George Ndukwe

A bioactive flavonoid from Pavetta crassipes K. Schum

Background In our continued search for bioactive compounds from plants, conscious effort is being made to rapidly analyze ethnobotanical plants used for treating various ailments by traditional healers before this information is irrevocably lost as societies advance and rural communities become urbanized. Results A compound isolated from the aqueous extract of Pavetta crassipes leaves showed activity against some pathogenic microorganisms which included Streptococcus pyogenes, Corynebacterium ulcerans, Klebsiella pneumoniae, Neisseria gonorrhoeae, Pseudomonas aeruginosa, and Escherichia coli at a concentration < 50 mg/mL. The compound had minimum inhibitory concentration ranging from 6.25 to 12.5 mg/mL and minimum bactericidal concentration ranging from 12.5 to 25 mg/mL. The compound was identified using 1D and 2D NMR experiments and comparison with literature data as quercetin-3-O-rutinoside. Conclusions This has supported the ethnomedicinal use of the plant, confirmed its activity, and has also provided an easy and simple method for isolating this compound which has a lot of pharmaceutical and cosmetic applications from a new source.

Syntheses and Biological Activity of Some Derivatives of C-9154 Antibiotic

This research was undertaken to design several new antibiotics, by structurally modifying the C-9154 antibiotic, simultaneously improving its activity and lowering toxicity. This was achieved by synthesizing an analogue to the C-9154 antibiotic and seven derivatives of this analogue. The approach was to significantly reduce the polarity of the synthesized analogue in the derivatives to achieve increased permeability across cell membranes by conversion of the highly polar carboxylic group to an ester functional group. The compounds were fully characterized using infrared, GC-MS, and 1D and 2D NMR experiments. The in vitro biological activity of the compounds showed that the derivatives were more active than the analogue as was anticipated and both were more active than the standard drugs used for comparison. Work is ongoing to establish applications for the compounds as antiplasmodials, antivirals, anticancers/tumours, antitrypanosomiasis, anthelminthic, and as general antibiotics for human, veterinary, and even agricultural use as they had marked effect on both Gram-positive and Gram-negative bacteria and some fungi.

Morphological and Microstructural Characterization of Organoclays from Low Smectite Containing Clays Materials

Emeka Thompson Nwankwere. Department of Physical Sciences, Kampala International University, Uganda.