Radioprotection of turmeric extracts in bacterial system

Effects of traditional oriental medicines as anti-cytotoxic agents in radiotherapy

The primary goal of radiotherapy in oncology is to enhance the efficacy of tumor cell death while decreasing damage to surrounding normal cells. Positive therapeutic outcomes may be accomplished by improved targeting, precisely targeting tumor cells or protecting normal cells against radiation-induced damage. The potential for antioxidants to decrease normal tissue damage induced by radiation has been investigated in animal models for a number of decades. In attempts for radioprotection, certain synthetic chemicals are suggested as antioxidants and normal tissue protectors against radiation-induced damage, but they have exhibited limitations in pharmacological application due to undesirable effects and high toxicities at clinical doses. The present review focuses on the radioprotective efficacy of traditional oriental medicines with the advantage of low toxicity at pharmacological doses and how such treatments may influence various harmful effects induced by radiation in vitro and in vivo. In addition, medicinal plants and their active constituents with biological activities that may be associated with alleviation of radiation-induced damage through antioxidant, anti-inflammatory, wound healing and immunostimulatory properties are discussed.

Chemical constituents and biological research on plants in the genus Curcuma

Curcuma, a valuable genus in the family Zingiberaceae, includes approximately 110 species. These plants are native to Southeast Asia and are extensively cultivated in India, China, Sri Lanka, Indonesia, Peru, Australia, and the West Indies. The plants have long been used in folk medicine to treat stomach ailments, stimulate digestion, and protect the digestive organs, including the intestines, stomach, and liver. In recent years, substantial progress has been achieved in investigations regarding the chemical and pharmacological properties, as well as in clinical trials of certain Curcuma species. This review comprehensively summarizes the current knowledge on the chemistry and briefly discusses the biological activities of Curcuma species. A total of 720 compounds, including 102 diphenylalkanoids, 19 phenylpropene derivatives, 529 terpenoids, 15 flavonoids, 7 steroids, 3 alkaloids, and 44 compounds of other types isolated or identified from 32 species, have been phytochemically investigated. The biological activities of plant extracts and pure compounds are classified into 15 groups in detail, with emphasis on anti-inflammatory and antitumor activities.

Multitargeting by turmeric, the golden spice: From kitchen to clinic

Although much has been published about curcumin, which is obtained from turmeric, comparatively little is known about turmeric itself. Turmeric, a golden spice obtained from the rhizome of the plant Curcuma longa, has been used to give color and taste to food preparations since ancient times. Traditionally, this spice has been used in Ayurveda and folk medicine for the treatment of such ailments as gynecological problems, gastric problems, hepatic disorders, infectious diseases, and blood disorders. Modern science has provided the scientific basis for the use of turmeric against such disorders. Various chemical constituents have been isolated from this spice, including polyphenols, sesquiterpenes, diterpenes, triterpenoids, sterols, and alkaloids. Curcumin, which constitutes 2-5% of turmeric, is perhaps the most-studied component. Although some of the activities of turmeric can be mimicked by curcumin, other activities are curcumin-independent. Cell-based studies have demonstrated the potential of turmeric as an antimicrobial, insecticidal, larvicidal, antimutagenic, radioprotector, and anticancer agent. Numerous animal studies have shown the potential of this spice against proinflammatory diseases, cancer, neurodegenerative diseases, depression, diabetes, obesity, and atherosclerosis. At the molecular level, this spice has been shown to modulate numerous cell-signaling pathways. In clinical trials, turmeric has shown efficacy against numerous human ailments including lupus nephritis, cancer, diabetes, irritable bowel syndrome, acne, and fibrosis. Thus, a spice originally common in the kitchen is now exhibiting activities in the clinic. In this review, we discuss the chemical constituents of turmeric, its biological activities, its molecular targets, and its potential in the clinic.

Hypotensive and endothelium-independent vasorelaxant effects of methanolic extract from Curcuma longa L. in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Curcuma longa L. (CL) is a yellow rhizome that is used in African traditional medicine to treat palpitation, hypertension or other related blood circulation disorders.

AIM OF THE STUDY

To justify the use of CL in ethnomedicine, we investigated the vasorelaxant effect of methanolic extract of CL (CLME) and its underlying mechanisms in isolated rat mesenteric artery.

MATERIALS AND METHODS

The effect of CLME on the mean arterial pressure (MAP) and heart rate (HR) (pulse interval) were determined in vivo in non-anaesthetized rats. Superior mesenteric rings were isolated, suspended in organ baths containing Tyrode solution at 37 degrees C and gassed with 95% O(2)+5% CO(2), under a resting tension of 0.75 g. The vasorelaxant effects of CLME were studied by means of isometric tension recording experiments.

RESULTS

In normotensive rats, CLME (10, 20 and 30 mg/kg, i.v.) induced dose-dependent hypotension (2.0+/-0.5%; 27.1+/-5.0% and 26.7+/-4.6%, respectively), and pronounced bradycardia (5.8+/-1.2%, 19.3+/-3.2% and 22.9+/-4.6%, respectively). CLME (1-1000 microg/mL) induced concentration-dependent relaxation of tonic contractions evoked by phenylephrine (Phe) (10 microM) and KCl (80 mM) in rings with intact-endothelium (E(max)=82.3+/-3.2% and 97.7+/-0.7%) or denuded-endothelium (E(max)=91.4+/-1.0% and 97.8+/-1.1%). Also, in a depolarized, Ca(2+) free medium, CLME inhibited CaCl(2) (1 microM-30 mM)-induced contractions and caused a concentration-dependent rightward shift of the response curves, indicating that CLME inhibited the contractile mechanisms involving extracellular Ca(2+) influx. In addition, in Ca(2+) free media containing EGTA (1 mM), CLME inhibited the transient contraction of denuded rings constricted with Phe, but not those evoked by caffeine (20 mM). In contrast, neither glibenclamide, BaCl(2), tetraethylammonium nor 4-aminopyridine affected CLME-induced relaxation.

CONCLUSIONS

These results demonstrate the hypotensive and bradycardic effects of CLME, as well as its potent vasodilation of rat mesenteric arteries. These effects, may in part, be due to the inhibition of extracellular Ca(2+) influx and/or inhibition of intracellular Ca(2+) mobilization from Phe-sensitive stores.

Role of Turmeric in Ultraviolet Induced Genotoxicity in a Bacterial System

Turmeric extracts contain more than one bioactive component, which have different properties when used to modulate ultraviolet induced genotoxicity. These differences were found depending on the nature and extent of the damage to the bacterial DNA, which indicates the existence of a natural switching process in sensing the damage.

Curcumin inhibits FtsZ assembly: an attractive mechanism for its antibacterial activity

The assembly and stability of FtsZ protofilaments have been shown to play critical roles in bacterial cytokinesis. Recent evidence suggests that FtsZ may be considered as an important antibacterial drug target. Curcumin, a dietary polyphenolic compound, has been shown to have a potent antibacterial activity against a number of pathogenic bacteria including Staphylococcus aureus, Staphylococcus epidermidis and Enterococcus. We found that curcumin induced filamentation in the Bacillus subtilis 168, suggesting that it inhibits bacterial cytokinesis. Further, curcumin strongly inhibited the formation of the cytokinetic Z-ring in B. subtilis 168 without detectably affecting the segregation and organization of the nucleoids. Since the assembly dynamics of FtsZ protofilaments plays a major role in the formation and functioning of the Z-ring, we analysed the effects of curcumin on the assembly of FtsZ protofilaments. Curcumin inhibited the assembly of FtsZ protofilaments and also increased the GTPase activity of FtsZ. Electron microscopic analysis showed that curcumin reduced the bundling of FtsZ protofilaments in vitro. Further, curcumin was found to bind to FtsZ in vitro with a dissociation constant of 7.3±1.8 μM and the agent also perturbed the secondary structure of FtsZ. The results indicate that the perturbation of the GTPase activity of FtsZ assembly is lethal to bacteria and suggest that curcumin inhibits bacterial cell proliferation by inhibiting the assembly dynamics of FtsZ in the Z-ring.

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".