Studies on the constituents of Indonesian Picrasma javanica. III. Structures of new quassinoids, javanicins A, C and D.

Three new quassinoids, javanicins A, C and D, were isolated from the bark of Picrasma javanica (Simaroubaceae). The structures were established on the basis of spectroscopic data and chemical evidence.

Antitumor agents, 104. Isolation of yadanziosides M and P from Brucea antidysenterica and identification of bruceantinoside B as a mixture of yadanzioside P and bruceantinoside C.

Yadanziosides M [3] and P [1] were isolated from Brucea antidysenterica. Their structures were elucidated by spectral data. Bruceantinoside B reported previously was reinvestigated and revealed to be a mixture of yadanzioside P and bruceantinoside C [2]. The structure of yadanzioside P was found to be identical to that of bruceantinoside B.

Two new quassinoids from Simaba multiflora fruits.

Two new quassinoids, 13, 18-dehydro-6 alpha-senecioyloxychaparrin (4) and 12-dehydro-6 alpha-senecioyloxychaparrin (5), have been isolated from Simaba multiflora fruits. Their structures were deduced from spectral data. 1H-13C 2-D chemical-shift correlation nmr was applied to the structural elucidation of the antileukemic quassinoid 4.

An enzyme-linked immunosorbent assay for quassin and closely related metabolites.

A microtitration plate enzyme-linked immunosorbent assay has been developed for quassin and closely related seco-triterpenes. The method is much more sensitive than conventional chromatographic techniques and enables the routine analysis of large numbers of samples with a detection limit of 5 ng quassin. Antibody production was elicited by injecting a conjugate of iso-quassinic acid linked to bovine serum albumin into rabbits. Important features of the technique are (a) the use of a double-antibody, noncompetitive enzyme-linked immunosorbent assay for a low-molecular-weight, nonantigenic compound using microtitration plates; and (b) that the initial incubation of samples with primary antiserum can be carried out in buffer containing up to 20% (v/v) methanol with minimal loss of sensitivity. The structural requirements for recognition of the hapten by the antiserum are considered based on the levels of cross-reaction found with a wide range of other quassinoids.

Anti-inflammatory agents III: Structure-activity relationships of brusatol and related quassinoids.

A series of quassinoids were observed to be potent inhibitors of induced inflammation and arthritis in rodents. Brusatol afforded the most potent activity followed by brucein-D. A 3-hydroxy-delta 3-2-oxo moiety in brusatol or a 1-hydroxy-delta 3-2-oxo moiety in brucein-D, as well as a C-15 ester-bearing delta-lactone ring in brusatol and C-11 and C-12 free hydroxyl groups are required in both quassinoids for potent anti-inflammatory activity. Preliminary studies indicate that one of the modes of action of quassinoids as anti-inflammatory agents is to stabilize lysosomal membranes, reducing the release of hydrolytic enzymes that cause damage to surrounding tissues.

Soularubinone, a new antileukemic quassionoid from Soulamea tomentosa.

The structure of soularubinone 3, a new antileukemic quassinoid isolated from the leaves of Soulamea tomentosa (Brongn, and Gris), has been established by spectral and chemical methods. It has been shown to be the C-15 beta-hydroxy-isovaleric ester of glaucarubolone. Soularubinone shows significant antineoplastic activity against mouse leukemia P-388 and inhibits cell transformation induced by Rous sarcoma virus. The known quassinoid chaparrinone I has also been isolated.

The antineoplastic quassinoids of Simaba cuspidata spruce and Ailanthus grandis Prain.

The South American Simaba cuspidata Spruce and North Indian Ailanthus grandis Prain were investigated as sources of potentially useful antineoplastic agents. Both of these Simaroubaceae plant species were found to produce 6 alpha-tigloyloxychaparrinone (4a) and the new quassinoid 6 alpha-tigloyloxychaparrin (3b). The latter structure was determined by interpretation of spectral data and oxidation to 6 alpha-tigloyloxychaparrinone (4a). While both glycol 3b and alpha-ketol 4a were found to significantly inhibit growth of the murine P388 lymphocytic leukemia cell line, only the alpha-ketol (4a) inhibited growth of the corresponding in vivo system.