Piper longum linn has traditionally been used for the treatment of respiratory and gastrointestinal disorders in India. Although various pharmacological effects of P. longum have been studied, its effects on bone have not been clearly elucidated. Therefore, this study examined the inhibitory effect of the water extract of P. longum Linn (WEPL) on osteoclast differentiation. WEPL directly affected the osteoclast precursors and suppressed osteoclast differentiation in vitro. In addition, the expression levels of c-Fos and nuclear factor of activated T cells 1, a critical transcription factor for osteoclastogenesis, were significantly downregulated by WEPL via the suppression of the receptor activator of nuclear factor (NF)-κB ligand-induced mitogen-activated protein kinase and NF-κB signaling pathways. Consistent with the in vitro results, oral administration of WEPL (100 and 300 mpk) to ovariectomized mice for six weeks relieved the OVX-induced bone loss. We also identified phytochemicals in WEPL that are reported to exert inhibitory effects on osteoclastogenesis and/or bone loss. Collectively, the findings of our study indicate that WEPL has an anti-osteoporotic effect on OVX-induced bone loss by diminishing osteoclast differentiation, suggesting that it may be useful to treat several bone diseases caused by excessive bone resorption.

Euonymus alatus (Thunb.) Siebold, a traditional medicinal plant, has been used in China and several other Asian countries to address a variety of health concerns. The extensive research conducted on E. alatus is driven by its diverse pharmacological applications. However, its biological effects on osteoclastogenesis and osteoporosis have not been previously studied. In this research, we investigated the impact of an ethanolic extract of E. alatus (EEEA) on osteoclast differentiation and function as well as estrogen deficiency-induced bone loss. We found that EEEA inhibits osteoclast differentiation by downregulating the expression of the receptor activator of nuclear factor-κB ligand (RANKL) in osteoclast-supporting cells and by directly impeding RANKL-mediated signaling pathways for osteoclastogenesis in precursor cells. In addition, EEEA inhibited the bone-resorptive function of mature osteoclasts in vitro. Furthermore, oral administration of EEEA significantly alleviated bone loss in an ovariectomy-induced osteoporosis mouse model. Additionally, we identified phytochemicals in EEEA that have suppressive effects on osteoclast differentiation and bone loss. Collectively, these results suggest that EEEA holds potential as a biotherapeutic candidate for anti-postmenopausal osteoporosis.

Fritillariae thunbergii bulbus has been widely used to treat symptoms of coughs and airway congestion in the chest due to pathological colds and damp phlegm in traditional Chinese medicine. Despite its long history of traditional use, its pharmacological activities on osteoclastogenesis and osteoporosis have not been evaluated. This study investigated the effects of the water extract of Fritillariae thunbergii bulbus (WEFT) on osteoclast differentiation in bone marrow-derived macrophage cells and on ovariectomy (OVX)-induced osteoporosis in mice. We found that WEFT significantly inhibited osteoclastogenesis by downregulating the receptor activator of the NF-κB ligand (RANKL) signaling-induced nuclear factor of activated T-cells cytoplasmic 1 (NFATc1) expression. In an OVX-induced osteoporosis model, WEFT significantly prevented the OVX-induced trabecular loss of femurs, accompanied by a reduction in fat accumulation in the bone marrow and liver. In addition, WEFT significantly prevented weight gain and gonadal fat gain without recovering uterine atrophy. Using ultrahigh-performance liquid chromatography-tandem mass spectrometry, seven alkaloids (peimisine glucoside, yibeissine, peiminoside, sipeimine-glucoside, peimisine, peimine, and peiminine) were identified in WEFT. The results of this study suggest that WEFT can be a potential pharmacological candidate to reduce menopausal osteoporosis and menopause-related symptoms, such as fat accumulation.

Angelica dahurica radix has a long history of traditional use in China and Korea for treating headaches, cold-damp pain and skin diseases. Despite various pharmacological studies on A. dahurica, its impact on bones remains unclear. Hence, this study investigated the inhibitory effect of A. dahurica’s radix water extract (WEAD) on osteoclast differentiation. In vitro experiments showed that WEAD effectively suppresses osteoclast differentiation. Treatment of an osteoclast precursor with WEAD significantly suppressed the expression of nuclear factor of activated T-cells 1 (NFATc1), essential transcription factor for osteoclastogenesis, while increasing the expression of negative regulators, interferon regulatory factor 8 (Irf8) and v-maf musculoaponeurotic fibrosarcoma oncogene homolog B (MafB). Consistent with the in vitro findings, the oral administration of WEAD (100 and 300 mg/kg/day) to mice subjected to surgical ovariectomy for a duration of six weeks alleviated bone loss, while also mitigating weight gain and liver fat accumulation. In addition, we also identified phytochemicals present in WEAD, known to regulate osteoclastogenesis and/or bone loss. These results suggest the potential use of WEAD for treating various bone disorders caused by excessive bone resorption.

Radix Asteris, the root of Aster tataricus L. f., is historically significant in East Asian medicine for treating respiratory conditions. Yet, its implications on bone health remain uncharted. This research investigated the impact of an aqueous ethanol extract of Radix Asteris (EERA) on osteoclast differentiation and its prospective contribution to osteoporosis management. We discerned that EERA retards osteoclast differentiation by inhibiting receptor activator of nuclear factor kappa-B ligand (RANKL) expression and obstructing RANKL-induced osteoclastogenesis. EERA markedly suppressed RANKL-induced expression of NFATc1, a pivotal osteoclastogenic factor, via modulating early RANK signaling. EERA’s therapeutic potential was underscored by its defense against trabecular bone degradation and its counteraction to increased body and perigonadal fat in ovariectomized mice, mirroring postmenopausal physiological changes. In the phytochemical analysis of EERA, we identified several constituents recognized for their roles in regulating bone and fat metabolism. Collectively, our findings emphasize the potential of EERA in osteoclast differentiation modulation and in the management of osteoporosis and associated metabolic changes following estrogen depletion, suggesting its suitability as an alternative therapeutic strategy for postmenopausal osteoporosis intertwined with metabolic imbalances.

Pulsatilla koreana Nakai (P. koreana) is a perennial herb traditionally used to treat malaria and fever. Although the pharmacological properties of P. koreana have been explored in various contexts, its effects on bone diseases, such as osteoporosis, remain poorly studied. In this study, we investigated the effects of water extracts of P. koreana (WEPK) on osteoclasts, which play a crucial role in bone remodeling, and an ovariectomized (OVX) mouse model, which mimics osteoporosis. Phytochemical profiling of WEPK revealed several compounds that regulate bone or fat metabolism. WEPK suppressed osteoclast differentiation by downregulating the expression of receptor activator of nuclear factor-κB ligand (RANKL), a cytokine that induces osteoclastogenesis. Additionally, WEPK directly inhibited RANKL-induced differentiation of osteoclast precursors by downregulating nuclear factor of activated T cells 1 (NFATc1), the master transcription factor for osteoclastogenesis, by modulating its upstream regulators. In vivo, oral administration of WEPK suppressed bone loss, reduced weight gain, and mitigated fat accumulation in the liver and gonadal tissues of OVX mice. Given its positive impact on bone and fat accumulation under estrogen deficiency, WEPK may serve as a promising alternative therapy for postmenopausal osteoporosis, especially when accompanied by other metabolic disorders, such as obesity and fatty liver.