Sphaeropsidin A, a pimarane diterpene with interesting biological activities and promising practical applications

The use of plants as therapeutic agents is part of the traditional medicine that is practiced by many indigenous communities in Ecuador. The aim of this study was to update a review published in 2016 by including the studies that were carried out in the period 2016–July 2021 on about 120 Ecuadorian medicinal plants. Relevant data on raw extracts and isolated secondary metabolites were retrieved from different databases, resulting in 104 references. They included phytochemical and pharmacological studies on several non-volatile compounds, as well as the chemical composition of essential oils (EOs). The tested biological activities are also reported. The potential of Ecuadorian plants as sources of products for practical applications in different fields, as well the perspectives of future investigations, are discussed in the last part of the review.

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Proanthocyanidins: Oligomeric Structures with Unique Biochemical Properties and Great Therapeutic Promise

Natural Product Communications ◽

10.1177/1934578x1200700321 ◽

2012 ◽

Vol 7 (3) ◽

pp. 1934578X1200700 ◽

Cited By ~ 3

Author(s):

Zhanjie Xu ◽

Peng Du ◽

Peter Meiser ◽

Claus Jacob

Keyword(s):

Protein Interactions ◽

Biological Activities ◽

Antioxidant Properties ◽

Chemical Properties ◽

Cancer Chemoprevention ◽

Biochemical Properties ◽

Synthetic Methods ◽

Practical Applications ◽

Wide Range ◽

Physical And Chemical

Proanthocyanidins represent a unique class of oligomeric and polymeric secondary metabolites found ubiquitously and in considerable amounts in plants and some algae. These substances exhibit a range of rather surprising physical and chemical properties which, once applied to living organisms, are translated into a multitude of biological activities. The latter include antioxidant properties, cancer chemoprevention, anti-inflammatory and anti-diabetic effects as well as some exceptional, yet highly interesting activities, such as anti-nutritional and antimicrobial activity. Despite the wide range of activities and possible medical/agricultural applications of proanthocyanidins, many questions still remain, including issues related to bioavailability, metabolism and the precise biochemical, extra- and intracellular targets and mode(s) of action of these highly potent materials. Among the various physical and chemical interactions of such substances, strong binding to proteins appears to form the basis of many of their biological activities. Once easy-to-use synthetic methods to produce appropriate quantities of pure proanthocyanidins are available, it will be possible to identify the prime biological targets of these oligomers, study oligomer-protein interactions in more detail and develop possible practical applications in medicine and agriculture.

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Structure–activity relationships of guanylated antimicrobial polymethacrylates

Pure and Applied Chemistry ◽

10.1515/pac-2014-0213 ◽

2014 ◽

Vol 86 (8) ◽

pp. 1281-1291 ◽

Cited By ~ 13

Author(s):

Katherine E.S. Locock ◽

Thomas D. Michl ◽

Hans J. Griesser ◽

Matthias Haeussler ◽

Laurence Meagher

Keyword(s):

Bacterial Resistance ◽

Biological Activities ◽

Antimicrobial Polymers ◽

Practical Applications ◽

Structure Activity Relationships ◽

New Class ◽

Human Red Blood Cells ◽

Structure Activity ◽

Ideal Composition ◽

Low Toxicity

AbstractHost-defense antimicrobial peptides (AMPs) are a promising lead in the search for novel antibiotics. Many of these peptides exhibit broad-spectrum antibacterial ability, low toxicity toward human cells, and little susceptibility to induction of bacterial resistance. Our research focuses on the development of synthetic polymers that are able to mimic the amphiphilic and cation-rich characteristics of AMPs. This derives bioactive polymers that retain the activity profile of AMPs while utilizing a construct that is less expensive and easier to produce and manipulate chemically. This review details structure–activity relationships (SARs) of a new class of arginine-rich, synthetic AMP mimicking polymers (SAMPs), the guanylated polymethacrylates. These are contrasted with those of amine-based polymers that are mimics of lysine-rich AMPs. The ideal composition for candidates for practical applications was identified as those containing guanidines as a cation source, having a low molecular weight and a low level of lipophilicity. This gave polymers with high potency against Gram-positive strains of bacteria (e.g., Staphylococcus epidermidis MIC = 10 μg/mL) and low toxicity towards human red blood cells (<4% hemolysis at given MIC). This work emphasizes the need to rationalize observed biological activities based not purely on the global lipophilic and cationic character of polymers but rather to consider the profound effect that specific pendant functional groups may have on the potency, selectivity, and mechanisms behind the action of antimicrobial polymers.

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Poriferan chitin: 3D scaffolds from nano- to macroscale. A review

Letters in Applied NanoBioScience ◽

10.33263/lianbs92.10041014 ◽

2020 ◽

Vol 9 (2) ◽

pp. 1004-1014 ◽

Cited By ~ 4

Keyword(s):

Biological Activities ◽

Toxic Waste ◽

Special Focus ◽

Practical Applications ◽

Terrestrial Invertebrates ◽

Macro Scale ◽

Scale Levels ◽

3D Architecture ◽

Scaffolding Strategy ◽

Multicellular Organisms

Modern scaffolding strategy with respect to chitin is based on the application of naturally prefabricated 3D chitinous scaffolds of both aquatical and terrestrial invertebrates origin, mostly in the form of decellularized matrices. The sources of such constructs should be renewable or represent biodegradable and non-toxic waste materials. Sponges (Porifera) have been recognized among the first multicellular organisms on Earth having survived for more than 500 million yearsdue to their ability to synthetize robust skeletons with uniquely developed microporous 3D architecture and protect themselves from predatory microorganisms through the production of diverse secondary metabolites with multi-target biological activities. In this study, we analysed the occurrence of naturally pre-designed 3D chitinous matrices reported in sponges on nano-, micro- and macro-scale levels for the first time. Special focus is dedicated to the practical applications of such unique constructs in biomedicine.

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A novel multidimensional strategy to evaluate Belamcanda chinensis (L) DC and Iris tectorum Maxim based on plant metabolomics, digital reference standard analyzer and biological activities evaluation

Chinese Medicine ◽

10.1186/s13020-021-00494-3 ◽

2021 ◽

Vol 16 (1) ◽

Author(s):

Hongxu Zhou ◽

Yi Zhang ◽

Hui Liang ◽

Huijie Song ◽

Jiaming Zhao ◽

...

Keyword(s):

Biological Activities ◽

Chemical Constituents ◽

Hepatoprotective Activity ◽

High Abundance ◽

Reference Standard ◽

Linear Calibration ◽

Practical Applications ◽

Plant Metabolomics ◽

Digital Reference ◽

Belamcanda Chinensis

Abstract Background Belamcanda chinensis (L.) DC. (BC) belongs to the family of Iridaceae and is widely cultivated and used in many Chinese patent medicine and Chinese medicinal formulae. However, due to the high similarities in appearance such as color and shape to Iris tectorum Maxim (ITM), another plant from the same family, BC is often confused or even misused with ITM. Methods Therefore, in order to distinguish the chemical constituents, qualities and biological activities of BC and ITM, multiple technologies including plant metabolomics, digital reference standard (DRS) analyzer and biological activities assay were employed to provide a sufficient basis for their practical applications. Results In plant metabolomics, the PCA and OPLS-DA score plot indicated the obvious differences in chemical profiling between BC and ITM and 6 compounds were successfully identified to contribute to the differences. In DRS study, the fingerprints of 10 and 8 compounds in BC and ITM were developed based on DRS analyzer, respectively, involving relative retention time (RRT) method and linear calibration using two reference substances (LCTRS) technique. The DRS analyzer also accurately identified 10 and 8 compounds from BC and ITM, respectively, by using only two reference standards. In biological activities assay, BC had a better anticancer effect than ITM due to the high abundance of irigenin, while ITM showed stronger hepatoprotective activity than BC because of the high abundance of tectoridin. Conclusions Therefore, due to the significant differences of B. chinensis and I. dichotoma in chemical composition and biological activities, the current studies strongly proved that these two medicinal plants could not be mixed in industrial production and clinical medication.

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Biological activity and chemical identification of ornithine lipid produced by Burkholderia gladioli pv. agaricicola ICMP 11096 using LC-MS and NMR analyses

Journal of Biological Research - Bollettino della Società Italiana di Biologia Sperimentale ◽

10.4081/jbr.2017.6534 ◽

2018 ◽

Vol 90 (2) ◽

Cited By ~ 3

Author(s):

Hazem Salaheldin Elshafie ◽

Licia Viggiani ◽

Mohamed Said Mostafa ◽

Maher A. El-Hashash ◽

Ippolito Camele ◽

...

Keyword(s):

Antibacterial Activity ◽

Secondary Metabolites ◽

Culture Filtrate ◽

Biological Activities ◽

Bacterial Species ◽

Bioactive Compound ◽

Chemical Identification ◽

Practical Applications ◽

Hplc Fractionation

Lipoamino acids (LAs) have been isolated from bacterial species and are included among the most important microbial secondary metabolites. Some synthetic LAs are being increasingly used in pharmaceutical applications such as ornithine lipid (OL) which is present in relatively large amounts in some G-ve bacteria. Many Burkholderia spp. produce in vitro secondary metabolites with lipodepsipeptide nature and have showed relevant biological activities and potential practical applications. The purposes of this research were i) to study the antibacterial activity of cell-free culture filtrate of B. gladioli pv. agaricicola strain ICMP 11096; ii) HPLC fractionation and antibacterial evaluation of isolated compounds; iii) Finally, the identification by LC-MS and NMR analysis of the principle bioactive compound produced by the bacterium. Results showed that the cell-free culture filtrate has a promising antibacterial activity against the two studied target microorganisms. In addition, HPLC fractionation demonstrated the presence of five single bioactive compounds produced by the bacterium and their antibacterial activity stated that peak no. 2 is the most bioactive one against B. megaterium and E. coli. Successively, the principal bioactive compound was identified by LC-MS and ¹H NMR as OL with mass spectrum (m/z) 719. This research is considered the first report of isolation and chemical identification of OL compound isolated from B. gladioli pv. agaricicola ICMP 11096.

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Ion Beam Induced Interfacial Reactions in Molybdenum Thin Films on Silicon

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100097466 ◽

1981 ◽

Vol 39 ◽

pp. 162-163

Author(s):

L. J. Chen ◽

L. S. Hung ◽

J. W. Mayer

Keyword(s):

Ion Beam ◽

Chemical Vapor ◽

Interfacial Reactions ◽

Practical Applications ◽

Microelectronic Devices ◽

Recent Emergence ◽

Chemical Vapor Deposited ◽

Atomic Mixing ◽

Silicon Interface ◽

Kinetics Of

When an energetic ion penetrates through an interface between a thin film (of species A) and a substrate (of species B), ion induced atomic mixing may result in an intermixed region (which contains A and B) near the interface. Most ion beam mixing experiments have been directed toward metal-silicon systems, silicide phases are generally obtained, and they are the same as those formed by thermal treatment.Recent emergence of silicide compound as contact material in silicon microelectronic devices is mainly due to the superiority of the silicide-silicon interface in terms of uniformity and thermal stability. It is of great interest to understand the kinetics of the interfacial reactions to provide insights into the nature of ion beam-solid interactions as well as to explore its practical applications in device technology.About 500 Å thick molybdenum was chemical vapor deposited in hydrogen ambient on (001) n-type silicon wafer with substrate temperature maintained at 650-700°C. Samples were supplied by D. M. Brown of General Electric Research & Development Laboratory, Schenectady, NY.

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1250-kilovolt scanning transmission electron microscope

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100113007 ◽

1984 ◽

Vol 42 ◽

pp. 624-625

Author(s):

T. Imura ◽

S. Maruse ◽

K. Mihama ◽

M. Iseki ◽

M. Hibino ◽

...

Keyword(s):

High Voltage ◽

Electron Probe ◽

Scanning Transmission Electron Microscope ◽

Pressure Vessels ◽

Practical Applications ◽

Voltage Generator ◽

Transmission Electron ◽

Scanning Transmission ◽

New Applications ◽

High Voltage Generator

Ultra high voltage STEM has many inherent technical advantages over CTEM. These advantages include better signal detectability and signal processing capability. It is hoped that it will explore some new applications which were previously not possible. Conventional STEM (including CTEM with STEM attachment), however, has been unable to provide these inherent advantages due to insufficient performance and engineering problems. Recently we have developed a new 1250 kV STEM and completed installation at Nagoya University in Japan. It has been designed to break through conventional engineering limitations and bring about theoretical advantage in practical applications.In the design of this instrument, we exercised maximum care in providing a stable electron probe. A high voltage generator and an accelerator are housed in two separate pressure vessels and they are connected with a high voltage resistor cable.(Fig. 1) This design minimized induction generated from the high voltage generator, which is a high frequency Cockcroft-Walton type, being transmitted to the electron probe.

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Characterization of intergranular cuprous oxide in polycrystalline YBa2Cu3O7-x

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100106466 ◽

1988 ◽

Vol 46 ◽

pp. 880-881

Author(s):

Bradley L. Thiel ◽

Chan Han R. P. ◽

Kurosky L. C. Hutter ◽

I. A. Aksay ◽

Mehmet Sarikaya

Keyword(s):

Grain Boundary ◽

Cuprous Oxide ◽

Room Temperature ◽

Boundary Phase ◽

Spectroscopic Techniques ◽

Transition Width ◽

Practical Applications ◽

Thin Foils ◽

Superconducting Oxides

The identification of extraneous phases is important in understanding of high Tc superconducting oxides. The spectroscopic techniques commonly used in determining the origin of superconductivity (such as RAMAN, XPS, AES, and EXAFS) are surface-sensitive. Hence a grain boundary phase several nanometers thick could produce irrelevant spectroscopic results and cause erroneous conclusions. The intergranular phases present a major technological consideration for practical applications. In this communication we report the identification of a Cu2O grain boundary phase which forms during the sintering of YBa2Cu3O7-x (1:2:3 compound).Samples are prepared using a mixture of Y2O3. CuO, and BaO2 powders dispersed in ethanol for complete mixing. The pellets pressed at 20,000 psi are heated to 950°C at a rate of 5°C per min, held for 1 hr, and cooled at 1°C per min to room temperature. The samples show a Tc of 91K with a transition width of 2K. In order to prevent damage, a low temperature stage is used in milling to prepare thin foils which are then observed, using a liquid nitrogen holder, in a Philips 430T at 300 kV.

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Resolution and measurement in the scanning electron microscope

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100127256 ◽

1987 ◽

Vol 45 ◽

pp. 534-537 ◽

Cited By ~ 2

Author(s):

Michael T. Postek

Keyword(s):

Electron Microscope ◽

Scanning Electron Microscope ◽

Engineering Design ◽

Resolving Power ◽

Practical Applications ◽

Instrument Resolution ◽

Accurate Definition ◽

Definition Of ◽

Scanning Electron ◽

Better Than

The term ultimate resolution or resolving power is the very best performance that can be obtained from a scanning electron microscope (SEM) given the optimum instrumental conditions and sample. However, as it relates to SEM users, the conventional definitions of this figure are ambiguous. The numbers quoted for the resolution of an instrument are not only theoretically derived, but are also verified through the direct measurement of images on micrographs. However, the samples commonly used for this purpose are specifically optimized for the measurement of instrument resolution and are most often not typical of the sample used in practical applications.SEM RESOLUTION. Some instruments resolve better than others either due to engineering design or other reasons. There is no definitively accurate definition of how to quantify instrument resolution and its measurement in the SEM.

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