Radix Tetrastigma extract from different origins protect RAW264.7 macrophages against LPS-induced inflammation

Radix Tetrastigma (RT) is a medicinal plant and functional food in China, distributed in various places in the south of China. Radix Tetrastigma extract (RTE) from different origins were collected and analyzed for their anti-inflammatory effects. Different RTEs showed different abilities to suppress shape deformation, decrease the nitric oxide (NO) production, inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) expression in RAW 264.7 cells. Subsequently, their bioactive components were compared, and results showed RTEs are rich in flavonoid (85.25-436.70 mg RE/g DW), polysaccharides (100.45-349.26 mg glucose/g DW), phenolic (12.92-225.40 mg GAE/g DW) and protein contents (4.429-7.719 mg/g DW). Principal component analysis (PCA) and correlation studies indicated that anti-inflammatory capacity could be more associated with total flavonoid contents. High-performance liquid chromatography (HPLC) and Ultraperformance liquid chromatography-time-of flight mass spectrometry (UPLC-TOF/MS) analysis were conducted, and results showed that rutin, isoquercitrin, kaempferol-3-O-rutinoside and astragalin were main flavonoid compounds, among them astragalin exhibited a prior protective effect, suggesting it might be responsible for RTE's excellent anti-inflammatory capacity.