Extracts and Composites of Equisetum for Bone Regeneration

The present chapter reviews the different preparation and characterization of Equisetum extracts and composites, including their biological properties and uses in the regeneration of bone defects derived from traumas and diseases, such as osteoporosis and arthritis. The results have shown that the Equisetum genus contains high amounts of silicon, potassium, zinc, sulfur, carbon, and other organic compounds with potential use as therapeutic drugs. The experimental variations in the preparation of extracts showed that the maximum yield (~20% w/w) can be obtained for the concentration of 10–50% of ethanol in ethanol/water solutions. The maximum total phenolic and antioxidant contents can be obtained at concentrations of 50–90% ethanol. The Equisetum genus-derived composite materials and extracts are promising for bone regeneration applications. In vivo studies revealed that the trabecular bone thickness increased by 11% and 46% when treating SHAM and ovariectomized (OVX) rats, respectively, with a diet containing 60 mg ⋅ kg−1 E. arvense (EA) extract. The cortical bone thickness of the EA extract group has increased by 14% compared to the OVX group. Quantitative analysis of composite EA extract and poly (lactic acid) (PLA) revealed alkaline phosphatase (ALP) activity three times higher in comparison to the polystyrene (21 days) and an increase in mineralization of adipose tissue-derived mesenchymal stem cells (AT-MSCs) after 14 and 21 days. In vivo and in vitro studies have concluded that E. arvense, E. hyemale, E. giganteum, and other Equisetum species showed antioxidants and osteoconductive and osteoinductive properties, which are vital for bone regeneration.