Developmental stage-dependent metabolite enrichment and antiviral pneumonia efficacy of Lonicera japonica cultivars in Shandong

Background: The dried buds and initial blooms of Lonicera japonica Thunb. are highly esteemed for their medicinal and edible uses. In Shandong, China, Sijihua (SF) and Beihua No. 1 (BF) cultivars are the most widely grown. These cultivars progress through 6 distinct developmental stages from bud emergence to flowering. However, research on metabolomics across these stages remains relatively scarce. Objective: This study sought to investigate the dynamic changes in metabolic profiles and efficacy variations between SF and BF throughout their developmental stages, aiming to provide valuable insights for cultivar enhancement and determining optimal harvest timing. Methods: Ultrahigh-performance liquid chromatography-Orbitrap Exploris-mass spectrometry (UHPLC-OE-MS) was used to analyze the metabolic profiles of each cultivar across various developmental stages. Possible biosynthetic pathways for the key bioactive components, namely phenolic acids and flavonoids, were constructed. Enrichment analyses of metabolic pathways were conducted based on differential metabolites between the 2 varieties. Additionally, the efficacy of SF extracts from all 6 stages was assessed using a zebrafish viral pneumonia model. Results: A total of 78 primary and secondary metabolites were identified. Between the 2 varieties, BF exhibited significantly higher levels of chlorogenic acid derivatives and total flavonoids compared with SF. At the developmental stage, the most pronounced metabolic differences between the 2 varieties were observed during the Mi-like stage (ML) and green stage (SQ), primarily driven by variations in the tricarboxylic acid cycle (TCA cycle) and phenylalanine metabolism pathways. Pharmacological evaluation revealed that SF extracts from all developmental stages exhibited antiviral activity against pneumonia, with the extracts from the white stage (DB) showing the strongest efficacy. Conclusion: This study elucidates the mechanism by which both cultivar and developmental stage jogintly regulate the accumulation of bioactive compounds in L. japonica . It confirms that BF variety exhibits superior advantages in bioactive compound accumulation, while the white stage (DB) of SF represents the optimal medicinal harvest period. This research provides important insights for selecting L. japonica cultivars and determining the appropriate harvest timing.