Royal's Institute of Mental Health Research, University of Ottawa, Ottawa, ON, Canada K1Z 6K4; School of Psychology, University of Ottawa, Ottawa, ON, Canada K1N 6N5; Scientific Director of Canadian Depression Research & Intervention Network (CDRIN), Canada.
Ottawa-Carleton Institute of Biology, University of Ottawa, Ottawa, ON, Canada K1N 6N5.
J Ethnopharmacol. 2018 Apr 24;216:63-70. doi: 10.1016/j.jep.2018.01.027. Epub 2018 Feb 3.
The Maya have traditionally used copal, Protium copal, as incense during ceremonies since pre-Columbian times. Anecdotally, copal (when burned as incense), is thought to elicit mentally uplifting and calming effects. The main objective of this study was to determine whether the incense elicits anxiolytic-like behavior in animal models using rats. A second objective was to characterize active constituents and discern potential mechanism(s) of action, specifically the involvement of the GABAergic and endocannabinoid (eCB) systems. Despite the extensive Central American use of this resin, there are currently no known scientific behavioral or pharmacological studies done with the incense.
Quantification of the triterpenes in the copal resin and cold trapped incense was achieved by HPLC MS. Behavioral effects in rats were assessed using the elevated plus maze (EPM), social interaction (SI) test, conditioned emotion response (CER) and Novel object recognition (NOR) paradigms. Rats were exposed to burning copal (200 mg) over 5 min in a smoking chamber apparatus and then immediately tested in each behavioral paradigm. Follow-up SI tests were done using two antagonists flumazenil (1 mg/kg) and AM251 (1 mg/kg) administered systemically. Inhibition of MAGL (monoacylglycerol lipase) was measured by microplate assay with recombinant human enzyme and probe substrate.
Phytochemical analysis revealed that copal resin and incense had high α- and β-amyrins and low lupeol triterpene content. Exposure to Protium copal incense significantly reduced anxiety-like behavior in the SI and CER tests. In contrast, no anxiolytic effects were observed in the EPM. The CER effect was time dependent. Both flumazenil and AM251 blocked the anxiolytic activity of copal revealing the involvement of GABAergic and endocannabinoid systems. Copal, as well as the identified triterpenes, potently inhibited monoacylglycerol lipase (MAGL) activity in vitro (IC ≤ 811 ng/mL).
This is the first study to show that copal incense from Protium copal elicits anxiolytic-like effects in fear and social interaction models as evidenced by a reduced learned fear behavior and an increase in active social interaction. It's high α and β-amyrin content suggests behavioral effects may be mediated, in part, by the known action of these terpenes at the benzodiazepine receptor. Furthermore, P. copal's observed activity through the eCB system via MAGL offers a new potential mechanism underlying the anxiolytic activity.
自前哥伦布时期以来，玛雅人就在仪式上使用 copal（乳香脂）、Protium copal（乳香脂）作为香薰。据传闻，乳香脂（当用作香薰燃烧时）被认为具有提神和平静的作用。本研究的主要目的是确定这种香薰是否会在动物模型中产生类似抗焦虑的行为，使用的动物是老鼠。第二个目标是确定其活性成分，并辨别潜在的作用机制，特别是涉及 GABA 能和内源性大麻素（eCB）系统。尽管这种树脂在中美洲被广泛使用，但目前还没有关于这种香薰的科学行为或药理学研究。
通过 HPLC-MS 定量分析 copal 树脂和冷捕集香薰中的三萜。使用高架十字迷宫（EPM）、社交互动（SI）测试、条件情绪反应（CER）和新物体识别（NOR）范式评估大鼠的行为效应。将老鼠暴露在吸烟室装置中燃烧 copal（200mg）5 分钟，然后立即在每个行为范式中进行测试。使用两种拮抗剂氟马西尼（1mg/kg）和 AM251（1mg/kg）进行系统给药，进行后续的 SI 测试。使用重组人酶和探针底物的微孔板测定法测量 MAGL（单酰基甘油脂肪酶）的抑制作用。
植物化学分析表明，乳香脂树脂和香薰具有高含量的 α-和 β-香树脂酸和低含量的羽扇豆醇三萜。暴露于 Protium copal 香薰可显著减少 SI 和 CER 测试中的焦虑样行为。相比之下，EPM 中没有观察到抗焦虑作用。CER 效应是时间依赖性的。氟马西尼和 AM251 均可阻断 copal 的抗焦虑活性，表明 GABA 能和内源性大麻素系统的参与。乳香脂以及鉴定出的三萜类化合物在体外强烈抑制单酰基甘油脂肪酶（MAGL）活性（IC≤811ng/mL）。
这是第一项表明 copal 香薰（来自 Protium copal）可在恐惧和社交互动模型中引起类似抗焦虑作用的研究，这表现为习得性恐惧行为减少和主动社交互动增加。它高含量的 α-和 β-香树脂酸表明，这些萜类物质在苯二氮䓬受体上的已知作用可能部分介导了其行为作用。此外，P. copal 通过 MAGL 观察到的对 eCB 系统的活性提供了一种潜在的新机制，为其抗焦虑活性提供了基础。
