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The beta-carboline alkaloids found in medical plants and in a variety of foods, beverages and cigarette smoke have a range of action in various biological systems. In vitro studies have demonstrated that these alkaloids can act as scavengers of reactive oxygen species. In this paper, we report the in vivo antioxidative properties of the aromatic (harmane, harmine, harmol) and dihydro-beta-carbolines (harmaline and harmalol) studied by using Saccharomyces cerevisiae strains proficient and deficient in antioxidant defenses. Their antimutagenic activity was also assayed in S. cerevisiae and the antigenotoxicity was tested by the comet assay in V79 cell line, when both eukaryotic systems were exposed to H(2)O(2). We show that the alkaloids have a significant protective effect against H(2)O(2) and paraquat oxidative agents in yeast cells, and that their ability to scavenge hydroxyl radicals contributes to their antimutagenic and antigenotoxic effects.

beta-carboline alkaloids are found in several medicinal plants and display a variety of actions on the central nervous, muscular and cardiovascular systems. The aim of the present study was to evaluate the effects of systemic administration of beta-carboline alkaloids on object recognition in mice. Adult Swiss mice received an intra-peritoneal injection (i.p.) of alkaloids (1.0, 2.5 or 5.0 mg/kg) 30 min before training in an object recognition task. The fully aromatic beta-carbolines, harmine and harmol, induced an enhancement of short-term memory (STM) at all doses tested when compared to controls. Harmaline, a dihydro beta-carboline and inverse agonist of the MK-801 binding site on the N-methyl-d-aspartate (NMDA) receptor, also induced an enhancement of both short-term memory (STM) and long-term memory (LTM). These results demonstrate that systemic administration of beta-carboline alkaloids can improve object recognition memory in mice.

The alkaloid lobeline (Lob) has been studied due to its potential use in treatment of drug abuse. This study evaluates the possible anticonvulsant and neuroprotective activities of Lob to obtain new information on its properties that could confirm it as a candidate in the treatment of alcohol addiction. The anticonvulsant effect of Lob was evaluated using a pilocarpine-induced seizure model. In addition, possible neuroprotective effects were investigated measuring DNA damage using the comet assay, assessing free radical levels by dichlorofluorescein diacetate (DCF) oxidation, and measuring the antioxidant potential using the α, α-diphenyl-β-picrylhydrazyl (DPPH) scavenging assay, besides measuring superoxide dismutase (SOD) and catalase (CAT) enzyme activities in brain tissues. Lobeline increased the latency to the first seizure and decreased the percentage of seizures in a similar way as diazepam, used as control. DNA damage induced by Pil and hydrogen peroxide were decreased in hippocampus and cerebral cortex from mice treated with Lob. The levels of free radicals and CAT activity increased in cortex and hippocampus, respectively, in mice treated with Pil. Lobeline decreased CAT in hippocampus, leading to similar values as in the saline negative control. In conclusion, Lob has anticonvulsant and neuroprotective actions that may be mediated by antioxidant-like mechanisms, indicating its potential as candidate drug in alcoholism therapy. [ABSTRACT FROM AUTHOR]

The article examines the antioxidant properties of brachycerine and a crude foliar extract from P. brachyceras as a possible protective agent against the secondary effect of radiation. Strains of Sacchromyces cerevisiae have been used in evaluating the proficiency and deficiency in antioxidant defenses. Likewise, the mutagenic and antimutagenic possibility have been analyzed. Results of the study reveal that brachycerine and the crude foliar extract of P.brachyceras have antioxidant and antimutagenic effects.