Abstract
Anonidium mannii is a tropical plant native to the central countries of Africa such as Cameroon. It belongs to the Annonaceae family and it is also referred to as the jungle sop. The plant is used to alleviate and treat ailments cancer, malaria, dysentery, diarrhea and gastroenteritis. In this study, the Anonidium mannii stem bark DCM/MeOH extract was chosen for host-guest complexation of β-Cyclodextrin(β-CD). The complexation serves to enhance the physiochemical properties of the plant extract and to reduce the amount of dosage and frequency at which it has to be administered. The β-CD is a macrocyclic oligosaccharide with a hollow cone-shape. It is characterized by seven glucopyranose units with a hydrophobic interior that can entrap the plant extract and an exterior that is hydrophilic and thus facilitates the dissolution of the complex in an aqueous medium. The A. mannii (plant extract)/β-CD complex was synthesized by Co-precipitation method. FTIR, NMR (1H ), SEM, PXRD, TGA-DSC are the analytical techniques that were used to characterize the formation of the complex.
The characterization techniques revealed that inclusion complex conferred a different morphology relative to its constituent molecules (A.mannii and pure β-cyclodextrin). The position of the O-H (3236.21 cm-1) band of β-CD was found to have shifted to a frequency that is higher on the β-CD/A.mannii inclusion complex (3274.0 cm-1). Furthermore, the hydroxyl band of β-CD, which was initially wide, had become narrow on the FTIR spectra of the inclusion complex, thus indicating an inclusion of the A.mannii into the cavity of the β-CD. The XRD results shows an intense β-CD peaks at 2θ=12.8˚ was significantly reduces in the
complex, whilst
peaks 2θ=21˚ and 23˚
were observed to have completely disappeared. The
pattern of the disappearance and appearance of some peaks on the diffractogram of the
inclusion complex relative to that of the A.mannii and β-CD, is congruent to the results
displayed by the SEM and FTIR . In the results of the 1H NMR, an up-field chemical shift of H3 (-0.09Δδ) and a downfield chemical field of H5 (0.06Δδ) was observed, suggesting that an internal Hydrogens in the β-Cyclodextrin cavity have been shifter, thus indicating that insertion
of A.mannii has occurred.