%0 Journal Article
%T Prediction of Total Phenolic Content in Extracts of Prunella Species from HPLC Profiles by Multivariate Calibration
%A Saliha £¿ahin
%A Esra I£¿£¿k
%A Cevdet Demir
%J ISRN Chromatography
%D 2012
%R 10.5402/2012/120780
%X The multivariate calibration methods¡ªprincipal component regression (PCR) and partial least squares (PLSs)¡ªwere employed for the prediction of total phenol contents of four Prunella species. High performance liquid chromatography (HPLC) and spectrophotometric approaches were used to determine the total phenol content of the Prunella samples. Several preprocessing techniques such as smoothing, normalization, and column centering were employed to extract the chemically relevant information from the data after alignment with correlation optimized warping (COW). The importance of the preprocessing was investigated by calculating the root mean square error (RMSE) for the calibration set of the total phenol content of Prunella samples. The models developed based on the preprocessed data were able to predict the total phenol content with a precision comparable to that of the reference of the Folin-Ciocalteu method. PLS model seems preferable, because of its predictive and describing abilities and good interpretability of the contribution of compounds to the total phenol content. Multivariate calibration methods were constructed to model the total phenol content of the Prunella samples from the HPLC profiles and indicate peaks responsible for the total phenol content successfully. 1. Introduction Prunella, belongs to the family of Lamiaceae, seems to be a rich source of plant species contain high amounts of phenolic compounds and anthocyanins [1, 2]. The research on antioxidant compounds in the Lamiaceae family has been focused on phenolic diterpenes, flavonoids and phenolic acids [3¨C6]. Several studies have shown that Prunella species exhibit high antioxidant potentials, which are tightly connected with the total phenolic content [7, 8]. The antioxidant activity could be dependent on the extraction solvent, the hydrophilicity of compounds, the sample, and type of phenolic compounds, which means that different phenolic compounds react in different ways in antioxidant activity assays. The phenolic compounds prove the importance of antioxidant behaviour and contribute significantly to the total antioxidant activity of medicinal and aromatic samples [9, 10]. Total phenolic content of plants is an important parameter for their antioxidant properties. The Folin-Ciocalteu procedure of Singleton [11] has been used as a measure of total phenolics in natural products for many years. On the other hand, analytical techniques have been used to isolate, identify, and determine individual phenolic compounds by gas chromatography and mass spectrometry (GC-MS) [12, 13], high
%U http://www.hindawi.com/journals/isrn.chromatography/2012/120780/