Marangoni Antonella, Foschi Claudio, Micucci Matteo, Nahui Palomino Rogers Alberto, Gallina Toschi Tullia, Vitali Beatrice, Camarda Luca, Mandrioli Mara, De Giorgio Marta, Aldini Rita, Corazza Ivan, Chiarini Alberto, Cevenini Roberto, Budriesi Roberta
Department of Specialized, Experimental, and Diagnostic Medicine (DIMES), Operative Unit of Clinical Microbiology, St. Orsola-Malpighi University Hospital, Alma Mater Studiorum-University of Bologna, Bologna, Italy.
Department of Pharmacy and Biotechnology (FaBit), Alma Mater Studiorum-University of Bologna, Bologna, Italy.
PLoS One. 2017 Nov 30;12(11):e0188567. doi: 10.1371/journal.pone.0188567. eCollection 2017.
The high incidence of vulvo-vaginal candidiasis, combined with the growing problems about azole resistance and toxicity of antifungal drugs, highlights the need for the development of new effective strategies for the treatment of this condition. In this context, natural compounds represent promising alternatives. The cyanobacterium Spirulina platensis, a blue-green alga, exhibits antimicrobial activities against several microorganisms. Nevertheless, only few data about the antifungal properties of Spirulina platensis are available and its potential toxic effects have not been largely investigated. The aim of this study was to evaluate the in vitro activity of a fully-characterized water extract of Spirulina platensis against 22 strains of Candida spp. Prior to considering its potential topical use, we both investigated whether the extract exerted target activities on guinea pig uterine smooth muscle, and the impact of Spirulina platensis on the dominant microorganisms of the vaginal microbiota (i.e., lactobacilli), in order to exclude possible adverse events. By means of a broth microdilution assay, we found that the microalga extract possesses good antifungal properties (MIC: 0.125-0.5 mg/ml), against all the Candida species with a fungicidal activity. At the concentrations active against candida, Spirulina platensis did not modify the spontaneous basic waves pattern of uterine myometrium as underlined by the absence of aberrant contractions, and did not affect the main health-promoting bacteria of the vaginal ecosystem. Finally, we evaluated the selectivity index of our extract by testing its cytotoxicity on three different cell lines and it showed values ranging between 2 and 16. Further in vivo studies are needed, in particular to evaluate the use of control-release formulations in order to maintain Spirulina platensis concentrations at anti-Candida active doses but below the toxic levels found in the present work.
外阴阴道念珠菌病的高发病率，再加上抗真菌药物的唑类耐药性和毒性问题日益严重，凸显了开发治疗这种疾病新有效策略的必要性。在这种背景下，天然化合物是很有前景的替代物。蓝藻钝顶螺旋藻，一种蓝绿色藻类，对多种微生物具有抗菌活性。然而，关于钝顶螺旋藻抗真菌特性的数据很少，其潜在的毒性作用也尚未得到充分研究。本研究的目的是评估钝顶螺旋藻一种经过充分表征的水提取物对22株念珠菌属菌株的体外活性。在考虑其潜在的局部应用之前，我们既研究了该提取物对豚鼠子宫平滑肌是否具有靶向活性，也研究了钝顶螺旋藻对阴道微生物群的优势微生物（即乳酸杆菌）的影响，以排除可能的不良事件。通过肉汤微量稀释试验，我们发现微藻提取物具有良好的抗真菌特性（MIC：0.125 - 0.5毫克/毫升），对所有念珠菌属物种都具有杀菌活性。在对念珠菌有活性的浓度下，钝顶螺旋藻并未改变子宫肌层的自发基础波模式，这一点由无异常收缩得以证实，并且也未影响阴道生态系统中主要的有益健康细菌。最后，我们通过测试提取物对三种不同细胞系的细胞毒性来评估其选择性指数，结果显示其值在2到16之间。还需要进一步的体内研究，特别是评估控释制剂的使用，以便将钝顶螺旋藻的浓度维持在抗念珠菌活性剂量，但低于本研究中发现的毒性水平。
