Universidade Comunitária Regional de Chapecó (UNOCHAPECO), Av. Sen. Attílio Fontana, 591-E, 89809-000 - Cx Postal: 747 - Chapecó - SC, Brazil.
J Photochem Photobiol B. 2010 Apr 2;99(1):15-20. doi: 10.1016/j.jphotobiol.2010.01.009. Epub 2010 Jan 25.
This study investigated the effect of photodynamic antimicrobial chemotherapy (PACT) using extracts from Alternanthera maritima on the viability of Candida dubliniensis. Human infections constitute a great health problem. Several antifungal drugs are currently available, but their uses are limited by a number of factors, such as low potency, poor solubility, microbial resistance, and drug toxicity. Therefore, the search for new and more effective antimicrobial agents and the development of alternative therapies, such as PACT, are necessary. Crude hexane and ethanol extracts of A. maritima were produced. The prepared extracts presented absorption at 650-700 nm. For bioassays, 50 microL of culture medium, 50 microL of extract (25 mg/mL) or control, and 5 microL of a suspension of the microorganism to be tested (C. dubliniensis ATCC 778157 or ATCC 777, 10(7)CFU/mL) were placed in a sterile 96-well microtiter plate (well cross section=0.38 cm(2)). The contents of each well were irradiated with a 685-nm diode laser with an output power of 35 mW, which was distributed through the well cross section yielding an energy dosage of 28 J/cm(2). In each assay (n=6), one plate was subjected to irradiation, and one was not. For each active sample, the number of colony-forming units per milliliter (CFU/mL) was obtained, and data were analyzed by the Tukey test. The chemical compositions of the extracts were determined by chromatographic and spectroscopic techniques. The results suggest inhibition of the growth of C. dubliniensis when irradiated with a diode laser in the presence of hexane and ethanol extracts from A. maritima as photosensitizers. Laser irradiation alone or crude extracts at 25mg/mL did not significantly reduce the number of CFU/mL. Steroids, triterpenes, and flavonoids were identified in the analyzed extracts. In conclusion, the photoactivation of crude hexane and ethanol extracts of A. maritima by red laser radiation at 685 nm promoted an antimicrobial effect, showing that these natural products can be used as photosensitizers in PACT.
本研究探讨了使用 Alternanthera maritima 提取物进行光动力抗菌化疗（PACT）对 Candida dubliniensis 活力的影响。人类感染构成了一个巨大的健康问题。目前有几种抗真菌药物，但由于效力低、溶解度差、微生物耐药性和药物毒性等多种因素，其应用受到限制。因此，有必要寻找新的、更有效的抗菌剂，并开发替代疗法，如 PACT。制备了 Alternanthera maritima 的粗己烷和乙醇提取物。制备的提取物在 650-700nm 处有吸收。对于生物测定，将 50μL 培养基、50μL（25mg/mL）提取物或对照物以及 5μL 待测试微生物（C. dubliniensis ATCC 778157 或 ATCC 777，10（7）CFU/mL）的悬浮液置于无菌 96 孔微量滴定板（孔横截面积=0.38cm（2））中。用输出功率为 35mW 的 685nm 二极管激光照射每个孔的内容物，该激光通过孔横截面积分布，产生 28J/cm（2）的能量剂量。在每个测定（n=6）中，一个平板进行照射，一个不进行照射。对于每个活性样品，获得每毫升（CFU/mL）的菌落形成单位数，并通过 Tukey 检验分析数据。通过色谱和光谱技术确定提取物的化学成分。结果表明，当以 Alternanthera maritima 的己烷和乙醇提取物作为光敏剂并用二极管激光照射时，抑制了 C.dubliniensis 的生长。单独激光照射或粗提取物在 25mg/mL 时，CFU/mL 的数量没有明显减少。在分析的提取物中鉴定出了甾体、三萜和类黄酮。结论：685nm 红光激光辐射对 Alternanthera maritima 粗己烷和乙醇提取物的光激活作用促进了抗菌作用，表明这些天然产物可用作 PACT 的光敏剂。
