Bioassay-guided isolation and evaluation of anti-osteoporotic polysaccharides from Morinda officinalis

Abstract

Ethnopharmacological relevanceMorinda officinalis is a well-known Chinese tonic herb that has shown clinical efficacy in the treatment of bone disease. However, its anti-osteoporotic potential and the M. officinalis polysaccharides (MOPs) responsible for activity require further investigation. Aim of the studyThis study aimed to investigate the anti-osteoporotic effects of different MOP fractions in ovariectomized (OVX) rats, and to identify the osteoprotective components by bioassay-guided isolation. Materials and methodsMOPs were prepared by hot water and alkali extraction, separated into three fractions (MO50, MO70, and MOB) and evaluated in the classic OVX rat model and in MC3T3-E1 cells for anti-osteoporotic activity. ResultsAdministration of MOPs (400 mg/kg/day) provided significant protection against ovariectomy-induced bone loss and biomechanical dysfunction in rats. Treated animals exhibited reduced deterioration of trabecular microarchitecture and lower levels of bone turnover markers. Bioactivity-guided fractionation led to the isolation of two inulin-type fructans from MO50, MOW50-1 and MOP50-2, with potential anti-osteoporotic activities. These consisted of (2 → 1)-linked β-D-fructosyl residues with degrees of polymerization (DP) of 7 and 13, respectively. Furthermore, MOW50-1 promoted osteogenic differentiation of MC3T3-E1 cells by increasing alkaline phosphatase activity. ConclusionsThese data suggest very strongly that MOPs, especially MO50 and MOW50-1, may play important roles in the prevention and treatment of osteoporosis.