Distortions and Deformations of Metaled Meso-Substituted and Unsubstituted Porphyrins and Derivatives in Crystal Structures

Experimental crystallographic structural parameters of a range of metaled meso-substituted and unsubstituted porphyrins were reviewed to show how far the meso-substitution by any functional group and the insertion of metal in the porphyrins core macrocycle may affect the geometry. The analysis of twists and angles has shown two kinds of distortions: external [T(Cβ-Cα-Cmeso-Xn) and T(Cβ-Cα-Cmeso-Cα)] and internal [T(Nm-Cα-Cmeso-Xn) and T(Nn-Cα-Cmeso-Cα)] with averages of [+6°and –6°] and [–5°and +5°], respectively. In the meso-substituted case, the external and internal twists Cβ-Cα-Cmeso-X and N-Cα-Cmeso-X, respectively are oppositely orientated. Similar effect is observed in meso-unsubstituted of Cβ-Cα- Cmeso-H and N-Cα-Cmeso-H. However, the external distortions are more significant than internal. Considering the same order, the limit of distortions is [97°and 132°(–48°)] for external and [91°(–89°) and 52°] for internal. In the two cases, the substituents have opposite directions of distortions. The meso-substituted porphyrins have a high limit of twisting than usubstituted one, depending of the weight of substituents. The average of the bond angular deformations is 168°, almost planar. However, the limit of angular deformation is 94°.

Chemical Fingerprint and Anti-Sickling Activity of Rosmarinic Acid and Methanolic Extracts from Three Species of Ocimum from DR Congo

The aim of this study was to characterize the polyphenolic composition by determination of chemical fingerprints of Methanolic extracts of Ocimum canum Sims, Ocimum basilicum L. and Ocimum gratissimum L. from Democratic Republic of Congo and to compare their antisickling activity of that of rosmarinic acid, the major compound to those of methanolic extracts. Phytochemical analysis performed by TLC and HPLC analysis, showed that rosmarinic acid is the most abundant phenolic acid in these Ocimum species according to the following order O. basilicum L., O. gratissimum L. and O. canum Sims. Methanolic extracts of these three species and pure rosmarinic acid showed significant antisickling activities with minimal concentration of normalization values of 0.18 ± 0.03, 0.23 ± 0.04, 0.26 ± 0.04 and 0.31 ± 0.05 mg/mL for rosmarinic acid, O. basilicum L., O. gratissimum L. and O. canum Sims methanolic extracts respectively. The antisickling activity order is the same as that of the rosmarinic acid content, indicating that this polyphenolic acid would be among the main active molecules in these extracts.

Anti-Sickle Cell Anemia and Bacterial Inhibitory Effects of <i>Uvariodendron molundense</i>(Diels) R.E.Fr. (Annonaceae) from Ubangi River Basin, DR Congo

The present study was carried out with the aim of evaluating the chemical composition and bioactivity of Uvariodendron molundense against Sickle cell disease and associated pathogenic bacteria agents. The antisickling and antibacterial activities were assessed using Emmel and micro-dilution methods respectively. The results revealed that the leaves and stem bark of U. molundense contains various secondary metabolites such as total phenols, flavonoids, anthocyanins, tannins, quinones, saponins, alkaloids, steroids, terpenoids and leuco-anthocyanins. The n-hexane (non-polar solvent) extract displayed poor yield (0.66) than the extracts obtained in the polar solvents which have a high yield (Methanol: 1.68, Ethanol: 1.46 and Ethyl acetate: 1.40). These results indicate that the abundant secondary metabolites/compounds in this plant species are those which pass easily through the polar solvents (methanol, ethanol and ethyl acetate). This is the case of phytomarkers like flavonoids and tannins (which are most concentrated in methanol) and anthocyanins which are concentrated in ethyl acetate. The extraction yield of organic/triterpenoic acids (betulinic acid rich extract) was 1.70%. All tested extracts displayed antisickling activity. At 100 μg/mL, the rates of normalization were 89% for organic extract (ED50 = 0.391 μg/ml) and 82% for anthocyanins extract (ED50 = 0.659 μg/mL). The antibacterial activity of tested extracts was very good toward Staphyloccocus areus (CMI ≤ 31.25 μg/mL) while, for Escherichia coli, only the organic extract exhibit interesting activity (CMI = 31.25 μg/mL). This study validates for the first time the in vitro antisickling activity of U. molundense. The bioactivity profiles of organic acids extract from the studied plant material indicate that they constitute promising fraction to be further investigated phytochemically for the discovery of new lead compounds for pharmaceutical application.

The Impact of the Bisubstituted Aromatics Functional Groups on the Inhibition of Methane Biosynthesis (Biogas)

Inhibitory compounds are often found to be the leading cause of anaerobic reactor upset and failure since they are present in substantial concentration in wastewaters and organic solid wastes. Among these inhibitory compounds, organic compounds are mentioned and more especially aromatic compounds. The purpose of this work was to evaluate the effect of bisubstituted aromatics functional groups on the methanogenic inhibition. The toxicity to acetoclastic methanogenic bacteria has performed in serum flasks, utilizing digested pig manure as inoculums, by measuring cumulative methane production. The results obtained indicate that some general relationships exist between the bisubstituted aromatic structures and their inhibitory effects on methanogenic bacteria. This demonstrates sufficiently that the grafting of hydrophobic or hydrophilic substituent on the benzene or monofunctional aromatic compound, make the obtained compound more or less toxic as the case and that in the same order of toxicity. A significant correlation was obtained indicating that the partitioning of bisubstituted aromatics into lipophilic membranes in bacteria may have a role in the inhibition of methane biosynthesis.

<i>In Vitro</i>Sickling Inhibitory Effects and Anti-Sickle Erythrocytes Hemolysis of <i>Dicliptera colorata</i>C. B. Clarke, <i>Euphorbia hirta</i>L. and <i>Sorghum bicolor</i>(L.) Moench

Diclipteracolorata C. B. Clarke, Euphorbia hirta L. and Sorghum bicolor (L.) Moench are reported among plant species used in Congolese traditional medicine to treat Sickle Cell Disease. These medicinal plants have been investigated for their inhibitory effect on the induced sickling process of red blood cells using Emmel’s test. Aqueous plant extracts showed good antisickling activity as revealed by the observed normal biconcave form of sickle red blood cells in anoxic conditions. The calculated radius of treated red blood cells by Euphorbia hirta L., Diclipteracolorata C. B. Clarke and Sorghum biocolor (L.) Moench extracts are 3.31 ± 0.55;3.34 ± 0.53;3.17 ± 0.52, respectively. Euphorbia hirta L. is the most active with a normalization rate, more than 70%. The chemical screening performed on these plants showed the presence of anthocyanins which were then extracted. The test carried out with anthocyanin extracts showed that these phenolic compounds have a good antisickling activity and, additionally, possess an anti-hemolytic effect on SS blood. This suggests that the evidenced biological activity of these plants would be due to anthocyanins. The results hence obtained justify the use of these plants in Congolese traditional medicine.

The Effect of the Monosubstituted Benzenes Functional Groups on the Inhibition of Methane Gas Biosynthesis

Aromatic compounds are inhibitors of methane biosynthesis in anaerobic treatment of solid wastes and industrial effluents. Anaerobic treatment of solid wastes and industrial effluents may be limited by the methanogenic bacteria inhibition exerted by these types of compounds, the production of biogas is not possible and the organic matter contained in the effluent is not reduced. These effluents poured in the nature can be the basis of the pollution. The objective of this study is to evaluate the effect of monosubstituted aromatic compounds functional groups on the methanogenic inhibition. The toxicity to acetoclastic methanogenic bacteria has performed in serum flasks, utilizing digested pig manure as inoculums, by measuring methane production. The nature of aromatic functional groups was observed to have a profound effect on the toxicity of the monosubstituted aromatics. Among the monosubstituted aromatic, the chlorobenzene was the most toxic with 50% of inhibition occurring at the concentration of 30.08 mg/l. In contrast, benzoic acid is the least inhibitory with IC50 of 2515.20 mg/l. The partition coefficient octanol/water (logPoct), an indicator of hydrophobicity, had a significant correlation with the methanogenic toxicity.