POSTER: Dissimilar chromatographic systems to identify peaks responsible for the antioxidant activity of Mallotus species

Awarded as runner-up for the Wiley Award for the best poster.info:eu-repo/semantics/nonPublishe

POSTER: Determination of antioxidative compounds in Mallotus species fingerprints using linear multivariate calibration techniques

info:eu-repo/semantics/nonPublishe

Potential antioxidant compounds in Mallotus species fingerprints. Part I: Indication, using linear multivariate calibration techniques.

Some Mallotus species are used in traditional medicine in Vietnam and China. Some also show interesting activities, such as antioxidant and cytotoxic ones. Combining fingerprint technology with data-handling techniques allows indicating the peaks potentially responsible for given activities. In this study it is aspired to indicate from chromatographic fingerprints the peaks potentially responsible for the antioxidant activity of several Mallotus species. Relevant information was extracted using linear multivariate calibration techniques, both before and after alignment of the fingerprints with correlation optimized warping (COW). From the studied techniques, stepwise multiple linear regression is least recommended as it made an inadequate variable selection. Principal component regression theoretically can take largely varying variables uncorrelated to the antioxidant activity into account. However, in practice in the actual case study this problem was limited. These problems in principle do not occur using partial least squares (PLS) models. Of the tested PLS methods, orthogonal projections to latent structures was preferred because of its simplicity, reproducibility, reduced model complexity and improved interpretability of the regression coefficients, yielding a clearer view on the individual contribution of the compounds. Furthermore, reducing analysis times from 60min to 35 and 22.5min resulted in the same main compounds, indicated responsible for the antioxidant activity. Models built after alignment by COW did not result in additional information.info:eu-repo/semantics/publishe

Potential antioxidant compounds in Mallotus species fingerprints. Part I: Indication, using linear multivariate calibration techniques

Some Mallotus species are used in traditional medicine in Vietnam and China. Some also show interesting activities, such as antioxidant and cytotoxic ones. Combining fingerprint technology with data-handling techniques allows indicating the peaks potentially responsible for given activities. In this study it is aspired to indicate from chromatographic fingerprints the peaks potentially responsible for the antioxidant activity of several Mallotus species. Relevant information was extracted using linear multivariate calibration techniques, both before and after alignment of the fingerprints with correlation optimized warping (COW). From the studied techniques, Stepwise Multiple Linear Regression is least recommended as it made an inadequate variable selection. Principal Component Regression theoretically can take largely varying variables uncorrelated to the antioxidant activity into account. However, in practice in the actual case study this problem was limited. These problems in principle do not occur using Partial Least Squares (PLS) models. Of the tested PLS methods, Orthogonal Projections to Latent Structures was preferred because of its simplicity, reproducibility, reduced model complexity and improved interpretability of the regression coefficients, yielding a clearer view on the individual contribution of the compounds. Furthermore, reducing analysis times from 60 min to 35 and 22.5 min resulted in the same main compounds, indicated responsible for the antioxidant activity. Models built after alignment by COW did not result in additional information

ORAL PRES. Identification of peaks from HPLC fingerprints responsible for the antioxidant activity of Mallotus species

info:eu-repo/semantics/nonPublishe

N-methyl-5-carboxamide-2-pyridone from Mallotus barbatus: a chemosystematic marker in the sub-tribe Rottlerinae of the Euphorbiaceae

info:eu-repo/semantics/publishe

ORAL PRES. Indication and identification of potential antioxidant compounds in Mallotus species fingerprints

info:eu-repo/semantics/nonPublishe

POSTER: Identification of antioxidative compounds in Mallotus species combining chemometrical treated fingerprints with HPLC-MS

info:eu-repo/semantics/nonPublishe