New Insights into the Culture Method and Antibacterial Potential of Gracilaria gracilis
New Insights into the Culture Method and Antibacterial Potential of Gracilaria gracilis
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DOI：
10.3390/md16120492
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发表时间：
2018-12-01
期刊：
影响因子：
5.4
通讯作者：
Faggio, Caterina
中科院分区：
文献类型：
--
作者：
Capillo, Gioele;Savoca, Serena;Faggio, Caterina
巨大的海洋生物多样性为许多应用提供了无穷无尽的化学储备。在这种情况下，海藻的提取代表了具有抗菌活性的化合物的有趣来源。特别是在不同的红藻中，由于其成分中存在重要的生物活性物质，所以虎尾草起着重要的作用。尽管有这些特点，一个有效的文化体系仍然缺乏。在本研究中，开发了一种新的藻类培养方法，并将其与文献中广泛报道的另一种更常见的培养方法进行了比较。评估了新方法在日生长率和生物量方面的更高效率。此外，以乙醇、甲醇、丙酮、氯仿或乙醚为溶剂，从培养的凤尾草中提取五种提取物，测试其对革兰氏阳性和革兰氏阴性病原体的生长抑制活性。藻提取物对枯草芽孢杆菌有较强的抑制作用，而对费氏弧菌有轻微的抑制作用。不同提取物对细菌生长的抑制作用有显著差异，其中乙醇提取物的抑制作用最高，其次是甲醇提取物。根据化学表征，这些发现可能与总碳水化合物和多酚的组合所发挥的抗菌活性有关，乙醇和甲醇提取物中总碳水化合物和多酚的含量较高，而单一多酚的数量和含量最高。相反，在氯仿和乙醚提取物中发现的较低的生长抑制活性可能与由脂肪酸组成的次要脂类（例如中性和中极性脂类）的分离有关，例如硬脂酸、油酸和花生四烯酸，这些脂肪酸通常具有抗菌活性。考虑到所获得的结果，本研究具有双重含义，既涉及文化实践领域，又涉及开发天然来源，以分离在制药和食品应用中有用的抗菌剂。
Enormous marine biodiversity offers an endless reservoir of chemicals for many applications. In this scenario, the extraction of seaweeds represents an interesting source of compounds displaying antimicrobial activity. In particular, among the different red algae, Gracilaria gracilis plays an important role due to the presence of important bioactives in its composition. In spite of these features, an efficient culture system is still absent. In the present study, a novel algal culture method was developed and compared to another more common cultural practice, widely reported in literature. A higher efficiency of the new method, both for daily growth rate and biomass, was assessed. Furthermore, the growth inhibitory activity of five extracts, obtained using ethanol, methanol, acetone, chloroform or diethyl ether as a solvent, from the cultured G. gracilis was tested against Gram-positive and Gram-negative pathogens. Algal extracts exhibited a considerable inhibitory activity against B. subtilis strains, while a slight inhibition was observed against V. fischeri. The different extracts showed significant differences in bacterial growth inhibition, with the highest activity that was recorded for the ethanol extract, followed by that of methanol. Based on the chemical characterization, these findings could be related to the antimicrobial activity played by the combination of total carbohydrates and polyphenols, which were determined at high levels in ethanol and methanol extracts, as well as by the highest number and levels of single polyphenols. Conversely, the lower growth inhibitory activities found in chloroform and diethyl ether extracts could be related to the isolation of minor lipid classes (e.g., neutral and medium polar lipids) composed by fatty acids, such as stearic, oleic and arachidonic acids, typically characterized by antimicrobial activity. In consideration of the results obtained, the present study has a double implication, involving both the field of cultural practices and the exploitation of natural sources for the isolation of antimicrobial agents useful both in pharmaceutical and food applications.