Purpose: To provide an experimental basis for the anti-diarrheal and anti-oxidant properties of the bark
extract of
Magnolia officinalis
Rehd. et Wils., a Chinese traditional herb called magnolol.
Methods: The effects of magnolol on castor oil-induced diarrhea, small intestinal transit (SIT) in mice
were investigated. Additionally, the antioxidant activity of magnolol was assessed in mice by the
following parameters: glutathione (GSH), total antioxidant capacity (T-AOC), antioxidant enzyme
activities and their gene expression level.
Results: Compared with diarrhea model control group, magnolol (25, 50, or 100 mg/kg body weight)
showed significant (p < 0.05) inhibitory activity against castor oil-induced diarrhea in mice.
Administration of magnolol (25, 50, and 100 mg/kg) also lowered neostigmine-induced SIT acceleration
to 60.34 ± 5.17, 59.61 ± 7.66, and 54.12 ± 7.27 %, respectively, as against 70.1 ± 6.89 % for
neostigmine control group. In vivo antioxidant assay results showed that mice treated with magnolol
exhibited significantly (p < 0.001) higher activities of catalase (CAT), superoxide dismutase (SOD), and
glutathione peroxidase (GSH-Px) activities in blood, compared to control. Similarly, magnolol proups
showed significantly higher CAT and SOD and T-AOC activities (p < 0.01) than control in liver tissues.
The 100 mg/kg magnolol group had significantly higher liver GSH content than normal control group
(1.01 vs. 0.79 mg/mg protein). At 25 and 50 mg/kg doses, magnolol significantly enhanced gene
expression levels of CAT (p < 0.01) in liver.
Conclusion: Findings from this study indicate that magnolol possesses anti-diarrheal activity and is
probably one of the main anti-diarrhea ingredients of Cortex Magnoliae Officinalis. Magnolol modulation
of the activity and gene expression of antioxidant enzymes may therefore exert beneficial effects in antioxidant
defense.
