Extraction, isolation and identification of four phenolic compounds from Pleioblastus amarus shoots and their antioxidant and anti-inflammatory properties in vitro

Pleioblastus amarus (P. amarus) shoots, belong to the grass family Gramineae, a traditional green vegetable in China, are rich in nutritional properties, and can provide various health benefits. This study isolated four compounds, namely (1-4), 3-O-coumaroylquinic acid (1), 3-O-feruloylquinic acid (2), 4-O-feruloylquinic acid (3), and 5-O-feruloylquinic acid (4) from Pleioblastus amarus shoots for the first time. The structures of the extracted compounds were determined using detailed spectroscopic (1D/2D NMR), high resolution electrospray ionization mass spectrometry (HR-ESI-MS), and infrared (IR) spectroscopy. The antioxidant capacity of 3-O-feruloylquinic acid (2) was stronger than that of the other compounds, while it also exhibited anti-inflammatory activity, significantly restricting the release of nitric oxide (NO) by lipopolysaccharide (LPS)-induced RAW 264.7 cells, displaying an inhibitory rate of 60.92 percent at a concentration of 400 μg/mL. Furthermore, 3-O-feruloylquinic acid (2) inhibited interleukin-1β (IL-1β), interleukin-6 (IL-6), inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), and nuclear factor-κB (NF-κB) expression and may be useful for developing novel antioxidant and anti-inflammatory substances.