Biomedicine, Courses, Universidade do Vale do Itajaí, Itajaí, Santa Catarina, Brazil.
Nutrition, Courses, Universidade do Vale do Itajaí, Itajaí, Santa Catarina, Brazil; Postgraduate Program in Pharmaceutical Science, Universidade do Vale do Itajaí, Itajaí, Santa Catarina, Brazil.
J Ethnopharmacol. 2019 Nov 15;244:112133. doi: 10.1016/j.jep.2019.112133. Epub 2019 Aug 1.
The leaves of Eugenia species are widely used in popular medicine to treat several diseases, such as arthritis, rheumatism and diabetes. Eugenia umbelliflora O. Berg is popularly known in Brazil as "baguaçu", name also conferred to Eugenia jambolana probably due to their apparent similarity. Although the popular use scientifically proved of E. jambolana as anti-diabetes and also as anti-inflammatory, there are only two scientific studies demonstrating anti-ulcer and bactericide activities of E. umbelliflora leaves extract, without reference to its possible anti-inflammatory activity.
The aim of this study was to show the anti-oxidant and anti-inflammatory activity of the methanol extract obtained from E. umbelliflora leaves (EuL) using in vitro and in vivo protocols.
The total phenolic content was evaluated using the folin-Ciocalteu colorimetric method and phloroglucinols content by HPLC. The anti-oxidant activity was evaluated by ORAC, ABTS, DPPH, and metal chelation methods. The anti-inflammatory activity was investigated using carrageenan-induced inflammation in the subcutaneous tissue of male Swiss mice orally pre-treated with the EuL (0.3, 1 or 3 mg/kg). The leukocyte influx (optical microscopy) and secretion of chemical mediators (TNF, IL-6, IL-1β and CXCL1, by enzyme-linked immunosorbent assay) were quantified in the inflamed exudate. Histological analysis of the pouches was also performed. The anti-hypersensitive activity was investigated using carrageenan-induced mechanical hypersensitivity and mice were then evaluated using the von Frey filaments. The Open Field test was used to evaluate possible interference of adverse effect of EuL on locomotor activity that could lead to misinterpretation of the hypersensitivity evaluation.
The EuL demonstrated important and moderate reducing capacity on ABTS and DPPH assays, respectively, but with slight activity in ORAC test. It reflects low protection against cell damage. The EuL also presented 30% of phenolic compounds. The phloroglucinols content of EuL was 25.9 mg/g, 18.4 mg/g and 16.6 mg/g of eugenial C, eugenial D and eugenial E, respectively. The in vivo analysis of the inflammatory exudate of EuL-treated mice demonstrated reduction in the polymorphonuclear cells (PMN) migration to the inflamed tissue, as well as the reduction of the pro-inflammatory cytokine IL-1β. Histologically, it was observed evident decrease in the oedema, formed essentially by non-haemorrhagic fibrin exudate, as well as PMN infiltrate, when compared with control mice injected with carrageenan. Furthermore, the extract also presented effective reduction of the mechanical hypersensitivity induced by carrageenan without any interference in animal's locomotor and exploratory activity.
Together, the results herein obtained show that EuL presented anti-inflammatory activity by decreasing the influx of PMN to the inflamed tissue, as well as the cytokine IL-1β level. This anti-inflammatory activity was also accompanied by significant anti-hypersensitive effect. The effects presented by EuL seem not to be correlated with an antioxidant activity. However other extract chemical compounds could be responsible for its important anti-inflammatory effects.
Eugenia 属植物的叶子在民间医学中被广泛用于治疗关节炎、风湿病和糖尿病等多种疾病。巴西的 Eugenia umbelliflora O. Berg 俗称“baguaçu”，可能由于其明显的相似性，Eugenia jambolana 也被称为“baguaçu”。虽然科学已经证明 E. jambolana 具有抗糖尿病和抗炎作用，但仅有两项科学研究表明 Eugenia umbelliflora 叶提取物具有抗溃疡和杀菌活性，而没有提到其可能的抗炎活性。
本研究旨在通过体外和体内实验证明 Eugenia umbelliflora 叶（EuL）甲醇提取物的抗氧化和抗炎活性。
采用福林-考尔法测定总酚含量，HPLC 法测定间苯三酚含量。采用 ORAC、ABTS、DPPH 和金属螯合方法评价抗氧化活性。用角叉菜胶诱导雄性瑞士小鼠皮下组织炎症，用 EuL（0.3、1 或 3mg/kg）进行口服预处理，研究其抗炎活性。用光学显微镜观察白细胞浸润，用酶联免疫吸附试验检测化学介质（TNF、IL-6、IL-1β和 CXCL1）的分泌。对囊袋进行组织学分析。用角叉菜胶诱导机械性超敏反应研究 EuL 的抗超敏活性，然后用 von Frey 纤维丝对小鼠进行评估。旷场试验用于评估 EuL 对运动活动的潜在不良反应干扰，这可能导致对超敏反应评估的误解。
EuL 在 ABTS 和 DPPH 测定中表现出重要且适度的还原能力，而在 ORAC 测定中活性较弱。这反映了对细胞损伤的低保护作用。EuL 还含有 30%的酚类化合物。EuL 中 phloroglucinols 的含量分别为 eugenial C、eugenial D 和 eugenial E 的 25.9mg/g、18.4mg/g 和 16.6mg/g。EuL 处理的小鼠炎性渗出物的体内分析表明，PMN 向炎症组织的迁移减少，以及促炎细胞因子 IL-1β的减少。组织学观察表明，与注射角叉菜胶的对照小鼠相比，水肿明显减少，水肿主要由非出血性纤维蛋白渗出物和 PMN 浸润形成。此外，该提取物还能有效减轻由角叉菜胶诱导的机械性超敏反应，而不影响动物的运动和探索活动。
综上所述，本研究结果表明，EuL 通过减少PMN 向炎症组织的浸润以及细胞因子 IL-1β的水平表现出抗炎活性。这种抗炎活性还伴随着显著的抗超敏作用。EuL 产生的作用似乎与抗氧化活性无关。然而，其他提取物的化学物质可能是其具有重要抗炎作用的原因。
