BackgroundExtracellular polymeric substances isolated from Aureobasidium pullulans (EAP), containing specifically 13% β-1,3/1,6-glucan, have shown various favorable bone-preserving effects. Textoria morbifera Nakai (TM) tree has been used as an ingredient in traditional medicine and tea for various pharmacological purposes. Thus, the present study was aimed to examine the synergistic anti-osteoporotic potential of mixtures containing different proportions of EAP and TM compared with that of the single formulations of each herbal extract using bilateral ovariectomized (OVX) mice, a renowned rodent model for studying human osteoporosis.MethodsThirty five days after bilateral-OVX surgery, 9 combinations of EAP:TM (ratios = 1:1, 1:3, 1:5, 1:7, 1:9, 3:1, 5:1, 7:1, 9:1) and single separate formulations of EAP or TM were supplied orally, once a day for 35 days at a final concentration of 200 mg/kg. Variations in body weight gains during the experimental periods, as well as femur weights, bone mineral density (BMD), bone strength (failure load), and mineral content (calcium [Ca] and inorganic phosphorus [IP]) following sacrifice were measured. Furthermore, histomorphometric and histological profile analyses of serum biochemical parameters (osteocalcin content and bone specific alkaline phosphatase [bALP] activity) were conducted following sacrifice. Femurs histomorphometric analyses were also conducted for bone resorption, structure and mass. The results for the mixed formulations of EAP:TM and separate formulations were compared with those of risedronate sodium (RES).ResultsThe EAP:TM (3:1) formulation synergistically enhanced the anti-osteoporotic potential of individual EAP or TM formulations, possibly due to enhanced variety of the active ingredients. Furthermore, the effects of EAP:TM were comparable to those of RES (2.5 mg/kg) treatment.ConclusionThe results of this study suggest that, the EAP:TM (3:1) combination might act as a new pharmaceutical agent and/or health functional food substance for curing osteoporosis in menopausal women.Electronic supplementary materialThe online version of this article (10.1186/s12906-018-2362-y) contains supplementary material, which is available to authorized users.

The dose‐dependent antiosteoporotic potentials of the exopolymers from Aureobasidium pullulans (EAP): Dendropanax morbifera (DM) 3:1 (g/g) were observed in bilateral ovariectomized (OVX) rats. Twenty‐eight days after bilateral OVX surgery, 200 mg/kg EAP or DM, and 400, 200, and 100 mg/kg EAP : DM (3:1) were orally administered, once a day for 56 days. We measured changes in body weight and weight gain, bone weight, length, thickness, strength, and bone mineral density and contents. Additionally, histological profiles and histomorphometric analyses of serum biochemistry and urine biochemistry were conducted at sacrifice. Femur, tibia, and the 4th or 5th lumbar vertebrae were sampled, and histomorphometry of bone mass, structure, and resorption were also performed. In this study, the findings suggest that EAP : DM (3:1) synergistically increased the distinct antiosteoporotic potentials of the single formulations of EAP and DM in OVX rats, suggesting a promising new potent protective agent for relieving osteoporosis in menopausal women. Practical applications Osteoporosis is a metabolic bone disease characterized by decreased bone strength, leading to increased risk of fractures. EAP have antiosteoporotic activity and DM has various health beneficial effects including immunological enhancement. We hypothesized that appropriated mixtures consisting of EAP and DM leaf extracts (EAP : DM) will show more favorable synergistic antiosteoporotic effects due to increases in the diversity of bioactive ingredients. In the present study, rats treated with 200 mg/kg of EAP : DM 3:1 (g/g) showed significantly more favorable inhibitory activity against estrogen‐deficient osteoporosis symptoms induced by OVX compared with those treated with 200 mg/kg of EAP or DM. Therefore, EAP : DM 3:1 (g/g) may be a promising new potent protective agent for relieving osteoporosis in menopausal women.