Improved Extraction of Acylated Anthocyanins from Purple Sweet Potato (Ipomoea Batata) for Enhanced Anti-inflammatory Activity and Their Metabolite Production During Porcine Fecal Digestion
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This study characterized Purple sweet potato (PSP) polyphenolics and heating increments associated to PPO inhibitors (citric acid, oxalic acid, and sodium borate) to inactivate enzyme and enhance pigment recovery. Hydrolyzed fractions were used to evaluate stability using an in vitro simulated gastrointestinal digestion for 7 hr, absorption, using a Caco-2 human intestinal cell model, anti-inflammatory and anticancer properties via TNF- ɑ induced CCD-18Co fibroblast and HT-29 colon cancer cells. Finally, PSP anthocyanin extracts stability were assessed and compared with other sources using an in vitro digestion as well as incubation with pig fecal microflora. Predominant PSP anthocyanins included acylated cyanidin or peonidin derivatives. Non-pigmented cinnamates acted as oxidase substrates and induced co-oxidation reactions with anthocyanins. Pre-heating PSP significantly increased polyphenolic yields in a temperature-dependent manner, consistent with tissue softening and PPO inactivation. Hydrolyzed anthocyanins were degraded in both presence and absence of phenolic acids while non-hydrolyzed anthocyanin fractions presented high recovery after intestinal incubation. Transport from the apical to basolateral side was demonstrated in the Caco-2 cell model where extent of transport was dependent on chemical structure and association complexes. Cancer cells were significantly inhibited (40% survival) whereas no toxicity was observed for non-cancer cells. ROS was suppressed at higher concentrations in non-cancer cells, while an increase was noted in cancerous cells. Fractions containing phenolic acids served to down-regulate mRNA and protein expressions of inflammatory markers (NF-ҡB, TNF-ɑ, IL-1β and IL-6) on non-cancer cells, thus showing cancer prevention properties. Non-hydrolyzed fractions modulated these biomarkers on cancer cells, thus acting as cancer inhibitors. Sources presented great stability under gastric digestion, whereas great losses were observed for nonacylated during intestinal digestion. Pig fecal incubation of stable acylated sources (Black carrot and PSP) showed fecal suspension was able to rapidly degrade anthocyanins, with di-acylated degrading faster than mono and non-acylated ones, likely produced as complex anthocyanins were decomposed. Free cinnamic and phenolic acids were formed during incubation with active suspension, with maximum concentration ranging from 1 to 6 hours of exposure, simultaneous to anthocyanin degradation. Anthocyanins from PSP showed great applicability in the food industry and stability during digestion with potential for health benefits.
Cipriano, Paula De Aguiar (2016). Improved Extraction of Acylated Anthocyanins from Purple Sweet Potato (Ipomoea Batata) for Enhanced Anti-inflammatory Activity and Their Metabolite Production During Porcine Fecal Digestion. Doctoral dissertation, Texas A & M University. Available electronically from