ARECA NUT EXTRACT INHIBITS THE GROWTH, ATTACHMENT, AND MATRIX PROTEIN-SYNTHESIS OF CULTURED HUMAN GINGIVAL FIBROBLASTS

BETEL QUID CHEWING IS a popular oral habit in India, South Africa, and many Southeast Asian countries. The effects of areca nut (AN) extract on the growth, attachment, and protein synthesis of healthy human gin gival fibroblasts (GF) were investigated to determine why betel quid ( BQ) chewers have higher prevalence of periodontal disease than non-che wers. Twenty-four hour exposure of human GF to AN extract (> 200 mu g/ ml) in culture led to the formation of numerous intracellular vacuoles . As analyzed by modified MTT 4,5-dimethylthiazol-2-yl)-2,5-diphenyl-t etrazolium bromide] assay, AN extract significantly suppressed the gro wth of GF over 5 days of incubation in a dose-dependent manner. At con centrations of 50 and 300 mu g/ml, AN extract suppressed the growth of GF with 30% and 57% (P < 0.05), respectively. AN extract also signifi cantly suppressed the synthesis of [H-3]proline incorporation into tri chloroacetic acid (TCA) precipitated proteins. At concentrations of 20 0, 400, and 600 mu g/ml, AN extract suppressed the protein synthesis w ith 33%, 58%, and 63% of inhibition (P < 0.05), respectively. Preincub ation of cells in a medium containing AN extract for 2 hours inhibits the subsequent attachment of cultured GF to type I collagen at the 50% inhibitory concentration (IC50) which is about 720 to 798 mu g/ml. Co nsidering the frequent consumption of BQ throughout the day, impairmen t of sequential fibroblast functions by BQ ingredients is a potential mechanism through which BQ chewing exert a deleterious effect to the g ingival tissues.