Antioxidant and Inflammatory Effects of Nelumbo nucifera Gaertn. Leaves

This study is aimed at identifying the bioactive components in lotus leaf flavonoid extract (LLFE) and analyzing the antioxidant and anti-inflammatory activities of LLFE in vitro and in vivo. The flavonoids in LLFE were determined by UHPLC-MS/MS. The effect of LLFE on damaged 293T cells (H₂O₂, 0.3 mmol/L) was determined by MTT assay, and the activity of antioxidant enzymes was measured by kits. We studied the antioxidant and anti-inflammatory effects of LLFE on D-Gal/LPS (30 mg/kg·bw and 3 μg/kg·bw)-induced aging mice. We also evaluated the main organ index, pathological changes in the liver, lung, and kidney, liver function index, biochemical index, cytokine level, and mRNA expression level in serum and liver. The results showed that LLFE contains baicalein, kaempferol, kaempferid, quercetin, isorhamnetin, hyperoside, lespenephryl, and rutin. LLFE reduced the oxidative damage sustained by 293T cells, increased the levels of SOD, CAT, GSH, and GSH-Px, and decreased the level of MDA. The animal studies revealed that LLFE reduced oxidative damage and inflammation in injured mice, inhibited increases in AST, ALT, MDA, and NO, increased SOD, CAT, GSH, and GSH-Px levels, upregulated anti-inflammatory cytokines IL-10 and IL-12, and downregulated proinflammatory cytokines IL-6, IL-1β, TNF-α, and IFN-γ. Furthermore, the expression of antioxidant- and anti-inflammatory-related mRNA was consistent with the above results.