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Abstract(s)
Radiation processing technology has been used to improve food security, safety and quality. However there
are a few reports in the literature on the effect of irradiation on bioactivity of herbs and medicinal plants1.
Hence, the present work was undertaken to investigate the dose-response effects of gamma irradiation on
free radical scavenging, reducing power and lipid peroxidation inhibition properties of hydroalcoholic
extracts prepared from wild Malva neglecta Wallr. In the north-eastern of Portugal, this annual herbaceous
plant is traditionally eaten raw as leafy vegetable or prepared in herbal beverages due to its disinfectant and
anti-inflammatory properties2. Thus, dried M. neglecta samples were exposed to 0 (control), 1, 5 and 10
kGy of γ-rays in a 60Co experimental chamber. After irradiation, processed samples were extracted using
methanol:water (80:20 v/v) and the radicals scavenging activity evaluated through the 2,2-diphenyl-1-
picrylhydrazyl (DPPH) free radicals assay, the reducing power by the ferricyanide/Prussian blue assay,
and the lipid peroxidation inhibition by β-carotene/linoleate and thiobarbituric acid reactive substances
(TBARS) assays. The obtained results suggest that the different irradiation doses affect the extracts
bioactivity. In general, the free radicals scavenging activity and the reduction power decreased in irradiated
samples (except for 5 kGy in the DPPH assay) compared with the non-irradiated control. On the other hand,
the lipid peroxidation inhibition was improved by the irradiation treatment (except for 1 kGy in the TBARS
assay). Both β-carotene/linoleate and TBARS assays showed low EC50 values (corresponding to a high lipid
peroxidation inhibition), while the DPPH assay demonstrated the highest ones (corresponding to a low free
radicals scavenging effect). The results herein reported support the use of gamma-irradiation as an effective
technology to maintain or improve the lipid peroxidation inhibition properties of hydroalcoholic extracts of
M. neglecta, and their traditional use in folk medicine.
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Pedagogical Context
Citation
Pinela, José; Antonio, Amilcar L.; Barros, Lillian; Carvalho, Ana Maria; Oliveira, M.B.P.P.; Ferreira, Isabel C.F.R. (2014). Effect of γ-irradiation on radical scavenging, reducing power and lipid peroxidation inhibition properties of hydroalcoholic extracts from Malva neglecta. In 4th International Nuclear Chemistry Congress. São Paulo