Enhanced ethanol-induced changes in disposition and toxic response to dietary aflatoxin B1 due to Sacoglottis gabonensis bark extract, a Nigerian alcoholic beverage additive

Antioxidant activity of (+)-bergenin: a phytoconstituent isolated from the bark of Sacoglottis uchi Huber (Humireaceae)

(+)-Bergenin (1) was isolated from Sacoglottis uchi, a species of vegetable found in the Amazon region and popularly used for the treatment of several hepatic problems. The structure of 1 was fully characterized using IR, GC-MS and NMR (1D and 2D) analyses. This phytoconstituent has been used as an oriental folk medicine for the treatment of many diseases and shows antihepatotoxic properties. Tests with beta-carotene, DPPH and a heterogeneous Fenton system were carried out, confirming the antioxidant activity of 1. Theoretical calculations were performed to investigate the formation of the radical derivatives of 1 using *H, *OH, *CH(3), and *CCl(3) as initiator radicals. DFT thermodynamic calculations showed that the methoxyl group (O-6-CH(3)) is the most favorable site for radical attack. Frontier molecular orbital analysis showed that nucleophilic radical attack is favored on the aromatic ring of 1 where the LUMO is localized, with antibonding character with respect to the O-6-CH(3) bond. The possibilities of attack at other sites on 1 were investigated in detail in order to understand the regiospecificity of this reaction.

The influence of Sacoglottis gabonensis stem bark extract and its isolate bergenin, Nigerian alcoholic beverage additives, on the metabolic and haematological side effects of 2,4-dinitrophenyl hydrazine-induced tissue damage

This study was designed to study the influence of Sacoglottis gabonensis stem bark extract on the metabolic and cytotoxic side effects of 2,4-dinitrophenyl hydrazine (2,4-DNPH) on the brain and blood using male weaving rats as the experimental model. This was after the effect of the bark extract and bergenin, its isolate, on membrane lipid peroxidation and tissue natural antioxidant defences was reported. Lipid peroxidation was induced experimentally with a single intraperitoneal phenylhydrazine (2,4-DNPH) administration at the end of 3 days exposure to the bark extract or bergenin in drinking water. Three hours later, the brain, liver and red blood cells of the experimental animals were analysed for glucose level and the blood was analysed for selected key indices of oxidative stress: red blood cell (RBC) count haemoglobin (Hb), packed cell volume (PCV) and white blood cell (WBC) count (total and differential). The bark extract exhibited a protective action on brain glucose, significantly inhibiting the glucose-depleting action of both 2,4-DNPH and ethanol. It also inhibited the lowering action of DNPH and ethanol on PCV, RBC and Hb concentration of rat blood, but inhibited proliferation of white blood cells (total and differential). The data on the effect of bergenin, on the side effects of 2,4-DNPH experimental lipid peroxidation and on ethanol followed an essentially similar trend to those of the bark extract on brain glucose. Bergenin, similar to the bark extract, exerted a protective action on the brain tissue, though to a lesser extent, against the oxidants, 2,4-DNPH and ethanol. It is evident that aqueous ethanol extract of S. gabonensis stem bark has biological antioxidant properties against 2,4-DNPH and ethanol-induced tissue damage exerting its action on the haematological and metabolic side effects of the oxidants. By virtue of its essentially similar activity under the same conditions, bergenin appears to be the phytochemical constituent that is largely responsible for the observed action of the bark extract.

Diet/toxin interactions

Biotoxins derived from bacteria, fungi and algae in food play an important role for development of diseases of unknown aetiology. Furthermore, dietary components modulate their toxicity and carcinogenicity. Current progress on their mode of action postulated the contribution of cytochrome P-450 system as well as oxygen radicals, and phosphoprotein phosphatases are the target of several tumour promoters. For prevention of biotoxin-mediated development of diseases, a detailed study and information on biological function of dietary components and a possible association between diet/toxins are needed.

An examination of the effect of pretreatment of rats with Sacoglottis gabonensis bark extract, a Nigerian palmwine additive, and ethanol on macromolecular binding of aflatoxin B1

In a previous study (Okoye and Neal, Food and Chemical Toxicology 1988, 26, 679) enhanced ethanol-induced reductions in albumin-bound and unbound serum aflatoxin B1 (AFB1) and increased hepatic DNA-AFB1 binding were observed in rats treated with bark extract of Sacoglottis gabonensis, a Nigerian palmwine additive. The present study was designed to examine further the mechanism of these effects. Male weanling rats were pretreated with the bark extract or ethanol, or both, in drinking-water (at three times the levels used in the previous study) for 8 days before the ip administration of a single dose of [3H]AFB1. [In the previous study the rats were fed all three compounds simultaneously.] In contrast to the results of the previous study, when both the additive and ethanol were administered, there were no significant effects on [3H]AFB1 binding to liver or serum albumin or liver DNA. The levels of DNA-bound aflatoxin were reduced in rats given the additive or ethanol alone.