Anti-inflammatory effects and HPLC-PDA quantification of the triterpene saponin-enriched extract of Combretum trifoliatum leaves

For the first time, the in vitro anti-inflammatory activity against Nitric oxide (NO) overproduction via Lipopolysaccharide (LPS) injection on RAW264.7 cells as well as the quantitative determination of triterpene saponin-enriched extract from the Combretum trifoliatum leaves (SE-CTL) via High-Performance Liquid Chromatography (HPLC) using Photodiode Array Detector (PDA) technique was investigated. The SE-CTL significantly exhibited the best inhibition of NO (IC₅₀ value of 46.39 ± 3.02 µg/mL). Accordingly, qualitative and quantitative analyses of two main triterpene saponins (1 & 2), were clearly and extensively concentrated by the HPLC-PDA method. Two primary markers (1 & 2) displayed a good linearity (R² > 0.999) in a relatively wide concentration (ranged from 6.25 to 100 µg/mL). The LOD and LOQ of them were respectively in the range of 2.08-3.12 and 6.94-10.42 µg/mL. Their recoveries were evaluated in the range of 98.56-101.58%. The concentrations of markers in SE-CTL were 0.040 and 0.013% (w/w), respectively.