Isolation of Pro-Osteogenic Compounds from Euptelea polyandra That Reciprocally Regulate Osteoblast and Osteoclast Differentiation.

Plants contain a large number of small-molecule compounds that are useful for targeting human health and in drug discovery. Healthy bone metabolism depends on the balance between bone-forming osteoblast activity and bone-resorbing osteoclast activity. In an ongoing study searching for 22 plant extracts effective against osteoporosis, we found that the crude extract of Euptelea polyandra Sieb. et Zucc (E. polyandra) had osteogenic bioactivity. In this study, we isolated two compounds, isoquercitrin (1) and astragalin (2), responsible for osteogenic bioactivity in osteoblastic MC3T3-E1 cells from the leaf of E. polyandra using column chromatography and the spectroscopic technique. This is the first report to isolate astragalin from E. polyandra. Compounds (1) and (2) promoted osteoblast differentiation by increasing alkaline phosphatase (ALP) activity and alizarin red S stain-positive calcium deposition, while simultaneously suppressing tartrate-resistant acid phosphatase (TRAP)-positive osteoclast differentiation in RAW264.7 cells at non-cytotoxic concentrations. Isoquercitrin (1) and astragalin (2) increased the expression of osteoblastic differentiation genes, Osterix, ALP, and Osteoprotegerin in the MC3T3-E1 cells, while suppressing osteoclast differentiation genes, TRAP, Cathepsin K, and MMP 9 in the RAW264.7 cells. These compounds may be ideal targets for the treatment of osteoporosis due to their dual function of promoting bone formation and inhibiting bone resorption.

Purification and Biological Function of Caldecrin.

Blood calcium homeostasis is critical for biological function. Caldecrin, or chymotrypsin-like elastase, was originally identified in the pancreas as a serum calcium-decreasing factor. The serum calcium-decreasing activity of caldecrin requires the trypsin-mediated activation of the protein. Protease activity-deficient mature caldecrin can also reduce serum calcium concentration, indicating that structural processing is necessary for serum calcium-decreasing activity. Caldecrin suppresses the differentiation of bone-resorbing osteoclasts from bone marrow macrophages (BMMs) by inhibiting receptor activator of NF-κB ligand (RANKL)-induced nuclear factor of activated T-cell cytoplasmic 1 expression via the Syk-PLCγ-Ca2+ oscillation-calcineurin signaling pathway. It also suppresses mature osteoclastic bone resorption by RANKL-stimulated TRAF6-c-Src-Syk-calcium entry and actin ring formation. Caldecrin inhibits lipopolysaccharide (LPS)-induced osteoclast formation in RANKL-primed BMMs by inducing the NF-κB negative regulator A20. In addition, caldecrin suppresses LPS-mediated M1 macrophage polarization through the immunoreceptor triggering receptor expressed on myeloid cells (TREM) 2, suggesting that caldecrin may function as an anti-osteoclastogenic and anti-inflammatory factor via TREM2. The ectopic intramuscular expression of caldecrin cDNA prevents bone resorption in ovariectomized mice, and the administration of caldecrin protein also prevents skeletal muscle destruction in dystrophic mice. In vivo and in vitro studies have indicated that caldecrin is a unique multifunctional protease and a possible therapeutic target for skeletal and inflammatory diseases.

Caldecrin inhibits lipopolysaccharide-induced pro-inflammatory cytokines and M1 macrophage polarization through the immunoreceptor triggering receptor expressed in myeloid cells-2.

Caldecrin was previously isolated as a serum calcium-decreasing factor from the pancreas and is known to suppress receptor activator of nuclear factor-κB ligand (RANKL)-induced calcium oscillation pathways in osteoclasts. Here, we explored the effects of caldecrin on lipopolysaccharide (LPS)-Toll-like receptor-4 (TLR-4) signaling pathways in macrophages. Caldecrin inhibited the LPS-induced gene expression of pro-inflammatory cytokines and M1 macrophage polarization in mouse bone marrow macrophages and the RAW264.7 mouse macrophage cell line. Next, we focused on triggering receptor expressed in myeloid cells-2 (TREM-2) as a co-receptor common to RANKL receptor and TLR-4, and established Trem2-KO RAW264.7 cells, in which Trem2 gene was deleted using the CRISPR/Cas9 system. Caldecrin-mediated alterations in pro-inflammatory cytokine expression and M1 macrophage polarization were not observed in Trem2-KO RAW264.7 cells. These results suggest that caldecrin is not only an inhibitor of osteoclast activation but also a negative regulator of LPS-induced inflammatory responses, functioning via TREM-2.

Further Quantitative Structure-Cytotoxicity Relationship Analysis of 3-Styrylchromones.

BACKGROUND/AIM: Very few studies are available about the biological activity of 3-styrylchromones. Our previous study demonstrated the importance of methoxy group at 6-position of the chromone ring and hydroxyl group at 4'-position of phenyl group in styryl moiety. As a sequel of this study, we synthesized fourteen compounds that include eight 3-styrylchromones where methoxy group was introduced at 7-position of chromone rings, and then evaluated their tumor-specificity. MATERIALS AND METHODS: Tumor-specificity (TS) was calculated by relative cytotoxicity against human oral squamous cell carcinoma cell lines versus human normal oral cells. Apoptosis induction and growth arrest were monitored by cell-cycle analysis. Quantitative structure-activity relationship analysis of TS was performed with 3,167 chemical descriptors. RESULTS AND DISCUSSION: Two compounds, 7-methoxy-3-[(1E)-2-phenylethenyl]-4H-1-benzopyran-4-one [7] and 3-[(1E)-2-(4-hydroxyphenyl)ethenyl]-7-methoxy-4H-1-benzopyran-4-one [14] showed higher tumor-specificity than doxorubicin and 5-FU, suggesting the importance of methoxy group in 7-position of the chromone ring. These compounds induced the apoptosis and mitotic arrest in HSC-2 cells. The tumor-specificity of 3-styrylchromone derivatives were most correlated with descriptors for molecule shape and electronic charge. The present study suggested that modification by introducing methoxy group at 7-position, instead at 6-position, further increased the tumor-specificity of 3-styrylchromone.

Quantitative Structure-Cytotoxicity Relationship of 2-Arylazolylchromones and 2-Triazolylchromones.

BACKGROUND/AIM: 4H-1-Benzopyran-4-one (chromone), present in various flavonoids as a backbone structure, has been used for the synthesis of anticancer drugs. The study aimed at investigating the cytotoxicity of eight 2-arylazolylchromones and twelve 2-triazolylchromones against four human oral squamous cell carcinoma (OSCC) cell lines and three human normal mesenchymal oral cells, and then performed a quantitative structure-activity relationship (QSAR) analysis. MATERIALS AND METHODS: Cell viability was determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide method. The distribution of cells to various phases of cell cycle was determined by cell cycle analysis. A total of 3,218 physicochemical, structural and quantum chemical features were calculated for QSAR analysis from the most stabilized structure optimized using CORINA. RESULTS: 2-[4-(4-fluorophenyl)-1H-imidazol-1-yl]-4H-1-benzopyran-4-one [6] had the highest tumor-specificity (TS), comparable with that of 5-flurouracil (5-FU) and doxorubicin, inducing cytostatic growth inhibition, accumulation of G2+M phase cells with no cells in the G1 phase. All eight 2-triazolylchromones showed much lower tumor-specificity, confirming our previous finding. Tumor-specificity was also correlated with 3D shape, topological shape, size, ionization potential, and the presence of more than two aromatic rings in the molecule and imidazole ring in the nitrogen-containing heterocyclic ring. CONCLUSION: [6] can be a lead compound for designing anticancer drugs.

Quantitative Structure-Cytotoxicity Relationship of 2-Styrylchromones.

BACKGROUND/AIM: Studies of biological activity of 2-styrylchromone derivatives focusing on antioxidant, anti-inflammatory, antiviral and antitumor activity are limited. In this study, eighteen synthetic 2-styrylchromone derivatives were investigated for their cytotoxicity against human malignant and non-malignant cells, and then subjected to quantitative structure-activity relationship (QSAR) analysis. MATERIALS AND METHODS: Tumor-specificity was calculated by the ratio of mean 50% cytotoxic concentration (CC50) against four normal oral cells to that against oral squamous cell carcinoma cell lines. Induction of apoptosis and growth arrest were evaluated by cell-cycle analysis. For QSAR analysis, 3,117 types of physicochemical, structural, and quantum chemical features were calculated from the most stabilized structure of 2-styrylchromone derivatives. RESULTS: Two 2-styrylchromone derivatives in which a methoxy group was introduced at the 4-position of the benzene ring showed tumor-specificity equivalent to or higher than doxorubicin in TS value. These compounds accumulated the subG1 and G2/M phase cells, suggesting the induction of apoptosis. Their tumor-specificity can be explained mainly by molecular shape and electronic state. CONCLUSION: These findings suggest the applicability of 2-styrylchromone to develop safe and effective anticancer agents as seed compounds.

Quantitative Structure-Cytotoxicity Relationship of Azulene Amide Derivatives.

BACKGROUND/AIM: Very few studies of anticancer activity of azulene amides led us to investigate the cytotoxicity of 21 N-alkylazulene-1-carboxamides introduced either with 3-methyl [1-7], 7-isopropyl-3-methyl [8-14] or 2-methoxy group [15-21] Materials and Methods: Tumor-specificity (TS) was calculated by the ratio of mean 50% cytotoxic concentration (CC50) against three normal human oral mesenchymal cells to that against four human oral squamous cell carcinoma (OSCC) cell lines. Potency-selectivity expression (PSE) was calculated by dividing TS value by CC50 value against OSCC cell lines. Apoptosis-inducing activity was evaluated by caspase-3 activation and appearance of subG1 cell population. RESULTS: [8-14] showed higher TS and PSE values, than [1-7] and [15-21] The most active compound [8-14] induced apoptosis in C9-22 OSCC cells at 4-times higher CC50 Quantitative structure-activity relationship analysis of [1-14] demonstrated that their tumor-specificity was correlated with chemical descriptors that explain the molecular shape and hydrophobicity. CONCLUSION: 7-Isopropyl-3-methyl-N-propylazulene-1-carboxamide [8] can be a potential candidate of lead compound for manufacturing new anticancer drug.

Screening for natural medicines effective for the treatment of osteoporosis.

Bone-forming osteoblasts are differentiated from mesenchymal stem cells and dysregulation of this differentiation can lead to osteoporosis. Meanwhile, bone-resorbing osteoclasts are both differentiated and multinucleated from hematopoietic precursor cells of monocyte and/or macrophage lineage. Bone resorption inhibitors such as bisphosphonates and estrogen are used to treat osteoporosis. However, the adverse effects of the long-term use of these medicines are of concern, and so the development of new therapies to ameliorate osteoporosis is desirable. Therefore, in the present study, we screened 22 plant extracts and found that nine methanolic extracts of plants promote the differentiation of MC3T3-E1 cells to osteoblasts. These nine extracts were then evaluated for their inhibitory activity on osteoclast differentiation in RAW264.7 mouse macrophage cells. Of the nine extracts, Daucus carota, Vitis spp., Sasa veitchii, Euptelea polyandra, and Sesamum indicum exhibited pro-osteoblastic and anti-osteoclastic activity with low cytotoxicity, suggesting their potential effectiveness against osteoporosis.

Quantitative Structure-Cytotoxicity Relationship of Pyrano[4,3-b]chromones.

BACKGROUND/AIM: 4H-1-Benzopyran-4-one (chromone) provides a backbone structure for the chemical synthesis of potent anticancer drugs. Since studies of the biological activity of pyrano[4,3-b]chromones are limited, we investigated a total of 20 pyrano[4,3-b]chromones (10 sets of diastereomers) for their cytotoxicity against four human oral squamous cell carcinoma (OSCC) cell lines and human normal oral cells, and then carried out a quantitative structure-activity relationship (QSAR) analysis. MATERIALS AND METHODS: Cytotoxicity was determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide method. Tumor-specificity (TS) was evaluated by the ratio of mean 50% cytotoxic concentration (CC50) against normal oral cells to that against human OSCC cell lines. Potency-selectivity expression (PSE) value was calculated by dividing the TS value by the CC50 against tumor cells. Apoptosis induction was evaluated by morphological observation, western blot analysis and cell-cycle analysis. For QSAR analysis, a total of 3,072 physicochemical, structural and quantum chemical features were calculated from the most stabilized structure optimized using CORINA. RESULTS: 8-Chloro-4,4a-dihydro-3-methoxy-3-methyl-3H,10H-pyrano[4,3-b][1]benzopyran-10-one (16) and 3-ethoxy-4,4a-dihydro-8-methoxy-3H,10H-pyrano[4,3-b][1]benzopyran-10-one (17) had the highest TS, higher than that of 5-flurouracil and melphalan, without induction of apoptosis. Compound 16 induced cytostatic growth inhibition and much lower cytotoxicity against human normal oral keratinocytes compared to doxorubicin. TS of 20 pyrano[4,3-b]chromones was correlated with 3D structure, polarity, ionic potential and electric state. CONCLUSION: Chemical modification of 16 may be a potential choice for designing a new type of anticancer drug.

Quantitative Structure-Cytotoxicity Relationship of 3-(N-Cyclicamino)chromone Derivatives.

BACKGROUND/AIM: 4H-1-Benzopyran-4-ones (chromones) provide a backbone structure for the chemical synthesis of potent anticancer drugs. In contrast to 2-(N-cyclicamino)chromones, the biological activity of 3-(N-cyclicamino)chromones has not been reported. In this study, cytotoxicity of 15 3-(N-cyclicamino)chromone derivatives was investigated and subjected to quantitative structure-activity relationship (QSAR) analysis. MATERIALS AND METHODS: Cytotoxicity against four human oral squamous cell carcinoma cell lines and three oral normal mesenchymal cells was determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method. Tumor-specificity (TS) was evaluated as the ratio of mean 50% cytotoxic concentration (CC50) against normal oral cells to that against human oral squamous cell carcinoma cell lines. Potency-selectivity expression (PSE) value was calculated by dividing the TS value by the CC50 against tumor cells. Apoptosis induction was evaluated by morphological observation, western blot analysis and cell-cycle analysis. For QSAR analysis, a total of 3,096 physicochemical, structural and quantum chemical features were calculated from the most stabilized structure optimized using CORINA. RESULTS: 3-(4-phenyl-1-piperazinyl)-4H-1-benzopyran-4-one (3a) had the highest tumor specificity, comparable with that of melphalan, without induction of apoptosis. Compound 3a caused cytostatic growth inhibition and had much lower cytotoxicity against human oral keratinocytes compared to doxorubicin. TS of the 15 3-(N-cyclicamino)chromones was correlated with 3D structure and lipophilicity. CONCLUSION: Chemical modification of 3a may be a potential choice for designing a new type of anticancer drug.

Quantitative Structure-Cytotoxicity Relationship of 2-(N-cyclicamino)chromone Derivatives.

BACKGROUND/AIM: 4H-1-Benzopyran-4-ones (chromones) have provided backbone structure for the chemical synthesis of potent anticancer drugs. In this study, the cytotoxicity of fifteen 2-(N-cyclicamino)chromone derivatives was investigated and subjected to quantitative structure-activity relationship (QSAR) analysis. MATERIALS AND METHODS: Cytotoxicity against four human oral squamous cell carcinoma cell lines and three oral normal mesenchymal cells was determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method. Tumor specificity (TS) was evaluated by ratio of mean 50% cytotoxic concentration (CC50) against normal oral cells to that against human oral squamous cell carcinoma cell lines. Potency-selectivity expression (PSE) value was calculated by dividing the TS value by CC50 against tumor cells. Apoptosis induction was evaluated by morphological observation, western blot analysis and cell-cycle analysis. For QSAR analysis, a total of 3,089 physicochemicals, structural and quantum chemical features were calculated from the most stabilized structure optimized using Corina. RESULTS: 7-Methoxy-2-(4-morpholinyl)-4H-1-benzopyran-4-one (5c) showed highest tumor-specificity, comparable with that of doxorubicin, without inducing apoptosis. Tumor-specificity of fifteen 2-(N-cyclicamino) chromones was correlated with molecular shape, especially 3D-structure. CONCLUSION: Chemical modification of 5c may be a potential choice for designing a new type of anticancer drugs.

Search of Neuroprotective Polyphenols Using the "Overlay" Isolation Method.

Previous studies of the neuroprotective activity of polyphenols have used ununiform culture systems, making it difficult to compare their neuroprotective potency. We have established a new and simple method for preparing differentiated PC12 cells by removing the toxic coating step. Cells were induced to differentiate with the nerve growth factor (NGF) in a serum-free medium, without a medium change, but with a one-time overlay supplementation of NGF. The optimal inoculation density of the cells was 6⁻12 × 10³ cells/cm², and the presence of serum inhibited the differentiation. Neuroprotective activity could be quantified by the specific index (SI) value, that is, the ratio of the 50% cytotoxic concentration to the 50% effective concentration. Alkaline extract from the leaves of Sasa senanensis Rehder (SE), having had hormetic growth stimulation, showed the highest SI value, followed by epigallocatechin gallate. The SI value of curcumin and resveratrol was much lower. This simple overly method, that can prepare massive differentiated neuronal cells, may be applicable for the study of the differentiation-associated changes in intracellular metabolites, and the interaction between neuronal cells and physiological factors.

Protection of Differentiating Neuronal Cells from Amyloid ß Peptide-induced Injury by Alkaline Extract of Leaves of Sasa senanensis Rehder.

BACKGROUND/AIM: We have previously reported the protection of doxorubicin-induced keratinocyte toxicity by alkaline extract of the leaves of Sasa senanensis Rehder (SE). In order to extend the generality of the cell protective effect of SE, we investigated whether it also protects rat PC12 and human SH-SY5Y neuron model cells from amyloid ß-peptide (Aß)-induced injury. MATERIALS AND METHODS: Viability of cells was determined by the MTT method. Cytotoxicity was evaluated by the concentration that reduces the cell viability by 50% (CC50). Protection from Aß-induced cytotoxicity was evaluated by the concentration that reversed the Aß-induced reduction of viability by 50% (EC50). The selectivity index (SI) of neuroprotective activity was defined as the ratio of EC50 to CC50 Aß1-42 aggregation was assayed using Aß1-42 ammonium hydroxide. RESULTS: SE showed hormetic growth stimulation at lower concentrations in both neuron precursors and differentiated cells. SE reproducibly inhibited Aß-induced cytotoxicity against both undifferentiated and differentiated neuron cells. Both the extent of differentiation induction and viability depended on the cell density, suggesting the release of growth and differentiation stimulation substances into culture supernatant. Higher concentrations of SE partially reduced the Aß1-42 aggregation. CONCLUSION: Hormetic growth stimulation and inhibition of aggregation may be involved in the neuroprotective activity of SE.

Evaluation of Biological Activity of Mastic Extracts Based on Chemotherapeutic Indices.

BACKGROUND: Most previous mastic investigators have not considered its potent cytotoxicity that may significantly affect the interpretation of obtained data. In the present study, we re-evaluated several biological activities of mastic extracts, based on chemotherapeutic indexes. MATERIALS AND METHODS: Pulverized mastic gum was extracted with n-hexane and then with ethyl acetate or independently with methanol or n-butanol. Tumor specificity (TS) of the extracts was determined by their cytotoxicity against human malignant and non-malignant cells. Antibacterial activity was determined by their cytotoxicity against bacteria and normal oral cells. Antiviral activity was determined by their protection of viral infection and cytotoxic activity. Cytochrome P-450 (CYP) 3A4 activity was measured by ß-hydroxylation of testosterone. RESULTS: Ethyl acetate extract showed slightly higher tumor specificity (TS=2.6) and one order higher antibacterial activity (selectivity index (SI)=0.813) than other extracts (TS=1.4-2.5; SI=0.030-0.063). All extracts showed no anti-human immunodeficiency virus (HIV) activity, but some anti-herpes simplex virus (HSV) activity, which was masked by potent cytotoxicity. They showed strong inhibitory activity against CYP3A4. CONCLUSION: Ethyl acetate extraction following the removal of cytotoxic and CYP3A4 inhibitory substances by n-hexane can enhance antitumor and antibacterial activity of mastic.

Morphological Changes of Myoepithelial Cells in the Rat Submandibular Gland Following the Application of Surgical Stimuli.

Myoepithelial cells (MECs) exist on the basal surface of acini in major exocrine glands, include myofilaments and various constructive proteins, and share characteristics with smooth muscle and epithelial cells. MECs project several ramified processes to invest acini, and possibly contract to compress acini to support the secretion by the glandular cells. However, the functional roles of MECs in salivary secretion are still unclear. We investigated morphological changes in immunostained MECs using the anti-α-smooth muscle actin (αSMA) antibody in operated or non-operated contralateral (NC) submandibular glands after partial or total resection. Furthermore, we investigated and discuss other salivary glands of rats. MECs in the parotid, sublingual and submandibular gland of adult rats exhibited different shapes and localizations. After surgery, in both operated and NC glands, the number of MECs and αSMA-immunopositive areas increased significantly. Three-dimensional analysis using a confocal laser-scanning microscope revealed that substantial and significant enhancement became evident in the number, length, and thickness of MEC-processes covering acini of the operated and NC submandibular glands. The preset findings indicate that MECs alter the morphology of their processes in operated and NC glands after surgery of the partial or total resection. It is suggested that MECs promote salivary secretion using elongated, thickened, and more ramified processes.

Caldecrin: A pancreas-derived hypocalcemic factor, regulates osteoclast formation and function.

Caldecrin was originally isolated from the pancreas as a factor that reduced serum calcium levels. This secreted serine protease has chymotrypsin-like activity and is also known as chymotrypsin C; it belongs to the elastase family. Although intravenous administration of caldecrin decreases the serum calcium concentration even when its protease activity is blocked, this effect does require cleavage of caldecrin's pro-peptide by trypsin, converting it to the mature enzyme. Ectopic intramuscular expression of caldecrin prevented bone resorption in ovariectomized mice. Caldecrin inhibited parathyroid hormone-stimulated calcium release from fetal mouse long bone organ cultures. Furthermore, caldecrin suppressed the formation of osteoclasts from bone marrow cells by inhibiting the receptor activator of nuclear factor-κ B ligand (RANKL)-stimulated phospholipase Cγ-calcium oscillation-calcineurin-nuclear factor of activated T-cells, cytoplasmic 1 pathway. Caldecrin also suppressed the bone resorption activity of mature osteoclasts by preventing RANKL-stimulated Src activation, calcium entry, and actin ring formation. In vivo and in vitro studies have indicated that caldecrin is a unique multifunctional protease with anti-osteoclastogenic activities that are distinct from its protease activity. Caldecrin might be a potential therapeutic target for the treatment of osteolytic diseases such as osteoporosis and osteoarthritis. This mini-review describes caldecrin's historical background and its mechanisms of action.

Rhinacanthin C Inhibits Osteoclast Differentiation and Bone Resorption: Roles of TRAF6/TAK1/MAPKs/NF-κB/NFATc1 Signaling.

Rhinacanthin C is a naphthoquinone ester with anti-inflammatory activity, found in Rhinacanthus nasutus (L) Kurz (Acanthaceae). We found that rhinacanthin C inhibited osteoclast differentiation stimulated by the receptor activator of nuclear factor-κB ligand (RANKL) in mouse bone marrow macrophage cultures, although the precise molecular mechanisms underlying this phenomenon are unclear. In this study, we investigated the inhibitory mechanisms of rhinacanthin C in osteoclastogenesis. Rhinacanthin C suppressed RANKL-induced nuclear factor of activated T cells c1 (NFATc1) expression. Phosphorylation of ERK, JNK, and NF-κB, but not p38, was inhibited by rhinacanthin C, which also inhibited RANKL-stimulated TRAF6-TAK1 complex formation. Thus, the anti-osteoclastogenic effect of rhinacanthin C is mediated by a cascade of inhibition of RANKL-induced TRAF6-TAK1 association followed by activation of MAPKs/NF-κB; this leads to suppression of c-Fos and NFATc1, which regulate transcription of genes associated with osteoclast differentiation. In vivo, rhinacanthin C also reduced RANKL-induced osteoclast formation and bone resorption in mouse calvaria. Rhinacanthin C also suppressed LPS-stimulated osteoclastogenesis and bone resorption in vitro and in vivo. Rhinacanthin C may provide a novel therapy for abnormal bone lysis that occurs during inflammatory bone resorption.

New biological activities of Rhinacanthins from the root of Rhinacanthus nasutus.

BACKGROUND: We recently reported that the ethyl acetate (EtOAc)-soluble fraction of the methanol extract of the root of Rhinacanthus nasutus showed tumor-specific non-apoptotic cytotoxicity and antiosteoclastogenic activity. In the present study, we investigated whether five rhinacanthins, mostly isolated from the EtOAc-soluble fraction of this plant, are responsible for these activities. MATERIALS AND METHODS: The cytotoxic activity was determined by 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) method. The 50% cytotoxic concentration (CC(50)) was determined by the dose-response curve. Tumor specificity (TS) was determined by the ratio of the mean CC(50) for normal cells to that of tumor cell lines. DNA fragmentation was assayed by agarose gel electrophoresis. Caspase-3 activation was monitored by substrate cleavage assay. Osteoclastogenesis was monitored by tartrate-resistant acid phosphatase (TRAP) activity in receptor activator of NF-κB ligand (RANKL)-stimulated bone marrow-derived macrophages. RESULTS: Among five rhinacanthins (rhinacanthin C, G, N and Q, and rhinacanthone), rhinacanthin C exhibited the highest tumor specificity (TS=15.2). Rhinacanthin C did not induce internucleosomal DNA fragmentation nor caspase-3 activation, suggesting non-apoptotic cell death. Rhinacanthin C most potently inhibited the RANKL-stimulated osteoclastogenesis. CONCLUSION: The present study suggests that rhinacanthin C may be responsible for the biological activity of the EtOAc-soluble fraction prepared from the methanolic extract of R. nasutus we previously reported on.

Pilot clinical study of Sasa senanensis Rehder leaf extract treatment on lichenoid dysplasia.

BACKGROUND: Previous studies have shown antiviral, antibacterial, and anti-inflammatory activity of alkaline extract of the leaves of Sasa senanensis Rehder (SE). Here, we investigated whether SE is effective on oral lichenoid dysplasia and osteoclastogenesis. MATERIALS AND METHODS: A male patient with white lacy streaks in the oral mucosa was orally administered SE three times a day for 11 months. The area of white streaks was monitored by intraoral photography. Interleukin-6 and -8 in the saliva were determined by enzyme-linked immunosorbent assay. Osteoclastogenesis of mouse macrophage-like RAW264.7 cells, induced by receptor activator of nuclear factor-κB ligand (RANKL) was monitored by tartrate-resistant acid phosphatase (TRAP)-positive multinuclear cell formation. RESULTS: Long-term treatment with SE progressively reduced both the area of white steaks and the levels of salivary interleukin-6 and -8. SE significantly inhibited the macrophage differentiation towards osteoclasts. CONCLUSION: The present study suggests the therapeutic potential of SE towards oral diseases.

In search of new biological activities of isolates from Odontoglossum Harvengtense 'Tutu'.

BACKGROUND: In the current study, we isolated four known compounds, two phenanthrenes, 2,5-dihydroxy-4,9-dimethoxy phenanthrene [1] and 4-methoxyphenanthrene-2,7-diol (flavanthrinin) [2], one phenanthrenequinone, 5-hydroxy-2,3-dimethoxy-1,4-phenanthrenequinone [3], and one flavone, 3,5,7-trihydroxyflavone (galangin) [4], from the ethyl acetate (EtOAc) extract of Odontoglossum Harvengtense 'Tutu' through bioassay-guided fractionation, and investigated their biological activities. MATERIALS AND METHODS: The isolated compounds were identified with spectroscopic analysis and through comparison to literature values. Cytotoxic activity towards human tumor and normal cells was determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method. Nitric oxide (NO) was determined by the Griess method. Radical scavenging activity was determined by electron spin resonance (ESR) spectroscopy. Osteoclastogenesis was monitored by tartrate-resistant acid phosphatase (TRAP) activity. RESULTS: The compounds had slightly higher cytotoxicity towards human oral squamous cell carcinoma and leukemia cell lines as compared with human normal oral cells, yielding a tumor specificity value of 1.1-2.7. Among these four compounds, 1 most potently inhibited the lipopolysaccharide (LPS)-stimulated NO production and the receptor activator of nuclear factor-κB ligand (RANKL)-stimulated osteoclastogenesis by mouse macrophage-like RAW264.7 cells. Micromolar concentrations of 1 scavenged the NO radical produced from 1-hydroxy-2-oxo-3-(N-3-methyl-3-aminopropyl)-3-methyl-1-triazene. CONCLUSION: The present study demonstrated, for the first time, that 1 inhibited both macrophage activation and osteoclast differentiation, suggesting its possible anti-inflammatory action.