ABSTRACT
ABSTRACT: Peltogyne mexicana heartwood might be a novel purple pigment source. The results of the present study demonstrate that the purple pigment is an important source of phenolic compounds (698.22 ± 2.99 mg GAE/g) and flavonoids (48.01 ± 0.51 mg EPE/g). UV-Vis spectrum and color parameters (L* a* b*) showed that purple pigment has different shades of purple-red (H° value 19.32 ± 0.02 in methanol and 22.85 ± 0.01 in ethanol) depending on the solvent and the pH. Also, the purple pigment did not exhibit acute oral toxicity at a single dose (2000 mg/kg body weight). No mutagenicity was observed in the Ames test with three Salmonella typhimurium strains. The purple pigment exhibited considerable coloring properties with a wider range of citric acid-dependent color hues in gelatin (H° from 280.3 to 319.9 and from 68.0 to 88.1), and higher color intensity than commercial anthocyanin. Minor variations in the hue were found in yogurt, for purple pigment with H° values from 317.5 to 315.0, and commercial anthocyanin from 82.6 to 88.7 and 276.9 to 295.5. However, purple pigment required lower concentrations to achieve superior effects. For gelatin and yogurt samples, similar variations in the color parameters L*, a*, b*, and pigment degradation were observed for purple pigment and commercial anthocyanin in the stability assay.
ABSTRACT
Peltomexicanin (7,10-dihydroxy-6,12-dioxa-5H-tetraphen-3-one) is a new peltogynoid quinone methide isolated from Palo Morado (Peltogyne mexicana Martínez) heartwood by column chromatography. Its chemical structure was elucidated by IR, NMR (¹H, (13)C), 2D NMR experiments (COSY, NOESY, HMQC, and HSQC), ESI-MS, and UV-Vis spectroscopic analysis. According to HPLC quantification, this compound is the main pigment and accounts for 1.21% of Palo Morado heartwood material. The antioxidant activity of peltomexicanin and dried methanolic extract (DEx) of purple heartwood was evaluated using the radical of 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) assay, and the corresponding values expressed as Trolox equivalents (µmol TE/mg sample) were 4.25 and 4.57, respectively.
