Inhibitors of COMT are clinically used for the treatment Parkinson’s disease. Here, we report first natural pentacyclic triterpenoid-type inhibitors and their structure-activity relationships inhibition mechanism. The most potent compounds were found to be oleanic acid, betulinic acid celastrol with IC50 values 3.89–5.07 μM, that acted as mixed (uncompetitive plus non-competitive) COMT, represe...

Three new ursane-type triterpenoids, 3α,6α,30-trihydroxy-ursan-28-oic acid (1), 3α,30-dihydroxy-6-oxo-ursan-28-oic acid (2) and 3α,6α,7α,30-tetrahydroxy-ursan-28-oic acid (3), together with one known triterpenoid, betulinic acid (4), one known anthraquinone, 1,7-dihydroxy-2-methylanthraquinone (5), four known phenols, 1,3,5-trimethoxybenzene (6), p-hydroxybenzoic acid (7), syringic acid (8), is...

Traditional medicines or herbal formulations can serve as the source of potential new chemotherapeutic drugs. Nowadays novel plant derived natural products have been designed to determine biological structure-activity relationships. A new family of betulinic acid derivatives were synthesized and the structure-activity relationship of the compounds was initially evaluated by comparing their in v...

BACKGROUND Apoptosis appears to have an essential role in the control of testis germ cell number and Fas expression has been reported in apoptotic spermatocytes and spermatids. We investigated if Fas (CD95) was present on ejaculated human sperm and any relationship between Fas on sperm and the apoptotic marker Syto16. METHODS Semen samples from 77 male partners of infertile couples were evalu...