Background: Long-term glucocorticoid therapy causes secondary osteoporosis leading to pathological fractures. Glucocorticoid action in bone is dependant upon the activity of 11β-hydroxysteroid dehydrogenase type 1 enzyme (11β-HSD1). Piper sarmentosum
is a local herb that possesses the ability to inhibit 11-βHSD1 enzyme activity. We aimed to determine the effects of Piper sarmentosum water extract on 11-βHSD1 expressions and activity in the bones of glucocorti-coid-treated adrenalectomized rats.
Methods: Forty male Sprague–Dawley rats (200-250 g) were used. Twenty-four animals were adrenalectomized and received intramuscular injection of dexamethasone (120 μg/kg/day). They were simultaneously administered with either Piper sarmentosum water extract (125 mg/kg/day), GCA (120 mg/kg/day) or distilled water as vehicle by oral gavage for two months. Eight animals were sham-operated and given vehicle daily, i.e. intramuscular olive oil and oral distilled water.
Results: Following two months treatment, dexamethasone-treated adrenalectomized rats had significantly lower 11β-HSD1 dehydrogenase activity and higher 11β-HSD1 expression in the femoral bones compared to the sham-operated and baseline group. The rats supplemented with Piper sarmentosum water extract had significantly higher 11β-HSD1 dehydrogenase activity and lower 11β-HSD1 expression in the bones.
Conclusion: The results showed that Piper sarmentosum water extract had the ability to prevent glucocorcoticoid excess in the bones of glucocorticoid-treated adrenalectomized rats through the local modulation of 11β-HSD1 expression and activity, and may be used as prophylaxis for osteoporosis in patients on long-term glucocorticoid treatment.