Antioxidant & Bioaccessibility properties of Blood Bird’s Nest

In vitro bioaccessibility and antioxidant properties of Blood Bird’s Nest following simulated human gastro-intestinal digestion.

Abstract

Background:

Blood Bird’s Nest is reported to be antioxidant-rich. However, the fate of its antioxidants after oral consumption is not yet reported. To explore this, we hypothesized that Blood Bird’s Nest antioxidants are released from their matrix when subjected to in vitro simulated gastrointestinal digestion.

Antioxidant & Bioaccessibility properties of Blood Bird’s Nest

Methods:

Blood Bird’s Nest samples were extracted using hot water (100°C) with or without subsequent sequential enzymatic digestion using pepsin (10,000 units), pancreatin (36 mg) and bile extracts (112.5 mg). Additionally, pH changes (8.9 to 2 and back to 8.9) similar to the gut were applied, and a 10 KDa dialysis tubing was used to simulate gut absorption. The antioxidant capacities of the water extracts of Blood Bird’s Nest before and after digestion were then determined using ABTS and oxygen radical absorbance capacity (ORAC) assays, while the protective effects of the Blood Bird’s Nest samples against hydrogen peroxide-induced toxicity in HEPG2 cells were determined using MTT assay and acridine orange (AO)/propidium iodide (PI) staining.

Results:

Antioxidant assays (ABTS and ORAC) showed that the undigested Blood Bird’s Nest water extract had little antioxidant activity (1 and 1%, respectively at 1000 μg/mL) while at similar concentrations the digested samples had significantly (p < 0.05) enhanced antioxidant activities, for samples inside (38 and 50%, respectively at 1000 μg/mL) and outside (36 and 50%, respectively at 1000 μg/mL) the dialysis tubing, representing absorbed and unabsorbed samples, respectively. Cell viability and toxicity assays also suggested that the Blood Bird’s Nest extracts were non-toxic to HEPG2 cells (cell viabilities of over 80% at 1000 μg/mL), while AOPI showed that the extracts protected HEPG2 cells from hydrogen peroxide induced-toxicity.

Conclusions:

Based on the findings, it is likely that Blood Bird’s Nest bioactives are released from their matrix when digested in the gut and then absorbed through the gut by passive-mediated transport to exert their functional effects. However, there is need to confirm these findings using in vivo systems to determine their clinical significance.