Activated charcoal fi lter effectively reduces p-benzosemiquinone from the mainstream cigarette smoke and prevents emphysema.

In this paper, we have made a comparative evaluation of the cytotoxicity and pathophysiological effects of mainstream smoke from cellulose acetate (CA)-fi ltered cigarettes with that of charcoal-fi ltered cigarettes developed in our laboratory. Previously, we had demonstrated that the mainstream smoke from an Indian CA-fi ltered commercial cigarette contains p-benzosemiquinone (p-BSQ), a major, highly toxic, long-lived water-soluble radical. Here, we have examined 16 brands of different CA-fi ltered cigarettes including Kentucky research cigarettes, and observed that mainstream smoke from all the cigarettes contains substantial amounts of p-BSQ (100–200 μg/cigarette). We also show that when the CA fi lter is replaced by a charcoal fi lter, the amount of p-BSQ in the mainstream smoke is reduced by 73–80%, which is accompanied by a reduction of carbonyl formation in bovine serum albumin to the extent of 70– 90%. The charcoal fi lter also prevented cytotoxicity in A549 cells as evidenced by MTT assay, apoptosis as evidenced by FACS analysis, TUNEL assay, overexpression of Bax, activation of p53 and caspase 3, as well as emphysematous lung damage in a guinea pig model as seen by histology and morphometric analysis. The results indicate that the charcoal fi lter developed in our laboratory may protect smokers from cigarette smoke-induced cytotoxity, protein modifi cation, apoptosis and emphysema.