Genotoxicity and Antigenotoxicity of selected South African indigenous plants

E.E. Elgorashi,R. Antonissen,R. Makhuvele,R.G. Matshoga,L. Pieters,L. Verschaeve

doi:10.1016/j.sajb.2017.10.016

Abstract

Twenty-two plant species extracted with dichloromethane and 90% methanol were investigated for their genotoxicity as well as antigenotoxicity against aflatoxin B1 induced-mutagenicity using the Ames (Salmonella typhimurium strains TA98 and TA100) and Vitotox assays in the presence of S9 rat liver fraction. The results obtained from Ames assay for some plant extracts correlated well with the results obtained from the Vitotox assay. Dichloromethane and methanolic extracts of Helichrysum petiolare, Protea hybrid, Protea roupelliae, Artabotrys brachypetalus (leaves), Friesodielsia obovata, Hexalobus monopetalus, Monanthotaxis caffra, Monodora junodis, Uvaria caffra, Xylopia parviflora, Podocarpus henkellii, Rhoicissus sekhukhuniensis, Podocarpus elongatus and Agapanthus praecox had moderate to strong antimutagenic activities in both Ames and Vitotox assays. The methanolic extract of Annona senegalensis and dichloromethane extract of Podocarpus falcutus also showed antigenotoxic potentials against aflatoxin B1 induced mutagenicity. Methanolic extracts of Xylopia sp., showed a co-mutagenic effect with aflatoxin B1 in the Ames assay (strain TA100). All extracts were not genotoxic in the Vitotox assay in the absence of S9. Plant extracts with promising antimutagenic effects could be used in the form of feed and food supplements as a preventative strategy against aflatoxin B1 induced mutagenicity and carcinogenicity.

Highlights

The assays were performed in the presence of S9 since aflatoxin B1 is an indirect mutagen and need to be converted metabolically to its 8,9-epoxide active derivative (Hamid et al 2013)
The results showed that 86% of methanolic extracts namely, H. petiolare, P. hybrid, P. roupelliae, A. brachypetalus, A. senegalensis, F. obovata, H. monopetalus, M. caffra, U. caffra, M. junodis, X. parviflora, A
Most plant extracts investigated in this study had antigenotoxic activities against aflatoxin B1 induced mutagenicity in either the Ames or Vitotox test or both

Summary

Introduction

Mutagenicity plays a crucial role in carcinogenesis and it may lead to different types of cancers and genetic diseases, which are increasing at an alarming rate in human beings and animals (Nagarathna et al 2013). Aflatoxins, a class of mycotoxins, contaminate various foodstuffs including animal feeds and foods such as nuts, corn, cereals, oilseeds, and dehydrated foods during production, harvest, storage and food processing (Bennett and Klich 2003; Madrigal-Santillan et al 2010). They are the most common known mutagens and linked with the incidences of genetic diseases, especially hepatocellular cancer and other liver diseases such as aflatoxicosis. Aflatoxins consist of four major groups namely, B 1, B2, G1 and G2

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Conclusion