Phillygenin prevents osteoclast differentiation and bone loss by targeting RhoA.

Forsythia suspensa tea is a popular traditional Chinese medicine decoction for its healthy and therapeutic benefits. However, its effects in bone metabolism were not clear. In recent study, we uncovered anti-osteoclastogenesis property of Phillygenin (Phi), a compound abundant in Forsythia suspensa leaves, and aimed to investigate the effect and mechanism of Phi on bone metabolism in vivo and in vitro. Lipopolysaccharides-induced murine calvaria osteolysis and ovariectomy-induced bone loss animal models were used to identify the bone-protective effect of Phi in vivo and micro-CT, pQCT, and TRAP staining were applied. We used CCK8, TUNEL, BrdU, and TRAP staining to evaluate the efficacy of Phi on the proliferation and formation of OCs in primary mBMMs. RNA sequence, activity-based protein profiling, molecular docking, G-LISA, and WB were used to inspect the target and underlying mechanism of Phi's actions in mBMMs. We found Phi significantly inhibited bone resorption in vivo and inhibited mBMMs osteoclastogenesis in vitro. Ras homolog gene family member A (RhoA) was identified as the direct target of Phi. It counteracted the effects of RhoA activator and acted as a RhoA inhibitor. By targeting RhoA, Phi modulated Rho-associated coiled-coil containing protein kinase 1 (ROCK1) activity and regulated its downstream NF-κB/NFATc1/c-fos pathway. Furthermore, Phi depressed the disassembling of F-actin ring through cofilin and myosin1a. Our findings provided Phi as a potential option for treating bone loss diseases by targeting RhoA and highlighted the importance of F. suspensa as a preventive approach in bone disorders.

α-Asarone Attenuates Osteoclastogenesis and Prevents Against Oestrogen-Deficiency Induced Osteoporosis.

Osteoporosis (OP) is defined as low bone mineral density which features over activated osteoclasts (OCs) and bone resorption. Targeting excessive OCs activity is thought to be an effective therapeutic approach for OP treatment. α-asarone (ASA), a compound from the traditional Chinese medicinal herb Acorus tatarinowii, has been widely used as a therapeutic agent against several diseases such as epilepsy, cough, bronchitis and asthma for many years. Recently, it was reported that ASA-derived lignins which were purified from Acorus tatarinowii root tissues effectively suppressed both RANKL-induced osteoclastogenesis and bone resorption. Besides, a classic Chinese formulation Bajitianwan (BJTW) which consisted of root and rhizome of Acorus tatarinowii Schott also showed positive effects on age-related bone loss. In the present study, we aimed to study the effects of ASA on osteoclastogenesis in vitro and in vivo. As illustrated by TRAP staining, ASA was capable of inhibiting RANKL-induced osteoclastogenesis in a dose-dependent manner, not only at an early-stage, but also in the late-stage. Besides, it also effectively suppressed bone resorption of mature OCs in a pit resorption assay. The formation of F-actin ring during osteoclastogenesis, which was important in OCs bone-resorption, was impaired as well. Subsequent mechanism experiments exposed that ASA inhibited osteoclastogenesis related genes in a time-dependent manner through AKT, p38 and NF-κB, followed by NFATc1/c-fos signaling pathway. Notably, our in vivo study uncovered that ASA was capable of improving the bone microstructure in oestrogen-deficiency induced OP models. Thus, our current work highlighted the important role of an old drug ASA in bone metabolism especially in OCs differentiation. ASA may find its potential as a lead compound to treat excessive OCs activity-induced bone loss diseases and more structure optimization is further needed.

First Report on Inhibitory Effect against Osteoclastogenesis of Dihydro-ß-agarofuran-Type Sesquiterpenoids.

Dihydro-ß-agarofuran-type sesquiterpenoids are characteristic metabolites of Celastraceae plants, and the extracts of these plants have been developed into botanical pesticides. In the course of our efforts to find novel natural biologically active products, eight new dihydro-ß-agarofuran-type sesquiterpenoids (1-8) were identified from the stems of Celastrus monospermus Roxb. Their structures were elucidated by extensive spectroscopic analysis, single crystal X-ray crystallography, and electronic circular dichroism (ECD) calculations. In consideration of the efficacy of certain Celastrus plants for the treatment of arthritis and arthralgia in folk medicine, the isolates were evaluated for their inhibitory activities against osteoclastogenesis. As a result, compounds 4, 6, and 7 were found to restrain osteoclastogenesis induced by receptor activator of nuclear factor-κB ligand (RANKL) with IC50 values of 0.58, 1.2, and 6.1 µM, respectively. Furthermore, compound 4 was found to inhibit osteoclastogenesis-related gene (c-Fos, MMP-9, CTSK, TRAP) expression and block c-Fos protein expression and inhibited bone resorption of mature osteoclasts induced by M-CSF and RANKL in a dose dependent manner. This is the first report of dihydro-ß-agarofuran-type sesquiterpenoid for their potential medical applications in bone metabolic diseases.

[Chemistry research on natural product derivatives of dihydro-ß-agarofuran sesquiterpenoids].

Dihydro-ß-agarofuran sesquiterpenoids possess chemical diversity and biodiversity. A dihydro-ß-agarofuran sesquiterpenoid with only hydroxyl groups has been prepared by basic hydrolysis of crude extract of Euonymus bungeanus with 0.4% yield. Twelve derivatives were available in esterification, oxidation, decarboxylation, etc. Extensive ~1H-NMR,~(13)C-NMR, MS spectroscopic analyses and single-crystal X-ray diffraction analysis with Cu Kα radiation indicated that eleven derivatives were new compounds. The results will provide reference for chemistry study on natural product derivatives of dihydro-ß-agarofuran sesquiterpenoids.

Natural ß-Dihydroagarofuran-Type Sesquiterpenoids as Cognition-Enhancing and Neuroprotective Agents from Medicinal Plants of the Genus Celastrus.

Alzheimer's disease (AD) is an irreversible, multifaceted, and progressive neurodegenerative disorder. Over the past 30 years, the search for anti-AD drugs has been primarily based on the cholinergic deficiency hypothesis and/or the ß-amyloid (Aß) cascade hypothesis. In this study, we report the identification of 16 new and 38 known ß-dihydroagarofuran-type sesquiterpenoids from Celastrus flagellaris and Celastrus angulatus. The ß-dihydroagarofuran-type sesquiterpenoids 58, 59, 61, and 63 significantly attenuated scopolamine-induced prolonged escape latency and increased number of errors compared with the control group. At 10 µM, 21 of the 62 tested ß-dihydroagarofuran-type sesquiterpenoids rescued Aß25-35-induced SH-SY5Y cells from viability reduction, which increased the cell viability from 64.6% for the model to more than 74.0%. The majority of the ß-dihydroagarofuran-type sesquiterpenoids with ester groups exhibited stronger activity than those with free hydroxy groups or without substituents at the same positions. These results identified a new chemical skeleton as drug lead for the investigation of novel therapeutic agents against AD.

Lithocarpic acids O-S, five homo-cycloartane derivatives from the cupules of Lithocarpus polystachyus.

Chemical investigation of the cupules of Lithocarpus polystachyus resulted in the identification of four 3,4-seco-homo-cycloartane and one homo-cycloartane derivatives named lithocarpic acids O-S. Their structures were determined based on extensive 1D/2D NMR, IR, MS spectroscopic analyses and chemical methods. Lithocarpic acid O (1) exhibited inhibitory activities on mouse and human isozymes of 11ß-hydroxysteroid dehydrogenase type 1 (11ß-HSD1) with IC50 values of 0.49 and 1.1 µM, respectively.

Lithocarpic Acids A-N, 3,4-seco-Cycloartane Derivatives from the Cupules of Lithocarpus polystachyus.

Fourteen new 3,4-seco-cycloartane-type triterpenes, lithocarpic acids A-N (1-14), together with one known compound, coccinetane E (15), were identified from the cupules of Lithocarpus polystachyus. The structures of 1-14 were determined by spectroscopic data analysis and chemical methods, and the absolute configurations of 1 and 4 were defined unequivocally by X-ray crystallography using Cu Kα radiation. Compounds 1-15 are the first examples of 3,4-seco-cycloartane derivatives isolated from the genus Lithocarpus. Among them, compounds 1 and 2, 9 and 10, and 11 and 12 were found to be three pairs of C-24 epimers, while compounds 7 and 8 represent the first examples of 3,4-seco-norcycloartane-type triterpenes. Compound 1, as the major component of the plant extract, showed potent antibacterial activity against Micrococcus luteus and Bacillus subtilis, with MIC values of 3.1 and 6.3 µg/mL, respectively, as well as inhibitory activity against human and mouse 11ß-hydroxysteroid dehydrogenase type 1, with IC50 values of 1.9 and 0.24 µM, respectively.