scholarly journals The Genus Nerine Herb. (Amaryllidaceae): Ethnobotany, Phytochemistry, and Biological Activity

Molecules ◽  
2019 ◽  
Vol 24 (23) ◽  
pp. 4238 ◽  
Author(s):  
Cahlíková ◽  
Vaněčková ◽  
Šafratová ◽  
Breiterová ◽  
Blunden ◽  
...  
Keyword(s):  
South Africa ◽  
Biological Activity ◽  
Summer Rainfall ◽  
Biological Properties ◽  
Present Review ◽  
Cholinesterase Inhibition ◽  
Amaryllidaceae Alkaloids ◽  
Structural Types ◽  
Autumn Flowering

Nerine Herbert, family Amaryllidaceae, is a genus of about 30 species that are native to South Africa, Botswana, Lesotho, Namibia, and Swatini (formerly known as Swaziland). Species of Nerine are autumn-flowering, perennial, bulbous plants, which inhabit areas with summer rainfall and cool, dry winters. Most Nerine species have been cultivated for their elegant flowers, presenting a source of innumerable horticultural hybrids. For many years, species of Nerine have been subjected to extensive phytochemical and pharmacological investigations, which resulted in either the isolation or identification of more than fifty Amaryllidaceae alkaloids belonging to different structural types. Amaryllidaceae alkaloids are frequently studied for their interesting biological properties, including antiviral, antibacterial, antitumor, antifungal, antimalarial, analgesic, cytotoxic, and cholinesterase inhibition activities. The present review aims to summarize comprehensively the research that has been reported on the phytochemistry and pharmacology of the genus Nerine.

scholarly journals Chemistry and Biological Activity of Alkaloids from the Genus Lycoris (Amaryllidaceae)

Molecules ◽  
2020 ◽  
Vol 25 (20) ◽  
pp. 4797
Author(s):  
Lucie Cahlíková ◽  
Kateřina Breiterová ◽  
Lubomír Opletal
Keyword(s):  
Biological Activity ◽  
Biological Properties ◽  
Present Review ◽  
Cholinesterase Inhibition ◽  
Eastern Asia ◽  
Amaryllidaceae Alkaloids ◽  
Structural Types ◽  
Temperate Woodlands ◽  
Warm Temperate ◽  
Small Genus

Lycoris Herbert, family Amaryllidaceae, is a small genus of about 20 species that are native to the warm temperate woodlands of eastern Asia, as in China, Korea, Japan, Taiwan, and the Himalayas. For many years, species of Lycoris have been subjected to extensive phytochemical and pharmacological investigations, resulting in either the isolation or identification of more than 110 Amaryllidaceae alkaloids belonging to different structural types. Amaryllidaceae alkaloids are frequently studied for their interesting biological properties, including antiviral, antibacterial, antitumor, antifungal, antimalarial, analgesic, cytotoxic, and cholinesterase inhibition activities. The present review aims to summarize comprehensively the research that has been reported on the phytochemistry and pharmacology of the genus Lycoris.

Chemical constituents and biological properties of liverworts from South Africa

Planta Medica ◽  
2015 ◽  
Vol 81 (16) ◽  
Author(s):  
S Combrinck ◽  
J Linde ◽  
A Ludwiczuk ◽  
S Van Vuuren ◽  
J Van Rooy ◽  
...  
Keyword(s):  
South Africa ◽  
Chemical Constituents ◽  
Biological Properties

Enzymes as a Reservoir of Host Defence Peptides

2020 ◽  
Vol 20 (14) ◽  
pp. 1310-1323
Author(s):  
Andrea Bosso ◽  
Antimo Di Maro ◽  
Valeria Cafaro ◽  
Alberto Di Donato ◽  
Eugenio Notomista ◽  
...  
Keyword(s):  
Innate Immunity ◽  
Biological Activity ◽  
Internal Structure ◽  
Catalytic Properties ◽  
Cellular Responses ◽  
Host Defence ◽  
Present Review ◽  
Active Peptides ◽  
Wide Range

Host defence peptides (HDPs) are powerful modulators of cellular responses to various types of insults caused by pathogen agents. To date, a wide range of HDPs, from species of different kingdoms including bacteria, plant and animal with extreme diversity in structure and biological activity, have been described. Apart from a limited number of peptides ribosomally synthesized, a large number of promising and multifunctional HDPs have been identified within protein precursors, with properties not necessarily related to innate immunity, consolidating the fascinating hypothesis that proteins have a second or even multiple biological mission in the form of one or more bio-active peptides. Among these precursors, enzymes constitute certainly an interesting group, because most of them are mainly globular and characterized by a fine specific internal structure closely related to their catalytic properties and also because they are yet little considered as potential HDP releasing proteins. In this regard, the main aim of the present review is to describe a panel of HDPs, identified in all canonical classes of enzymes, and to provide a detailed description on hydrolases and their corresponding HDPs, as there seems to exist a striking link between these structurally sophisticated catalysts and their high content in cationic and amphipathic cryptic peptides.

Biological Function and Chemistry of Endothelin. A Review

1999 ◽  
Vol 64 (8) ◽  
pp. 1211-1252 ◽  
Author(s):  
Jan Hlaváček ◽  
Renáta Marcová
Keyword(s):  
Biological Activity ◽  
Amino Acid ◽  
Biological Function ◽  
Biological Properties ◽  
Structural Basis ◽  
Amino Acid Residues ◽  
Snake Venoms ◽  
Vasoactive Peptides ◽  
Physico Chemical ◽  
Endothelin A

The first part of this review deals with the biosynthesis and a biological function of strongly vasoactive peptides named endothelins (ETs) including vasoactive intestinal contractor. Where it was useful, snake venoms sarafotoxins which are structural endothelin derivatives, were also mentioned. In the second part, an attention is paid to structural basis of the ETs biological activity, with respect to alterations of amino acid residues in the parent peptides modifying the conformation and consequently the physico-chemical and biological properties in corresponding ETs analogs. Special attention is focussed on the area of ETs receptors and their interaction with peptide and non peptide agonists and antagonists, important in designing selective inhibitors of ETs receptors potentially applicable as drugs in a medicine. A review with 182 references.

scholarly journals Applications of Radiolabelled Curcumin and Its Derivatives in Medicinal Chemistry

2021 ◽  
Vol 22 (14) ◽  
pp. 7410
Author(s):  
Matteo Mari ◽  
Debora Carrozza ◽  
Erika Ferrari ◽  
Mattia Asti
Keyword(s):  
Nuclear Medicine ◽  
Early Diagnosis ◽  
Clinical Application ◽  
Medicinal Chemistry ◽  
Biological Properties ◽  
Present Review ◽  
Chemical Modifications ◽  
Technetium 99M ◽  
Curcumin Derivatives ◽  
Gallium 68

Curcumin is a natural occurring molecule that has aroused much interest among researchers over the years due to its pleiotropic set of biological properties. In the nuclear medicine field, radiolabelled curcumin and curcumin derivatives have been studied as potential radiotracers for the early diagnosis of Alzheimer’s disease and cancer. In the present review, the synthetic pathways, labelling methods and the preclinical investigations involving these radioactive compounds are treated. The studies entailed chemical modifications for enhancing curcumin stability, as well as its functionalisation for the labelling with several radiohalogens or metal radionuclides (fluorine-18, technetium-99m, gallium-68, etc.). Although some drawbacks have yet to be addressed, and none of the radiolabelled curcuminoids have so far achieved clinical application, the studies performed hitherto provide useful insights and lay the foundation for further developments.

scholarly journals The Role of Mesoscale Convective Complexes in Southern Africa Summer Rainfall

2013 ◽  
Vol 26 (5) ◽  
pp. 1654-1668 ◽  
Author(s):  
R. C. Blamey ◽  
C. J. C. Reason
Keyword(s):  
South Africa ◽  
Southern Africa ◽  
Rainfall Variability ◽  
Warm Season ◽  
Tropical Rainfall Measuring Mission ◽  
Summer Rainfall ◽  
Spatial And Temporal Variability ◽  
Eastern Region ◽  
Southwest Indian Ocean ◽  
Mesoscale Convective

Abstract A combination of numerous factors, including geographic position, regional orography, and local sea surface temperatures, means that subtropical southern Africa experiences considerable spatial and temporal variability in rainfall and is prone to both frequent flooding and drought events. One system that may contribute to rainfall variability in the region is the mesoscale convective complex (MCC). In this study, Tropical Rainfall Measuring Mission (TRMM) Multisatellite Precipitation Analysis (TMPA) data is used to document the precipitation produced by MCCs over southern Africa for the 1998–2006 period. Most of the rainfall associated with MCCs is found to occur over central Mozambique, extending southward to eastern South Africa. High precipitation totals associated with these systems also occur over the neighboring southwest Indian Ocean, particularly off the northeast coast of South Africa. MCCs are found to contribute up to 20% of the total summer rainfall (November–March) in parts of the eastern region of southern Africa. If the month of March is excluded from the analysis, then the contribution increases up to 24%. In general, the MCC summer rainfall contribution for most of the eastern region is approximately between 8% and 16%. Over the western interior and Botswana and Namibia, the MCC contribution is much less (<6%). It is also evident that there is considerable interannual variability associated with the contribution that these systems make to the total warm season rainfall.

Aktywność biologiczna ekstraktów z propolisu

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Magdalena Woźniak ◽  
Anna Kwiatkowska ◽  
Elżbieta Hołderna-Kędzia ◽  
Katarzyna Sosnowska ◽  
Lucyna Mrówczyńska ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Biological Activity ◽  
Phenolic Compounds ◽  
Propylene Glycol ◽  
Ethyl Alcohol ◽  
Antiradical Activity ◽  
Colorimetric Method ◽  
Biological Properties ◽  
Bioactive Substances ◽  
Dpph Test

Introduction. Propolis, also known as bee glue, is a resinous material collected by honeybees with numerous biological properties, including antibacterial, antifungal, antioxidant and anticancer effects. Due to its health-promoting properties, propolis is a component of many products, including dietary supplements, cosmetics and healthy food. Aim. The aim of the study was to determine the antibacterial, antifungal and antioxidant activity of propolis extracts, as well as to compare the biological activity of propolis extracts, depending on the solvent used – ethyl alcohol or propylene glycol. Material and methods. Two propolis extracts were used in the research – the first was prepared in ethyl alcohol, and the second in propylene glycol. The antimicrobial activity of the examined extracts was determined against S. aureus, E. coli and C. albicans. The antioxidant activity was determined on the basis of the evaluation of their antiradical activity in the DPPH· test and Fe2+ chelating activity. Moreover, the total content of phenolic compounds and flavonoids in the tested extracts was determined using the colorimetric method. Results. The tested propolis extracts, regardless of the solvent used (ethyl alcohol or propylene glycol), showed high antibacterial (against S. aureus), antifungal (against C. albicans) and antioxidant (antiradical activity in the DPPH· test and ferrous iron chelating potency in the ferrozine test) activity. Moreover, both tested extracts were characterized by a high and similar content of bioactive compounds – phenolic compounds and flavonoids. Conclusions. The results of the conducted tests showed that the solvent used did not affect determined biological activity and the content of bioactive substances in the tested propolis extracts.

Further Notes on Structural Types and Earth Movements

1931 ◽  
Vol 68 (1) ◽  
pp. 15-24
Author(s):  
J. S. Lee
Keyword(s):  
South Africa ◽  
North America ◽  
Critical Points ◽  
Eastern China ◽  
Point Of View ◽  
Continental Scale ◽  
Structural Types ◽  
Tectonic Features ◽  
Geological Magazine

In a previous paper published in the Geological Magazine, the writer made an attempt to discuss the mechanism of earth movement on a continental scale purely from a tectonic point of view. The problem is so vast and involved that some of the vital points were hardly touched upon, partly because of lack of space and partly of literature. The arrival of the admirable works of Dr. A. du Toit and Dr. E. Krenkel has enabled the writer to deduce the mechanism of the movements of South Africa directly from its tectonic features, which process is thought to be far more reliable than the type of argument used in the previous case although the results arrived at are essentially the same. The earlier movements in North America are now seen to furnish evidence of the same type of mechanism as that which staged the later movements. An epsilon type of structure has been recognized in Eastern China, which was then described as a mere arc. The problem of the distribution of concealed coalfields in England was in the previous paper barely touched upon. It is now proposed to consider some of the critical points bearing on the problem.

scholarly journals Influence of Pollution by Antibiotics on Biological Properties of Soils (Through the Example of Ordinary Chernozem)

2021 ◽  
Author(s):  
Yuliya Akimenko
Keyword(s):  
Biological Activity ◽  
Polyphenol Oxidase ◽  
Catalase Activity ◽  
Direct Relationship ◽  
Negative Impact ◽  
Biological Indicators ◽  
Biological Properties ◽  
Field Conditions ◽  
Ordinary Chernozem ◽  
Biological Parameters

Abstract In model laboratory and field conditions, the influence of pollution by antibiotics (benzylpenicillin, ampicillin, streptomycin, oxytetracycline, tylosin, pharmasin, tromexin, aliseryl, and nystatin) on the biological properties of ordinary chernozem was examined in concentrations of 1-1000 mg/kg. A decrease in the majority of the basic biological parameters of chernozem occurs when the concentration of antibiotics is 100 mg/kg of soil. In most cases, there was a direct relationship between the content of antibiotics in the soil and the scale of a decrease in the studied parameters. The degree of the influence of antibiotics was determined by their nature, concentration and time of exposure. Antibacterial antibiotics had more negative impact on the studied indicators than fungicidal ones. By the degree of inhibiting the biological properties of chernozem, antibiotics formed the following sequence: ampicillin > benzylpenicillin ≥ streptomycin ≥ oxytetracycline > tylosin ≥ pharmasin > nystatin > tromexin > aliseryl. Among the examined biological parameters when polluted by antibiotics, the most informative one was the number of ammonifying bacteria and the activity of dehydrogenases. The least informative was the indicator of catalase activity. The abundance of bacteria of the genus Azotobacter in case of pollution by antibiotics was not informative. The degree of a decrease in biological indicators was more pronounced in laboratory conditions than in the field ones. The rate of the biological activity recovery of chernozem after pollution in the field was 2 times higher. According to the degree of resistance to antibiotics, the investigated microorganisms of chernozem formed the following sequence: bacteria of the genus Azotobacter > micromycetes > amylolytic bacteria > ammonifying bacteria. Enzymes formed the following sequence: peroxidase ≥ polyphenol oxidase > catalase > dehydrogenase > invertase ≥ phosphatase. Antibiotics had prolonged influence on the biological properties of ordinary chernozem. The examined parameters were observed not to be recovered to control values even on the 120th day after the pollution.

scholarly journals Temporal Dominance of B.1.1.7 over B.1.354 SARS-CoV-2 Variant: A Hypothesis Based on Areas of Variant Co-Circulation

2021 ◽  
Author(s):  
Evangelia Georgia Kostaki ◽  
Ioulia Tseti ◽  
Sotirios Tsiodras ◽  
George N. Pavlakis ◽  
Petros P. Sfikakis ◽  
...  
Keyword(s):  
South Africa ◽  
Monoclonal Antibodies ◽  
Comparative Analysis ◽  
Biological Properties ◽  
Community Transmission ◽  
Temporal Dominance ◽  
Over Time

Some emergent SARS-CoV-2 variants raise concerns due to their altered biological properties. For both B.1.1.7 and B.1351 variants, named as variants of concern (VOC), increased transmissibility was reported, whereas B.1.351 was more resistant to multiple monoclonal antibodies (mAbs), as well as convalescent and vaccination sera. To test this hypothesis, we examined the proportion of VOC over time across different geographic areas where the two VOC, B.1.1.7 and B.1.351, co-circulate. Our comparative analysis was based on the number of SARS-CoV-2 sequences on GISAID database. We report that B.1.1.7 dominates over B.1.351 in geographic areas where both variants co-circulate and the B.1.1.7 was the first variant introduced in the population. The only areas where B.1.351 was detected at higher proportion were South Africa and Mayotte in Africa, where this strain was associated with increased community transmission before the detection of B.1.1.7. The dominance of B.1.1.7 over B.1.351 could be important since B.1.351 was more resistant to certain mAbs, as well as heterologous convalescent and vaccination sera, thus suggesting that it may be transmitted more effectively in people with pre-existing immunity to other VOC. This scenario would lessen the effectiveness of vaccine and urge the need to update them with new strains.

Sign in / Sign up

Export Citation Format

Share Document