Cytotoxic Effects of Syzygium aromaticum Leaf Extract against Aedes albopictus Cells

Abstract

Syzygium aromaticum consists of anti-microbial and anti-parasitic activity. S. aromaticum is rich in many phytochemicals such as eugenol, terpenes, and phenolic compounds. In this research, we tested the cytotoxicity of S. aromaticum in Aedes albopictus (C6/36) cells using the CytoTox 96® Non-radioactive cytotoxicity assay. This is a colorimetric assay that quantitatively measures lactate dehydrogenase, a stable cytosolic enzyme released upon cell lysis. S. aromaticum leaf extract was prepared in a two-fold dilution series. Two 96-well plates were prepared with C6/36 cells, and the assay was set up with analytical system based negative control - without C6/36 cells, vehicle control - untreated cells, positive control - lysis solution with four replicates. S. aromaticum extract was added to the test wells at different concentrations, one plate was incubated for 5 hours, and the next plate was incubated for 24 hours at 280 C. The absorbance data were measured using a standard 96-well plate reader (Labtech LT-4500, Singapore) and the percentage of cytotoxicity was calculated for each of the concentrations tested. The colour intensity and absorbance values decreased with the decreasing concentrations of S. aromaticum leaf extract. High concentrations of S. aromaticum extract caused high number of cell lysis. High concentrations of S. aromaticum leaf extracts were cytotoxic to C6/36 cells at dilutions >1/128. Cytotoxicity data of S. aromaticum leaf extracts help to select the minimum toxic concentrations for testing the anti-Aedes inhibitory activity of the product. The data corroborated with the larvicidal activity of S. aromaticum leaf extract against Aedes larvae.