7-Hydroxymitragynine

Abstract: Background Kratom (Mitragynia speciosa korth) is recognized increasingly as a remedy for opioid withdrawal by individuals who self-treat chronic pain. Case description A patient who had abruptly ceased injection hydromorphone abuse self-managed opioid withdrawal and chronic pain using kratom. After co-administering the herb with modafinil he experienced a tonic-clonic seizure, but he reported only modest abstinence once kratom administration stopped. We confirmed the identity of the plant matter he ingested as kratom and identified no contaminants or adulterants. We also conducted high-throughput molecular screening and the binding affinity at mu, delta and kappa receptors of mitragynine. Conclusion We report the self-treatment of chronic pain and opioid withdrawal with kratom. The predominant alkaloid of kratom, mitragynine, binds mu- and kappa-opioid receptors, but has additional receptor affinities that might augment its effectiveness at mitigating opioid withdrawal. The natural history of kratom use, including its clinical pharmacology and toxicology, are poorly understood.

Abstract: Mu-opioid receptor agonists represent mainstays of pain management. However, the therapeutic use of these agents is associated with serious side effects, including potentially lethal respiratory depression. Accordingly, there is a longstanding interest in the development of new opioid analgesics with improved therapeutic profiles. The alkaloids of the Southeast Asian plant Mitragyna speciosa, represented by the prototypical member mitragynine, are an unusual class of opioid receptor modulators with distinct pharmacological properties. Here we describe the first receptor-level functional characterization of mitragynine and related natural alkaloids at the human mu-, kappa-, and delta-opioid receptors. These results show that mitragynine and the oxidized analogue 7-hydroxymitragynine, are partial agonists of the human mu-opioid receptor and competitive antagonists at the kappa- and delta-opioid receptors. We also show that mitragynine and 7-hydroxymitragynine are G-protein-biased agonists of the mu-opioid r...

Abstract: Natural products found in Mitragyna speciosa, commonly known as kratom, represent diverse scaffolds (indole, indolenine, and spiro pseudoindoxyl) with opioid activity, providing opportunities to better understand opioid pharmacology. Herein, we report the pharmacology and SAR studies both in vitro and in vivo of mitragynine pseudoindoxyl (3), an oxidative rearrangement product of the corynanthe alkaloid mitragynine. 3 and its corresponding corynantheidine analogs show promise as potent analgesics with a mechanism of action that includes mu opioid receptor agonism/delta opioid receptor antagonism. In vitro, 3 and its analogs were potent agonists in [35S]GTPγS assays at the mu opioid receptor but failed to recruit β-arrestin-2, which is associated with opioid side effects. Additionally, 3 developed analgesic tolerance more slowly than morphine, showed limited physical dependence, respiratory depression, constipation, and displayed no reward or aversion in CPP/CPA assays, suggesting that analogs might repres...

Abstract: Mitragynine (1) is a major alkaloidal component in the Thai traditional medicinal herb, Mitragyna speciosa, and has been proven to exhibit analgesic activity mediated by opioid receptors. By utilizing this natural product as a lead compound, synthesis of some derivatives, evaluations of the structure−activity relationship, and surveys of the intrinsic activities and potencies on opioid receptors were performed with guinea pig ileum. The affinities of some compounds for μ-, δ-, and κ-receptors were determined in a receptor binding assay. The essential structural moieties in the Corynanthe type indole alkaloids for inducing the opioid agonistic activity were also clarified. The oxidative derivatives of mitragynine, i.e., mitragynine pseudoindoxyl (2) and 7-hydroxymitragynine (12), were found as opioid agonists with higher potency than morphine in the experiment with guinea pig ileum. In addition, 2 induced an analgesic activity in the tail flick test in mice.