Stimulatory effect of curcumin on osteoclast apoptosis

Inhibitors of osteoclast differentiation from Cephalotaxus koreana

Three new flavonoid glycosides ( 1- 3), 11-hydroxyhainanolidol ( 4), and a new dibenzylbutyrolactone lignan glycoside ( 5) were isolated from the aerial parts of Cephalotaxus koreana Nakai, along with 19 known flavonoids. The structures of the new compounds were elucidated using spectroscopic evidence, primarily NMR and MS. Twenty-four compounds were isolated, and among these isoscutellarein 5-O-beta-D-glucopyranoside ( 3), apigenin ( 6), kaempferol 3-O-alpha-L-rhamnopyranosyl(1'''-->6'')-beta-D-glucopyranoside ( 7), tamarixetin 3-O-alpha-L-rhamnopyranosyl(1'''-->6'')-beta-D-glucopyranoside ( 8), quercetin 3-O-[6''-O-acetyl]-beta-D-glucopyranoside ( 9), and quercetin 3-O-alpha-L-rhamnopyranoside ( 10) showed significant inhibitory activities against osteoclast differentiation at concentrations of 0.1 and 1.0 microg/mL.

CURCUMIN: THE INDIAN SOLID GOLD

Turmeric, derived from the plant Curcuma longa, is a gold-colored spice commonly used in the Indian subcontinent, not only for health care but also for the preservation of food and as a yellow dye for textiles. Curcumin, which gives the yellow color to turmeric, was first isolated almost two centuries ago, and its structure as diferuloylmethane was determined in 1910. Since the time of Ayurveda (1900 Bc) numerous therapeutic activities have been assigned to turmeric for a wide variety of diseases and conditions, including those of the skin, pulmonary, and gastrointestinal systems, aches, pains, wounds, sprains, and liver disorders. Extensive research within the last half century has proven that most of these activities, once associated with turmeric, are due to curcumin. Curcumin has been shown to exhibit antioxidant, anti-inflammatory, antiviral, antibacterial, antifungal, and anticancer activities and thus has a potential against various malignant diseases, diabetes, allergies, arthritis, Alzheimer's disease, and other chronic illnesses. These effects are mediated through the regulation of various transcription factors, growth factors, inflammatory cytokines, protein kinases, and other enzymes. Curcumin exhibits activities similar to recently discovered tumor necrosis factor blockers (e.g., HUMIRA, REMICADE, and ENBREL), a vascular endothelial cell growth factor blocker (e.g., AVASTIN), human epidermal growth factor receptor blockers (e.g., ERBITUX, ERLOTINIB, and GEFTINIB), and a HER2 blocker (e.g., HERCEPTIN). Considering the recent scientific bandwagon that multitargeted therapy is better than monotargeted therapy for most diseases, curcumin can be considered an ideal "Spice for Life".

Efficacy and mechanism of action of turmeric supplements in the treatment of experimental arthritis

OBJECTIVE

Scientific evidence is lacking for the antiarthritic efficacy of turmeric dietary supplements that are being promoted for arthritis treatment. Therefore, we undertook studies to determine the antiarthritic efficacy and mechanism of action of a well-characterized turmeric extract using an animal model of rheumatoid arthritis (RA).

METHODS

The composition of commercial turmeric dietary supplements was determined by high-performance liquid chromatography. A curcuminoid-containing turmeric extract similar in composition to these supplements was isolated and administered intraperitoneally to female Lewis rats prior to or after the onset of streptococcal cell wall-induced arthritis. Efficacy in preventing joint swelling and destruction was determined clinically, histologically, and by measurement of bone mineral density. Mechanism of action was elucidated by analysis of turmeric's effect on articular transcription factor activation, microarray analysis of articular gene expression, and verification of the physiologic effects of alterations in gene expression.

RESULTS

A turmeric fraction depleted of essential oils profoundly inhibited joint inflammation and periarticular joint destruction in a dose-dependent manner. In vivo treatment prevented local activation of NF-kappaB and the subsequent expression of NF-kappaB-regulated genes mediating joint inflammation and destruction, including chemokines, cyclooxygenase 2, and RANKL. Consistent with these findings, inflammatory cell influx, joint levels of prostaglandin E(2), and periarticular osteoclast formation were inhibited by turmeric extract treatment.

CONCLUSION

These translational studies demonstrate in vivo efficacy and identify a mechanism of action for a well-characterized turmeric extract that supports further clinical evaluation of turmeric dietary supplements in the treatment of RA.

Momordin I, an inhibitor of AP-1, suppressed osteoclastogenesis through inhibition of NF-kappaB and AP-1 and also reduced osteoclast activity and survival

Osteoclasts originating from hematopoietic precursor cells differentiate into multinucleated cells through multiple steps. The essential roles of NF-kappaB and AP-1 in osteoclast differentiation have been clearly demonstrated in numerous studies. c-Fos, a component of AP-1 transcription factor, plays a key role in osteoclast differentiation. Recently, we found a strong inhibitor of AP-1 transcriptional activity, named momordin I, based on the structure of oleanolic acid glycosides and originally isolated from Ampelopsis radix. So, we hypothesized that momordin I might be able to regulate osteoclast formation, activity, and survival. Here, we report the ability of momordin I to suppress osteoclastogenesis in a co-cultured system and a RANKL-induced osteoclast precursor system. Momordin I remarkably inhibited the activation of NF-kappaB as well as AP-1 in RANKL-induced RAW264.7 cells, in which momordin I appeared to target IkappaB degradation and c-Fos expression, respectively, but not MAPK signaling pathways. The ability of momordin I to change the ratio of RANKL and OPG in primary osteoblasts was partially responsible for the reduction of osteoclast formation. Furthermore, pit formation on dentin slices was suppressed by momordin I with stimulating actin ring disruption. Our results also showed that momordin I highly shortened osteoclast lifespan and induced osteoclast apoptosis. In conclusion, the present results demonstrate for the first time that momordin I is a potent inhibitor of osteoclast differentiation via the reduction of NF-kappaB and AP-1, and also suppresses osteoclast function and survival.

Curcumin: The story so far

Curcumin is a polyphenol derived from the herbal remedy and dietary spice turmeric. It possesses diverse anti-inflammatory and anti-cancer properties following oral or topical administration. Apart from curcumin's potent antioxidant capacity at neutral and acidic pH, its mechanisms of action include inhibition of several cell signalling pathways at multiple levels, effects on cellular enzymes such as cyclooxygenase and glutathione S-transferases, immuno-modulation and effects on angiogenesis and cell-cell adhesion. Curcumin's ability to affect gene transcription and to induce apoptosis in preclinical models is likely to be of particular relevance to cancer chemoprevention and chemotherapy in patients. Although curcumin's low systemic bioavailability following oral dosing may limit access of sufficient concentrations for pharmacological effect in certain tissues, the attainment of biologically active levels in the gastrointestinal tract has been demonstrated in animals and humans. Sufficient data currently exist to advocate phase II clinical evaluation of oral curcumin in patients with invasive malignancy or pre-invasive lesions of the gastrointestinal tract, particularly the colon and rectum.

Curcumin (diferuloylmethane) inhibits receptor activator of NF-kappa B ligand-induced NF-kappa B activation in osteoclast precursors and suppresses osteoclastogenesis

Numerous studies have indicated that inflammatory cytokines play a major role in osteoclastogenesis, leading to the bone resorption that is frequently associated with cancers and other diseases. Gene deletion studies have shown that receptor activator of NF-kappaB ligand (RANKL) is one of the critical mediators of osteoclastogenesis. How RANKL mediates osteoclastogenesis is not fully understood, but an agent that suppresses RANKL signaling has potential to inhibit osteoclastogenesis. In this report, we examine the ability of curcumin (diferuloylmethane), a pigment derived from turmeric, to suppress RANKL signaling and osteoclastogenesis in RAW 264.7 cells, a murine monocytic cell line. Treatment of these cells with RANKL activated NF-kappaB, and preexposure of the cells to curcumin completely suppressed RANKL-induced NF-kappaB activation. Curcumin inhibited the pathway leading from activation of IkappaBalpha kinase and IkappaBalpha phosphorylation to IkappaBalpha degradation. RANKL induced osteoclastogenesis in these monocytic cells, and curcumin inhibited both RANKL- and TNF-induced osteoclastogenesis and pit formation. Curcumin suppressed osteoclastogenesis maximally when added together with RANKL and minimally when it was added 2 days after RANKL. Whether curcumin inhibits RANKL-induced osteoclastogenesis through suppression of NF-kappaB was also confirmed independently, as RANKL failed to activate NF-kappaB in cells stably transfected with a dominant-negative form of IkappaBalpha and concurrently failed to induce osteoclastogenesis. Thus overall these results indicate that RANKL induces osteoclastogenesis through the activation of NF-kappaB, and treatment with curcumin inhibits both the NF-kappaB activation and osteoclastogenesis induced by RANKL.

Plants used in cosmetics

This review describes the use of some natural products in cosmetic preparations, due to their low mammalian toxicity, with a brief description of the major use, plant parts used, the actives responsible for effect and the benefits of such products. Their use in skin care; such as dryness, eczema, acne, free-radical scavenging, antiinflammatory, antiaging and skin protection effects are explained, and also the use in hair care as hair growth stimulants, hair colorants, and for hair and scalp complaints such as dandruff. Essential oils when incorporated into finished products impart many benefits such as a pleasant aroma in perfumery, shine or conditioning effects in hair care products, emolliency and improving the elasticity of the skin.

Emodin induces apoptosis in human promyeloleukemic HL-60 cells accompanied by activation of caspase 3 cascade but independent of reactive oxygen species production

Emodin (1,3,8-trihydroxy-6-methylanthraquinone) is an active constituent of Rheum palmatum, and showed inhibitory activity on lipopolysaccharide-induced NO production in our previous study. However, the apoptosis-inducing activity of emodin has remained undefined. Among three structurally related anthraquinones, including emodin, physcion, and chrysophanol, emodin showed the most potent cytotoxic effects on HL-60 cells, accompanied by the dose- and time-dependent appearance of characteristics of apoptosis including an increase in DNA ladder intensity, morphological changes, appearance of apoptotic bodies, and an increase in hypodiploid cells. Emodin at apoptosis-inducing concentrations causes rapid and transient induction of caspase 3/CPP32 activity, but not caspase 1 activity, according to cleavage of caspase 3 substrates poly(ADP-ribose) polymerase and D4-GDI proteins, the appearance of cleaved caspase 3 fragments being detected in emodin- but not physcion- or chrysophanol-treated HL-60 cells. A decrease in the anti-apoptotic protein, Mcl-1, was detected in emodin-treated HL-60 cells, whereas other Bcl-2 family proteins including Bax, Bcl-2, Bcl-XL, and Bad remained unchanged. The caspase 3 inhibitor, Ac-DEVD-CHO, but not the caspase 1 inhibitor, Ac-YVAD-CHO, attenuated emodin-induced DNA ladders, associated with the blockage of PARP and D4-GDI cleavage. Free radical scavenging agents including NAC, catalase, SOD, ALL, DPI, L-NAME and PDTC showed no preventive effect on emodin-induced apoptotic responses, whereas NAC, CAT and PDTC prevented HL-60 cells from ROS (H(2)O(2))-induced apoptosis through inhibition of caspase 3 cascades. Induction of catalase, but not SOD, activity was detected in emodin-treated HL-60 cells by in gel activity assays, and H(2)O(2)-induced intracellular peroxide level was significantly reduced by prior treatment of emodin in HL-60 cells. Our experiments provide evidence that emodin is an effective apoptosis inducer in HL-60 cells through activation of the caspase 3 cascade, but that it is independent of ROS production.

Curcumin disrupts mitotic spindle structure and induces micronucleation in MCF-7 breast cancer cells

The dietary phytochemical curcumin possesses anti-inflammatory, -oxidant, and cytostatic properties, and exhibits significant potential as a chemopreventative agent in humans. Although many cell types are arrested in the G2/M-phase of the cell cycle after curcumin treatment, the mechanisms by which this occurs are not well understood. The purpose of this study was to examine the effects of curcumin on the cell cycle of MCF-7 breast cancer cells to determine whether growth arrest is associated with structural changes in cellular organization during mitosis. For this purpose, MCF-7 breast cancer cells were treated with 10-20 microM curcumin, and the effects on cell proliferation and mitosis studied. Structural changes were monitored by immunolabeling cells with antibodies to a number of cytoplasmic and nuclear proteins, including beta-tubulin, NuMA, lamins A/C and B1, lamin B receptor, and centromere antigens. At the concentrations used, a single dose of curcumin does not induce significant apoptosis, but is highly effective in inhibiting cell proliferation for over 6 days. During the first 24-48 h of treatment, many cells are arrested in M-phase, and DNA synthesis is almost completely inhibited. Remarkably, arrested mitotic cells exhibit monopolar spindles, and chromosomes do not undergo normal anaphase movements. After 48 h, most cells eventually leave M-phase, and many form multiple micronuclei instead of individual daughter nuclei. These observations indicate that the curcumin-induced G2/M arrest previously described for MCF-7 cells is due to the assembly of aberrant, monopolar mitotic spindles that are impaired in their ability to segregate chromosomes. The production of cells with extensive micronucleation after curcumin treatment suggests that at least some of the cytostatic effects of this phytochemical are due to its ability to disrupt normal mitosis, and raises the possibility that curcumin may promote genetic instability under some circumstances.

Biological activities of Curcuma longa L

There are several data in the literature indicating a great variety of pharmacological activities of Curcuma longa L. (Zingiberaceae), which exhibit anti-inflammatory, anti-human immunodeficiency virus, anti-bacteria, antioxidant effects and nematocidal activities. Curcumin is a major component in Curcuma longa L., being responsible for its biological actions. Other extracts of this plant has been showing potency too. In vitro, curcumin exhibits anti-parasitic, antispasmodic, anti-inflammatory and gastrointestinal effects; and also inhibits carcinogenesis and cancer growth. In vivo, there are experiments showing the anti-parasitic, anti-inflammatory potency of curcumin and extracts of C. longa L. by parenteral and oral application in animal models. In this present work we make an overview of the pharmacological activities of C. longa L., showing its importance.

Curcumin induces the mitochondrial permeability transition pore mediated by membrane protein thiol oxidation

Curcumin is a natural compound showing antiproliferative properties. Recent studies suggest that these properties might be due to its ability to induce apoptosis in tumor cells. As mitochondria play a pivotal role in the induction of the apoptotic process, we analyzed the effect of curcumin on mitochondrial function. Curcumin induced an increase in rat liver mitochondrial membrane permeability, resulting in swelling, loss of membrane potential and inhibition of ATP synthesis. These effects were mediated by the opening of the permeability transition pore. Curcumin pore induction involved the oxidation of membrane thiol functions and required the presence of low Ca(2+) concentrations. These data suggest that mitochondria might be a target by which curcumin induces apoptosis of tumor cells.