Antiviral potency of lupane and oleanane alkynyl-derivatives against human cytomegalovirus and papillomavirus

A library of 18 structurally diverse semisynthetic lupane, oleanane, and ursane types triterpenoids, including C19- or C28-(1,2,3-triazolyl)- and aminomethylated derivatives obtained by the «click» reaction with various aromatic and sugar azides or by Mannich reaction with secondary amines, were tested for antiviral activity against HCMV, HSV-1, and HPV-11 types. C28-Triazolyl-derivative with a benzyl substituent of 2,3-indolo-oleanolic acid was the most active against the HCMV virus with EC₅₀ < 0.05 (SI > 81). Lupane 3,28-diacetoxy-triazolyl derivatives with phenyl- and fluorophenyl-fragments possess the highest activity among all screened compounds toward HPV-11 type virus with EC₅₀ values of 2.97 µM and 1.20 μM, SI₉₀ values of 28 and >125, respectively. One can see that modification of triterpenic alkynes to Mannich bases was more efficient in increasing an activity against HSV-1 than their conversion to triazoles.