Cytogenetic effects of Jacareubin from Calophyllum brasiliense on human peripheral blood mononucleated cells in vitro and on mouse polychromatic erythrocytes in vivo

Jacareubin is a xanthone isolated from the heartwood of Calophyllum brasiliense with antibacterial and gastro-protective properties and the intention for clinical use as an anti-cancer treatment (due to the similar chemical structure to other anti-neoplastic drugs) requires an investigation of whether this compound can generate adverse effects on non-transformed cells. Jacareubin (0.5-1000 mu M in DMSO) was more cytotoxic on phytohemagglutinin (PHA)-stimulated normal human peripheral blood mononuclear cells (PBMCs; IC50 at 72 h by MTT: 85.9 mu M) than on G(0) phase-PBMCs (IC50 315.6 mu M) using trypan blue exclusion and formazan metabolism assays. Jacareubin had lower toxicity on PBMCs than Taxol (1 mu M). Jacareubin presented cytostatic activity because it inhibited PHA-stimulated PBMCs proliferation (from 2.5 mu M; CFSE dilution and replication index). Jacareubin induced PBMCs arrest in G(0)/G(1) phase of the cell cycle (from 5 mu M) as evaluated by DNA content. Moreover, Jacareubin generated genotoxicity by breaking DNA strands selectively in PHA-stimulated PBMCs (from 5 mu M) rather than on resting PBMCs using the single-cell gel electrophoresis assay and increasing the frequency of micronucleated (MN) PBMCs in vitro (from 5 mu M) and frequency of hypodiploid cells (from 10 mu M). When 100 mg/kg Jacareubin was injected i.p. into mice (a fifth of the LD50; 0.548 g/kg. Approximately to 300 mu M in vitro), we observe no increase in the MN level in bone marrow cells. Jacareubin can be consider for further anti-tumoural activity due to its preferential genotoxic, cytotoxic and cytostatic actions on proliferating cells rather than on resting cells and the lack of in vivo genotoxicity.