonols A-C (1-3), and one known compound (S)-(+)-sydonol (4) were isolated from the fermentation broth of a marine-derived fungus Aspergillus sp., which was isolated from the sponge Xestospongia testudinaria collected from the South China Sea. Their structures were elucidated on the basis of comprehensive spectral analysis including 1D and 2D NMR spectra and HR-ESI-MS. These compounds were evaluated for cytotoxic activity against HepG-2 and Caski human tumour cell lines. Among them, compounds 1 and 3 exhibited cytotoxicity against the two cell lines.     

Peimisine and peiminine production by endophytic fungus Fusarium sp. isolated from Fritillaria unibracteata var. wabensis

Steroidal alkaloids, as the major biologically active components in Bulbus Fritillariae, possess a variety of toxicological and pharmacological effects on humans. The objective of this work was to determine whether endophytic fungi isolated from fresh bulbs of Fritillaria unibracteata var. wabensis can produce one or more alkaloids like its host plant. Four classical reagents including Wagner's, iodine-potassium iodide, Mayer's and improved Dragendorff's were used for primary screening. Then thin-layer chromatography (TLC) and high performance liquid chromatography-evaporative light scattering detection (HPLC-ELSD) were employed to identify the fermentation products of the selected strains. The results showed that extract from one stain (WBS007) has positive reactions in process of primary screening. A further TLC scan and HPLC-ELSD showed that strain WBS007 had two components with the same TLC relative front (Rf) value and HPLC retention time (RT) as authentic peimisine and peiminine. In addition, strain WBS007 was identified as Fusarium sp. based on phylogenetic analysis of ITS sequences. Thus, strain WBS007 produced the bioactive ingredient peimisine and peiminine, as does its host plant, and could be used for the production of peimisine and peiminine by fermentation.     

黄芩内生真菌N.SBA10代谢产物抗氧化活性及结构鉴定

黄芩内生真菌N.SBA10固体发酵培养物的乙酸乙酯提取物有较好的抗氧化活性。从乙酸乙酯提取物中分离得到3个化合物,根据波谱数据,化合物1–3的结构分别被鉴定为：邻苯二甲酸二正丁酯（DBP）,alternariol methyl ether（AME）和alternariol（AOH）。     

Betagamma-dehydrocurvularin and related compounds as nematicides of Pratylenchus penetrans from the fungus Aspergillus sp

The new nematicidal compound, betagamma-dehydrocurvularin (1), together with three known compounds, alphabeta-dehydrocurvularin (2), 8-beta-hydroxy-7-oxocurvularin (3) and 7-oxocurvularin (4), were isolated from the culture filtrate and mycelial mats of Aspergillus sp. The structures of 1-4 were established by spectroscopic methods including 2D NMR. The biological activities of 1-4 were examined by bioassays with root-lesion nematodes, and lettuce and rice seedlings.     

银杏内生真菌Aspergillus oryzae YX-5抗肿瘤活性物质的分离与鉴定

【背景】植物内生真菌是天然活性物质的重要来源。【目的】对一株具有抗肿瘤活性的银杏内生真菌米曲霉Aspergillus oryzae YX-5进行活性物质的分离与鉴定。【方法】将该菌株发酵培养后,发酵液经乙酸乙酯萃取,采用减压柱层析、葡聚糖凝胶柱层析和高效液相色谱分析,从其代谢产物中分离活性化合物,在分离过程中以MTT法跟踪检测分离到的各组分及纯化合物的抗肿瘤活性。【结果】从菌株YX-5的发酵产物中分离纯化得到4个化合物。经核磁共振和高分辨质谱分析,将其分别鉴定为羟基曲霉酸(1)、环(4-羟脯氨酸-苯丙氨酸)(2)、环(亮氨酸-苯丙氨酸)(3)和环(丙氨酸-苯丙氨酸)(4)。其中羟基曲霉酸对人宫颈癌HeLa细胞具有显著的细胞毒活性,其IC_(50)为1.07μg/mL。【结论】报道羟基曲霉酸在抗肿瘤方面的活性,表明米曲霉及羟基曲霉酸在抗肿瘤天然产物开发中具有一定的应用潜力。