16beta-Acetoxyhopane-6alpha,22-diol

Ecdysteroids are not endogenous to mammals, but are normal components of the food intake of many mammalian species consuming phytoecdysteroid-containing plants. The most frequently encountered phytoecdysteroid is 20-hydroxyecdysone (20E). Several pharmaceutical effects have been observed after ecdysteroid injection or ingestion, but it is not clear to what extent metabolites generated in the mammalian body contribute to these effects. The C21-ecdysteroid poststerone (Post) is a metabolite of 20E in rodents. Post analogues are key intermediates in the metabolism of exogenous ecdysteroids possessing a C20/22-diol. The pharmacokinetics, bioavailability and metabolism of Post have been assessed in male rats after ingestion and injection. The bioavailability of Post is significantly greater than that of 20E and the presence of an efficient entero-hepatic cycle allows Post to be effectively metabolised to a wide range of metabolites which are excreted mainly in the faeces, but also to some extent in the urine. Several of the major metabolites in the bile have been identified unambiguously as 3-epi-poststerone, 16α-hydroxypoststerone, 21-hydroxypoststerone and 3-epi-21-hydroxypoststerone. Conjugates are also present. Parallels are drawn to the metabolism of endogenous vertebrate steroid hormones, to which Post bears more similarity than 20E.

The aerial parts of Ageratina vernalis provided the new germacranolide 1,10-epoxydeltoidin A (3), together with the known pentacyclic triterpenoid hopane-6α,22-diol (1), and the also known germacranolides deltoidin A (2) and 15-hydroxydeltoidin A (4). In addition, pTsOH catalyzed cyclization of 2 afforded the new guaianolide 5. The absolute configuration of 2, 4, and 5 was assigned by vibrational circular dichroism spectroscopy, while the complete 1H and 13C NMR data assignments of 2-5 followed from 1 D- and 2 D-NMR experiments.

Chemical investigation of the lichen Dirinaria applanata led to isolate nine compounds including a new hopane derivative, 1β-acetoxy-21α-hopane-3β,22-diol (1) together with six phenolic compounds naming divaricatinic acid (2), methyl divaricatinate (3), methyl-β-orcinolcarboxylate (4), methyl haematommate (5), divarinol (6), ramalinic acid A (7), and two xanthones namely lichenxanthone (8), 4,5-dichlorolichenxanthone (9). Their structures were elucidated by spectroscopic data in combination with published literature. Except compound 2, all compounds were isolated from this species for the first time.