In this study, the metabolites in the flowers and leaves of single- and double-petal jasmine were determined and compared by ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) combined with multivariate statistical analysis. The results showed that a total of 935 metabolites were identified from all samples, including amino acids and derivatives, phenolic acids, nucleotides and derivatives, flavonoids, lignans and coumarins, tannins, alkaloids, terpenoids, organic acids, lipids, saccharides and sugar alcohols, vitamins, and other compounds. Totally 348 and 337 significantly changed metabolites (SCMs) from the flowers and leaves were identified between single- and double-petal jasmine, respectively. The major SCMs were phenolic acids, flavonoids, lipids, saccharides and sugar alcohols. The leaves of double-petal jasmine were rich in flavonoids. In addition, the flavone and flavonol biosynthesis pathways were more active, leading to accumulation of more compounds with biological and pharmacological activities such as nicotiflorin, cynaroside, quercetin, quercetin-3-O-glucoside, astragalin, and afzelin. Lipids were the major unique metabolites in the flowers and leaves of single-petal jasmine. The unique metabolites in the flowers and leaves of double-petal jasmine were more diverse and abundant than those in single-petal jasmine. The results of this study are very meaningful for guiding the development of jasmine resources.

In order to study dynamic changes and variations in aroma between single- and double- petal jasmine flowers (Jasminum sambac) during the opening process, headspace solid-phase microextraction (HS-SPME) coupled to gas chromatography-mass spectrometry (GC-MS) was used for qualitative and quantitative analysis of jasmine aroma components at different opening periods. The results showed that phenylacetaldehyde, methyl anthranilate, methyl benzoate, α-farnesene, benzyl acetate were the major aroma components of jasmine flower. The contents of aroma components such as β-ethyl phenylacetate, methyl anthranilate, α-stigmasterol and α-farnesene in single-pedal jasmine flowers initially increased and subsequently decreased during the opening process, and so did the contents of aroma components such as benzyl acetate, cis-3-hexenyl benzoate and benzyl benzoate in double-petal jasmine flowers, being higher at the end than in the beginning of the opening period. In addition, benzaldehyde, phenylacetaldehyde, and β-ethyl phenylacetate were the key substances responsible for the fresh and clean aroma of single-pedal jasmine flowers, while hexyl benzoate, cis-3-hexenyl benzoate, and α-farnesene were the key substances contributing to the strong floral aroma of double-petal jasmine flowers. This study provides a basis for the application of single-pedal jasmine flowers in jasmine tea production.