Rooibos (Aspalathus linearis), honeybush (Cyclopia intermedia) and cancer bush (Sutherlandia frutescens subsp. microphylla) protect against tobacco-specific mutagenesis in vitro

Available online 22 June 2016 Edited by D De Beer Antimutagenesis studies against the tobacco-specific mutagens 4-(methylnitrosamino)-1-(3-pyridyl)-1butanone (NNK) and N-oxide, 4 (methyl-nitrosamino)-1-(3-pyridyl)-1-butanol (NNAL), were conducted using hot water aqueous extracts of rooibos (Aspalathus linearis), honeybush (Cyclopia intermedia), and cancer bush (Sutherlandia frutescens). Aqueous extracts of both “fermented” and “unfermented” (green) rooibos and honeybush were included, while extracts of green and black teas (Camellia sinensis) served as benchmarks. A polyphenol-enriched methanol extract of unfermented rooibos (RgM) was included to further elucidate the possible role of rooibos polyphenols. Studies were performed in the presence of the metabolic activation against Salmonella typhimurium tester strain TA1535, using the standard plate incorporation andmicro-suspension, preincubation assays. The mutagenic effects of NNK against the strain TA1535 was best demonstrated using the standard plate incorporation assay, while a higher mutagenicity was demonstrated for NNAL using the microsuspension, pre-incubation method. Black tea and RgM exhibited the highest protection against NNK-induced mutagenesis followed by the aqueous extracts of rooibos ≥ green tea ≥ honeybush ≥ cancer bush. Black tea, green tea, RgM and unfermented rooibos were the most effective against NNAL-induced mutagenesis, followed by fermented rooibos. The two honeybush extracts exhibited similar, but theweakest protective response.When considering the amount of total polyphenols (TPP) incorporated in the plate incorporation assay, cancer bush exhibited similar protection to that of fermented and unfermented honeybush against NNKmutagenesis. The involvement of specific polyphenol-cytochrome P450 (CYP450) interactions is likely to be involved in the protection against tobacco-relatedmutagenesis. Polyphenol constituents of rooibos, honeybush and cancer bush could play an important role in the protection against mutagenesis induced by themajor tobacco-specific carcinogens. © 2016 SAAB. Published by Elsevier B.V.