Faculty of Veterinary Medicine University of Zagreb
Abstract
Ethanolic extracts prepared from the leaves of Psidium guajava were evaluated for anti-trypanosoma and cytotoxicity activity in the bloodstream species of Trypanosoma brucei brucei (BS427) and HEK293 in 384-well Alamar Blue assays respectively. Cytotoxicity activity in HEK293 cells was subsequently used to estimate the selectivity index of the extracts. The activities of the plant extracts were determined to evaluate if further chemical and biological profi ling may be warranted for potential development in early drug discovery for African Sleeping Sickness. Two trypanocides, pentamidine and diminazene, were employed as reference drugs, while puromycin was also included as control for general cell growth inhibition. The results show that the extracts inhibited growth of T. b. brucei with an IC50 of 6.3 μg/mL and 48.9 μg/mL for 80% and 20% ethanolic preparations respectively, with corresponding activity of less than 50% against HEK293 at the highest screening dose of 238.10 μg/mL. The estimated selectivity index of the extracts compares favourably with pentamidine and diminazene. Meanwhile the reference compounds were found to have activities in agreement with published sensitivities at the doses screened. The lack of cytotoxicity at the doses screened and direct activity against T. b. brucei whole cells, make these extracts suitable candidates for further chemical elucidation and biological profiling.Istraženo je tripanocidno djelovanje etanolskog iscrpka lišća Psidium guajava na vrstu Trypanosoma brucei brucei (BS427) i njegova citotoksičnost na stanice HEK293 bojanjem alamarskim plavilom u 384 jažice. Citotoksični učinak na stanice HEK293 rabljen je za procjenu indeksa selektivnosti. Učinkovitost biljnih iscrpaka određivana je da bi se procijenila svrhovitost budućih kemijskih i bioloških istraživanja potencijalnoga lijeka za afričku bolest spavanja. U istraživanju su rabljena dva tripanocida, pentamidin i diminazen, te puromicin kao sredstvo koje usporava rast stanica. Rezultati su pokazali da 80% etanolskih pripravaka s IC50 od 6,3 μg/mL koči rast i razvoj tripanosoma, a samo 20% onih s IC50 od 48,9 μg/mL, s odgovarajućom aktivnosti manjom od 50% na stanice HEK293 u najvećoj dozi od 238,10 μg/mL. Indeks selektivnosti iscrpaka bio je sukladan s aktivnošću pentamidina i diminazena. Aktivnost istraživanih sastojaka bila je sukladna s razinom prije objavljene osjetljivosti. Izostanak citotoksičnosti na razini rabljenih koncentracija i izravna djelotvornost na stanice T. b. brucei daju osnovu za daljnja kemijska i biološka istraživanja predmetnih pripravaka
