Cisplatin chemotherapy causes myelosuppression and often limits treatment duration and dose escalation in patients. Novel approaches to circumvent or lessen myelotoxicity may improve clinical outcome and quality of life in these patients. Chlorella sorokiniana (CS) is a freshwater unicellular green alga and exhibits encouraging efficacy in immunomodulation and anticancer in preclinical studies. However, the efficacy of CS on chemoprotection remains unclear. We report here, for the first time, that CS extract (CSE) could protect normal myeloid cells and PBMCs from cisplatin toxicity. Also, cisplatin-induced apoptosis in HL-60 cells was rescued through reservation of mitochondrial function, inhibition of cytochrome c release to cytosol, and suppression of caspase and PARP activation. Intriguingly, cotreatment of CSE attenuated cisplatin-evoked hypocellularity of bone marrow in mice. Furthermore, we observed the enhancement of CSF-GM activity in bone marrow and spleen in mice administered CSE and cisplatin, along with increased CD11b levels in spleen. In conclusion, we uncovered a novel mechanism of CSE on myeloprotection, whereby potentially supports the use of CSE as a chemoprotector against cisplatin-induced bone marrow toxicity. Further clinical investigation of CSE in combination with cisplatin is warranted.

Plant-derived exosome-like extracellular vesicles (PELVs) have recently emerged as novel bioactive materials. Although members of the Orchidaceae family have been reported to possess various biological activities and are widely used as cosmetic ingredients, no studies to date have investigated exosome-like extracellular vesicles derived from Phalaenopsis species. In the present study, we report for the first time a novel exosome-like extracellular vesicles preparation isolated from Phalaenopsis aphrodite (called Exorigin^® OR) and characterize its physical and biological properties. The purified vesicles exhibited a spherical shape surrounded by a bilayered membrane with an average particle size of approximately 98 nm and expressed a CD9 marker. Fluorescent labeling with BODIPY TR indicated that Exorigin^® OR can be internalized by cells. In in vitro assays, Exorigin^® OR alleviated hydrogen peroxide-induced damage in keratinocytes and inhibited melanin production in melanocytes, possibly associated with the downregulation of Tyrp1 expression as shown by qPCR analysis. Moreover, reconstructed human epidermis and cornea-like epithelium models demonstrated that Exorigin^® OR is non-irritant. Collectively, these findings suggest that Exorigin^® OR represent a promising and safe bioactive ingredient for promoting skin health in cosmeceutical applications.