Microvesicles from Turmeric Extracts Contain Curcuminoids and Modulate Macrophage Polarization and Migration

Background/Objectives: Recent studies have revealed that plants produce lipid-derived microvesicles with potent anti-inflammatory properties. In turmeric (Curcuma longa L.), such microvesicles have been identified in rhizome juice and shown to exert beneficial effects in murine models of colitis. In this study, we investigated whether turmeric extracts commonly used in phytotherapy (30% ethanolic or aqueous extracts, and freeze-dried or spray-dried preparations) contain Curcuma-derived microvesicles (CuMVs), and we evaluated the influence of extraction processes on their aggregation and morphology. Methods: All extracts were processed using a standardized protocol involving differential centrifugation, filtration, and ultracentrifugation. CuMVs with sizes from 50 to 200 nm were detected in all pellets, but CuMVs from dehydrated extracts were markedly aggregated compared to those from liquid preparations. Results: The 30% ethanolic extract yielded the most polydisperse CuMVs and was therefore selected for functional immunomodulatory analyses on macrophages. Protein quantification indicated that 600 mL of 30% ethanolic extract contained approximately 60 µg of CuMVs which contained curcumin and its derivatives demethoxycurcumin (DMC), and bisdemethoxycurcumin (BDMC) identified by high-performance thin-layer chromatography (HPTLC). Green fluorescence in the form of small dots close to the nuclei was detected in recipient THP-1 macrophages, indicating the incorporation of CuMVs and therefore the transfer of the naturally fluorescent curcumin. CuMV treatment reduced ROS production, downregulated CD86, and upregulated CD163 expression. Furthermore, CuMVs increased the expression of IL-10 and TGF-β, as well as antibacterial cytokines (IL-1β, IL-6, and TNF-α), and enhanced RAW macrophage migration. Depletion of CuMVs from turmeric extracts markedly reduced their immunomodulatory effects. Conclusions: Collectively, these findings emphasize the importance of preserving CuMVs during the industrial processing of turmeric, as they play a crucial role in curcuminoid delivery and in mediating the immunomodulatory properties of turmeric extracts.