Cytotoxicity of the Aqueous Extract of Clerodendrum splendens on HaCaT Keratinocytes

Clerodendrum splendens G. Don (Family Verbenaceae) has been used for centuries to treat various medicinal problems in Africa, including the treatment of wounds and other skin conditions. Though several studies have been conducted on the biological activities of this plant, none so far determines the effect of the leaves extract of C. splendens on skin cells and hence predicting its toxicity. This research aims at investigating the in vitro physiological effect of the aqueous extract of C. splendens on human adult low calcium high temperature keratinocytes (HaCaT). Keratinocytes are the main cells of the skin epidermis and any agent used for the treatment of skin conditions will first come in contact with these cells. The functional activities of the aqueous extract of C. splendens were investigated by determining effect on the cellular metabolic activity, proliferation and necrotic cytotoxicity by the 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), bromodeoxyuridine (BrdU) and lactate dehydrogenase (LDH) assays respectively. The HPLC finger print chromatogram was also developed for quality control. There was no significant effect on the metabolic activity, rate of proliferation as well as LDH leakage from the HaCaT cells. According to these results, the aqueous extract of C. splendens did not show toxicity over the tested concentrations of the extract. The extract showed a tendency towards increased proliferation and viability at low concentrations of 0.1 and 1 µg/mL.

The positive effect at 0.1 and 1 µg/mL seems to suggest the absence of toxicity at those concentrations but a decrease in metabolic activity and proliferation at higher concentrations could be a dose dependent cytotoxic effect.