Objective To study the non-saponin chemical constituents of the flower buds of Panax notoginseng and evaluate their antioxidant and anti-inflammatory activities. Methods The extraction was performed by refluxing with 65% aqueous ethanol, followed by successive liquid-liquid extraction with petroleum ether, ethyl acetate (EtOAc) and n-butanol. The compounds were isolated and purified using RP-18, silica gel, MCI gel CHP20P, Sephadex LH-20 column chromatography and semi-preparative liquid chromatography. Structural identification was carried out by comprehensive analysis of nuclear magnetic resonance (NMR) spectroscopy, high-resolution mass spectrometry (HR-MS), ultraviolet (UV) spectroscopy, and computational electronic circular dichroism (ECD) spectroscopy. Some purified compounds were evaluated for preliminary antioxidant activity and anti-inflammatory activity. Results A total of seven non-saponin components were isolated from the EtOAc fraction of P. notoginseng flower buds, including one isocoumarin (1), four simple phenols (2—5), and two loliolides (6, 7), were obtained from the EtOAc fraction. These were identified as isocoumarin F1 (1), ferulic acid (2), evofolin A (3), p-hydroxybenzoic acid (4), 4-hydroxybenzaldehyde (5), (＋)-epiloliolide (6), and (-)-loliolide (7), respectively. Conclusion All compounds (1—7) were isolated from P. notoginseng for the first time. Of which, compound 1 is a new isocoumarin and named isocoumarin F1, while compound 2 exhibited obvious DPPH radical scavenging ability.

flower buds of Panax notoginseng  /  isocoumarin  /  phenolics  /  antioxidant activity  /  anti-inflammatory  /  isocoumarin F1  /  ferulic acid  /  4-hydroxybenzaldehyde  /  (-)-loliolide