Orthogonal Partial Least Squares Model for Rapid Prediction of Antioxidant Activity ofPereskia bleoby Fourier Transform Infrared Spectroscopy

Abstract

Pereskia bleo is a species of primitive cactus. In the present study, infrared spectroscopy was used to characterize the antioxidant activity of P. bleo leaves by multivariate analysis. A total of twenty-four extracts were prepared in different solvents. Antioxidant activities were measured by 1,1-diphenyl-2-picrylhydrazyl assay and fingerprinted by infrared spectroscopy between 4000 and 400 cm À1 at a resolution of 2 cm À1 . A three component multivariate orthogonal partial least squares model with R 2 Y of 0.88 and Q 2 of 0.86 was developed to correlate infrared spectra with antioxidant activity and evaluated by internal cross-validation and a true external test. For external validation, bioactivity of new extracts of P. bleo was predicted using the model, and -OH, -NH, and -CH were identified as functional groups responsible for the activity. In summary, a successful orthogonal partial least squares model was developed using infrared spectroscopy as a rapid method to predict antioxidant activity.

Effect of bound water on the quality of dried Lentinus edodes during storage

“…The volatile compounds with negative value of pq indicated a negative correlation with the peak area . Moreover, variable importance in projection determined the importance of volatile compounds contributing to the T 21 peak area . Figure 5(b) shows that 14 volatile compounds with variable importance in projection > 1 were selected, indicating a strong correlation between those volatile compounds and the T 21 peak area .…”

“…It was used to describe the correlations between volatile compounds identified by GC–MS analysis and the corresponding T 21 peak area of dried L. edodes . An OPLS model has been described in the literature …”

“…33 Moreover, variable importance in projection determined the importance of volatile compounds contributing to the T 21 peak area. 20 Figure 5(b) shows that 14 volatile compounds with variable importance in projection > 1 were Volatile compounds number (a) (b) Figure 5. Orthogonal partial least squares loading scatter plot of volatile compounds and T 21 peak area (a) and variable importance in projection (b) Variable importance in projection (VIP) was used to evaluated the importance of each volatile compound in OPLS.…”

Multivariate analysis of PRISMA optimized TLC image for predicting antioxidant activity and identification of contributing compounds from Pereskia bleo

“…Hence, the traditional method of analysis of isolating compounds and determining their activity by comparison with some standard compounds does not correlate well with the bioactivity of the herbal preparation (Buriani et al, 2012). The use of simple and more affordable equipment like infrared spectroscopy can be an effective alternative for herbal bioactivity analysis (Sharif et al, 2014). In this method, the full herbal extract is considered as one active compound for bioactivity and then the chromatograms arising from that extract are analyzed to find the multiple peaks/bands responsible for the studied bioactivity by a mathematical model (Gad, 2013).…”

“…Although NMR, GC-MS and HPLC-MS are the main chromatographic systems used in herbal analysis, they are not always affordable in developing countries, where herbal products are mostly familiar. The use of simple and more affordable equipment like infrared spectroscopy can be an effective alternative for herbal bioactivity analysis (Sharif et al, 2014). Thin-layer chromatography (TLC), a type of planar chromatography, is another option of affordable equipment and is still frequently used in herbal analysis because of its simplicity, versatility, high velocity, specific sensitivity and simple sample preparation.…”