Size Matters: Influence of Particle Size on Antioxidant, β-Glucan and Anti-inflammatory Potential in Pleurotus floridanus

Cellular damage resulting from elevated levels of free radicals can lead to persistent health issues. Pleurotus floridanus, an edible white oyster mushroom, is rich in β-glucans with potent antioxidant and anti-inflammatory properties. In this research, we examined the β-glucan content, total phenolic content, as well as antioxidant and anti-inflammatory potential of hot water extracts with varying particle sizes (<75 µm, 75-154 µm, 154-300 µm, and 300-600 µm) of both whole (WFB) and sliced (SFB) fruiting bodies of P. floridanus. The findings revealed that the β-glucan content increased as the particle size increased, though no significant differences were observed. Conversely, smaller particle sizes (<75 µm) of whole and sliced fruiting bodies of P. floridanus exhibited higher phenolic content, DPPH and ABTS scavenging activity and reducing ability compared to larger particle size (>75 µm). Out of the four samples (AW2, AW3, AS1, and AS2) with the highest antioxidant activity, selected for anti-inflammatory assays, all demonstrated the ability to reduce NO and TNF-α levels but did not enhance IL-10 expression in LPS-stimulated RAW264.7 cells. Interestingly, particle size < 75 to 300 µm did not appear to influence the anti-inflammatory activity, as no significant differences were observed among the particle sizes. Therefore, it is suggested that the particle size <300 µm of P. floridanus hot water extract could serve as a valuable source of antioxidant and anti-inflammatory compounds to counteract the harmful effects of free radicals.