Mechanistic insights into a compound essential oil (Lemon-Angelica sinensis-Boswellia) for anxiety-melasma comorbidity: An integrated network pharmacology and experimental study.

The high comorbidity between anxiety disorders and melasma highlights the urgent need for integrated therapeutic strategies. Aromatherapy, utilizing volatile plant extracts, serves as a promising holistic intervention by modulating both physiological and psychological states. In this study, a compound essential oil (CEO) was developed from lemon (Citrus×limon (L.) Osbeck), Angelica sinensis (Oliv.) Diels, and boswellia (Boswellia sacra Flück) at a volume ratio of 1:1:1. An integrated approach combining network pharmacology and experimental validation was employed to elucidate its mechanisms against anxiety-melasma comorbidity (AMC). A total of 28 active components (e.g., neryl acetate, citral, 3-butylidenephthalide, octyl acetate) and 26 shared targets (e.g., ESR1, CCND1, PIK3CA) were identified. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses revealed significant enrichment in hormone response and apoptotic processes, with the PI3K/Akt signaling pathway identified as the central regulatory hub. In vitro experiments showed that CEO significantly suppressed tyrosinase activity and the production of pro-inflammatory cytokines (NO, TNF-α, IL-6), while downregulating the mRNA expression of key targets (ESR1, CCND1, PIK3CA) in LPS-induced HaCaT cells. In vivo, CEO ameliorated anxiety-like behaviors and reduced hippocampal levels of IL-1β, ESR1, and CCND1 in a chronic unpredictable mild stress (CUMS) mouse model. Collectively, this study demonstrates that CEO alleviates AMC through a "multi-component, multi-target, multi-pathway" mechanism, primarily by modulating the PI3K/Akt pathway to regulate inflammatory responses, melanogenesis, and neural homeostasis.