RESULTS: Comparison of the PLS and RF showed that RF exhibited poorer generalization and hence poorer predictive performance. Both the regression coefficient of PLS and the variable importance of RF revealed that quercetin and kaempferol derivatives, caffeic acid and vitexin-2-O-rhamnoside were significant towards the tested bioactivities. Furthermore, principal component analysis (PCA) and partial least squares-discriminant analysis (PLS-DA) results showed that sonication and absolute ethanol are the preferable extraction method and ethanol ratio, respectively, to produce N. oleracea extracts with high phenolic levels and therefore high DPPH scavenging and α-glucosidase inhibitory activities.
CONCLUSION: Both PLS and RF are useful regression models in metabolomics studies. This work provides insight into the performance of different multivariate data analysis tools and the effects of different extraction conditions on the extraction of desired phenolics from plants. © 2017 Society of Chemical Industry.
Methods: Mice (n = 48) were fed high-fat diet (HFD) for 25 weeks to induce obesity, after which half were maintained on HFD and half switched to low-fat diet (LFD)while they were given normal water (H2O) or 0.1% (w/v) SCE in water at week 0-4 which was increased to 1% (w/v) at week 5-9. Effects of treatment with SCE were compared between HFDH2O, HFDSCE, LFDH2O and LFDSCE groups. Respiratory exchange ratios (RER) were measured at weeks 0, 5 and 10. Food, water intake and body weight were measured weekly. Plasma lipid profile and organ weights were determined at week 10.
Results: SCE had significantly reduced RER at week 9 (P = 0.011). Food intake, body weight, and abdominal adipose tissue weight were not altered by SCE at weeks 5 and 10. However, significant increase in plasma and liver cholesterol (P < 0.050) was observed.
Conclusion: Our findings suggest that SCE induced lipolysis and body fat oxidation and increased energy expenditure. Further studies in other animal models should be done to confirm the consistency of these results.
RESULTS: Defatted kenaf seed powder yielded four DF fractions: alkali-soluble hemicellulose (146.4 g kg-1 ), calcium-bound pectin (10.3 g kg-1 ) and acid-soluble pectin (25.4 g kg-1 ) made up the soluble fibre fraction, whereas cellulose (202.2 g kg-1 ) comprised the insoluble fraction. All fractions were evaluated for their physicochemical properties. The DF fractions contained glucose, mannose, xylose and arabinose, and a small amount of uronic acid (1.2-2.7 g kg-1 ). The isolated pectin fractions had a low degree of esterification (14-30%). All the isolated DF fractions had high average molecular weights ranging from 0.3 to 4.3 × 106 g mol-1 . X-ray diffractogram analysis revealed that the fractions consisted mainly of an amorphous structure with a relative crystallinity ranging from 31.6% to 44.1%. The Fourier-transform infrared spectroscopy spectrum of kenaf seed and its DF fractions showed typical absorption of polysaccharides, with the presence of hydroxyl, carboxyl, acetyl and methyl groups. Scanning electron microscopy analysis demonstrated that the raw material with the rigid structure resulted in soluble and insoluble DF fractions with more fragile and fibrous appearances, respectively. The soluble DF demonstrated greater flowability and compressibility than the insoluble fractions.
CONCLUSION: These findings provide novel information on the DF fractions of kenaf seeds, which could be used as a potential new DF for the food industry. © 2023 Society of Chemical Industry.