Exosome-Like Nanoparticles Derived from the Rhizome of Zingiber officinale Suppress Neuroinflammatory Responses in BV-2 Microglial Cells

Plant-derived exosome-like nanoparticles (ELNs) are promising bioactive nanovesicles that can modulate physiological functions across species boundaries. Although ELNs derived from fresh plants have been extensively investigated, little is known about ELNs present in hot-water extracts used in traditional herbal medicines. We aimed to isolate and characterize ELNs derived from a hot-water extract of the rhizome of Zingiber officinale (Z-ELNs) and to evaluate their anti-neuroinflammatory effects in lipopolysaccharide (LPS)-stimulated BV-2 microglial cells. Z-ELNs were isolated from ginger decoctions by differential ultracentrifugation and characterized using dynamic light scattering and transmission electron microscopy. The nanoparticles exhibited a mean diameter of 183 ± 56 nm and a zeta potential of -24.8 ± 12.1 mV. RNA sequencing analysis identified several known and putative microRNAs, while LC/MS analysis detected characteristic ginger-derived secondary metabolites, including 6-gingerol and 6-shogaol. Confocal microscopy demonstrated the uptake of fluorescently labeled Z-ELNs by BV-2 cells. The Z-ELN preparation significantly suppressed LPS-induced nitric oxide (NO) production and reduced the expression of inflammatory mediators, including inducible NO synthase, tumor necrosis factor-α, and interleukin-1β. Z-ELNs significantly upregulated heme oxygenase-1 (HO-1) expression in BV-2 cells. These findings suggest that the Z-ELN preparation attenuates microglial inflammatory responses through multiple potential mechanisms, with HO-1 induction possibly being associated with these effects. Z-ELNs present in herbal decoctions may contribute to the pharmacological effects of traditional herbal medicines and warrant further investigation as potential sources of bioactive components targeting neuroinflammation.