Of pristimerin

Murayama, T. Eizuru, Y. Yamada, R. Sadanari, H. Matsubara, K Rukung, G. Tolo,F. M. Mungai, G. M. Kofi-Tsekpo, M. Anticytomegalovirus activity of pristimerin, a triterpenoid quinone methide isolated from Maytenus heterophylla (Eckl. Zeyh.). Antiviral Chem. Chemother. 2007, 18, 133-139. 

A possible biogenetic route to triterpene quinones with an extra double bond (e.g., netzahualcoyone and derivatives) may involve dehydrogenation and subsequent pristimerin regrouping. Indeed, (Table V) two epimeric di-triterpene quinone ethers umbelatin a and p (118,119) have been isolated from the roots of Rzedowskia tolantonguensis [68]. The structures of pristimerin and netzahualcoyone were ascertained by the standard spectral methods. The H... 

Itokawa et al. [71] have recently isolated and characterized four new dimeric triterpenes from M. illicifolia (Paraguay), three of which have two units of pristimerin while the fourth (cangorosin B) has one pristimerin and one tingenone unit (Fig. 11). 

TABLE XV. 13c NMR ( 50 MHz ) Data ( 8, CDCI3, Chemical Shifts in ppm Relative to Me4Si) of Pristimerin and Ethers 121and 122... 

Bearing a 7-oxoquinonemethide structure, but with a skeleton related to tingenone insted of pristimerin, as exhibited by dispermoquinone, a new celastroloid (73) of this uncommon type was isolated from the roots of M. amazonica by Chavez et al. [81]. The structure was elucidated by spectroscopic evidences, exhibiting a molecular formula C28H32O5, and characteristic features of 7-oxo-quinonemethides in the H NMR spectrum as the signals of H-l and H-6 as non-interchangeable with D2O... 

The first natural celastroloid-related structure described bearing a phenolic system in ring A was zeylasterone (75), isolated from Kokoona zeylanica [82]. That compound was characterized as a 6-oxo-diphenol derivative of pristimerin (53). 

These compounds were assayed for antibiotic and cytotoxic activities and from them compound 202 was the only dimer that showed antibiotic activity against Gram positive bacteria its MICs on Bacillus subtilis and B. pumilus were 1-2 and 20 pg/ml, respectively. None of the dimers showed cytotoxic activity against the HeLa (cervix carcinoma) and Hep-2 (larynx carcinoma) cell lines at least at 20 pg/ml. These results support the fact that the additional double bond C-14(15) plays an important role for the antibiotic activity, as 202 was the only assayed dimer with a triterpene quinoid unit derived from netzahualcoyone skeleton, instead of pristimerin. 

The structurally related cephalosporin and helvolic acid do not appear to have the same antibacterial potency as fusidic acid [271, 336, 337] and so would not seem destined for equivalent status in medicine. Similarly the antibacterial potency of the triterpenoid antibiotics polyporenic acid A [338] and polyporenic acid C [339], like that [340] of pristimerin (LXI) [341, 342], which is one of the most highly oxidised naturally occurring pentacyclic triterpenes... 

Harada, R., H. Kakisawa, S. Kobayashi, M. Musya, K. Nakanishi, and Y. Taka-HASHi Structure of pristimerin, a quinonoid triterpene. Tetrahedron Letters 14, 603 (1962). 

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