Neurotoxic effect of Caulerpa racemosa var. cylindracea by neurite inhibition on the neuroblastoma cell line

In the present study, antiproliferative, apoptotic and especially neurotoxic effects of Caulerpa racemosa var. cylindracea dry and wet extracts on mouse neuroblastoma cell line, NA2B were investigated by neurotoxicity screening test (NST). C. racemosa var. cylindracea wet and dry extracts were obtained by methanol (MT) extraction. The effect of the extracts on viability and proliferation was measured by MTT. NA2B cells were induced to differentiate using 1 μM dcAMP and the amount of inhibition of growing neurites in different dilutions (50, 35, 25, 15, 10 and 5 μl/ml) by extracts was measured. The number of apoptotic cells was computed by TUNEL method using cells in culture. It was found that majority of the cells died with dry extract above the level of 15 μl/ml due to the MT effect. Below this level, on the other hand, presence of cell death and antiproliferative effect was noted due to the toxic effects of C. racemosa var. cylindracea which was independent of MT. In all doses of wet extracts, similar but less prominent dose-dependent effects were observed. Below the level of 15 μl/ml, mild toxic effect presented itself with neurite inhibition. In addition to the toxic, apoptotic and antiproliferative effects of C. racemosa var. cylindracea, its neurotoxic effects possessing property at low concentrations which manifesting itself by neurite inhibition was also showed. This species offers a potential for developing new drugs due to its antiproliferative, toxic and apoptotic effects. Nevertheless, its neurotoxic effect is a factor to be considered as multifunctional agents especially in neuronal metabolism.