Circular dichroism, a powerful tool for the assessment of absolute configuration of flavonoids.

Antimalarials from nature

https://cyberleninka.org/article/n/365946.pdf

The use of plants in the traditional management of diabetes in Nigeria: pharmacological and toxicological considerations.

Isoflavonoids of the leguminosae

Infections with protozoan parasites are a major cause of disease and mortality in many tropical countries of the world. Diseases caused by species of the genera Trypanosoma (Human African Trypanosomiasis and Chagas Disease) and Leishmania (various forms of Leishmaniasis) are among the seventeen "Neglected Tropical Diseases" (NTDs) defined by the WHO. Furthermore, malaria (caused by various Plasmodium species) can be considered a neglected disease in certain countries and with regard to availability and affordability of the antimalarials. Living organisms, especially plants, provide an innumerable number of molecules with potential for the treatment of many serious diseases. The current review attempts to give an overview on the potential of such plant-derived natural products as antiprotozoal leads and/or drugs in the fight against NTDs. In part I, a general description of the diseases, the current state of therapy and need for new therapeuticals, assay methods and strategies applied in the search for new plant derived natural products against these diseases and an overview on natural products of terpenoid origin with antiprotozoal potential were given. The present part II compiles the current knowledge on natural products with antiprotozoal activity that are derived from the shikimate pathway (lignans, coumarins, caffeic acid derivatives), quinones of various structural classes, compounds formed via the polyketide pathways (flavonoids and related compounds, chromenes and related benzopyrans and benzofurans, xanthones, acetogenins from Annonaceae and polyacetylenes) as well as the diverse classes of alkaloids. In total, both parts compile the literature on almost 900 different plant-derived natural products and their activity data, taken from over 800 references. These data, as the result of enormous efforts of numerous research groups world-wide, illustrate that plant secondary metabolites represent an immensely rich source of chemical diversity with an extremely high potential to yield a wealth of lead structures towards new therapies for NTDs. Only a small percentage, however, of the roughly 200,000 plant species on earth have been studied chemically and only a small percentage of these plants or their constituents has been investigated for antiprotozoal activity. The repository of plant-derived natural products hence deserves to be investigated even more intensely than it has been up to present.

The Potential of Secondary Metabolites from Plants as Drugs or Leads Against Protozoan Neglected Diseases – Part I

The tertiary and quaternary alkaloids isolated from the stem bark, root bark and seeds of Peschiera fuchsiaefolia are reported The tertiary alkaloid crude extract from the stem bark was tested in vitro against Plasmodium falciparum on the basis of the antimalarial use of the plant It showed good activity against both the D6 strain (IC50 = 495 ng/ml) and chloroquine-resistant W2 strain (IC50 = 817 ng/ml) and voacamine was the most active of the tested alkaloids (IC50 = 238 ng/ml for D6 and 290 ng/ml for W2) The tertiary alkaloid crude extract from the root bark of the same plant is more active than voacamine (IC50 = 179 ng/ml for D6 and 282 ng/ml for W2 strain), and is particularly rich in dimeric alkaloids (022% of the vegetable material)

Antiplasmodial activity of the alkaloids of Peschiera fuchsiaefolia.

The in vivo antiplasmodial activity of voacamine was assessed in a 4-day test. It was shown to exhibit in vivo activity with 25.4% and 43.4% inhibition of parasitaemia with 2.5 and 10 mg/kg, respectively. In synchronized cultures, it was found to act on trophozoite and schizont stages of Plasmodium falciparum. Using the FMC29 strain of Plasmodium falciparum as parasite and the isobologram curve as a method to assess interaction in drug combination, it was shown to lack any chloroquine-enhancing activity and its in vitro antiplasmodial effect was not potentiated by the chemosensitizer malagashanine.

Biological activities of the plant-derived bisindole voacamine with reference to malaria.

Chemical fingerprinting of Equisetum arvense L. using HPTLC densitometry and HPLC

Efficient, useful and sensitive analytical devices for the quality control of complex mixtures of natural products are urgently needed. Controls should be based on simple, viable, comprehensible and low cost methods. High Performance Thin Layer Chromatography (HPTLC) the last evolution of planar chromatography, is a reliable candidate for analysis of botanicals. Although HPLC remains the best choice for organic substances, HPTLC can solve several problems in a quicker, simpler and easier method. Furthermore, the visualization and the analysis of similar products performed exactly in the same conditions, allow an evident, good and safe result of comparison. The paper is dedicated to HPTLC application on selected market products, in order to evidence benefits and limits of the HPTLC fingerprint approach.

Elena Federici

Papers

Antiplasmodial activity of the alkaloids of Peschiera fuchsiaefolia.

Biological activities of the plant-derived bisindole voacamine with reference to malaria.

Chemical fingerprinting of Equisetum arvense L. using HPTLC densitometry and HPLC

The Modern Analytical Determination of Botanicals and Similar Novel Natural Products by the HPTLC Fingerprint Approach

Two prenylated isoflavanones from Millettia pervilleana