A new polyacetylene glycoside, (5R)-6E-tetradecene-8,10,12-triyne-1-ol-5-O-β-glucoside (1), was isolated from the flower of Coreopsis lanceolata (Compositae), together with two known compounds, bidenoside C (10) and (3S,4S)-5E-trideca-1,5-dien-7,9,11-triyne-3,4-diol-4-O-β-glucopyranoside (11), which were found in Coreopsis species for the first time. The other known compounds, lanceoletin (2), 3,2′-dihydroxy-4-3′-dimethoxychalcone-4′-glucoside (3), 4-methoxylanceoletin (4), lanceolin (5), leptosidin (6), (2R)-8-methoxybutin (7), luteolin (8) and quercetin (9), were isolated in this study and reported previously from this plant. The structure of 1 was elucidated by analyzing one and two dimensional nuclear one-dimensional and two-dimensional nuclear magnetic resonance and high resolution-electrospray ionization-mass spectrometry data. All compounds were tested for their dipeptidyl peptidase IV (DPP-IV) inhibitory activity and compounds 2-4, 6 and 7 inhibited DPP-IV activity in a concentration-dependent manner, with IC50 values from 9.6 to 64.9 μM. These results suggest that C. lanceolata flower and its active constituents show potential as therapeutic agents for diseases associated with type 2 diabetes mellitus.

Coreopsis species have been developed to produce cultivars of various floral colors and sizes and are also used in traditional medicine. To identify and evaluate mutant cultivars of C. rosea and C. verticillata, their phytochemical profiles were systematically characterized using ultra-performance liquid chromatography time-of-flight mass spectrometry, and their anti-diabetic effects were evaluated using the dipeptidyl peptidase (DPP)-IV inhibitor screening assay. Forty compounds were tentatively identified. This study is the first to provide comprehensive chemical information on the anti-diabetic effect of C. rosea and C. verticillata. All 32 methanol extracts of Coreopsis cultivars inhibited DPP-IV activity in a concentration-dependent manner (IC50 values: 34.01–158.83 μg/mL). Thirteen compounds presented as potential markers for distinction among the 32 Coreopsis cultivars via principal component analysis and orthogonal partial least squares discriminant analysis. Therefore, these bio-chemometric models can be useful in distinguishing cultivars as potential dietary supplements for functional plants.

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Pueraria lobata (Willd.) Ohwi. is a widely used medicinal plant in Korea, China, and Japan. The flower of P. lobata (Puerariae Flos) contains various bioactive substances such as triterpenoidal saponins and isoflavonoids. In this study, we developed a quantitative analysis of the isoflavones of Puerariae Flos by quantitative proton nuclear magnetic resonance (qHNMR) spectroscopy using the internal calibrant (IC). From the qHNMR results, the isoflavone content was found to be 7.99% and 10.57% for the MeOH sonication extract (PLs) and the MeOH reflux extract (PLr) of Puerariae Flos, respectively. The quantified isoflavone content was validated using the conventional analytical method, high-performance liquid chromatography with ultraviolet detection (HPLC-UV). The present study shows that validated qHNMR spectroscopy is a reliable method for quantifying and standardizing the isoflavone content in Puerariae Flos.

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