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Effects of soya bean flakes and liquorice root extract on enzyme induction and toxicity in B6C3F1 mice
J C Mirsalis1, C M Hamilton, J E Schindler
1Toxicology Laboratory, SRI International, Menlo Park, CA 94025-3493.
Abstract:
Both soya bean flakes (SBF) and liquorice root extract (LRE) have previously been reported to have anticarcinogenic properties, which have been thought to be related to an increased activity of specific enzymes responsible for the detoxification of chemical carcinogens. 30- and 90-day studies were conducted in male B6C3F1 mice to determine which, if any, of several detoxification enzymes are induced by SBF or LRE. Mice fed 8 and 25% LRE showed a variety of adverse clinical signs, poor weight gain and 30% mortality. Significant increases in liver:body weight ratios were observed in both the SBF and LRE groups. No significant treatment-related gross autopsy findings were observed in any of the SBF groups. A number of abnormalities were observed in the LRE groups, including lesions of the kidney, liver, spleen and thymus. Liver samples from the 90-day study were analysed for 7-ethoxycoumarin O-deethylase (7-ECOD), benzo[a]pyrene hydroxylase (BPH), superoxide dismutase (SOD), glutathione S-transferase (GST) and UDP-glucuronyl transferase (UDPGT) at 90 days, and at an interim 30-day autopsy. No treatment-related increases were observed for BPH or SOD. Both SBF and LRE induced modest increases in UDPGT activity. SBF induced modest increases in GST activity, but LRE decreased this activity. 7-ECOD activity was significantly increased by LRE and decreased by SBF. Samples from a 30-day study in which both LRE and SBF were administered at various dose levels were examined for UDPGT activity; all dose groups showed decreases in UDPGT activity relative to controls. The results suggest that both SBF and LRE may alter the activities of specific enzymes involved in the detoxification of chemical carcinogens; however, the combination of these two foodstuffs may not produce an additive effect in B6C3F1 mice.
Insights
Soya bean flakes (SBF) and liquorice root extract (LRE) alter detoxification enzymes in mice. While both affect UDP-glucuronosyltransferase (UDPGT), SBF increases glutathione S-transferase (GST), and LRE decreases it, showing no additive anticarcinogenic effect.
Area of Science:
- Toxicology and Pharmacology
- Nutritional Biochemistry
- Carcinogenesis Research
Background:
- Soya bean flakes (SBF) and liquorice root extract (LRE) possess potential anticarcinogenic properties.
- These properties are hypothesized to stem from enhanced activity of carcinogen-detoxifying enzymes.
Purpose of the Study:
- To investigate the effects of SBF and LRE on specific detoxification enzymes in male B6C3F1 mice.
- To determine if SBF and LRE induce changes in enzymes like 7-ethoxycoumarin O-deethylase (7-ECOD), benzo[a]pyrene hydroxylase (BPH), superoxide dismutase (SOD), glutathione S-transferase (GST), and UDP-glucuronyl transferase (UDPGT).
Main Methods:
- Conducted 30- and 90-day feeding studies in male B6C3F1 mice with varying doses of SBF and LRE.
- Monitored clinical signs, weight gain, mortality, and liver:body weight ratios.
- Analyzed liver enzyme activities including 7-ECOD, BPH, SOD, GST, and UDPGT at 30 and 90 days.
Main Results:
- LRE administration led to adverse clinical signs, reduced weight gain, and mortality, along with organ lesions.
- Both SBF and LRE increased liver:body weight ratios; SBF increased GST activity, while LRE decreased it.
- LRE significantly increased 7-ECOD activity, whereas SBF decreased it. Both increased UDPGT activity, but LRE showed a dose-dependent decrease in a 30-day study.
Conclusions:
- SBF and LRE individually alter the activity of key detoxification enzymes in mice.
- The observed effects, particularly on GST and 7-ECOD, differ between SBF and LRE.
- The combination of SBF and LRE does not appear to produce an additive beneficial effect on these enzymes in this mouse model.