Structural Identification and Bioactivities of Red-Violet Pigments Present in Basella alba Fruits

Mature Basella alba L fruit, with dark blue skin and deep red-violet flesh, is a potential source of natural colorants Its pigment components and bioactivities deserve particular attention and investigation In this study, fruit flesh was extracted with 80% methanol (containing 0.2% formic acid) and subjected to solid-phase extraction, semipreparative HPLC isolation, mass spectrophotometric analysis, and structural elucidation The major red pigment was identified as gomphrenin I Its quantity increased with the increase of fruit maturity The gomphrenin I extract yield from ripe fruits was 36 1 mg/100 g of fresh weight In addition to gomphrenin I, betanidin-dihexose and isobetanidin-dihexose were also detected The antioxidant activities of gomphrenin I determined by Trolox equivalent antioxidant capacity (TEAC), alpha,alpha-diphenyl-beta-picrylhydrazyl (DPPH) radical scavenging activity, reducing power, and antioxidative capacity assays were equivalent to 534 mu M Trolox, 103 mu M butylated hydroxytoluene (BHT), 129 mu M ascorbic acid, and 68 mu M BHT at 180, 23, 45, and 181 mu M, respectively The anti-inflammatory function was tested at concentrations of 25, 50, and 100 mu M in murine macrophages stimulated with hpopolysacchande (LPS) The results revealed that gomphrenin I suppressed LPS-induced nitric oxide (NO) production in a dose-dependent manner and decreased PGE(2) and IL-1 beta secretions at the highest concentration tested The transcriptional inhibitory activities of gomphrenin I on the expression of inflammatory genes encoding INOS, COX-2. IL-1 beta, TNF-alpha, and IL-6 were also observed It is of merit to identify gomphrenin I as a principal pigment of B alba fruits and as a potent antioxidant and inflammatory inhibitor These findings suggest that B alba fruit is a rich source of betalains and has value-added potential for use in the development of food colorants and nutraceuticals