Abstract
The alkaloidal distribution in young plants of Mitragyna speciosa has been investigated. The major indole alkaloids, as distinct from those in the mature plants, are those possessing C–3Hβ with isocorynantheidine and isopaynantheine, two new alkaloids and mitraciliatine (found for the first time in Mitragyna speciosa) being the dominant ones although speciogynine, a C–3Hα alkaloid occurred in the major quantities. The oxindole alkaloids rhynchociline and ciliaphylline were also found in Mitragyna speciosa for the first time – although not in the leaves, while spe–cionoxeine and isospecionoxeine were found for the first time in this species obtained from Thailand.
Following the recent work by Zenk there is a discussion on the possible biogenetic route of the Mitragyna alkaloids and a modification of the previous hypothesis is put forward.
Key Word Index
Mitragyna speciosa (young plants) - Rubiaceae - Isocorynantheidine - Isopaynantheine - Mitraciliatine - Rhynchociline - Ciliaphylline
