Antiviral iridoid glycosides from Clerodendrum myricoides.

The methanol root extract of Clerodendrum myricoides (Hochst.) Vatke afforded two new (1, 2) and two known (3, 4) iridoid glycosides. The structures of the isolated compounds were established based on NMR, IR, UV and MS data analyses. The crude extract and the isolated constituents were assayed for antiviral activity against the human respiratory syncytial virus (RSV) in human laryngeal epidermoid carcinoma (HEp-2) cells. The crude extract inhibited RSV infectivity at EC50 = 0.21 µg/ml, while it showed cytotoxicity against HEp-2 cells with CC50 = 9 µg/ml. Compound 2 showed 43.2% virus inhibition at 100 µM, while compounds 1 as well as 3 and 4 had only weak antiviral and cytotoxic activities.

Antibacterial and cytotoxic prenylated dihydrochalcones from Eriosema montanum.

Two new prenylated dihydrochalcones (1,2) and eighteen known secondary metabolites (3-20) were isolated from the CH2Cl2-MeOH (1:1) extracts of the roots, the stem bark and the leaves of Eriosema montanum Baker f. (Leguminosae). The structures of the isolated compounds were characterized by NMR, IR, and UV spectroscopic and mass spectrometric analyses. The structures of compounds 5, 10, 11 and 13 were confirmed by single crystal X-ray diffraction. The antibacterial activity of the crude extracts and the isolated constituents were established against Gram-positive and Gram-negative bacteria. Among the tested compounds, 1-4 and 10 showed strong activity against the Gram-positive bacterium Bacillus subtilis with minimum inhibitory concentration (MIC) ranging from 3.1 to 8.9 µM, as did the leaf crude extract with an MIC of 3.0 µg/mL. None of the crude extracts nor the isolated compounds were active against Escherichia coli. Compounds 1, 3 and 4 showed higher cytotoxicity, evaluated against the human breast cancer cell line MCF-7, with EC50 of 7.0, 18.0 and 18.0 µM, respectively. These findings contribute to the phytochemical understanding of the genus Eriosema, and highlight the pharmaceutical potential of prenylated dihydrochalcones.

Nutritional value assessment of umufumba: A Rwandan wild edible plant Mondia whytei (Hook. F).

This study reports findings on the macro- and micronutrient content of the root bark of Mondia whytei Skeels (Hook. F) (Asclepiadaceae), from five Rwandan different localities Northern part, and the nutritional content was found to vary locality of the plant. Vitamins were analyzed using high-performance liquid chromatography (HPLC). The vitamins analyzed included ß-carotene (fat soluble), niacin, riboflavin, and thiamine (water soluble) whose content was found to range from 4.4 to 73.5 µg/g dry matter. Atomic absorption spectrophotometry (AAS) was used to analyze calcium, iron, copper, manganese, magnesium, zinc, cadmium, and lead, whereas flame emission spectrophotometry (FES) was used for the determination of sodium and potassium. The highest mineral (mg/g of dry matter) was K (11.34-32.05), while the lowest was Pb (0.03-0.06). Mean total protein content was determined using the combustion method, and the mean percentage range was 4.7%-15.4%. The sugars (fructose, glucose, sucrose, and xylose) were analyzed by HPLC. There were significant differences (2.5-132.2 mg/g) in the free sugar contents. The results obtained in this study indicate that Mondia whytei Skeels (Hook. F) is rich in nutrients and can be developed for use as a food supplement since the nutrient contents are within the ranges recommended by FAO and WHO.

Synthesis of D-glucosamine quaternary ammonium derivatives and evaluation of their antifungal activity together with aminodeoxyglucose derivatives against two wood fungi Coriolus versicolor and Poria placenta: structure-activity relationships.

BACKGROUND: Structure-activity relationships are often reported in scientific studies. These may be employed in searching for new acceptable biocides to use against harmful microorganisms, because the biocides used hitherto encounter various problems, including lack of efficiency, high toxicity and persistence. Nowadays, scientists are trying to find new, environmentally acceptable biocides to replace these earlier biocides. Different compounds from renewable materials have been studied and have shown pronounced antifungal activity against wood fungi. These include aminopolysaccharide derivatives and different quaternary ammonium polymers. A biological study carried out with these products indicated a possible relationship between amino groups and differences in biological activity observed. RESULTS: In this study, an amino group was successively fixed to different carbon atoms of glucose, and glucosamine was also modified by both N-alkylation and quaternisation. The impact of the amino group position on antifungal activity against two wood decay fungi was investigated. The amino group at the anomeric position showed the highest antifungal activity against both Coriolus versicolor Quel. and Poria placenta (Fr.) Cooke. Furthermore, the positive impact of both N-alkylation and quaternisation on the growth of both strains was demonstrated. CONCLUSION: The anomeric position of the amino group and the N-alkylation and quaternisation of amino sugars considerably increase the antifungal activity of these compounds.

Synthesis and antibacterial activity of aminodeoxyglucose derivatives against Listeria innocua and Salmonella typhimurium.

In this study aminodeoxyglucose derivatives were synthesized and evaluated for their antibacterial activity against two food bacteria, Listeria innocua and Salmonella typhimurium . 6-Amino-6-deoxy-alpha-D-methylglucopyranose (GSA-6), 3-amino-3-deoxy-D-glucopyranoside (GSA-3), and beta-D-glucopyranosylamine (GSA-1) were synthesized and concurrently tested with commercially available D-glucosamine (GSA-2) for antibacterial activity. Results obtained from this study showed a pronounced antagonist effect due to the position of amino groups of aminoglucose derivatives on the antibacterial activity. GSA-3 was the most active compound. At a concentration of 2 x 10(-4) mol mL(-1), it delayed the growth of both bacteria with percentages of inhibition of 29 and 15% for L. innocua and S. typhimurium, respectively. At the same concentration the percentages of inhibition for other aminodeoxyglucoses varied between 5 and 18% and between 2 and 11% for L. innocua and S. typhimurium, respectively. All compounds were characterized by FTIR, (1)H NMR, and (13)C NMR spectroscopy.

Synthesis and evaluation of N-alkyl-beta-D-glucosylamines on the growth of two wood fungi, Coriolus versicolor and Poria placenta.

Various glucosylamines were synthesized from glucose and different alkyl amine compounds. These amino compounds are beta-D-glucopyranosylamine (GPA), N-ethyl-beta-D-glucopyranosylamine (EtGPA), N-butyl-beta-D-glucopyranosylamine (BuGPA), N-hexyl-beta-D-glucopyranosylamine (HeGPA), N-octyl-beta-D-glucopyranosylamine (OcGPA), N-dodecyl-beta-D-glucopyranosylamine (DoGPA), N-(2-hydroxyethyl)-beta-D-glucopyranosylamine (HEtGPA) and N,N-di(2-hydroxyethyl)-beta-D-glucopyranosylamine (DHEtGPA). They were tested for their antifungal activity against the growth of Coriolus versicolor and Poria placenta. An improvement of the antifungal activity with the increase of alkyl chain length was observed. DoGPA exhibited the best antifungal activity against both strains. It completely inhibited the fungal growth at 0.01x10(-3)molmL(-1) and 0.0075x10(-3)molmL(-1) for C. versicolor and P. placenta, respectively. For other glucosylamines higher concentrations were needed for complete inhibition of fungi.