Beibam Luc Sondengam

In vivo anti-nociceptive and anti-inflammatory effect of the two triterpenes, ursolic acid and 23-hydroxyursolic acid, from Cussonia bancoensis.

Triterpenoids, ursolic acid (1) and 23-hydroxyursolic acid (2) were obtained from the hydrolysis of BuOH fraction ofCussonia bancoensis extract to test antinociceptive and anti-inflammatory effect ofC. bancoensis (Araliaceae). Compound1 and2 exhibited anti-nociceptive effects, which were determined by acetic acid-induced writhing test and hot plate test. The effect of2 was much more potent in acetic acid-induced writhing test than in hot plate test. Compound1 and2 significantly inhibited 1%-carrageenan-induced edema in the rat. These results suggest that the two triterpenes, ursolic acid and 23-hydroxyursolic acid, are responsible for the antinociceptive and anti-inflammatory effect ofC. bancoesnsis.

Isolation and structural elucidation of a new pentaflavonoid from Ochna calodendron

A new pentaflavonoid, ochnachalcone, was isolated from the stem bark of Ochna calodendron and its structure elucidated by spectroscopic means including HMQC, HMBC and ROESY experiments.

Minor alkaloids from the seeds of Voacanga africana

Abstract The isolation and 13 C-NMR spectra of Δ 14 -vincanol, O -methyl-16-epi-Δ 14 -vincanol, Δ 14 -vincamone from the seeds of Voacanga africana are reported.

Two new fatty acid glucosides from the root bark of Ochna calodendron.

Two new fatty acid glucosides, (3E,8Z)-8-carboxy-1-(O-beta-D-glucopyranosyl)-2,6-dihydroxytritriaconta-3,8-diene (1) and (8Z)-8-carboxy-1-(O-beta-D-glucopyranosyl)-3,4-epoxy-2,6-dihydroxytritriacont-8-ene (2), have been isolated from the root bark of Ochna calodendron and their structures elucidated by extensive two-dimensional NMR methods including HMQC, HMBC and NOESY experiments.

Synthesis and antimicrobial activities of some novel thiophene containing azo compounds

Abstract A series of new thienylazothiophenes were prepared by coupling reactions of diazotized thienocoumarins with their corresponding free amines. The structures of the products 3–7 were assigned on the basis of their elemental and spectroscopic data. The HMBC and HSQC techniques were used in some cases to ascertain the structural assignments. The antimicrobial screenings of compounds 3–7 along with substituted 2-aminothiophenes 1a,b were performed against three bacteria and three fungal species and their activities compared to those of nystatin, gentamycin and ciprofloxacin used as reference drugs. It was found that the antimicrobial activities of the tested new hybrid compounds were in some cases equal or better than those of the reference drugs.

Electrochemical behavior and in-vitro antimicrobial screening of some thienylazoaryls dyes

BackgroundA series of recently reported phenolic azo dyes 7a–e were prepared by coupling the thienyl diazonium sulfate of 3-Amino-4H-benzo[f]thieno[3,4-c](2H)chromen-4-one with selected diversely substituted phenolic and naphtholic derivatives. These compounds were evaluated for their antibacterial and antifungal activities. Furthermore their voltammetric behavior was compared at a glassy carbon electrode.ResultsThe voltammetric behavior of the five recently reported azo dyes has been compared at a glassy carbon electrode. It is shown that the azo dyes 7a–e with a hydroxyl group in the ortho position with respect to the azo bridge give rise to well defined, irreversible peaks for the oxidation and reduction process within a pH range of 2–7. The mechanisms of electrochemical oxidation of compound 7a–c and 7e are proposed. For the hydroxyl-substituted dyes, re-oxidation peaks were obtained in the subsequent scan. The antimicrobial activities of the reported compounds 7a–e along with the entire precursors 1–4 and 6a–e were performed against selected bacterial and fungal species and their activities compared to those of nystatin, griseofulvin and ciprofloxacin used as reference drugs.ConclusionsThe present study showed significant antimicrobial activity of compounds 6d, 7a and 7c,e against the tested microorganisms; this result confirms the antimicrobial potency of azo compounds and some of their precursors.

Synthesis, Characterization, and Antimicrobial Activity of a Novel Trisazo Dye from 3-Amino-4H-thieno[3,4-c][1]benzopyran-4-one

A new trisazo dye has been synthesized by coupling the diazonium ion of 3-amino-4H thieno[3,4-c][1]benzopyran-4-one with 2-tert-butyl-4-methoxyphenol. The newly prepared trisazo dye was characterized by its physical, elemental, and spectroscopic data. 2D-NMR (COSY, HSQC, and HMBC) techniques were used to secure the structural assignments. The new trisazo dye (compound 7) along with precursors 3, 4, and 6 was screened by microdilution susceptibility assay for antibacterial and antifungal activities towards eight bacterial strains and three yeasts selected on the basis of their relevance as human pathogens. The results showed that compound 7 (MIC = 2–128 μg/mL) was the most active as compared with its precursors. The most resistant microorganisms were V. cholerae NB2 and V. cholerae SG24, whereas the most sensitive microorganism was C. neoformans. The overall results of this study indicated that compound 7 had the greatest potential value against both yeasts and multidrug-resistant bacteria, so further investigation is warranted.