RESUMO
Quinoa (Chenopodium quinoa Willd.) is a pseudocereal originally grown in the Andean region of South America. This study focused on investigating the changes in phenolic profile and antioxidant capacity in white and red quinoa varieties after short-term fermentation with Lactiplantibacillus plantarum 299v®. During fermentation, pH and lactic acid formation were monitored every three hours until pH was below 4.6. The quinoa phenolic profile was quantified via LC-UV-MS. Total polyphenol content (TPC) and total antioxidant capacity (DPPH and FRAP) were determined via spectrophotometric methods. The findings showed that fermentation resulted in a significant increase (p < 0.001) in TPC from 4.68 to 7.78 mgGAE·100 g-1 for the white quinoa and from 5.04 to 8.06 mgGAE·100 g-1 for the red quinoa variety. Gallic acid was the most abundant phenolic acid detected in unfermented quinoa samples (averaging 229.5 µg·g-1). Fermented white quinoa showed an 18-fold increase in epicatechin, while catechin was found only in fermented red quinoa (59.19 µg·g-1). Fermentation showed a significantly positive impact on the iron-reducing antioxidant capacity (FRAP) of quinoa (p < 0.05). Red quinoa had a higher FRAP antioxidant capacity than the white variety; a similar trend was observed with the DPPH assay. There was a significant correlation (r > 0.9, p < 0.05) between TPC and antioxidant capacity. In conclusion, short-time lactic fermentation effectively increased phenolic content and antioxidant capacity in both quinoa varieties. Overall, red quinoa showed higher polyphenol content and antioxidant capacity compared to the white variety.
RESUMO
The study was an extension of our earlier work on antiinflammatory and anticancer properties of G. asiatica fruit. We aimed to develop a bioassay guided multistep purification technique for producing bioactive fractions of G. asiatica crude extracts. Dried fruit powder was sequentially fractionated with 100% dichloromethane, 100% methanol (MeOH), and 50% MeOH. Active extracts were subjected to liquid-liquid partitioning followed by subfractionation using RP-HPLC. Antioxidant, antiinflammatory, and anticancer activities of the fruit extracts, and their potent fractions were evaluated in vitro, while identification of compounds from the bioactive fractions was performed by ESI-MS/MS analysis. The amount of the identified compounds present was confirmed using external standards adopting a simple, accurate, and rapid analytical HPLC method. The results showed that 100% and 50% MeOH extracts possessed bioactivity; one of which (the 50% MeOH extract) displayed potent activity in all in vitro bioassays. MeOH extract (50%) derived fraction C and hydroalcoholic fraction 5 (GAHAF5) were observed to possess higher antioxidant, antiinflammatory, and in vitro anticancer activity. IC50 of GAHAF5 against MCF-7, HEp-2, and NCI-H522 cancer cells was recorded as 26.2, 51.4, and 63 µg/mL, respectively. ESI-MS/MS and HPLC analysis identified catechin, chlorogenic acid, caffeic acid, and morin as potential bioactive compounds in the GAHAF5 fraction with concentrations of 1230, 491, 957, and 130 µg/g, respectively. The findings indicated that G. asiatica bioactive fractions possessed antiinflammatory activity in vitro and were cytotoxic against breast cancer, lung cancer, and laryngeal cancer cell lines.