Chromolaena odorata is a medicinal plant that is widely used in folk medicine many Nigerian communities for treatment of several ailments and diseases. In particular, local formulations of the herbal plant are used to treat wounds, burns and skin infections. The plant extracts have also shown anticancer, antidiabetic, hepaprotective, anti-inflammatory, antimicrobial and antioxidant properties. The aim of the study was to quantitatively determine the total phenolic content in methanolic extract of C. odorata using a spectrophotometric method. Furthermore, we conducted a UV and IR spectral study of the herbal drug in order to identify and characterize the genuine herbal drug. The total phenolic content of methanolic extract was determined by spectrophotometric method using the Folin Ciocalteu reagent, and Gallic acid as the standard. The UV and IR spectra was also determined and recorded using a spectrophotometer. The total phenolic content of the methanolic extract of C. odorata was found to be 306.56 mg/g of the Gallic acid equivalent (GAE). The UV spectrum revealed a wavelength of maximum absorption (λmax) at 283.50 nm. The characteristics frequencies in the IR spectrum were 3953.06, 3845.39, 3665.07, 3460.41, 3391.61, 3133.30, 3017.36, 2840.37, 2642.75, 2481.08, 2285.94, 2059.60, 1895.41, 1557.23, 1198.01, 1075.30, 927.27, 817.08, 749.79 and 650.13 cm-1. The UV and IR spectral study of C. odorata was determined to help for confirming the identity and purity of the genuine herbal drug. The total phenolic content will also prove useful for development of new drugs as well as standardization of the drug. The presence of the high phenolic content of C.odorata indicates that the herbal drug may possess good antioxidant compounds which may promote newer arrays of antioxidant research in the future.
Keywords: UV-Visible, C. odorata, Spectrophotometer, Total phenolic content, UV and IR study