Isolation and characterization of pyropheophorbide-a from moringa oleifera lam

Moringa oleifera is a plant rich in pharmacologically active compounds. This study investigated the phytochemical constituents of Moringa oleifera leaf extracts. Dried M. oleifera leaves were ground and extracted successively with hexane, ethyl acetate and methanol using a Soxhlet apparatus. Different chromatographic techniques were used to fractionate the ethyl acetate extract. Thin layer chromatography was used to pool similar fractions together. Fractions obtained were purified using sephadex glass column. The structures of isolated compounds were identified using nuclear magnetic resonance (NMR), electrospray ionization mass spectrometry (ESI-MS) and comparison with published data. Phytochemical screening revealed the presence of flavonoids, terpenoids, carbohydrates and phenols. Ethyl acetate extract which was subjected to column chromatography resulted to the isolation of two compounds: mono acetyl glycerol and pyropheophorbide-a, from the leaves of M. oleifera. This is the first report on the isolation of pyropheophorbide-a from the leaves of M. oleifera

QUENCHING STUDIES OF DUAL FLUORESCING 1-N α\alpha-DIMETHYLAMINO-4- METHOXY-CARBOXYLIC ACID BENZENE (DMABMCA) BY KI IN 2-PROPANOL/WATER MIXED SOLVENTS

Author Institution: Division of Physical \& Life Sciences, Fayetteville State UniversityDMABMCA fluoresces from a double potential minimum in the excited state in polar solvents. The high energy band decays from $S_{2} (\pi-\pi^{\ast})$ state whereas the low energy fluorescence band originates from a closely-lying $S_{1} (1-\alpha_{\pi})$ state. Stern-Volmer kinetics is applied to study the dynamic quenching process of both states by iodide ion. The results of this investigation will serve as a preliminary study towards the interpretation of the nature of fluorescence quenching mechanism, the nature and efficiency of the electronic energy transfer and the dependence of both excited state potential minima with one another

HICELIAR EFFECTS ON DUAL FLUORESCING COMPOUNDS

Author Institution: Division of Physical \& Life Science, Fayetteville State University; Department of Natural Science, State UniversityDual fluorescing compounds emit it from two states. The local (short wavelength) fluorescence band is less polar then the long wavelength band resulting from change transfer of a strong donor substituent. Three hicellar cellar types have been used to study the effect of the $\pi$ - and n- electron systems of dual fluorescing compounds in the excited state. Enhancement and spectral changes are evaluated. Determined suitable hicellar concentration will provide information for the separation of charges necessary to study the association energy of the hicellar aggregates