Der Pharma Chemica
Journal for Medicinal Chemistry, Pharmaceutical Chemistry, Pharmaceutical Sciences and Computational Chemistry


Extraction, Phytochemical, Antibacterial Screening and Spectroscopic Analysis of the Crude Samples of Stem Bark Extract of Lonchocarpus cyanescens

Author(s): Nwokonkwo DC, Okpani AN, Elom N

Powdered stem bark of Lonchocarpus cyanescens was batch extracted with chloroform, methanol and water to yield varying proportions of the extracts: Stem Bark Aqueous Extract (SAE), Stem Methanol Extract (SME) and Stem Chloroform Extract (SCE) respectively. The thin-layer chromatography revealed 5-6 constituents for each extract. The extracts were each washed in a column packed with alumina using n-butanol-glacial acetic acid-water (5:1:4) upper layer and screened for the presence of phytochemicals. The extracts indicated the presence of alkaloids, saponins, tannins, cardiac glycosides, flavonoids and phenols. The ultraviolet-visible (UV-VIS) spectroscopy of SCE showed peaks between 650-776.0 nm, SME between 497.0-795.5 nm and SAE showed bands between 208.5-760.1 nm. The Infrared Spectroscopy (IR) of SCE showed significant broad stretches at 3444.03 cm-1 for the presence of hydrogen bonds (OH), 2932.50 cm-1 C=C of aromatic compounds, 1645 cm-1 for aromaticity and overtoned at 1186 cm-1. The IR of SME showed identical peaks at 3442.09 cm-1. 2931.90 cm-1, 1644.37 cm-1 and 1063.78 cm-1. The IR peaks or bands of SAE appeared at 3431.48 cm-1, 2944.44 cm-1, 1634.73 cm-1 and 1096.57 cm-1. The Gas Chromatography-Mass Spectrometry (GC-MS) of SCE showed a molecular peak (m/z) at 282, SME at 206 and SAE at 256. The antimicrobial activity of the extracts showed sensitivity at a concentration as low as 1.0 × 10-4 mg/mL against four human pathogens; Pseudomonas aeruginosa, Escherichia coli, Salmonella typhi and Staphylococcus aureus. The extracts did not inhibit the growth of Klebsiella pneumonia and Streptococcus pneumonia.