The purpose of this study was to elucidate the chemical basis for the sweet property produced by Gynostemma pentaphyllum and find new natural high-potency (HP) sweeteners. Sixteen new compounds (gypenosides YN 1-16) were obtained by sensory-guided isolation and identification, in which fifteen of them were sweet-tasting constituents with sweetness intensities 10-100 times higher than that of sucrose evaluated by human sensory panel test. Their structures were established by 1D and 2D nuclear magnetic resonance spectra, mass spectroscopy, infrared spectroscopy, UV-visible spectroscopy, and chemical method. Gypenoside YN 4 was the sweetest compound with a concentration of 15.504 ± 1.343 mg/kg, while gypenoside YN 12 has the highest concentration (1397.674 ± 12.948 mg/kg), as shown by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). Structure-activity relationship analysis implied that the compounds' sweetness intensity was associated with side-chain substitutions at C-20 or the number of glucosyl groups at C-3. These new plant-derived natural products may be potential natural sweeteners.
Keywords: Gynostemma pentaphyllum; Gypenosides; Natural sweetener; Sensory evaluation; Sweetness intensity.
Copyright © 2022 Elsevier Ltd. All rights reserved.