Analysis of additivity and synergism in the anti-plasmodial effect of purified compounds from plant extracts

In the search for antimalarials from ethnobotanical origin, plant extracts are chemically fractionated and biological tests guide the isolation of pure active compounds. To establish the responsibility of isolated active compound(s) to the whole antiplasmodial activity of a crude extract, the literature in this field was scanned and results were analysed quantitatively to find the contribution of the pure compound to the activity of the whole extract. It was found that, generally, the activity of isolated molecules could not account on their own for the activity of the crude extract. It is suggested that future research should take into account the “drugs beside the drug”, looking for those products (otherwise discarded along the fractionation process) able to boost the activity of isolated active compounds

Antioxidant, genotoxic and antigenotoxic activities of daphne gnidium leaf extracts

<p>Abstract</p> <p>Background</p> <p>Plants play a significant role in maintaining human health and improving the quality of human life. They serve humans well as valuable components of food, as well as in cosmetics, dyes, and medicines. In fact, many plant extracts prepared from plants have been shown to exert biological activity <it>in vitro</it> and <it>in vivo</it>. The present study explored antioxidant and antigenotoxic effects of <it>Daphne gnidium</it> leaf extracts.</p> <p>Methods</p> <p>The genotoxic potential of petroleum ether, chloroform, ethyl acetate, methanol and total oligomer flavonoid (TOF) enriched extracts from leaves of <it>Daphne gnidium</it>, was assessed using <it>Escherichia coli</it> PQ37. Likewise, the antigenotoxicity of the same extracts was tested using the “SOS chromotest test”. Antioxidant activities were studied using non enzymatic and enzymatic method: NBT/Riboflavine and xantine oxidase.</p> <p>Results</p> <p>None of the different extracts produced a genotoxic effect, except TOF extract at the lowest tested dose. Our results showed that <it>D. gnidium</it> leaf extracts possess an antigenotoxic effect against the nitrofurantoin a mutagen of reference. Ethyl acetate and TOF extracts were the most effective in inhibiting xanthine oxidase activity. While, methanol extract was the most potent superoxide scavenger when tested with the NBT/Riboflavine assay.</p> <p>Conclusions</p> <p>The present study has demonstrated that <it>D. gnidium</it> leaf extract possess antioxidant and antigenotoxic effects. These activities could be ascribed to compounds like polyphenols and flavonoid. Further studies are required to isolate the active molecules.</p