Plant-derived exosomes can exert therapeutic effects against various dermatological conditions. Several studies have demonstrated that plant-derived exosomes can have positive effects on the skin, preventing aging, hyperpigmentation, and hair loss. In this study, the protective effects of Iris germanica L. rhizome-derived exosomes (Iris-exosomes) on oxidative-stress-induced cellular dysfunction were investigated in human epidermal keratinocytes (nHEKs). Iris-exosomes with a diameter range of 100–300 nm were detected. In the cytotoxicity assay, Iris-exosomes with up to 10⁷ particles per milliliter were found to possess no cytotoxicity, and we recovered H₂O₂-induced cell viability loss. In nHEKs, H₂O₂-induced ROS levels were significantly reduced using Iris-exosomes and additionally associated with increases in antioxidant enzyme transcription. The H₂O₂-induced SA-β-gal-positive nHEKs were decreased using Iris-exosomes; these effects correlate with the changed levels of cell cycle arrest marker p21. Furthermore, the H₂O₂-induced loss of in vitro wound-healing properties and early detection of keratin 1 and 10—keratinization markers—were restored to control levels using Iris-exosomes. Altogether, these results indicate the possibility that Iris-exosomes exert antioxidant and anti-senescence effects in order to protect against oxidative-stress-induced cellular dysfunction in nHEKs.

Studies on plant-derived natural products that have no side-effects have attracted great attention from the cosmetics industry. Plant-derived exosomes are nanovesicles (30–150 nm in size) that contain biomolecules, which protect plants from stress and pathogens. In this study, we determined the availability of physiologically active Centella asiatica (Cica) extract and Cica exosome for cosmetic use with human keratinocytes using an in vitro efficacy assay, transcriptome analysis, and miRNA profiling. In vitro efficacy analysis revealed that Cica extract and Cica exosome have regenerative and wrinkle-improving effects. Comparative transcriptome analysis between Cica exosome- and Cica extract-treated-human keratinocytes revealed 46% more gene expression in Cica exosome-treated cells than Cica extract-treated cells; moreover, the expression of marker genes involved in skin aging and regeneration was upregulated. miRNA analysis of Cica exosomes identified 11 novel miRNAs. Prediction of miRNA targets revealed that Cica exosomal miRNA can inhibit genes involved in melanin biosynthesis and dermatitis. Transcriptome analysis confirmed that the predicted human target genes were downregulated by Cica exosome miRNA compared with the control. Thus, Cica exosomes and Cica extracts can have a positive effect on skin regeneration, wrinkle improvement, and skin barrier improvement. Cica exosomal miRNA has potential whitening and anti-dermatitis effects.