Plant-based extracts such as coffee (coffea) and Mauby (Colubrina Arborescens) were tested for chemopreventative potential by measuring their antioxidant activity (i.e., reducing power and free radical scavenging capacity) conventionally using chemical assays 1, 1-Diphenyl-2-picryl-hydrazyl (DPPH) and Ferric Reducing Antioxidant Power (FRAP). Alternately, extracts were also analyzed for their chemopreventative potential via a novel method (Global Antioxidant Response [GAR]), where they were subjected to simulated digestion before their antioxidant activity was determined via conventional methods previously mentioned. Next, the antioxidant capacities of the extracts, conventional versus the novel (GAR) method were compared. Overall, the analysis indicated that the reducing power (FRAP) and free radical scavenging capacity (DPPH) of coffee and Mauby were reduced (~16%) after undergoing simulated digestion. It was also observed that while the antioxidants in Mauby scavenged radicals at a significantly higher capacity than those in coffee (95.7% ± 0.67 and 90% ± 2.1 before digestion, and 77.7% ± 2.2 and 74.6% ± 2.3 after digestion, respectively), antioxidants in coffee exhibited higher reducing power compared to those in Mauby. Specifically, after undergoing simulated digestion, 1.12 mM FeSO4/mL ± 0.05 to 0.68 mM FeSO4/mL ± 0.07 ions were reduced before digestion, and 0.73 mM FeSO4/mL ± 0.09 to 0.48 mM FeSO4/mL ± 0.04 ions were reduced after digestion for coffee and Mauby, respectively. These findings suggest that while the antioxidants in coffee may have been more powerful in their ability to reduce ions, the antioxidants in Mauby may have been more effective in scavenging and neutralizing radicals.
Antioxidant activity and free radical-scavenging capacity of Gynura divaricata leaf extracts at different temperatures