Quassinoids from Picrasma ailanthoides

Quassinoids.— The full paper on the structural elucidation of picrasins A—G has been published. Two new compounds, nigakihemiacetals E (79) and F (80), have been isolated from Picrasma ailanthoides. 

Quassinoids of the Japanese Picrasma ailanthoides Planchon (= P. quassioides Bennett) have been investigated in detail and more than twenty quassinoids have been obtained until 1984. However, very few reports for quassinoid glycosides have been found [63]. Eight quassinoids glycosides, picrasinoside A (141), B (142), C (143), D (144), E (145), F (146), G (147), H (148), and quassinoids hemiacetals, picrasinol A (149), B (150), C (151), and D (152) were isolated from Picrasma ailanthoides the last two decades [63-66]. 

Okano M, Fukamiya N, Kondo K, Fujita T et al. 1982 Picrasinoside-A, a novel quassinoid glucoside from Picrasma ailanthoides. Chem Lett pp. 1425-1426... 

Okano, M., N. Fukamiya, K. Kondo, T. Fujita, and T. Aratani Picrasinoside-A, A Novel Quassinoid Glucoside from Picrasma Ailanthoides Planchon. Chemistry Lett. 1425 (1982). 

Quassinoids.—Simarolide (136) had previously been the only substance providing a structural link between limonoids and quassinoids. The related picrasin A (137) has now been isolated from Picrasma quassioides P. ailan-thoides). It was accompanied in the extract by picrasin B (138) which was converted to quassin (139) by bismuth oxide oxidation and methylation. A series of closely related quassin derivatives, nigakilactones A (140), B (141), C (142), E (143), and F (144) occur with quassin in P. ailanthoides. - The structure of amarolide has been revised to (145). Observation of a large coupling between H-9 and H-11 in the n.m.r. spectrum makes the previous... 

Forty-five quassinoids isolated from the three Simaroubaceous plants, Brucea javanica, Brucea antidysenterica and Picrasma ailanthoides, and fourteen isolated from Ailanthus altissima were tested for Okano et al. [106-108] for their inhibitory activities using a short-term in vitro assay of the EBV-EA activation induced by TP A in Raji cells. 

Matsuzaki T, Fukamiya N, Okano M, Fujita T (1991) Pitaasinoside H, a new quassinoid glucoside, and related compounds from the stem wood of Picrasma ailanthoides. J Nat Prod 54 844-848... 

Investigation of the minor bitter constituents of Picrasma ailanthoides Planchon led to the isolation and structural elucidation of the following new quassinoids Nigakilactone K (8), L (9), M (10) and N (11) (62). Quite recently two quassinoids hemiacetals, picrasinol-A (12) and -B (13) have been isolated from the bark of the same plant (77) they all have a methyl group at C-8. 

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