Abstract:

The aim of this study is to investigate the anti-hair loss mechanism of supercritical CO₂ extraction of Platycladus orientalis （L.） Franco （SC-CO₂-PO）. Supercritical CO₂ extraction technology was used to prepare the extract of Platycladus orientalis （L.） Franco. Full component analysis and quantification of the characteristic active ingredients were performed by gas chromatography-mass spectrometry （GC-MS）. An AI-based target prediction model was established to screen key anti-shedding targets. The cytotoxic effect of SC-CO₂-PO on human sebaceous gland cells （SZ95） was determined by MTT assay. Nile red fluorescence staining was used to evaluate its inhibitory effect on lipid synthesis. Enzyme activity assays were used to measure the inhibition rate of type II 5α-reductase （SRD5A2）. Semi-quantitative RT-PCR was used to detect the relative expression levels of androgen receptor （AR） mRNA. An in vitro hair follicle culture model was used to observe its regulatory effect on the hair follicle growth cycle. The results show that SC-CO₂-PO contains 25 active ingredients, with the contents of the characteristic active ingredients cedarol and β-caryophyllene being 1.32% and 0.10%, respectively. The safe concentration of SC-CO₂-PO in SZ95 cells is 0.019 5 mg/mL. SC-CO₂-PO can inhibit neutral lipid synthesis, suppress SRD5A2 activity, reduce the relative expression levels of AR mRNA, increase hair follicle length and vascular endothelial growth factor （VEGF） content. These results indicate that SC-CO₂-PO exerts anti-hair loss effects via dual pathways: it reduces sebum secretion by inhibiting SRD5A2 activity and down-regulating AR mRNA expression, thereby modulating the androgen signaling pathway. SC-CO₂-PO increases the expression level of VEGF, promoting the reconstruction of blood vessels around hair follicles during the hair follicle cycle, enhancing the activity of hair follicles, stimulating hair growth, and prolonging the growth period of hair follicles.

Key words: Platycladus orientalis （L.） Franco, androgenetic alopecia, neutral lipids, molecular docking, ex vivo hair follicle assay