New insights of the pharmacological properties of curcumin: cytotoxicity and immuno-modulation study

Abstract

The current study aims to appreciate curcumin’s anti-inflammatory and immuno-modulation properties through the investigation of its effect on the neutrophil enzymes (MPO and elastase) activities. The toxicity of pure curcumin was studied using three cell types: human neutrophils, NOD mouse Langerhans β cell line (NIT-1), and mouse breast cancer carcinoma cell line (EMT-6). Neutrophil isolation from whole blood was assessed using the histopaque gradient density method. After the MPO and elastase extraction from isolated neutrophils, the modulatory effect of curcumin on the activity of these enzymes was assayed using 3,3′,5,5′- tétramethylbenzidine and le N-Methoxy-Suc-(Ala)2-Pro-Val-p-Nitroanilide as specific substrates, respectively. Also, the Cytotoxic of curcumin was investigated on the EMT6, NIT-1, and neutrophils cells using XTT and trypan blue exclusion assays, respectively. Results indicate that curcumin modulates the neutrophil's activity by inhibiting its enzymes. In effect, curcumin exerts a significant dose-dependent inhibitory effect on both MPO and elastase activities with IC50 of 14.41± 1.74 μg/ml and 6.06± 3.67 μg/ml. On the other hand, we reveal that curcumin significantly decreases neutrophil viability in a dose-dependent manner with IC50 = 25.60 ± 7.88 μg/ml. Moreover, no significant cytotoxic effect on EMT6 and NIT-1cells lines was shown. The IC50 of EMT6 breast cancer cell and NIT-1cell lines were higher than 30 μg/ml and 60 μg/ml, respectively. While, doxorubicin, an anti-cancer drug used as a positive control, significantly reduces EMT6 viability with IC50 of 4.885± 0.063 μg/ml. These results indicate that curcumin has a potential anti-inflammatory effect considering neutrophil viability and some of its activities. Moreover, curcumin has shown selective cytotoxicity toward neutrophils with no prominent cytotoxic effect on EMT6 and NIT-1 cell lines. Given these results, we can think of proposing curcumin for anti-inflammatory and immunomodulatory use.