Coutinho Henrique D M, Vasconcellos Alexandre, Freire-Pessôa Hilzeth L, Gadelha Carlos A, Gadelha Tatiane S, Almeida-Filho Geraldo G
Laboratório de Pesquisa em Produtos Naturais, Departamento de Ciências Biológicas, Universidade Regional do Cariri, Crato (CE), 63105-000, Brazil.
Pharmacogn Mag. 2010 Jan;6(21):1-4. doi: 10.4103/0973-1296.59958. Epub 2010 Feb 13.
Bacterial infectious agents present a risk to populations, as they are responsible for high morbidity and mortality. For combating these pathogens, our main line of defense is the use of antibiotics. However, indiscriminate use of these drugs develops resistant strains to these same drugs. The present study has tested the antibacterial and modifying antibiotic activity of natural products from Nasutitermes corniger (Termitidae) (Motschulsky), a termite used in folk medicine in Northeast Brazil, by the microdilution and checkerboard methods, respectively. In this study, the aqueous extract from the nest of N. corniger (ANCE) was prepared and tested with chlorpromazine (CPZ) for its antimicrobial activity, using the microdilution method. CPZ and ANCE were used independently and also in combination with aminoglycosides, against a strain of Escherichia coli resistant to these antibiotics, to determine the participation of efflux systems in resistance mechanisms. The fractional inhibitory concentration (FIC) index was calculated and evaluated for the occurrence of synergism, using the checkerboard method. The minimum inhibitory concentrations (MIC) and minimum bactericidal concentrations (MBC) values were >/= 2048 mug/mL for both strains of E. coli assayed, indicating low antibacterial activity. However, synergism was observed with kanamycin when the decoction was used, but when chlorpromazine was used, synergism was observed with kanamycin, amikacin, and neomycin. This synergism with CPZ indicated the involvement of an efflux system in the resistance to these aminoglycosides. Therefore, it was suggested that the natural products from N. corniger could be used as a source of zoo-derived natural products with kanamycin-modifying activity, resulting in a new approach against bacterial resistance to antibiotics.
细菌感染源对人群构成风险，因为它们会导致高发病率和高死亡率。为了对抗这些病原体，我们的主要防线是使用抗生素。然而，这些药物的滥用会产生对相同药物的耐药菌株。本研究分别通过微量稀释法和棋盘法测试了来自巴西东北部民间医学中使用的一种白蚁——角鼻白蚁（鼻白蚁科）（莫氏）的天然产物的抗菌和修饰抗生素活性。在本研究中，制备了角鼻白蚁巢穴的水提取物（ANCE），并使用微量稀释法与氯丙嗪（CPZ）一起测试其抗菌活性。CPZ和ANCE单独使用，也与氨基糖苷类药物联合使用，以对抗一株对这些抗生素耐药的大肠杆菌菌株，以确定外排系统在耐药机制中的作用。使用棋盘法计算并评估分数抑制浓度（FIC）指数以确定协同作用的发生情况。对于所检测的两株大肠杆菌，最低抑菌浓度（MIC）和最低杀菌浓度（MBC）值均≥2048μg/mL，表明抗菌活性较低。然而，当使用煎剂时，与卡那霉素观察到协同作用，但当使用氯丙嗪时，与卡那霉素、阿米卡星和新霉素观察到协同作用。与CPZ的这种协同作用表明外排系统参与了对这些氨基糖苷类药物的耐药性。因此，有人提出，角鼻白蚁的天然产物可作为具有卡那霉素修饰活性的动物源天然产物的来源，从而产生一种对抗细菌抗生素耐药性的新方法。
