Ginseng (Panax ginseng) leaf extract modulates the expression of heme oxygenase-1 to attenuate osteoclast differentiation.

Osteoporosis is an aging disease characterized by an imbalance between bone formation and resorption. However, drugs that inhibit bone resorption have various adverse effects. Ginseng (Panax ginseng), a prominent herbal medicine in East Asia for >2000 years, is renowned for its manifold beneficial properties, including antioxidant, anti-cancer, anti-diabetic, and anti-adipogenic activities. Despite its long history of use, the pharmacological functions of ginseng leaves are not yet fully comprehended. In this study, we evaluated the potential effects of ginseng leaf extract (GLE) on receptor activator of nuclear factor κB ligand (RANKL)-induced osteoclast differentiation in RAW264.7 macrophage cells. Tartrate-resistant acid phosphatase (TRAP) staining revealed that GLE had significant anti-osteoclastogenic activity. GLE significantly reduced mRNA levels of osteoclast differentiation markers including TRAP, nuclear factor of activated T cell cytoplasmic 1, and cathepsin K. It also suppressed the production of reactive oxygen species (ROS) and secretion of high mobility group box-1 (HMGB1) in RANKL-treated RAW264.7 cells. In addition, GLE upregulated dose- and time-dependently the expression of heme oxygenase-1 (HO-1), eventually suppressing ROS production and HMGB1 secretion. This effects of GLE were significantly reversed by Tin Protoporphyrin IX dichloride, an inhibitor of HO-1, and HO-1 shRNA, indicating that HO-1 potently inhibits RANKL-induced osteoclast differentiation by inhibiting ROS production and HMGB1 secretion. Taken together, these observations suggest that GLE could have therapeutic potential as a natural product-derived medicine for the treatment of bone disorders.

Red clover (Trifolium pratense L.) extract inhibits ferroptotic cell death by modulating cellular iron homeostasis.

ETHNOPHARMACOLOGICAL RELEVANCE: Red clover (Trifolium pratense L.) is a traditional Chinese medicine and use as herbal medicine which has the effects of regulating menopausal symptoms, heart problem, inflammatory disease, psoriasis and cognitive deficits. In previous reported, the studies of red clover were mainly focused on clinical practice. the pharmacological functions of red clover not fully elucidated. AIM OF THE STUDY: To identify the molecules that regulate ferroptosis, we examined whether red clover (Trifolium pratense L.) extracts (RCE) affected ferroptosis induced by chemical treatment or cystine/glutamate antiporter (xCT) deficiency. MATERIALS AND METHODS: Cellular models for ferroptosis were induced by erastin/Ras-selectiv lethal 3 (RSL3) treatment or xCT deficiency in mouse embryonic fibroblasts (MEFs). Intracellular iron and peroxidized lipid levels were determined using Calcein-AM and BODIPY-C11 fluorescence dyes, respectively. Protein and mRNA were quantified by Western blot and real-time polymerase chain reaction, respectively. RNA sequencing analysis was performed on xCT-/- MEFs. RESULTS: RCE significantly suppressed ferroptosis induced by both erastin/RSL3 treatment and xCT deficiency. The anti-ferroptotic effects of RCE correlated to ferroptotic phenotypic changes such as cellular iron accumulation and lipid peroxidation in cellular ferroptosis models. Importantly, RCE affected levels of iron metabolism-related proteins including iron regulatory protein 1, ferroportin 1 (FPN1), divalent metal transporter 1, and transferrin receptor. RNA sequencing analysis of xCT-/- MEFs identified that expression of cellular defense genes was upregulated, while expression of cell death-related genes was downregulated, by RCE. CONCLUSION: RCE potently suppressed ferroptosis triggered both by erastin/RSL3 treatment and xCT deficiency by modulating cellular iron homeostasis. This is the first report that RCE has therapeutic potential in diseases associated with ferroptotic cell death, particularly ferroptosis induced by dysregulation of cellular iron metabolism.

Ginseng leaf extract ameliorates the survival of endotoxemic mice by inhibiting the release of high mobility group box 1.

High mobility group box 1 (HMGB1) is a well-defined mediator involved in the pathophysiologic response to endotoxemia and sepsis. However, the mechanisms and therapeutic agents that could prevent its release are not fully elucidated. Here, the present study demonstrates that the ginseng leaf extract (GLE) regulates lipopolysaccharide (LPS)-triggered release of HMGB1 in macrophages and endotoxemic animal model. Treatment of RAW264.7 macrophages with GLE significantly inhibited the release of HMGB1 stimulated by LPS. GLE also suppressed the generation of nitric oxide (NO) and expression of inducible NO synthase (iNOS) in a dose-dependent manner. These effects of GLE were accompanied by inhibition of HMGB1 release stimulated by LPS, indicating a potential mechanism by which GLE regulates HMGB1 release through NO signaling. Furthermore, induction of suppressor of cytokine signaling 1 by GLE-mediated GLE-dependent suppression of HMGB1 release and NO/iNOS induction by inhibiting Janus kinase 2/signal transducer and activator of transcription 1 signal in RAW 264.7 cells exposed to LPS. Finally, administration of the GLE ameliorated the survival rate of LPS-injected endotoxemic mice in a NO-dependent manner. Thus, GLE may block the LPS-stimulated release of HMGB1 by regulating cellular signal networks, thereby providing a therapeutic strategy for endotoxemia as a functional food. PRACTICAL APPLICATIONS: High mobility group box 1 (HMGB1) is released into the extracellular milieu when immune cells are exposed to pathogen-related molecules such as lipopolysaccharide (LPS), in which it acts as a critical mediator of lethality in sepsis and endotoxemia. The extract of ginseng leaf, which is a part that can be easily thrown away, ameliorated the survival rate of endotoxemic mice by inhibiting HMGB1 secretion in a NO-dependent manner. Thus, this study suggests that ginseng leaf can be used as a functional food by resolving the immune responses in the pathology of endotoxemia.