Multi-Target Mechanisms of Citrus Essential Oils in Cosmetics: Chemical Profiling, Bioactivity Assessment, and Network Pharmacology Insights

Abstract

Citrus essential oils (EOs) are valued in cosmetics primarily for their appealing aromas; however, a systematic understanding of their chemical composition, bioactivities, and mechanisms of action remains limited. This study characterised the volatile profiles of eight citrus EOs using gas chromatography–mass spectrometry (GC–MS), evaluated their antioxidant, anti-tyrosinase, and anti-hyaluronidase activities, and explored the underlying mechanisms of action. A total of 127 volatile compounds (relative peak area > 0.05%) were identified across the eight EOs, with limonene being the predominant component in most samples. Seven components, including α-pinene, α-phellandrene, sabinene, myrcene, limonene, β-phellandrene, and α-terpineol, were common to all eight EOs. In vitro assessment at 0.4% revealed that all eight citrus EOs exhibited antioxidant and enzyme-inhibitory activities. Notably, grapefruit pink and lemon EOs exhibited the strongest tyrosinase inhibition (77.35% ± 4.01% and 75.32% ± 3.08%, respectively), whereas tangerine and lemon EOs showed the highest hyaluronidase inhibition (32.19% ± 2.08% and 30.07% ± 3.51%, respectively). Using network pharmacology, 71 bioactive components were screened, and their potential interactions with key targets associated with free radical scavenging, skin soothing, and anti-tyrosinase activity were mapped. Key targets (e.g., STAT3 and SRC) and pathways (e.g., PI3K-Akt and MAPK signalling), were identified as potential regulators of these multi-target effects. This study not only clarified the chemical and bioactivity profiles of eight citrus EOs but also provided a mechanistic foundation for their application as multi-functional natural ingredients in cosmetics.