L-quebrachitol extracted from industrial rubber serum: a study on its antioxidant activities and bone mineral density enhancing functions

In Southeast Asia, the natural rubber (Hevea brasiliensis) industry has expanded dramatically, and throughout the production process, a sizeable portion of industrial rubber serum is treated as effluent. L-quebrachitol has been proved as a natural product abundantly present in natural rubber serum. In order to improve the utilization rate of natural rubber, a method was provided to extract L-quebrachitol from industrial rubber serum, and the yield was 0.1∼0.2%. By using mass spectrometer, Fourier transform infrared, and nuclear magnetic resonance spectroscopy, the isolated molecule was identified as L-quebrachitol. Meanwhile, there is a lack of complete research on the antioxidant capacity of L-quebrachitol, and the effect of L-quebrachitol on bone mineral density remains at the cellular level. In this work, L-quebrachitol was confirmed to have a great ability to scavenge free radicals, especially at a concentration of 0.5 mg/mL. The protective capacity of antioxidant enzymes (catalase, total glutathione peroxidase, and superoxide dismutase) and the ability to inhibit lipid peroxidation of L-quebrachitol at concentrations of 50 and 100 μg/mL was remarkable. Furthermore, animal experiment showed that L-quebrachitol at 125 mg/kg·bw can significantly reduce weight gain, increase bone mineral density and bone calcium content of ovariectomized rats. Consequently, L-quebrachitol could be used as a novel antioxidant to prevent oxidative stress-related diseases or as an agent to increase bone density to prevent osteoporosis.