Antiparasitic and antimicrobial isoflavanquinones from Abrus schimperi

The EtOH extract of Abrus schimperi (Fabaceae), collected in Kenya, demonstrated significant activity against Leishmania donovani promastigotes with IC50 value of 3.6 microg/mL. Bioassay-guided fractionation of CHCl3 fraction using Centrifugal Preparative TLC afforded two antiparasitic isoflavanquinones, namely amorphaquinone (1) and pendulone (2). They displayed IC50 values of 0.63 microg/mL and 0.43 microg/mL, respectively, against L. donovani promastigotes. Both the compounds were also evaluated against L. donovani axenic amastigotes and amastigotes in THPI macrophage cultures. In addition, compounds 1 and 2 showed antiplasmodial activity against Plasmodium falciparum D6 and W2 strains, while 2 displayed antibacterial activity against Staphylococcus aureus and methicillin-resistant S. aureus (each IC50 1.44 microg/mL). The 1H and 13C data of 1, not fully assigned previously, were unambiguously assigned using 1D and 2D NMR HMBC and HMQC experiments. In addition, the absolute stereochemistry of the isolated compounds 1 and 2 was revised as C-(3S) based on Circular Dichroism experiments. This appears to be the first report of amorphaquinone (1) and pendulone (2) from the genus Abrus.     

Chemical profiling and standardization of Lepidium meyenii (Maca) by reversed phase high performance liquid chromatography

Lepidium meyenii (Maca) is one of the few plants that can be cultivated in the harsh climate of the Andes. Its nutritious hypocotyl is traditionally used as food and medicine, and Maca products are increasingly becoming popular in the western world as tonics. This paper describes the first analytical method allowing the determination of the main macamides and macaenes, the marker compounds of L. meyenii. A separation within 35 min was possible by using a C-12 stationary phase, an acidic mobile phase comprising of acetonitrile and water, and raising the column temperature to 40 degrees C. By monitoring the separation at 210 and 280 nm, the markers were detectable as low as 0.40 microg/ml. In order to validate the method, accuracy, precision, linearity, limit of detection and intra/inter day repeatability were determined. The analysis of several commercially available Maca products showed a similar qualitative pattern but significant differences in the quantitative composition. The percentage of total markers in the preparations varied from 0.15 to 0.84%, resulting in daily intakes for the consumer from 1.52 to 14.88 mg, respectively.     

Structural parameters of the ground states of the quasi‐stable diatomic anions CO−, BF−, and BCl− as obtained by conventional Ab Initio methods

The experimental electron affinity (EA) of CO(X¹Σ⁺) is ?1.5 eV, signifying the metastability of the CO^?(X²Π) anion. The electronic structure and bonding of CO^?, BF^?, and BCl^? vis‐à‐vis their neutral counterparts have been studied by conventional coupled‐cluster (CCSD(T)) and multireference (MRCI) methods. Our results are in agreement with experiment for the CO/CO^? system, indicating as well the metastable nature of the BF^?(X²Π) and BCl^?(X²Π) anions, their MRCI EAs being ?0.8 ± 0.1 and ?0.3 ± 0.1 eV, respectively. Our work clearly shows the usefulness of stationary state ab initio methods to the elucidation of metastable species. © 2015 Wiley Periodicals, Inc.     

Adsorption of atrazine from aqueous electrolyte solutions on humic acid and silica

The adsorption of, the still widely used, herbicide atrazine on model soil components, such as humic acid and humic acid-silica gel mixtures, was investigated in a series of batch experiments, under different experimental conditions (ionic strength, temperature, and pH). The investigation aimed at obtaining an estimate of the contribution of each of the soil components on the adsorption of atrazine from aqueous solutions. The kinetics of atrazine adsorption on humic acid showed two steps: a fast step, of a few hours duration, and a second slow step, which continued for weeks. The kinetics of adsorption data gave a satisfactory fit to the Elovich equation. Τhe adsorption of atrazine on the test substrates was found to be reversible in all cases. The atrazine uptake data on the test substrates were fitted best with the Freundlich adsorption isotherm. The ionic strength of the atrazine aqueous solutions did affect the amount of the atrazine adsorbed on the test substrates, suggesting that electrostatic forces between atrazine molecules and soil play a significant role in the adsorption process. An increase of temperature resulted in a decrease of atrazine adsorption on humic acid at low atrazine equilibrium concentrations. However, for higher levels of equilibrium concentrations (≥3 mg/L) the amount of atrazine adsorbed onto the test substrate increased as temperature increased. The calculated isosteric enthalpies of adsorption ranged between slightly exothermic at low atrazine uptake and slightly endothermic at high atrazine uptake, all values being in the range of physisorption.     

Two stereoisomeric pentacyclic oxin­dole alkaloids from Uncaria tomentosa: uncarine C and uncarine E

The chloro­form solvate of uncarine C (pteropodine), (1′S,3R,4′aS,5′aS,10′aS)‐1,2,5′,5′a,7′,8′,10′,10′a‐octa­hydro‐1′‐methyl‐2‐oxospiro­[3H‐indole‐3,6′(4′aH)‐[1H]­pyrano­[3,4‐f]indolizine]‐4′‐carboxyl­ic acid methyl ester, C₂₁H₂₄N₂O₄·CHCl₃, has an absolute configuration with the spiro C atom in the R configuration. Its epimer at the spiro C atom, uncarine E (isopteropodine), (1′S,3S,4′aS,5′aS,10′aS)‐1,2,5′,5′a,7′,8′,10′,10′a‐octahydro‐1′‐methyl‐2‐oxospiro[3H‐indole‐3,6′(4′aH)‐[1H]pyrano[3,4‐f]indolizine]‐4′‐carboxylic acid methyl ester, C₂₁H₂₄N₂O₄, has Z′ = 3, with no solvent. Both form intermolecular hydrogen bonds involving only the ox­indole, with N?O distances in the range 2.759 (4)–2.894 (5) Å.     

Therapeutic Intervention of COVID-19 by Natural Products: A Population-Specific Survey Directed Approach

To date very few promising leads from natural products (NP) secondary metabolites with antiviral and immunomodulatory properties have been identified for promising/potential intervention for COVID-19. Using in-silico docking studies and genome based various molecular targets, and their in vitro anti-SARS CoV-2 activities against whole cell and/or selected protein targets, we select a few compounds of interest, which can be used as potential leads to counteract effects of uncontrolled innate immune responses, in particular those related to the cytokine storm. A critical factor for prevention and treatment of SARS-CoV-2 infection relates to factors independent of viral infection or host response. They include population-related variables such as concurrent comorbidities and genetic factors critically relevant to COVID-19 health disparities. We discuss population risk factors related to SARS-CoV-2. In addition, we focus on virulence related to glucose-6-phosphate dehydrogenase deficiency (G6PDd), the most common human enzymopathy. Review of data on the response of individuals and communities with high prevalence of G6PDd to NP, prompts us to propose the rationale for a population-specific management approach to rationalize design of therapeutic interventions of SARS-CoV-2 infection, based on use of NP. This strategy may lead to personalized approaches and improve disease-related outcomes.     

Automated Segmentation and Registration of Dermatological Images

During the last years, there has been a significant increase in the level of interest in image morphology, full-color image processing, image data compression, image recognition and knowledge based analysis systems for medical images. The present paper describes the implementation and tests the efficiency of algorithms dealing with the issues of segmentation and registration of digital images containing skin lesions. Those steps are considered of great importance in computer based characterization systems as they are responsible for the isolation of pathological findings and the matching of sequential images during follow-up studies in medical imaging. This revised version was published online in July 2006 with corrections to the Cover Date.