Laura Silvia González-Valdez

Rapid Determination of Phenolics, Flavonoids, and Antioxidant Properties of Physalis ixocarpa Brot. ex Hornem. and Physalis angulata L. by Infrared Spectroscopy and Partial Least Squares

ABSTRACT Physalis ixocarpa Brot. ex Hornem. and Physalis angulata L. are two edible species of the family Solanaceae, which have an important variety of antioxidant compounds present in their roots, stems, leaves, calyces, and fruits. This work reports the development of multivariate models based on the use of partial least square (PLS) analysis and Fourier transform infrared (FTIR) spectroscopy for the quantitative determination of total phenolics, total flavonoids, free radical scavenging activity, total antioxidant capacity, and reducing power in the extracts of roots, stems, and leaves of both P. ixocarpa and P. angulata. Standard chromatographic and colorimetric techniques were used to determine the quantitative actual values (references) in the extracts, which served as input data to develop the multivariate PLS models. Optimized FTIR-PLS models were realized by cross-validation procedures, obtaining the determination coefficients for prediction between 0.792 and 0.905 for P. ixocarpa, and between 0.756 and 0.893 for P. angulata. In this form, FTIR spectroscopy with multivariate analysis could represent a versatile tool to evaluate quantitatively concentrations of bioactive compounds and antioxidant properties in the extracts of both species, requiring a very short time at low cost.

Phytochemical characterization and antioxidant properties of the wild edible acerola Malpighia umbellata Rose

ABSTRACT The objective of the current study was to determine the phenolic composition and carotenoid contents of leaves, bark, and fruits of Malpighia umbellata, assess the changes in the phenolic composition and contents of carotenoids and vitamin C of its fruits in different stages of maturity, and evaluate the antioxidant properties of its leaves, bark, and fruits. Leaves accumulated the highest levels of flavonoids (10.55 mg/g dry extract), tannins (21.16 mg/g dry extract), and carotenoids (424 63 µg/g dry tissue); whereas, the highest level of total phenolics was found in bark (47.12 mg/g dry extract). The vitamin C content decreased with the maturity of fruits. Twenty-two phenolics were characterized by high performance liquid chromatography with diode array detection (HPLC-DAD). Apigenin-7-O-glycosides, phenolic acids, and flavonols were predominant in leaves, bark, and fruits, respectively. Important chemical variations were found during fruit ripening. The 2,2-diphenyl-1-picrylhydrazyl (DPPH•) scavenging activity and 2,2ʹ-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) inhibition assays revealed important antioxidant properties for this acerola.