Pleiocarpa tubicina

From the leaves of Pleiocarpa tubicina, in addition to bases described in Sections III, G, and VI, C, there has been isolated an alkaloid, tubotaiwine, of structure CCXXIV (119). The same substance also occurs in the root bark of Aspidosperma limae (120). 

Three related alkaloids have been found in the leaves of Pleiocarpa tubicina. One is the known compound 19,20-dihydroakuammicine (CCXXXVII, 70, 69, 137a), while the other two, tubifoline and tubi-folidine, are respectively its decarbomethoxy derivative, the indolenine, CCXXXIX, and the corresponding dihydroindole, CCIII (119). A compound strychene of structure CCXXXIX has been prepared from dihydrodeoxyisostrychnine (67, 125). 

Aspidosperma peroba) Pleiocarpa tubicina (= Pleiocarpa pycnantha var. tubicina) Strychnos amazonica Strychnos decussata Strychnos ignatii Strychnos toxifera Strychnos usambarensis... 

The new alkaloids of this group, all from Pleiocarpa species, are tubo-flavine (I) from Pleiocarpa tubicina Stapf [P. pycnantha. (K. Schum.) Stapf var. tubicina (Stapf) Pichon], the same alkaloid, isotuboflavine (II) (mp 263°-265°) and norisotuboflavine (III) (mp 282°-284°) from Pleiocarpa mutica Benth. l-Methoxycarbonyl-(8-carboline was also isolated along with the latter alkaloids (3). 

A continuing examination of Pleiocarpa mutica Benth. and P. tubicina Stapf has revealed the alkaloids summarized in Table II. Although extracts of these plants have shown prolonged blood pressure-lowering properties (41), the active component(s) has not yet been identified. 

Pleiocarpa tuhicina Stapf. [Pleiocarpa pycantha (K. Schum) Stapf var. tubicina (Stapf) Pichon] d... 

---