Anti-inflammatory, analgesic, and immunostimulatory effects of Luehea divaricata Mart. & Zucc. (Malvaceae) bark

Luehea divaricata (Malvaceae) is a plant widely used for treatment of various inflammatory and infectious conditions; however few reports discuss its biological properties. The aim of this study was to evaluate the anti-inflammatory and analgesic effects as well as the macrophage activity in mice treated with the hydroalcoholic crude extract of L. divaricata(CLD). Thin layer chromatography revealed presence of epicathequin, stigmasterol, lupeol and α,β-amyrin in the extract. To evaluate the anti-inflammatory and analgesic activities, animals were subjected to paw edema induced by carrageenan test, writhing, formalin and capsaicin tests. Immunomodulatory activity was evaluated by adhesion and phagocytic capacity, lysosomal volume, and reactive oxygen species (ROS) production by peritoneal macrophages, after daily treatment with CLD for 15 days. CLD promoted reduction in paw edema (36.8% and 50.2%; p<0.05 at doses of 100 and 300 mg/kg, respectively), inhibited writhing behavior at the higher dose (64.4%, p<0.05), reduced formalin reactivity (81.2% and 91.6% at doses of 100 and 300 mg/kg, respectively, p<0.05), and reduced capsaicin reactivity by 63.9% (300 mg/kg). CLD (200 mg• kg-1• day-1) increased phagocytosis capacity of macrophages (~3 fold, p<0.05), neutral red uptake (~50%, p<0.001), and ROS production (~90%, p<0.001). These data suggest that CLD possesses anti-inflammatory, analgesic and immunostimulatory properties.

叉枝椴（Luehea divaricata，锦葵科（Malvaceae））是一种被广泛用于治疗各类炎症与感染性疾病的植物，但目前相关研究对其生物学活性的报道仍较为匮乏。本研究旨在考察叉枝椴水醇粗提物（hydroalcoholic crude extract of L. divaricata，简称CLD）对小鼠的抗炎、镇痛作用及巨噬细胞活性的影响。薄层色谱分析结果显示，该粗提物中含有表儿茶醌（epicathequin）、豆甾醇（stigmasterol）、羽扇豆醇（lupeol）以及α,β-香树脂醇（α,β-amyrin）。为评估其抗炎与镇痛活性，本研究通过角叉菜胶致足肿胀实验、扭体实验、福尔马林实验及辣椒素实验对受试小鼠进行检测。在每日予以CLD给药15天后，本研究通过检测腹膜巨噬细胞的黏附与吞噬能力、溶酶体体积以及活性氧（reactive oxygen species，ROS）生成水平，对其免疫调节活性进行评估。实验结果表明，CLD可显著减轻小鼠足肿胀程度（100mg/kg与300mg/kg剂量组分别降低36.8%与50.2%，p<0.05）；高剂量CLD可显著抑制小鼠扭体行为（抑制率64.4%，p<0.05）；100mg/kg与300mg/kg剂量组均可显著降低福尔马林诱导的疼痛反应（分别降低81.2%与91.6%，p<0.05）；300mg/kg剂量组可使辣椒素诱导的疼痛反应降低63.9%。在200mg·kg⁻¹·d⁻¹的给药剂量下，CLD可显著提升巨噬细胞的吞噬能力（提升约3倍，p<0.05）、中性红摄取量（提升约50%，p<0.001）以及ROS生成水平（提升约90%，p<0.001）。上述实验结果表明，CLD具备抗炎、镇痛及免疫增强活性。