Department of Pharmacognosy and Phytotherapy, Faculty of Pharmacy, "Grigore T. Popa" University of Medicine and Pharmacy Iasi, 700115, Iasi, Romania.
Department of Biochemistry and Pharmacogenomics, Faculty of Pharmacy, Medical University of Warsaw, 02-097, Warsaw, Poland; Centre for Preclinical Research, Medical University of Warsaw, 02-097, Warsaw, Poland.
J Ethnopharmacol. 2023 Mar 1;303:116010. doi: 10.1016/j.jep.2022.116010. Epub 2022 Dec 7.
Comfrey (Symphytum officinale L., Boraginaceae) root preparations are used as both traditional remedies and therapeutic agents in treating pain and inflammation associated with joint, bone, and muscle ailments. Even though numerous phytochemicals contribute to the beneficial effects of comfrey, the presence of toxic pyrrolizidine alkaloids (PAs) overshadows its uses.
In this work, different PA-/mucilage-depleted/undepleted comfrey root extracts were subjected to detailed phytochemical characterization and biological evaluation.
The phytochemical profiling was performed by LC-HRMS/MS. The quantification of PAs and major phenolic compounds was carried out by LC-MS/MS and LC-DAD. Antioxidant and enzyme inhibitory activity was determined by in vitro free radical scavenging, ion reducing, metal chelating, cholinesterase, tyrosinase, amylase, and glucosidase assays. Using an ex vivo model of LPS-stimulated neutrophils, their viability (as measured by flow cytometry) and the release of IL-1β, IL-8, and TNF-α were determined (ELISA assay).
12 phenolic acids, six PAs, three organic acids, two fatty acids, and two sugars were identified in the obtained comfrey extracts. The PA-depleted materials contained PAs levels below 2 ppm, whereas the removal of mucilage increased the content of rosmarinic acid, globoidnan A, globoidnan B, and rabdosiin. PA-depletion did not significantly affect the antioxidant potential. However, the radical scavenging and metal reducing properties were higher in the mucilage-depleted extracts. Neither PA-depletion nor mucilage-depletion had considerable effects on the in vitro inhibitory activity of cholinesterases, tyrosinase, amylase, and glucosidase or release of ex vivo pro-inflammatory cytokines (e.g., IL-1β, IL-8, and TNF-α) in LPS-stimulated neutrophils.
In light of their superior safety profiles, PA-depleted comfrey extracts can be utilized further in cosmetic and pharmaceutical products.
紫草（筋骨草属 officinale L.，紫草科）根制剂既被用作传统疗法，也被用作治疗关节、骨骼和肌肉疾病相关疼痛和炎症的治疗剂。尽管许多植物化学物质对紫草的有益作用有贡献，但有毒吡咯里西啶生物碱（PA）的存在使其用途黯然失色。
在这项工作中，不同的 PA-、黏液素-耗尽/未耗尽的紫草根提取物进行了详细的植物化学特征和生物学评价。
采用 LC-HRMS/MS 进行植物化学分析。采用 LC-MS/MS 和 LC-DAD 对 PA 和主要酚类化合物进行定量。通过体外自由基清除、离子还原、金属螯合、乙酰胆碱酯酶、酪氨酸酶、淀粉酶和葡萄糖苷酶测定来确定抗氧化和酶抑制活性。使用 LPS 刺激的中性粒细胞的体外模型，通过流式细胞术测定其活力（作为细胞活力的指标）和白细胞介素-1β、白细胞介素-8 和肿瘤坏死因子-α的释放（ELISA 测定）。
在获得的紫草提取物中鉴定出 12 种酚酸、6 种 PA、3 种有机酸、2 种脂肪酸和 2 种糖。PA 耗尽材料中的 PA 含量低于 2ppm，而黏液素去除增加了迷迭香酸、球形体 A、球形体 B 和 Rabdosin 的含量。PA 耗尽对抗氧化潜力没有显著影响。然而，黏液素耗尽提取物的自由基清除和金属还原特性更高。PA 耗尽和黏液素耗尽都没有对体外乙酰胆碱酯酶、酪氨酸酶、淀粉酶和葡萄糖苷酶的抑制活性或 LPS 刺激的中性粒细胞中细胞因子（如白细胞介素-1β、白细胞介素-8 和肿瘤坏死因子-α）的释放产生显著影响。
鉴于其更安全的特性，PA 耗尽的紫草提取物可进一步用于化妆品和制药产品。
