In this study, ginkgo biloba leaf extract (GBE) was added to sample cigarettes, including in the filter (0.8 mg/cigarette) and/or the cut filler (0.8 mg/cigarette). The effects of GBE in scavenging free radicals and reducing mutagenicity and toxicity of cigarette smoke in vivo were investigated. Smoke analysis results indicated that GBE eliminated up to 30% of free radicals. Biological experiments, conducted for both GBE cigarettes and control samples, included the Ames test, acute toxicity, neutral red cytotoxicity assay and chronic toxicity. Results showed that the mutagenicity and toxicity of the GBE cigarettes were lower than for the control cigarettes. A possible mechanism of GBE in scavenging free radicals is discussed in this article.

Two protoporphyrin derivatives were prepared by a facile method using inexpensive hemin as starting material. They were added to cigarette filters to reduce the carcinogenic tobacco specific N-nitroamines (TSNAs), especially toward NNK (4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone) and NNN (N-nitrosonornicotine) for environment protection and public health. The reduction level of TSNAs was reached to 37.6% from MSS, with greater reductions when more porphyrin was included in the filter. The decrease level for NNK by protoporphyrin derivatives is more effective than NNN. The interaction between protoporphyrin derivatives and TSNAs (NNK and NNN) were investigated by fluorescence spectra and UV-visible titration. The correlation coefficients were 0.978~0.997 and the binding constants was the scope from 1.26 × 103 to 4.04 × 104. The interaction mechanisms between protoporphyrin derivatives and, NNK and NNN are possibly the co-interaction of hydrogen bond binding and strong π–π stacking.