Comparative Analysis of Metabolites of White and Purple Flower Germplasms in Isodon lophanthoides based on UPLC-MS/MS Technology

Abstract

【Objective】Xihuangcao is a traditional Chinese herbal medicine commonly used in Chinese folk culture. As a medicinal commodity, "Xihuangcao" has about 3-4 plant species as its source. The existing identification and researches suggest that Isodon lophanthoides is one of the authentic products of "Xihuangcao". The widely cultivated Isodon lophanthoides plants are mostly of the purple flower type. The project team used metabolomics technology to conduct comparative studies on the metabolites of newly obtained white flower type germplasm and conventional purple flower type germplasm, which could provide a basis for the creation of authentic I. lophanthoides germplasm and the breeding of new varieties.【Method】With white flower germplasm as the research object and widely cultivated purple flower germplasm as the control, UPLC-MS/MS technology was used to compare the differential metabolites between the two germplasms and conduct differential metabolite enrichment pathway analysis.【Result】A total of 125 differential metabolites were screened from 868 metabolites detected in two germplasm samples, of which 67 were significantly upregulated and 58 were downregulated in the white flower germplasm. The differential metabolites between the two germplasms mainly included flavonoids, organic acids, amino acids and their derivatives, phenolic acids, alkaloids, free fatty acids, and etc. Among them, flavonoids accounted for the highest proportion, reaching 45.6%. Among the three differential metabolites of flavonoids, flavonoid glycosides and isoflavones, their upregulated quantity of white flower germplasm were higher than that of purple flower germplasm; flavonoids were the category with the most differential metabolites between the two germplasms, and most of them were significantly upregulated in purple flower germplasm. Further pathway enrichment analysis revealed that 125 differential metabolites were annotated into 47 metabolic pathways. Among them, significantly enriched pathways included flavonoid, isoflavone, anthocyanin, flavone, flavanol, stilbenoid, diarylheptanoid and gingerol biosynthesis and purine metabolism, etc.【Conclusion】The contents of flavonoids and flavonols in white flower I. lophanthoides germplasm are significantly higner than those in the purple flower germplasm. This will provide good materials for the exploration, creation and new variety selection of I. lophanthoides germplasm resources in the later stage.

Keywords

• isodon lophanthoides
• germplasm
• metabolomics
• uplc-ms/ms
• metabolic pathway