Abstract:
The present study aimed to compare the absorption and transport patterns of three main
betalains, betanin, vulgaxanthin I and indicaxanthin, into intestinal epithelial cells and to assess their
distinct molecular effects on inflammatory and redox-related cell signalling in association with their
radial scavenging potencies. All three betalains showed anti-inflammatory effects (5–80 µM), reflected
by attenuated transcription of pro-inflammatory mediators such as cyclooxygenase-2 and inducible
NO-synthase. Concomitant increases in antioxidant enzymes such as heme oxygenase-1 were only
observed for betanin. Moreover, betanin uniquely demonstrated a potent dose-dependent radical
scavenging activity in EPR and cell-based assays. Results also indicated overall low permeability for
the three betalains with Papp of 4.2–8.9 × 10−7
cm s−1
. Higher absorption intensities of vulgaxanthin
and indicaxanthin may be attributed to smaller molecular sizes and greater lipophilicity. In conclusion,
betanin, vulgaxanthin I and indicaxanthin have differentially contributed to lowering inflammatory
markers and mitigating oxidative stress, implying the potential to ameliorate inflammatory intestinal
disease. Compared with two betaxanthins, the greater efficacy of betanin in scavenging radical
and promoting antioxidant response might, to some extent, compensate for its poorer absorption
efficiency, as demonstrated by the Caco-2 cell model.
