Differentiation of skeletal osteogenic progenitor cells to osteoblasts with 3,4-diarylbenzopyran based amide derivatives: Novel osteogenic agents.

A series of 3,4-diarylbenzopyran based amide derivatives was synthesized and evaluated for osteogenic activity in in vitro and in vivo models of osteoporosis. Compounds 17a, 21b-c and 22a-b showed significant osteogenic activity in osteoblast differentiation assay. Among the synthesized compounds, 22b was identified as lead molecule which showed significant osteogenic activity at 1 pM concentration in osteoblast differentiation assay and at 1 mg kg(-1) body weight dose in estrogen deficient balb/c mice model. In vitro bone mineralization and expression of osteogenic marker genes viz BMP-2, RUNX-2, OCN, and collagen type 1 further confirmed the osteogenic potential of 22b. Gene expression study for estrogen receptor α and β (ER-α and ER-β) in mouse calvarial osteoblasts (MCOs) unveiled that possibly 22b exerted osteogenic efficacy via activation of Estrogen receptor-β preferentially. In vivo pharmacokinetic, estrogenicity and acute toxicity studies of 22b showed that it had good bioavailability and was devoid of uterine estrogenicity at 1 mg kg(-1) and inherent toxicity up to 1000 mg kg(-1) body weight dose respectively.