Abstract

Tuberculosis (TB) remains a worldwide public health threat because of the emergence of resistant strains and subsequent inappropriate response to current therapy. We have been studying the restinga plants’ antimycobacterial and anti-inflammatory potential. Dichloromethane fraction (DCM) from Vitex polygama Cham. showed high activity against Mycobacterium tuberculosis (Mtb) H37Rv. In this context, DCM fraction and isolated compounds were investigated against Mtb H37Rv and M299 (MDR strain) and for their immunomodulatory and cytotoxicity actions. Orientin showed the best antimycobacterial effect against Mtb M299 MDR strain (MIC₅₀ 15.4 ± 1.6 µg/mL), capacity of inhibiting NO production by macrophages (IC₅₀ 6.5 ± 1.2 µg/mL) and no significant cytotoxicity. The antimycobacterial effect of orientin was also observed on Mtb H37Rv intracellular growth in RAW 264.7 macrophages (MIC₅₀ 3.5 ± 1.1 and MIC₉₀ 9.1 ± 1.0 µg/mL). This is the first report describing the antimycobacterial effect of orientin, in both extra- and intracellular growth.

摘要

由于耐药菌株的出现以及随后对当前治疗的不适当反应，结核病 (TB) 仍然是世界范围内的公共卫生威胁。我们一直在研究restinga植物的抗分枝杆菌和抗炎潜力。来自Vitex polygama Cham的二氯甲烷馏分 (DCM) 。对结核分枝杆菌(Mtb) H37Rv显示出高活性。在此背景下，针对 Mtb H37Rv 和 M299（MDR 菌株）研究了 DCM 级分和分离的化合物以及它们的免疫调节和细胞毒性作用。Orientin 对 Mtb M299 MDR 菌株表现出最好的抗分枝杆菌作用（MIC ₅₀ 15.4 ± 1.6 µg/mL），抑制巨噬细胞产生 NO 的能力（IC ₅₀6.5 ± 1.2 µg/mL）并且没有明显的细胞毒性。_{在 RAW 264.7 巨噬细胞（MIC 50} 3.5 ± 1.1 和 MIC ₉₀ 9.1 ± 1.0 µg/mL）中，还观察到荠菜素对 Mtb H37Rv 细胞内生长的抗分枝杆菌作用。这是第一份描述荭草素在细胞外和细胞内生长中的抗分枝杆菌作用的报告。