Osteoporosis is the result of an imbalance in the bone-remodeling process via an increase in osteoclastic activity and a decrease in osteoblastic activity. Our previous studies have shown that Perilla frutescens seed meal has anti-osteoclastogenic activity. However, the role of perilla leaf hexane fraction (PLH) in osteoporosis has not yet been investigated and reported. In this study, we aimed to investigate the effects of PLH in osteoclast differentiation and osteogenic potential using cell-based experiments in vitro. From HPLC analysis, we found that PLH contained high luteolin and baicalein. PLH was shown to inhibit RANKL-induced ROS production and tartrate-resistant acid phosphatase (TRAP)-positive multi-nucleated osteoclasts. Moreover, PLH significantly downregulated the RANKL-induced MAPK and NF-κB signaling pathways, leading to the attenuation of NFATc1 and MMP-9 expression. In contrast, PLH enhanced osteoblast function by regulating alkaline phosphatase (ALP) and restoring TNF-α-suppressed osteoblast proliferation and osteogenic potential. Thus, luteolin and baicalein-rich PLH inhibits osteoclast differentiation but promotes the function of osteoblasts. Collectively, our data provide new evidence that suggests that PLH may be a valuable anti-osteoporosis agent.
Keywords: Perilla frutescens; RANKL; TNF-α; osteoblast; osteoclast; osteoporosis.