The Mitragyna Species of Asia

Abstract

h n t a = media ~b~t~e s e a r~h Abstract During the TLC examination of extracts of leaves and young twigs of Mitragyna speciosa from Thailand [I] there was evidence of small quantities of oxindole alkaloids corresponding to C (9)-OCH, heteroyohimbine alkaloids and of possible indole N-oxides. Some of them were isolated and in order to identify these alkaloids it was essential to have authentic alkaloids for comparative purposes, which could only be

Chemistry and Pharmacology of Analgesic Indole Alkaloids from the Rubiaceous Plant, Mitragyna speciosa

“…Houghton and Said reported the isolation of a new alkaloid (6), 2) i.e., a 3,4-dehydro derivative of mitragynine, from the fresh leaves of M. speciosa growing on the campus of Universiti Kebangsaan Malaysia. They also found new types of indole alkaloids, mitragynaline (7), corynantheidaline (8), mitragynalinic acid (9), and corynantheidalinic acid (10) (Fig. 2), in the very young leaves of the same plant.…”

“…[4][5][6] Almost ten years later, Shellard et al, in their investigation of the alkaloidal constituents in various samples of M. speciosa from Thailand, isolated more than twenty kinds of Corynanthetype alkaloids, including oxindole derivatives. [7][8][9] They pointed out that the variation in the constituents among different batches of leaves may be an indication of the presence of geographical variants of the species within Thailand. For chemical re-investigation, we chose the plant growing on the campus of the Faculty of Pharmaceutical Sciences, Chulalongkorn University in Bangkok, in collaboration with Dr. Ponglux.…”

Chemistry of Indole Alkaloids Related to the Corynanthe-Type from Uncaria, Nauclea and Mitragyna Plants

“…We then found that this characteristic phenomenon can be explained by the proton-deuterium exchange caused by the equilibration between the imine and enamine forms. To study the generality of this interesting phenomenon, we investigated the NMR behavior with a model compound, 1-methyl-3,4-dihydro-β-carboline (68). When 68 was dissolved in DMSO-d 6 , a signal corresponding to the methyl group at the C-1 position was detected at δ H 2.26 (br-t, J 3, 10 = 1.5 Hz) in the 1 H-NMR spectrum and at δ C 22.0 in the 13 C-NMR spectrum.…”

Formation of an Unusual Dimeric Compound by Lead Tetraacetate Oxidation of a Corynanthe-Type Indole Alkaloid, Mitragynine.

“…In the recent chemical [1][2][3][4][5][6][7][8][9] and pharmacological [10][11][12][13][14][15] studies on the Rubiaceous plant, Mitragyna speciosa, [16][17][18][19][20] which has been traditionally used in tropical areas as a substitute for opium, 21) we have found that mitragynine (1), a major Corynanthe-type indole alkaloid of this plant, exhibited potent analgesic activity mediated by m-and d-opioid receptors.…”

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In the recent chemical [1][2][3][4][5][6][7][8][9] and pharmacological [10][11][12][13][14][15] studies on the Rubiaceous plant, Mitragyna speciosa, [16][17][18][19][20] which has been traditionally used in tropical areas as a substitute for opium, 21) we have found that mitragynine (1), a major Corynanthe-type indole alkaloid of this plant, exhibited potent analgesic activity mediated by m-and d-opioid receptors.

22)Further, 7-hydroxymitragynine (3), 23) an oxidative derivative of 1, was found as a novel opioid agonist with higher potency than that of morphine.24) This remarkable opioid ligand was prepared from mitragynine (1) by conventional procedure, i.e., oxidation of 1 with lead tetraacetae [Pb(OAc) 4 ] followed by alkaline hydrolysis of the resultant 7-acetoxyindolenine (2). In investigating the first oxidation step in detail, we found a structurally and mechanistically novel dimerization product, as described in this publication.

Results and Discussion

In general, 7-acetoxyindolenine derivatives are prepared from the corresponding indoles by oxidation with Pb(OAc) 4 .

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