Foliar phenolic compounds of ten wild species of Verbenacea as antioxidants and specific chemomarkers

Abstract The family Verbenaceae hosts important species used in traditional medicine of many countries. The taxonomic controversies concerning the specific delimitation of several of its species make it difficult to guarantee the botanical origin of herbal preparations based on species of this family. To contribute to the development of both specific chemomarkers and a quality control tool to authenticate the botanical origin of herbal preparations of Verbenacea species, we determined the foliar HPLC-DAD phenolic profiles and the antioxidant properties of 10 wild species of this family occurring in Mexico. The contents of phenols and flavonoids varied significantly among species. Priva mexicana showed the highest levels of total phenolics (53.4 mg g-1 dry tissue) and Verbena carolina had the highest levels of flavonoids (17.89 mg g-1 dry tissue). Relevant antioxidant properties revealed by antiradical and reducing power were found for the analyzed species. These properties varied significantly in a species-dependent manner. The phenolic compounds accumulated were flavones and phenolic acids. Flavones were the only type of flavonoids found. The results of a cluster analysis showed that the compounds were accumulated in species-specific profiles. The phenolic profiles are proposed as valuable chemomarkers that can become a useful tool for the quality control concerning the botanical origin of herbal medicinal preparations based on the species analyzed. In addition, phenolic profiles could contribute importantly to solve the taxonomic controversies concerning species delimitation in the family Verbenaceae.

摘要：马鞭草科（Verbenaceae）包含众多在多国传统医药中应用的重要物种。针对该科多个物种的物种界定问题存在分类学争议，这使得基于该科物种的草药制剂难以确保其植物学来源的真实性。为助力专属化学标记物开发及质量控制工具研发，以实现马鞭草科物种基草药制剂植物学来源的鉴定，本研究针对墨西哥境内分布的10种野生马鞭草科物种，测定了其叶片的高效液相色谱-二极管阵列检测器（High Performance Liquid Chromatography-Diode Array Detector，HPLC-DAD）酚类物质谱图与抗氧化活性。不同物种间的酚类与黄酮类物质含量存在显著差异：墨西哥假马鞭（Priva mexicana）的总酚含量最高（53.4 mg·g⁻¹干重组织），而卡罗来纳马鞭草（Verbena carolina）的黄酮类物质含量最高（17.89 mg·g⁻¹干重组织）。供试物种均表现出通过抗自由基活性与还原力检测得到的显著抗氧化活性，且该活性呈现显著的物种依赖性差异。供试物种体内积累的酚类化合物包括黄酮类与酚酸类，且本次检测到的黄酮类物质仅为黄酮（flavones）。聚类分析结果显示，酚类物质的积累模式呈现物种特异性。本研究提出，该酚类物质谱图可作为极具应用价值的化学标记物，成为管控基于供试物种开发的草药制剂植物学来源质量的有效工具。此外，酚类物质谱图可有效助力解决马鞭草科（Verbenaceae）内物种界定相关的分类学争议。