Impact of drying on yield and composition of extracellular vesicles from Centella asiatica.

Plant-derived extracellular vesicles (EVs) have attracted growing interest as scalable nanocarriers in medicine and biotechnology. Yet little is known about post-harvest processing particularly drying, affects their EV yield, size, morphology, and biochemical composition. In this study, microvesicles (MVs), a major class of EVs, were isolated via differential centrifugation and purified by size-exclusion chromatography. Then, MVs were characterized morphologically by transmission electron microscopy and assessed for hydrodynamic size and zeta potential using dynamic light scattering. Antioxidant activity was quantified through 2,2-diphenyl-1-picrylhydrazyl radical scavenging assays. Fatty acid profiles were determined by gas chromatography, while triterpenoids and polyphenols were quantified by high performance liquid chromatography. Spherical, cup-shaped vesicles were successfully isolated from both dried and fresh C. asiatica. Dried plant biomass yielded higher MV quantities, producing smaller vesicles comparable to fresh samples. Unique fatty acids-including trans-oleic, erucic, trans-linoleic acids- were detected exclusively in dried MVs, but not in fresh samples. Our findings demonstrated that dried medicinal herbs can serve as a practical and, in some respects, advantageous source of MVs compared to fresh material, providing higher yields while retaining key bioactive components. This supports potential future use of dried biomass for efficient and large-scale MV preparation, with application in biotechnology and possibly biomedicine.