Potential antimutagenic activity of berberine, a constituent of Mahonia aquifolium

BACKGROUND: As part of a study aimed at developing new pharmaceutical products from natural resources, the purpose of this research was twofold: (1) to fractionate crude extracts from the bark of Mahonia aquifolium and (2) to evaluate the strength of the antimutagenic activity of the separate components against one of the common direct-acting chemical mutagens. METHODS: The antimutagenic potency was evaluated against acridine orange (AO) by using Euglena gracilis as an eukaryotic test model, based on the ability of the test compound/fraction to prevent the mutagen-induced damage of chloroplast DNA. RESULTS: It was found that the antimutagenicity of the crude Mahonia extract resides in both bis-benzylisoquinoline (BBI) and protoberberine alkaloid fractions but only the protoberberine derivatives, jatrorrhizine and berberine, showed significant concentration-dependent inhibitory effect against the AO-induced chloroplast mutagenesis of E. gracilis. Especially berberine elicited, at a very low dose, remarkable suppression of the AO-induced mutagenicity, its antimutagenic potency being almost three orders of magnitude higher when compared to its close analogue, jatrorrhizine. Possible mechanisms of the antimutagenic action are discussed in terms of recent literature data. While the potent antimutagenic activity of the protoberberines most likely results from the inhibition of DNA topoisomerase I, the actual mechanism(s) for the BBI alkaloids is hard to be identified. CONCLUSIONS: Taken together, the results indicate that berberine possesses promising antimutagenic/anticarcinogenic potential that is worth to be investigated further

Ginkgo biloba, DNA damage and DNA repair: overview

Despite the ancient use in Chinese popular medicine and, more recently, in western modern medicine in many European countries, the biological effects of extracts of G. biloba (GBE) are still not clearly known. In modern medicine GBE has been used for tinnitus, to reverse memory loss, for dementia, and Alzheimer's and Parkinson's diseases in elderly people. Besides reports on improvement of blood circulation in the brain, there are a number of studies pointing to complex cellular effects, involving signal transduction pathways and epigenetic modifications. Evidence are presented from recent reports concerning genotoxic and antigenotoxic properties and the corresponding mechanisms underlying such activities, mostly regarding the prooxidant and antioxidant activities of the extract. However, several examples of direct interaction of the extract and its components with specific proteins are provided, especially for DNA damage repair, contributing for antigenotoxicity. Evidence of epigenetic effects of GBE are also presented from approaches involving transcriptomics, detection of activity of histone deacetylases, and screening of plant extracts with cell-based systems for detection of posttranslational modifications. The modulation of chromatin-remodeling enzymes by GBE and their interaction with proteins involved in DNA damage repair, apoptosis, and signal transduction are discussed in the context of neurodegeneration.(undefined)info:eu-repo/semantics/publishedVersio