Metabolite Profiling Analysis and the Correlation with Biological Activity of Betalain-Rich Portulaca grandiflora Hook. Extracts

Abstract

The aim of the study was to evaluate the possible correlation between the bioactivity and the phytochemical profile of four betalain-rich extracts from Portulaca grandiflora Hook. The HPLC-DAD-ESI-MS analysis indicated the presence of 19 betaxanthins and two betacyanins. The highest concentrations of betaxanthins (982 mg/100 g DE) and betacyanins (650 mg/100 g DE) were noticed in orange and purple flowers extracts, respectively. The HPLC-DAD-ESI-HRMS/MS analyses revealed the presence of a total of 71 compounds. Fifteen new betaxanthins and fifty other metabolites were identified for the first time. The antioxidant activity of the studied flower extracts increased in the sequence of yellow < orange < purple < red (0.066–0.176 mM TE/g DE). Betalains showed less effect on the antioxidant activity of extracts than other metabolites did. Extracts from yellow and orange flowers were more active against Gram-positive bacteria (MIC = 4–16 mg/L), whereas extracts from red and purple flowers were slightly more active against Gram-negative bacteria (MIC = 16–32 mg/L). All the extracts showed the same activity against yeasts (MIC = 32 mg/L). Betaxanthins were active against Gram-positive bacteria, whereas betacyanins were active against Gram-negative bacteria. Remaining metabolites also exhibited antimicrobial activities. The cytotoxicity assessment showed that the P. grandiflora extracts were non-toxic to normal VERO cells. No significant antiviral activity towards Human Herpesvirus type 1 was observed (62 µg/mL). Among the tested varieties, the purple one showed anticancer selectivity towards colon carcinoma cells (RKO).

Betaxanthin Profiling in Relation to the Biological Activities of Red and Yellow Beta vulgaris L. Extracts

“…is also a proven rich source of betaxanthins. Our research team [ 33 ] investigated the quantitative and qualitative profile of betaxanthins from yellow, orange, red, and purple flowers of P. grandiflora . The content of betaxanthins decreased according to the following flower color order: orange > yellow > purple > red (982, 417, 323, and 162 mg/100 g DE, respectively) [ 33 ].…”

“…Our research team [ 33 ] investigated the quantitative and qualitative profile of betaxanthins from yellow, orange, red, and purple flowers of P. grandiflora . The content of betaxanthins decreased according to the following flower color order: orange > yellow > purple > red (982, 417, 323, and 162 mg/100 g DE, respectively) [ 33 ]. It should be noted that a comparable source of these pigments to the peel extract of the Ceryl cultivar (919 mg/100 g DE) is the orange flower extract of P. grandiflora (982 mg/100 g DE).…”

“…For the identification of betaxanthins, authentic standards from previous betalain studies were used [ 33 ] or semi-synthesized [ 34 ].…”

“…The quantitative determination of single betaxanthins was estimated from the peak areas using MS chromatograms of studied B. vulgaris extracts. P. grandiflora extract [ 33 ], including 19 identified betaxanthins, was used as the reference standard for the description of individual betaxanthins in B. vulgaris extracts. All samples (30 mg/1 mL) were analyzed in triplicate.…”

“…The qualitative and quantitative determination of single betaxanthins in yellow and red B. vulgaris were determined by HPLC-DAD-ESI-MS (LCMS-8030 system, Shimadzu, Japan). Quantitative analysis was performed as previously described [ 33 ]. The LC-MS system consisted of SIL-20ACXR autosampler, degasser, and LC-20ADXR Nexera binary pump.…”