[In vitro effect of lupeol and casearin G on peripheral blood mononuclear and tumor cells].

BACKGROUND

The rainforest is an important source of natural compounds with therapeutic properties. Although there are many anti-inflammatory and antineoplastic drugs available to the clinician, there is an ongoing need for new therapeutic drugs with fewer serious adverse effects.

OBJECTIVE

To evaluate the in vitro cytotoxic effects of lupeol and casearin G on tumor cells, on phagocytic activity and nitric oxide (NO) production by blood mononuclear cells.

METHODS

The cytotoxic effect of these compounds on cell lines MCF-7 (human breast adenocarcinoma) and PC-3 (human prostate cancer) was measured by a colorimetric assay (MTS/PMS) and the sulphorhodamine B assay. Peripheral blood mononuclear cells were obtained from eight healthy volunteers. The effect of these compounds on nitric oxide (NO) production was measured using the Griess reaction. Their effect on phagocytic activity of PBMC was also evaluated.

RESULTS

Lupeol (≥ 2 mM) resulted in a reduction of both the phagocytic index and the percentage of phagocytic monocytes and macrophages. Treatment of monocytes/macrophages with lupeol (72 µM) and casearin G (4 µM) reduced the production of NO. Neither lupeol (< 969 µM) nor casearin G (< 55 µM) had cytotoxic effects on PBMC. Casearin G showed both cytotoxic (IC50, LC50) and cytostatic (GI50) effects against tumor cells, PC-3 (IC50 = 12.5 µM; GI50 = 13.3 µM; LC50 = 51.9 µM) and MCF-7 (IC50 = 112.8 µM; GI50 = 11.8 µM; LC50 = 49.4 µM), as well as a hemolytic effect (≥ 182 µM).

CONCLUSIONS

These observations indicate that lupeol and casearin G might be useful compounds in the preparation of anti-inflammatory drugs, whereas casearin G might be useful in the elaboration of antitumor drugs.