Mitragyna parvifolia, alkaloids

The N-oxide of the alkaloid dihydrocorynantheol (21) has also been mentioned as a natural product from the leaves of Mitragyna parvifolia (Roxb.) Korth. however, it was detected only by mass spectroscopy and no further evidence for the structure has been given (31). 

During the period under review several species of the Mitragyrm genus have been closely reexamined, but no new alkaloids have been isolated with the possible exception of 3-isoajmalicine (i) and uncarine-F 2), two bases known previously from in vitro experiments but recently isolated from plant material, apparently for the first time. The results of all these extractions have recently been summarized (3). Mitragyna parvifolia has been particularly carefully studied (i, 2, A-6) and the variations in alkaloid content in plants from eight different geographical sources in India and southeast Asia have been noted (3, 4) the seasonal variations in alkaloid content in plants grown in Poona and Ceylon have also been studied (6). A similar study of the alkaloid content of M. stipulosa forms the subject of another communication (7). 

New occurrences of the Picralima alkaloids and their derivatives are occasionally reported they are summarized in Table I 2, 8-20a). Ni,-Methylakuammicine has previously been isolated from the bark of Hunteria ehurnea, and it is now shown to be present in the seeds. The occurrence of akuammigine in the leaves of Mitragyna parvifolia collected in the Maharashtra State of India, near Poona, and in Ceylon is of some interest, since it appears not to be present in plants grown... 

Ajmalicine (139a) and 3-isoajmalicine (140a) were both converted to oxindole alkaloids, mitraphylline (167) and isomitraphylline (168) in Mitragyna parvifolia (Roxb.) Korth. (Rubiaceae)(S4). Feeding experiments on Vinca minor Linn. (Apocynaceae) had shown that vincamine (169) is biosynthesized via geissoschizine, stemmadenine, secodine, and tabersonine (85). Apparicine (170), which lacks one carbon atom of the tryptamine side chain, appears to be derived in Aspidosperma pyricollum Miiell. Arg. (Apocynaceae) from stemmadenine (86). 

Pandey R, Singh SC, Gupta MM. Heteroyohimbinoid type alkaloids from Mitragyna parvifolia. Phytochemistry 2006 67(19) 2164—9. 

The distribution of alkaloids in young plants of Mitragyna parvifolia (Rubiaceae) grown from seeds obtained from Sri Lanka (142) and India (143) were studied separately, and the functions, movements, and biogenesis of these alkaloids were discussed. 

Fig. 5.2.17. Alkaloids present in young leaves of Mitragyna parvifolia...

Shellard E J, Houghton P J 1972 The Mitragyna species of Asia. XXL The distribution of alkaloids in young plants of Mitragyna parvifolia grown from seed obtained from Ceylon. Planta Med 21 382-392... 

The occurrence of alkaloids in Mitragyna species was first reported by Hooper, who isolated a crystalline alkaloid in 0.15% yield from the leaves of M. parvifolia (1) this alkaloid was not named and has not since been reinvestigated. The leaves of M. speciosa contain the amorphous alkaloid mitragynine, mp 105°-115° (2, 3), while the bark contains mitraspecine, C23H30N2O5, mp 244°-245°, [a]ff° -59.15° (4, 5). A third base, giving an amorphous picrate, mp 123°-127°, is also present, but this has not been studied further, since no crystalline derivatives could be obtained (6). The alkaloid mitraphylline, C21H24N2O4, mp 270°,... 

Biosynthesis of oxindole alkaloids in Mitragyna species was studied by Shellard and Houghton, who fed ajmalicine (80) and 3-isoajmalicine to young plants of Sri Lankan M. parvifolia. Both precursors were incorporated into mitraphylline (149) and isomitraphylline (148) produced by M. parvifolia (97). This and a similar series of biosynthetic experiments led to the modification of a previously postulated hypothesis for the biosynthesis of oxindole alkaloids. This modified biosynthethic pathway to oxindole alkaloids in Mitragyna species is presented in Scheme 11. 

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