Metabolite Profile, Antioxidant Activity and Anti-Candida Activity of Fermented Star Fruit Bioextract (Averrhoa carambola L.)

Abstract

Nowadays bioextracts are widely used in various applications, however there is limited information on chemical constituents and biological activities of the bioextract produced for consumption. Therefore, the purpose of this study was to investigate the antioxidant activity, anti-candida activity and metabolic profile of fermented star fruit (Averrhoa carambola L.) bioextract. The fermented star fruit bioextract was produced through fermentation lasting 180 days, during which the activity and the metabolite profile were determined at 30-day intervals. The antioxidant activity was tested using the DPPH radical scavenging assay and the anti-candida activity was determined by the broth micro-dilution method. The metabolic profile was analyzed using LC-ESI-QTOF-MS/MS. The results showed that as fermentation proceeded, the potency of antioxidant and anti-candida activity observed from the bioextract increased. The lowest IC50 value for DPPH inhibition (25 %v/v) and the lowest minimum inhibitory concentration (6.25 %v/v) against Candida albicans were both observed after fermentation for 150 days. The metabolite analysis identified 4 main chemical classes: Sugars, organic acids, flavonoids and nitrogen compounds. The chemical diversity was highest in the Day 120 through Day 150 samples. This study shows that fermented bioextract from star fruit at incubation time 150-180 days carries potential health benefits for application in anti-candida and antioxidant products. Possible toxicity, skin and oral mucosal irritation should be considered for further study.