mao activity further studies were conducted to evaluate if this agent was inhibiting mao a or b activity using the methods described above tobacco extract was found to inhibit both mao a and mao b activity as shown in fig1 fig1 presents the means plus or minus the standard errors of the means for 8 determinations for the percent inhibition of mao a and mao b activity the effects of tobacco extract on both forms of mao activity were statistically significantly different from control enzyme conditions student t test p lt 0 005 the results demonstrate that tobacco extract inhibits both mao a and b forms of the enzyme the extract of gumsmoke chewing gum or lozenges was prepared as follows five slices each of gum or lozenges formulated with tobacco extract were extracted with 50 ml of distilled water at room temperature for 12 hours the undissolved gum substance was removed by filtration the lozenges dissolved completely dilutions of these extracts were prepared for evaluation the gum and lozenges extracts were effective in inhibiting mao activity at maximal or saturating concentrations the extracts were able to inhibit mao activity by approximately 50 to 60 fig1 presents the means plus or minus the standard errors of the means for the percent inhibition of mao activity produced by saturating concentrations of an extract of gumsmoke chewing gum prepared as described above over 60 minutes of mao activity measured as described above each data point represented the mean of 4 determinations gumsmoke extract was an effective mao inhibitor at maximal concentrations inhibiting the enzyme by approximately 50 60 all the data points shown in fig1 were statistically significantly different from the sham control at each time point tested student t test.