Improvement of natural product production in Streptomyces by manipulating pathway-specific regulators / 生物工程学报

Streptomyces are major sources of bioactive natural products. Genome sequencing reveals that Streptomyces have great biosynthetic potential, with an average of 20-40 biosynthetic gene clusters each strain. However, most natural products from Streptomyces are produced in low yields under regular laboratory cultivation conditions, which hamper their further study and drug development. The production of natural products in Streptomyces is controlled by the intricate regulation mechanisms. Manipulation of the regulatory systems that govern secondary metabolite production will strongly facilitate the discovery and development of natural products of Streptomyces origin. In this review, we summarize progresses in pathway-specific regulators from Streptomyces in the last five years and highlight their role in improving the yields of corresponding natural products.

Preliminary study on memory function of Sorbus aucuparia suspension cell to biotic stress / 中国中药杂志

Plants have a memory function for the environmental stress they have suffered. When they are subjected to repeated environmental stress, they can quickly and better activate the response and adaptation mechanism to environmental stress, thus realizing long-term stable reproduction. However, most of the relevant studies are applied to crops and Arabidopsis thaliana rather than medicinal plants about the improvement of plant growth status and the effect on phytoalexin biosynthesis. In this study, yeast extract(YE) was used as an elicitor to simulate biotic stress, and the changes in biomass and the content of some secondary metabolites were measured by giving repeated stresses to Sorbus aucuparia suspension cell(SASC). The results showed that the accumulation levels of biomass and some secondary metabolites in SASC subjected to repeated stress are significantly increased at some time points compared with single stress. A phenomenon that SASC can memorize biotic stress is confirmed in this study and influences phytoalexin accumulation in SASC. Furthermore, the work laid the groundwork for research into the transgenerational stress memory mechanism of medicinal plant.

Core position of secondary metabolism of medicinal plants in ecological planting of Chinese materia medica and its utilization / 中国中药杂志

This paper summarized the effects of ecological planting on secondary metabolism firstly and pointed out that ecological planting can increase the content of secondary metabolites in plants, especially the content of defensive secondary metabolites. The possible mechanism was analyzed subsequently. Then, we reviewed the induction and utilization of secondary metabolism in the ecological planting of Chinese materia medica from the perspectives of biological control of pests and diseases, promotion of beneficial microorganism accumulation, optimization of mixed planting, regulation of no-tillage and straw cover. In this article, we pointed out that paying close attention to secondary metabolism is the most important feature of ecological planting of Chinese materia medica. Ecological planting can promote the accumulation of secondary metabolites of Chinese materia medica which means can improve the quality of Chinese materia medica, beneficial to the prevention and control of diseases, insects and weeds. Furthermore, lacking of systemic researches,the extensive verifications and systematic in-depth researches on the ecological planting of Chinese materia medica should be carry out urgently.

Influence and mechanism of stress combination on medicinal plants secondary metabolism / 中国中药杂志

Numerous studies showed that the growth of medicinal plants in their native areas was simultaneously affected by abiotic stress combinations. Compared with single stress, plants have unique responses to a combination of different abiotic stresses and cannot be inferred directly from plants' responses to each individual stress. The effect of combined stresses on plants usually has three types of synergistic antagonism or independence. The secondary metabolism in the process of medicinal plant stress combination response also played a vital role, and environmental stresses can spur the accumulation of secondary metabolites, but under the stress combination, plants induce specific gene expression of key enzymes on secondary metabolic pathways, in turn, the accumulation of secondary metabolites against stress is formed. When plants are subjected to stress combination, the interaction of multiple signaling pathways makes it highly complex for plants to respond to stress combination. This paper summarized the effects of stress combination on physiological and secondary metabolism of medicinal plants, and discussed the related physiological, biochemical and molecular mechanisms. It provides theoretical basis for improving the adaptability of medicinal plants to adversity, improving the quality of Chinese medicinal materials, and further optimizing the cultivation of medicinal plants.

Study on the secondary metabolites of grasshopper-derived fungi Arthrinium sp. NF2410 / 中国天然药物

Two new 2-carboxymethyl-3-hexyl-maleic anhydride derivatives, arthrianhydride A (1) and B (2), along with three known compounds 3-5, were isolated from the fermentation broth of a grasshopper-associated fungus Arthrinium sp. NF2410. The structures of new compounds 1 and 2 were determined based on the analysis of the HR-ESI-MS and NMR spectroscopic data. Furthermore, compounds 1 and 2 were evaluated on inhibitory activity against the enzyme SHP2 and both of them showed moderate inhibitory activity against SHP2.

Stress and defense responses in plant secondary metabolites production

In the growth condition(s) of plants, numerous secondary metabolites (SMs) are produced by them to serve variety of cellular functions essential for physiological processes, and recent increasing evidences have implicated stress and defense response signaling in their production. The type and concentration(s) of secondary molecule(s) produced by a plant are determined by the species, genotype, physiology, developmental stage and environmental factors during growth. This suggests the physiological adaptive responses employed by various plant taxonomic groups in coping with the stress and defensive stimuli. The past recent decades had witnessed renewed interest to study abiotic factors that influence secondary metabolism during in vitro and in vivo growth of plants. Application of molecular biology tools and techniques are facilitating understanding the signaling processes and pathways involved in the SMs production at subcellular, cellular, organ and whole plant systems during in vivo and in vitro growth, with application in metabolic engineering of biosynthetic pathways intermediates.

Genome sequence of Streptomyces gilvigriseus MUSC 26T isolated from mangrove forest

Abstract Streptomycetes remain as one of the important sources for bioactive products. Isolated from the mangrove forest, Streptomyces gilvigriseus MUSC 26T was previously characterised as a novel streptomycete. The high quality draft genome of MUSC 26T contained 5,213,277 bp with G + C content of 73.0%. Through genome mining, several gene clusters associated with secondary metabolites production were revealed in the genome of MUSC 26T. These findings call for further investigations into the potential exploitation of the strain for production of pharmaceutically important compounds.

Exogenous H₂O₂ regulated secondary metabolism of Scutellaria baicalensis and enhanced drug quality / 中国中药杂志

The increasing demand of Chinese materia medica could not be supplied by wild resource, and the cultivated medicinal materials become popular, which led to decreased quality of many medicinal materials due to the difference of the circumstance between the wild and the cultivated. How to improve quality becomes key points of Chinese medicine resource. The leaves of Scutellaria baicalensis were sprayed with H₂O₂, the activities of superoxide dismutase (SOD) and catalase (CAT) changed little, but there had been a marked decrease of peroxidase (POD) and ascorbic oxidase (APX), which showed that the antioxidase system declined. Meanwhile, H₂O₂, as enhanced the expression of phenylalnine ammonialyase (PAL) and β-glucuronidase (GUS) as well as activity of PAL, promoted the biosynthesis and biotransformation of flavonoids. At the day 2 after treated, H₂O₂ of 0.004 μmol·L⁻¹ the contents of the baicalin and the wogonoside decreased slightly, but the contents of the baicalein and the wogonin increased significantly, the baicalein from 0.094% to 0.324%, the wogonin from 0.060% to 0.110%, i. e. increased 246% and 83.3%, respectively.

Microbial interactions: ecology in a molecular perspective

ABSTRACT The microorganism-microorganism or microorganism-host interactions are the key strategy to colonize and establish in a variety of different environments. These interactions involve all ecological aspects, including physiochemical changes, metabolite exchange, metabolite conversion, signaling, chemotaxis and genetic exchange resulting in genotype selection. In addition, the establishment in the environment depends on the species diversity, since high functional redundancy in the microbial community increases the competitive ability of the community, decreasing the possibility of an invader to establish in this environment. Therefore, these associations are the result of a co-evolution process that leads to the adaptation and specialization, allowing the occupation of different niches, by reducing biotic and abiotic stress or exchanging growth factors and signaling. Microbial interactions occur by the transference of molecular and genetic information, and many mechanisms can be involved in this exchange, such as secondary metabolites, siderophores, quorum sensing system, biofilm formation, and cellular transduction signaling, among others. The ultimate unit of interaction is the gene expression of each organism in response to an environmental (biotic or abiotic) stimulus, which is responsible for the production of molecules involved in these interactions. Therefore, in the present review, we focused on some molecular mechanisms involved in the microbial interaction, not only in microbial-host interaction, which has been exploited by other reviews, but also in the molecular strategy used by different microorganisms in the environment that can modulate the establishment and structuration of the microbial community.

Concentraciones de alcaloides, glucósidos cianogénicos, polifenoles y saponinas en plantas medicinales seleccionadas en Ecuador y su relación con la toxicidad aguda contra Artemia salina / Concentrations of alkaloids, cyanogenic glycosides, polyphenols and saponins in selected medicinal plants from Ecuador and their relationship with acute toxicity against Artemia salina

ResumenEntre los principales compuestos químicos sintetizados por las plantas, pero considerados no esenciales para su metabolismo básico, están los alcaloides, los polifenoles, los glucósidos cianogénicos y las saponinas que tienen diversas funciones en las plantas y reconocidas propiedades medicinales y farmacológicas. En esta investigación se determinaron las concentraciones de los mencionados metabolitos secundarios en los extractos de las hojas de las plantas medicinales Taraxacum officinale, Parthenium hysterophorus, Artemisia absinthium, Cnidoscolus aconitifolius y Piper carpunya y se relacionaron con la toxicidad aguda contra Artemia salina. En cada bioensayo con A. salina se usaron los extractos alcohólicos de las hojas de las plantas seleccionadas a diferentes concentraciones, calculándose la proporción de organismos muertos y los CL50. Las concentraciones de alcaloides, fenoles totales, taninos, glucósidos cianogénicos y saponinas fueron determinadas mediante métodos espectrofotométricos. Este es el primer reporte de cuantificación de metabolitos secundarios en las plantas analizadas provenientes de Ecuador. T. officinale presentó las mayores concentraciones de fenoles (22.30 ± 0.23 mg/g) y taninos (11.70 ± 0.10 mg/g), C aconitifolius de glucósidos cianogénicos (5.02 ± 0.37 µg/g) y P. hysterophorus de saponinas (6.12 ± 0.02 mg/g). Las plantas evaluadas presentaron actividades hemolíticas dependiendo de las concentraciones de saponinas. Los valores de taninos determinados estuvieron entre 0.20 ± 0.01 y 11.70 ± 0.10 mg/g, por lo que no son adversos para su consumo. Aunque los valores de glucósidos cianogénicos son permisibles, es necesario monitorear la presencia de estos compuestos químicos en las plantas para minimizar problemas de salud. Los CL50 obtenidos oscilaron entre los valores 3.37 µg/mL, extremadamente letal o tóxica, para P. carpunya y 274.34 µg/mL, altamente tóxica, para T. officinale. De los análisis de correlaciones realizados a los resultados, se observó que los alcaloides favorecen de manera significativa (p<0.001) a la toxicidad aguda contra A. salina, mientras que a mayor contenido de polifenoles dicha toxicidad disminuye significativamente (p<0.001) el nivel de toxicidad de las plantas. Del análisis de componentes principales, se demuestra que las saponinas están en sinergia con los polifenoles para disminuir la toxicidad, pero tienen un efecto antagónico con los alcaloides y los glucósidos cianogénicos, lo cual evidencia que estos metabolitos secundarios presentan variabilidades en los mecanismos de acción contra A. salina, como compuestos citotóxicos. Estos resultados demuestran que las saponinas y los polifenoles pueden ser letales para A. salina a bajas concentraciones, evidenciando que este bioensayo permite evaluar extractos vegetales que contengan bajas concentraciones de compuestos con altas polaridades. La correspondencia significativamente positiva entre citoxicidad y concentración de los alcaloides, confirmada con el bioensayo de Artemia salina, puede ser útil para hallar fuentes promisorias de compuestos antitumorales y para evaluar los límites tolerables que no afecten otras células benignas. El contenido de metabolitos secundarios hallados en las plantas analizadas les atribuye un gran valor farmacológico.

Abstract:Alkaloids, polyphenols, cyanogenic glycosides and saponins are among the main chemical compounds synthesized by plants but not considered essential for their basic metabolism. These compounds have different functions in plants, and have been recognized with medicinal and pharmacological properties. In this research, concentrations of the mentioned secondary metabolites were determined in the medicinal plants Artemisia absinthium, Cnidoscolus aconitifolius, Parthenium hysterophorus, Piper carpunya and Taraxacum officinale, from Ecuador, and related with cytotoxic effects against Artemia salina. Alcoholic and aqueous extracts from leaves of these selected plants were prepared at different concentrations. To assess cytotoxicity of these extracts, different bioassays with A. salina were undertaken, and the mortality rates and LC50 were obtained. Besides, concentrations of alkaloids, cyanogenic glycosides, phenols, tannins and saponins were determined by spectrophotometric methods; this constituted the first report of quantification of secondary metabolites in the selected plants from Ecuador. T. officinale had the highest concentration of total phenols (22.30 ± 0.23 mg/g) and tannins (11.70 ± 0.10 mg/g), C. aconitifolius of cyanogenic glycosides (5.02 ± 0.37 µg/g) and P. hysterophorus of saponins (6.12 ± 0.02 mg/g). Tannins values obtained were not adverse to their consumption. Alcoholic and aqueous extracts of selected plants had hemolytic activity depending on the concentration of saponins. Although the values of cyanogenic glycosides were permissible, it was necessary to monitor the presence of this metabolite in plants to minimize health problems. LC50 values ranged from extremely toxic (3.37 µg/mL) to highly toxic (274.34 μg/mL), in P. carpunya and T. officinale, respectively. From correlation analysis, it was observed that increase values of alkaloids concentrations had highly significant (p<0.001) acute toxicity against A. salina, while at a higher polyphenol concentration the level of plants cytotoxicity decreased significantly (p<0.001). The results of principal component analysis showed that saponins apparently were in synergy with polyphenols to decrease cytotoxicity, but antagonize with alkaloids and cyanogenic glycosides, indicating that these secondary metabolites present variability in the mechanisms of action against A. salina, as cytotoxic compounds. These results also demonstrate that polyphenols and saponins can be lethal at low concentrations, demonstrating the potential of brine shrimp bioassay as a model to evaluate plant extracts containing low concentrations of chemical compounds with high polarities. The significant positive correlation between cytotoxicity and concentration of alkaloids confirmed by the bioassay of brine shrimp can be useful to identify promising sources of antitumor compounds, and to evaluate tolerable limits not affecting other benign cells. Contents of secondary metabolites found in the selected plants confer them great pharmacologic values. Rev. Biol. Trop. 64 (3): 1171-1184. Epub 2016 September 01.

Substâncias fenólicas, flavonoides e capacidade antioxidante em erveiras sob diferentes coberturas do solo e sombreamentos / Phenolic Substances, Flavonoids, and Antioxidant Capacity in Herbs under Different Soil Covers and Shadings

RESUMO Objetivou neste trabalho analisar a concentração de polifenóis totais, flavonoides e capacidade antioxidantes por meio dos métodos ABTS e FRAP, em erveiras jovens cultivadas em solo coberto e com sombreamento. Mudas de erva-mate foram submetidas aos tratamentos com solos cobertos e desnudos em sombreamentos de 0, 18, 35 e 50%, após sete e onze meses de cultivo, verão e outono, respectivamente. Foram coletadas folhas maduras para realização dos extratos utilizados para as análises de compostos fenólicos por meio da reação de oxirredução com reagente de Folin-Ciocalteu, flavonoides por método colorimétrico e capacidade antioxidante por frente ao radical ABTS e poder de redução do ferro (FRAP). O teor de compostos fenólicos foi maior nos tratamentos com 35% de sombreamento em comparação ao grupo dos flavonoides e capacidade antioxidante, o que foi demonstrado pela correlação do sombreamento com estes parametros. No método FRAP a maior correlação demonstra que o outono é a melhor época de colheita por apresentar maior concentração de compostos fitoquímicos. Ficou evidente a influência positiva dos sombreamentos (35 e 50%) no teor de compostos fenólicos e flavonoides relacionados à capacidade antioxidante e à qualidade da erva-mate para atender ao mercado consumidor.

ABSTRACT This study aimed to analyze the concentration of total polyphenols, flavonoids, and antioxidant capacity, by the methods ABTS and FRAP, in young herbs grown in covered and shaded soil. Yerba mate seedlings were subjected to treatment with bare and covered soils in shadings of 0, 18, 35, and 50%, after seven and eleven months cultivation, summer and fall, respectively. Mature leaves were collected to perform the analyses of phenolic compounds by redox reaction with Folin-Ciocalteu reagent, of flavonoids by colorimetric method, and of antioxidant capacity by ABTS radical and FRAP (iron reduction method). The content of phenolic compounds was higher in the treatments with 35% shading in correlation with the group of flavonoids and antioxidant capacity. In the FRAP method, the higher correlation shows that autumn is the best time to harvest because of the higher concentration of phytochemical compounds. The positive influence of shading (35 and 50%) was evident in the content of phenolic compounds and flavonoids related to antioxidant capacity and better quality of yerba mate to meet the consumer market.

Isolation, identification and structural characterization of secondary metabolites from amarine sponge-derived rare actinobacterium Dermacoccus sp. X4 / 生物工程学报

We isolated and identified the symbiotic and adnascent microorganisms from an unidentified sponge collected from 10-meter-deep seawater of the Paracel Islands in China. A total of 16 strains were obtained and identified. Through bacteriostatic activity assay, one of the strains, Dermacoccus sp. X4, was found to effectively inhibit the growth of Staphylococcus aureus. Subsequently, its secondary metabolites were purified by silica gel partition, octadecylsilane (ODS) reverse phase, Sephadex™LH-20 size exclusion, and C18 reverse phase chromatography. Using liquid chromatography, mass spectrometry, and nuclear magnetic resonance, three of the purified compounds were structurally characterized to be one 3-(4-hydroxybenzyl) hexahydropyrrolo [1,2-a]pyrazine-1,4-dione and two indole acid glycerides. This is the first report about indole acid glyceride isolated from microbial secondary metabolites, enriching marine drug candidate resources.

Efeito do herbicida glifosato sobre o crescimento e produção de metabólitos secundários em Microcystis aeruginosa e Cylindrospermopsis raciborskii / The effect of herbicide glyphosate on the growth and of secondary metabolites production in Microcystis aeruginosa and Cylindrospermopsis raciborskii

ianobactérias, conhecidas por sua habilidade de sintetizar metabólitos com ação tóxica, podem se tornar dominantes em águas com altas concentrações de nitrogênio e fósforo. Embora a toxicidade do glifosato, o herbicida mais usado no mundo, em alguns organismos aquáticos seja conhecida, poucos estudos abordam o efeito desse composto sobre a produção de metabólitos secundários por cianobactérias. O objetivo deste trabalho foi avaliar a influência de diferentes concentrações de glifosato (produto técnico) sobre o crescimento e produção de cianotoxinas e microgininas pelas cepas brasileiras Microcystis aeruginosa LTPNA 08 e Cylindrospermopsis raciborskii CENA 302. Na presença de 15 mg/L de glifosato, o crescimento e a produção de toxinas pela M. aeruginosa foram reduzidos e de microgininas significativamente aumentada. Já a C. raciborskii, quando exposta à 20 mg/L de glifosato teve seu crescimento e síntese de clorofila-a, carotenoides e saxitoxinas aumentados. Concentrações superiores a 20 e 30 mg/L impediram o crescimento celular das cepas LTPNA 08 e CENA 302, respectivamente. A análise de ácidos graxos mostrou perfis bastante distintos entre as cepas. Na cepa LTPNA 08, enquanto que na presença de 10 mg/L de glifosato ocorreu diminuição do teor do ácido linoleico, o ácido estearidônico foi aumentado. Nenhuma das concentrações testadas promoveu alteração sobre o perfil de ácidos graxos da cepa CENA 302. A toxicidade de 5 produtos formulados a base de glifosato foi comparada ao produto técnico em ambas as linhagens-teste. Observou-se uma resistência distinta entre as cepas e toxicidade também variável entre as formulações comerciais. Sendo assim, diante da elevada resistência das cianobactérias M. aeruginosa e C. raciborskii ao glifosato, e considerando-se a elevada interferência antrópica através das práticas agrícolas, pode-se inferir que o uso excessivo e frequente desse herbicida é capaz de estimular o crescimento e dominância desses organismos, podendo modificar a estrutura e funcionalidade de ecossistemas aquáticos

Cyanobacteria, known for their ability to synthesize toxic metabolites, can become dominant in water bodies with high concentrations of nitrogen and phosphorus. Although the toxicity of glyphosate, the most widely used herbicide in the world, in some aquatic organisms is well known, few studies address the effect of this compound on the production of secondary metabolites by cyanobacteria. The aim of this study was to evaluate the influence of different concentrations the herbicide glyphosate (technical grade) on growth and production of cyanotoxins and microginins by Brazilian strains of Microcystis aeruginosa LTPNA 08 and Cylindrospermopsis raciborskii CENA 302. In the presence of 15 mg/L of glyphosate, growth and toxin production by M. aeruginosa were reduced and microginins cell quota significantly increased. The C. raciborskii strain, when exposed to 20 mg/L of glyphosate, had the growth, and chlorophyll-a, carotenoids and saxitoxins production increased. Concentrations above 20 and 30 mg/L prevented cell growth of LTPNA 08 and CENA 302 strains, respectively. Fatty acid analysis showed distinct profiles among the strains. When exposed to 10 mg/L of glyphosate, a decrease in the linoleic acid and increase in stearidonic acid content were observed in M. aeruginosa LTPNA 08 strain. None of the tested concentrations of glyphosate promoted change on the fatty acid profile of CENA 302 strain. The toxicity of 5 glyphosate formulated products was compared to technical product to both strains. There was a distinct resistance among strains and also a variable toxicity among formulated products. Thus, given the high glyphosate resistance of M. aeruginosa and C. raciborskii cyanobacteria, and considering the high anthropogenic interference through agri cultural practices, it can be inferred that excessive and frequent use of this herbicide is able to stimulate growth and dominance of these organisms, which may modify the structure and function of aquatic ecosystems

Teor e composição do óleo essencial de patchouli (Pogostemon cablin (Blanco) Benth. ) após diferentes tempos de secagem em estufa e temperatura ambiente / Yield and composition of essential oil of patchouli (Pogostemon cablin (Blanco) Benth. ) after different drying periods in oven and at room temperatur

RESUMOPatchouli é uma espécie aromática pertencente à família Lamiaceae que possui óleo essencial com alto valor comercial devido à aplicação nas indústrias de higiene, cosméticos e perfumarias. Considerando as características voláteis e estruturas de armazenamento em diferentes órgãos das plantas aromáticas, a determinação de métodos de secagem é de extrema importância e pode afetar tanto o rendimento como a composição do óleo essencial. Este trabalho teve como objetivo principal avaliar o teor e a composição do óleo essencial de patchouli após secagem por diferentes períodos em estufa e a temperatura ambiente. O experimento foi realizado durante o mês de fevereiro de 2011 em delineamento experimental inteiramente casualizado em esquema fatorial 2X6, correspondente a dois métodos de secagem (estufa 65ºC e temperatura ambiente) e seis tempos para o início da extração do óleo essencial após a (0, 2, 4,6,8 e 10 dias após a colheita),com três repetições. O óleo essencial foi extraído por meio hidrodestilação em aparelho graduado de Clevenger e os constituintes do óleo essencial foram analisados por cromatografia em fase gasosa acoplada à espectrometria de massas. Houve interação significativa entre os métodos e tempos de secagem tanto para o teor como para a composição do óleo essencial. A secagem das plantas por dois dias em estufa a 65ºC aumentou o teor de óleo essencial, após este período houve redução significativa. Para as folhas secas em temperatura ambiente, o teor de óleo essencial foi superior aos quatro e aos seis dias após a colheita. Comparando-se os métodos, a secagem em estufa mostrou-se mais eficiente, sendo o teor significativamente superior após dois dias de secagem. Após este período, no entanto, houve drástica redução do teor de óleo essencial, sendo inferior ao teor observado em todos os períodos nas folhas secas em temperatura ambiente. Os diferentes métodos e tempos de secagem alteraram também a composição do óleo essencial. Embora a secagem em estufa a 65º por dois dias não tenha resultado em redução dos teores dos constituintes majoritários patchoulol e pogostol, maiores teores foram observados após seis ou oito dias de secagem. Quando a secagem foi realizada a temperatura ambiente, não houve alteração dos teores de ambos os constituintes.

ABSTRACTPatchouli is an aromatic species belonging to the Lamiaceae family that has essential oil with high commercial value to the hygiene, cosmetic and perfume industries. Considering its volatile characteristics and storage structures in different organs of aromatic plants, the determination of drying methods is extremely important and can affect both the yield and the composition of the essential oil. This work aimed to evaluate the content and composition of the patchouli essential oil after drying it in different periodin an oven and at room temperature. The trial was carried out in February 2011 at an experimental design completely randomized in 2X6 factorial scheme, corresponding to two drying methods (oven at 65˚C and room temperature) and six periods of essential oil extraction after harvest (0, 2, 4, 6, 8, and 10 days after harvest), with three replications. The essential oil was extracted by hydrodistillation in a Clevenger apparatus and the essential oil components were analyzed by gas chromatography coupled to mass spectrometry. There was significant interaction among the methods and drying times for both the content as well as for the composition of essential oil. The drying of the plants for two days in an oven at 65˚C increased the essential oil content; after this period, there was a significant reduction. For the leaves that dried at room temperature, their contentof essential oil was superior at the fourth and sixth days after the harvest. When comparing the methods, the drying in the oven was more efficient, with the oil content being significantly higher after two days of drying. After this period, however, there was a drastic reduction in the essential oil content, lower than the one observed in all periods when the leaves dried at room temperature. The different methods and drying periods also altered the essential oil`s composition. Although drying in oven at 65˚ for two days did not result in reduction of the contents of patchoulol and pogostol, higher contents were observed after six or eight days of drying. When drying was carried out at room temperature, no change in relative content of both components was observed.

In vitro antioxidant capacity and free radical scavenging evaluation of active metabolite constituents of Newbouldia laevis ethanolic leaf extract

BACKGROUND: The aim of the present study was to evaluate the in vitro antioxidant and free radical scavenging capacity of bioactive metabolites present in Newbouldia laevis leaf extract. RESULTS: Chromatographic and spectrophotometric methods were used in the study and modified where necessary in the study. Bioactivity of the extract was determined at 10 µg/ml, 50 µg/ml, 100 µg/ml, 200 µg/ml and 400 µg/ml concentrations expressed in % inhibition. The yield of the ethanolic leaf extract of N.laevis was 30.3 g (9.93%). Evaluation of bioactive metabolic constituents gave high levels of ascorbic acid (515.53 ± 12 IU/100 g [25.7 mg/100 g]), vitamin E (26.46 ± 1.08 IU/100 g), saponins (6.2 ± 0.10), alkaloids (2.20 ± 0.03), cardiac glycosides(1.48 ± 0.22), amino acids and steroids (8.01 ± 0.04) measured in mg/100 g dry weight; moderate levels of vitamin A (188.28 ± 6.19 IU/100 g), tannins (0.09 ± 0.30), terpenoids (3.42 ± 0.67); low level of flavonoids (1.01 ± 0.34 mg/100 g) and absence of cyanogenic glycosides, carboxylic acids and aldehydes/ketones. The extracts percentage inhibition of DPPH, hydroxyl radical (OH.), superoxide anion (O2 .-), iron chelating, nitric oxide radical (NO), peroxynitrite (ONOO-), singlet oxygen (1O2), hypochlorous acid (HOCl), lipid peroxidation (LPO) and FRAP showed a concentration-dependent antioxidant activity with no significant difference with the controls. Though, IC50 of the extract showed significant difference only in singlet oxygen (1O2) and iron chelating activity when compared with the controls. CONCLUSIONS: The extract is a potential source of antioxidants/free radical scavengers having important metabolites which maybe linked to its ethno-medicinal use.

Diversity, bioactivities, and metabolic potentials of endophytic actinomycetes isolated from traditional medicinal plants in Sichuan, China / 中国天然药物

The present study was designed to determine the taxonomic diversity and metabolic activity of the actinomycetes community, including 13 traditional medicinal plants collected in Sichuan province, China, using multiple approaches such as morphological and molecular identification methods, bioactivity assays, and PCR screening for genes involved in antibiotics biosynthesis. 119 endophytic actinomycetes were recovered; 80 representative strains were chosen for 16S rRNA gene partial sequence analyses, with 66 of them being affiliated to genus Streptomyces and the remaining 14 strains being rare actinomycetes. Antimicrobial tests showed that 12 (15%) of the 80 endophytic actinomycetes displayed inhibitory effects against at least one indicator pathogens, which were all assigned to the genus Streptomyces. In addition, 87.5% and 58.8% of the isolates showed anticancer and anti-diabetic activities, respectively. Meanwhile, the anticancer activities of the isolates negatively correlated with their anti-diabetic activities. Based on the results of PCR screening, five genes, PKS-I, PKS-II, NRPS, ANSA, and oxyB, were detected in 55.0%, 58.8%, 90.0%, 18.8% and 8.8% of the 80 actinomycetes, respectively. In conclusion, the PCR screening method employed in the present study was conducive for screening and selection of potential actinomycetes and predicting potential secondary metabolites, which could overcome the limitations of traditional activity screening models.

Influence of diethyl sulfate (DES) mutagenesis on growth properties and pigment secondary metabolites of Phellinus igniarius / 中国中药杂志

The diethyl sulfate (DES) mutagenesis was chosen for the mutagenic treatment to Phellinus igniarius, and the relationship of mutagenesis time and death rate was investigated with 0.5% DES. The differences of mycelial growth speed, liquid fermentation mycelia biomass, morphology and pigment classes of secondary metabolites production speed and antioxidant activities of metabolite products were discussed. The study displayed that DES mutagenesis could change mycelial morphology without obvious effect on mycelium growth, and the DES mutagenesis improved antioxidant activities of the active ingredients of P. igniarius and had more antioxidant activity of hypoxia/sugar PC12 nerve cells than that of P. igniarius.

Secondary metabolites from a deep-sea-derived actinomycete Micrococcus sp. R21 / 中国中药杂志

To investigate cytotoxic secondary metabolites of Micrococcus sp. R21, an actinomycete isolated from a deep-sea sediment (-6 310 m; 142 degrees 19. 9' E, 10 degrees 54. 6' N) of the Western Pacific Ocean, column chromatography was introduced over silica gel, ODS, and Sephadex LH-20. As a result, eight compounds were obtained. By mainly detailed analysis of the NMR data, their structures were elucidated as cyclo(4-hydroxy-L-Pro-L-leu) (1), cyclo(L-Pro-L-Gly) (2), cyclo( L-Pro-L-Ala) (3), cyclo( D-Pro-L-Leu) (4), N-β-acetyltryptamine (5), 2-hydroxybenzoic acid (6), and phenylacetic acid (7). Compound 1 exhibited weak cytotoxic activity against RAW264. 7 cells with IC50 value of 9.1 μmol x L(-1).

Effects of elicitors on growth of adventitious roots and contents of secondary metabolites in Tripterygium wilfordii Hook. f / 生物工程学报

To study the effects of the extract of fungal elicitor, AgNO3, MeJA and yeast on the growth and content of secondary metabolites of adventitious roots in Tripterygium wilfordii. The above elicitors were supplemented to the medium, the growth and the content of secondary metabolites were measured. When the medium was supplemented with the elicitor Glomerella cingulata or Collectotrichum gloeosporioides, the content of triptolide was increased by 2.24 and 1.93-fold, the alkaloids content was increased by 2.02 and 2.07-fold, respectively. The optimal concentration of G. cingulata was 50 μg/mL for accumulation of triptolide, alkaloids and for the growth of adventitious roots. AgNO3 inhibited the growth of adventitious roots and the accumulation of the alkaloids, whereas it (at 25 μmol/L) increased the accumulation of triptolide by 1.71-fold compared to the control. The growth of adventitious roots, the contents of triptolide and alkaloids were increased 1.04, 1.64 and 2.12-folds, respectively when MeJA was at 50 μmol/L. When the concentration of yeast reached 2 g/L, the content of triptolide increased 1.48-folds. This research demonstrated that supplementation of AgNO3 and yeast enhanced the biosynthesis of triptolide in adventitious roots and the synergism of G. cingulata and MeJA could promote the biosynthesis of both triptolide and alkaloids.