Isobrucein

Sergeolide (206) and isobrucein B (235) isolated from Cedronia granatensis showed significant activity against several... 

The most seven potent compounds include isobrucein-B (235), bruceanol A (64), G (70), D (67), B (65), E (68), and bruceantin (234), which were all isolated from Brucea antidysenterica. All these compounds are aglycones with C=0 and OH groups in ring A, a -... 

The most potent compounds were further tested at a lower concentration of 1.0-4.0 pg/cm2. These results can be summarized as follows a) the aglycone, isobrucein-B (235), showed the highest potency in both assays. The antifeedant activity may result in its... 

An earlier investigation of the antileukemic constituents of the Ethiopian Brucea aniidysenterica by Kupchan and associates [2] led to the isolation of quassinoids such as bruceantin (1), bruceantarin (2), dehydrobruceantin (3), dehydrobruceantarin (4), and isobrucein-B (5). Among these quassinoids, bruceantin (1) demonstrated potent antileukemic activity, including the P-388 and L-1210 lymphocytic leukemias, the Lewis lung carcinoma, and the B-16 melanoma. This compound was in Phase II clinical trial as an anticancer drug by the US National Cancer Institute (NCI). 

Further investigation of the B. antidysenterica extract [7] led to two new isobrucein type quassinoids, which were provisionally named bruceanol-A (11) and -B (12). Both were amorphous solids. Bruceanol-A (11) eluted after isobrucein-B (5) on preparative HPLC and bruceanol-B... 

The NCI in vitro primary disease-oriented antitumor screen was used to select and guide the fractionation of the organic and aqueous extracts of Cedronia granatensis. Two quassinoids, sergeolide (69) and isobrucein-B (5), were isolated, to which the screening panel cell lines exhibited up to a 1000-fold range of differential sensitivity, were isolated. The compounds typically produced ICso-level responses at concentrations of 10-5 - lO- M... 

A series of quassinoids was tested for antifeedant activity against the aphid Myzus persicae (Hemiptera, Aphididae) as shown in Table 7. Isobrucein-B (5), brucein-B (75), brucein-C (76), glaucarubinone (77), and quassin (78) decreased feeding at concentrations <0.05% and isobrucein-A (79) was effective at 0.01%. However, only quassin (78) showed no phytotoxic effects. Therefore, Polonsky et al. concluded that quassin (78) was the most promising compound for further development [28]. 

The same assay was carried out for five semi-synthetic quassinoids, which were obtained by esterification of the C-15 OH group of desacetyl-isobrucein-B (124) as shown in Table 13. All ester derivatives showed higher antitumor promoting activity than that of the starting quassinoid, desacetyl-isobrucein-B (124). A compound containing a fluorinated aliphatic ester showed the highest potency [36]. 

Other quassinoids are known to have antiviral activity (Polonsky, 1983). Among these are isobruceine A (54), si-malikalactone D (55), chaparrinone (56), glaucarubolone (57), and castelanone (58). 

Supelcosil LC-18 analytical column (250 mm x 4.6 mm,5 pm) Gradient acetonitrile, 0.5% aq. trifluoroacetic acid UV-Vis detector, 254 nm Picrolemma sprucei Neosergeolide, isobrucein B [95]... 

Nunomura RCS, SilvaECC, Nimomura SM, Amaral ACF, Barreto AS, Siani AC, Pohlit AM (2012) Quantification of antimalarial quassinoids neosergeolide and isobrucein b in stem and root infusions of Picrolemma sprucei Hook F. by HPLC-UV analysis. In Dhanarasu S (eds) Chromatography and its applications. In-Tech Publishers, Rijeka, Croatia, pp 187-200. ISBN 978-953-51-0357-8... 

Sergeolide (62) 60) is the first natural quassinoid to possess a butenolide function. It was isolated along with the known isobruceine B (45) 45) from the roots of the French Guyanan Simaroubaceae Picrolemma pseudocoffea. The structure of sergeolide was established by analysis of the 400 MHz- H-n.m.r. data and the C-n.m.r. spectrum. 

The structural similarity of (45) and (62) suggests that the latter arises from isobruceine B via the intermediacy of its 1-0-acetyl derivative. A Claisen-type rearrangement (vide infra) followed by appropriate double bond migration and lactonisation would lead to (62). 

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