Senna alata is widely used in Cameroon for the treatment of several infections which include gonorrhoea, gastro-intestinal and skin diseases. Therefore, its leaves were investigated for antibacterial principles. Extraction of plant material was done with methanol, follow by partition with hexane. Separation and purification of compounds was done using a combination of chromatographic techniques. Isolated compounds were identified by means of spectroscopic methods and comparison with literature data. The antibacterial activity of extracts, fractions and compounds was assessed by evaluating the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) against Multi-Drug-Resistant (MDR) Vibrio cholerae and Shigella flexneri. Three secondary metabolites namely kaempferol, luteolin and aloeemodin were isolated from methanol residue active extract. The antibacterial results showed that the MeOH residue extract, fractions A and C, as well as compounds 1-3 exhibited variable MIC values, depending on the bacterial strains. Aloe-emodin (MIC = 4 to 128 μg/mL) exhibited the highest antibacterial activity against MDR Vibrio cholerae and Shigella flexneri. From these results obtained, S. alata leaf could be considered as a natural antibacterial source due to the presence of flavonoid and anthraquinone compounds.

A novel bismuth(III) complex with 2-amino-3-carbomethoxy-4,5,6,7-tetrahydrobenzo[b]thiophene (ACTT) as a ligand have been synthesized. The novel complex was characterized on the basis of its IR, NMR, elemental analysis and MS spectral data. It was found that the ligand behaves as a monodentate chelating agent and bonds to the metal ion through the nitrogen atom of the amino group to form the [Bi III (ACTT) 6 ]Cl 3 complex. The new complex compound displayed significant antimicrobial activity (MIC = 8-32 μg/mL) against Bacillus subtilis, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Shigella flexneri, Candida albicans, Candida tropicalis and Cryptococcus neoformans.

Background : The present study describes for the first time, the synthesis of two pyrrolidine-2,5-dione derivatives that belong to N-arylsuccinimid (compound 5) and of azo (compound 8) class of molecules. The initial step of the reaction involved the preparation of the intermediate compound (9R, 10R, 11S)-9, 10-dihydro-9, 10-[3, 4] furanoanthracene-12, 14-dione (3) through [4 + 2]-cycloaddition between anthracene and maleic anhydride in xylene which was then condensed with para-hydroxyaniline to give compound 5. Subsequent coupling of 5 with the aryldiazonium ion of aniline gave compound 8.Results: These compounds were characterized by their physical, elemental, and spectroscopic data. 2D-NMR (COSY, HSQC, and HMBC) techniques were used to complete the elucidation of their structures. Compounds 5 (MIC = 32–128µg/mL) and 8 (MIC = 16–256µg/mL) along with the precursor 3 (MIC = 64–128µg/mL) displayed moderate antimicrobial activities against selected bacterial and fungal species when compared with those of nystatin (MIC = 0.50–2µg/mL) and ciprofloxacin (MIC = 0.50–16µg/mL) used as reference drugs.Conclusion: The results of biological tests showed that compounds 3, 5, 8 possess antimicrobial activities. Although being less active than the compound taken as a reference, the azo compound has better antibacterial activity than the other two compounds especially on Staphylococcus aureus, V. choleraeSG24 and, V. choleraeCO6 strains. These results show that the azo function (N = N) is indeed a pharmacophore and would be responsible for the biological activity in the azo molecules.

Background: Biological significance of Amaryllidaceae is well advocated from the literature. In Cameroon, plants from this fam- ily are routinely used for the cure of liver, cancer and cardiovascular diseases. To date, no scientific investigation corresponding to the anti-cancer activity of extracts and isolated compounds of Scadoxus pseudocaulus is available. Objective: Current study is focused to elaborate the anti-proliferative effects of natural isolates (compounds 1-6, 9) and hemi-synthetic analogs (compounds 7-8) extracted from S. pseudocaulu. Methods: Column chromatography of the ethyl acetate extract followed by purification of different fractions led to the isolation of seven compounds (1 – 6, 9). Esterification reaction of compound 6 was carried out using butyroyl chlorides and triethylamin to produce two derivatives (7 – 8). The cytotoxic activity was performed after staining of treated cells with florescent dye propid- ium iodide. Dead cells were detected using cytometer FL2 or FL3 channels/filters. Results: Trans-derivative of narciclasine (a natural isolate from S. pseudocaulus), was found to be most potent among all tested compounds. Its effects were more significant on low malignant follicular lymphoma (DoHH2 cells) as compared to highly ma- lignant (EBV infected) Burkitts lymphoma (Raji cells). Conclusion: From our results, narciclasine appears to hold the potential of a lead molecule that can be used to bridge the ther- apeutic gaps in cancer research. Keywords: Scadoxus pseudocaulus; Amaryllidaceae; 7-deoxy-trans-dihydronarciclasin; farrerol; derivatization; cytotoxic activity.

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