In this study, researchers from the Johannes Gutenberg University of Mainz in Germany investigated the effect of two flavanoids on the mineralization of primary human osteoblasts after their encapsulation in amorphous calcium polyphosphate (Ca-polyP) microparticles. The results of their study were published in The American Journal of Chinese Medicine.
The researchers used baicalin (baicalein 7-O-B- d-glucuronic acid) and its aglycone, baicalein (5,6,7-trihydroxyflavone), for the study.
They obtained the two flavonoids from the root extracts of Chinese skullcap (Scutellaria baicalensis), a plant used in traditional Chinese medicine.
Both flavonoids are nontoxic to cells at concentrations lower than 3 mcg/mL.
The researchers used primary human osteoblasts (phOSB) for in vitro experiments.
Ca-polyP particles with a stoichiometric P:Ca ratio of 1:2 are normally degraded by cellular alkaline phosphatase (ALP) into ortho-phosphate and used for bone hydroxyapatite formation.
The researchers reported that flavone-loaded Ca-polyP microparticles were taken up by phOSB, which resulted in the accumulation of polyP around the nuclei and the formation of intracellular vesicles containing ALP.
By activating phospholipase C, baicalin/baicalein caused a rise in intracellular calcium [Ca2+]i, which was augmented after encapsulation in Ca-polyP.
Both flavonoids, either alone or associated with Ca-polyP microparticles, upregulated the expression of the osteoblast calcium efflux channel and the plasma membrane Ca2+-ATPase.
Both flavonoids also induced the expression of ALP, which promotes bone mineralization, but only in the Ca-polyP-microparticle-associated form. Ca-polyP without flavones also induced ALP expression.
The researchers observed markedly enhanced bone mineralization.
Based on these results, the researchers concluded that the baicalin/baicalein encapsulated in Ca-polyP microparticles enhances bone mineralization and the two flavones are good components of nutriceuticals for osteoporosis prevention or bone implants.
Wang X-H, Guo Y-W, Tolba E, Kokkinopoulou M, Wiens M, Schröder HC, Müller WE. TWO-ARMED ACTIVATION OF BONE MINERAL DEPOSITION BY THE FLAVONES BAICALIN AND BAICALEIN, ENCAPSULATED IN POLYPHOSPHATE MICROPARTICLES. The American Journal of Chinese Medicine. 2017;45(03):533–555. DOI: 10.1142/s0192415x1750032x