Department of Environmental Biology, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185, Rome, Italy.
Department of Public Health and Infectious Diseases, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185, Rome, Italy.
Plant Cell Rep. 2018 Nov;37(11):1471-1484. doi: 10.1007/s00299-018-2317-2. Epub 2018 Jun 28.
Water-soluble chitosan oligosaccharides (COS) affect xanthone and volatile organic compound content, as well as antifungal activity against human pathogenic fungi of extracts obtained from Hypericum perforatum root cultures. Several studies have demonstrated the elicitor power of chitosan on xanthone biosynthesis in root cultures of H. perforatum. One of the major limitations to the use of chitosan, both for basic and applied research, is the need to use acidified water for solubilization. To overcome this problem, the elicitor effect of water-soluble COS on the biosynthesis of both xanthones and volatile organic compounds (VOCs) was evaluated in the present study. The analysis of xanthones and VOCs was performed by HPLC and GC-MS headspace analysis. The obtained results showed that COS are very effective in enhancing xanthone biosynthesis. With 400 mg L COS, a xanthone content of about 30 mg g DW was obtained. The antifungal activity of extracts obtained with 400 mg L COS was the highest, with MIC of 32 µg mL against Candida albicans and 32-64 µg mL against dermatophytes, depending on the microorganism. Histochemical investigations suggested the accumulation of isoprenoids in the secretory ducts of H. perforatum roots. The presence of monoterpenes and sesquiterpenes was confirmed by the headspace analysis. Other volatile hydrocarbons have been identified. The biosynthesis of most VOCs showed significant changes in response to COS, suggesting their involvement in plant-fungus interactions.
水溶性壳寡糖（COS）影响贯叶连翘根培养物提取物中的酮和挥发性有机化合物含量以及对人体致病真菌的抗真菌活性。多项研究表明壳聚糖对贯叶连翘根培养物中酮生物合成具有激发作用。在基础和应用研究中，壳聚糖的主要局限性之一是需要使用酸化水进行溶解。为了克服这个问题，本研究评估了水溶性 COS 对酮和挥发性有机化合物（VOCs）生物合成的激发作用。通过 HPLC 和 GC-MS 顶空分析对酮和 VOCs 进行分析。所得结果表明，COS 非常有效地增强了酮的生物合成。使用 400 mg/L COS 可获得约 30 mg/g DW 的酮含量。用 400 mg/L COS 获得的提取物具有最高的抗真菌活性，对白色念珠菌的 MIC 为 32 µg/mL，对皮肤真菌的 MIC 为 32-64 µg/mL，具体取决于微生物。组织化学研究表明贯叶连翘根的分泌道中积累了异戊二烯。顶空分析证实了单萜和倍半萜的存在。还鉴定了其他挥发性碳氢化合物。COS 显著改变了大多数 VOC 的生物合成，表明它们参与了植物-真菌相互作用。
