Interaction of tRNA with Safranal, Crocetin, and Dimethylcrocetin

Therapeutic Potential of Certain Terpenoids as Anticancer Agents: A Scoping Review

Cancer is a life-threatening disease and is considered to be among the leading causes of death worldwide. Chemoresistance, severe toxicity, relapse and metastasis are the major obstacles in cancer therapy. Therefore, introducing new therapeutic agents for cancer remains a priority to increase the range of effective treatments. Terpenoids, a large group of secondary metabolites, are derived from plant sources and are composed of several isoprene units. The high diversity of terpenoids has drawn attention to their potential anticancer and pharmacological activities. Some terpenoids exhibit an anticancer effect by triggering various stages of cancer progression, for example, suppressing the early stage of tumorigenesis via induction of cell cycle arrest, inhibiting cancer cell differentiation and activating apoptosis. At the late stage of cancer development, certain terpenoids are able to inhibit angiogenesis and metastasis via modulation of different intracellular signaling pathways. Significant progress in the identification of the mechanism of action and signaling pathways through which terpenoids exert their anticancer effects has been highlighted. Hence, in this review, the anticancer activities of twenty-five terpenoids are discussed in detail. In addition, this review provides insights on the current clinical trials and future directions towards the development of certain terpenoids as potential anticancer agents.

Uracil-doped DNA thin solid films: a new way to control optical dispersion of DNA film using a RNA constituent

Among five nucleobases, adenine (A), guanine (G), cytosine (C), thymine (T) and uracil (U), uracil is a key distinctive constituent existing only in ribonucleic acid (RNA). RNA shares the common A, G, and C with deoxyribonucleic acid (DNA) made of A-T, G-C hydrogen bonding. We explored a new attempt to combine uracil (U) with DNA, successfully realizing U-doped DNA thin solid films for the first time. Impacts of uracil on optical properties of the films were thoroughly investigated. The method was based on optimal spin-coating of an aqueous solution of DNA and uracil over silicon or silica substrates. Optical absorption of both aqueous solution and U-doped DNA thin solid films was characterized in a wide spectral range covering UV-visible-IR. Immobilization of uracil within DNA thin solid films was experimentally confirmed by FTIR spectroscopy studies. By using an ellipsometer, we measured the refractive indices of the films and discovered that U-doping was a very effective means to control optical dispersion DNA thin solid film. We further investigated thermo-optic behavior to find impacts of U-doping in DNA films. Detailed thin film processes and optical characterizations are discussed.

Crocetin and Crocin from Saffron in Cancer Chemotherapy and Chemoprevention

INTRODUCTION

Cancer is a disorder which has a powerful impact on the quality life and life expectancy despite the increase in drugs and treatments available for cancer patients. Moreover, many new therapeutic options are known to have adverse reactions without any improvement in outcome than before. Nowadays, natural products or plant derivatives are used as chemoprevention drugs and chemotherapy is the new approach that uses specific cell premalignant transformation in the malignant form. Natural substances derived from plants, such as polyphenols, flavonoids, carotenoids, alkaloids and others, can be biologically active and have a wide spectrum of effects. The protective effects of Saffron carotenoids (crocin and crocetin) have been extensively studied mainly for their antioxidant properties, however, they have various other biological activities including tumor growth inhibition with the induction of cell death.

METHODS

The relevant information on Saffron and its carotenoids was collected from scientific databases (such as PubMed, Web of Science, Science Direct). To identify all published articles in relation to saffron, crocin and crocetin, in different types of cancer, no language restriction has been used.

RESULTS

To date, crossing the words saffron and cancer, approximately 150 articles can be found. If crossing is made between crocin and cancer, approximately 60 articles can be found. With the crossing between crocetin and cancer, the number is approximately 55, while between carotenoids and cancer, the number exceeds 16.000 reports. In all the papers published to date, there are evidences that saffron and its carotenoids exert chemopreventive activity through anti-oxidant activity, cancer cells apoptosis, inhibition of cell proliferation, enhancement of cell differentiation, modulation of cell cycle progression and cell growth, modulation of tumor metabolism, stimulation of cell-to-cell communication and immune modulation.

CONCLUSION

Here, we have tried to offer an up-to-date overview of pre-clinical experimental investigations on the potential use of the main carotenoids of saffron in tumor models and focus the attention on the molecular mechanisms involved.

RNA targeting by an anthracycline drug: spectroscopic and in silico evaluation of epirubicin interaction with tRNA

Anthracyclines are putative anticancer agents used to treat a wide range of cancers. Among these anthracyclines, epirubicin is derived from the doxorubicin by the subtle difference in the orientation of C4-hydroxyl group at sugar molecule. Epirubicin has great significance as it has propitious anticancer potential with lesser cardiotoxicity and faster elimination from the body. The present study is done to understand the molecular aspect of epirubicin binding to tRNA. We have used various spectroscopic techniques like Fourier transform infrared spectroscopy (FTIR), absorption spectroscopy and circular dichroism to illustrate the binding sites, the extent of binding and conformational changes associated with tRNA after interacting with epirubicin. From infrared studies, we infer that epirubicin interacts with guanine and uracil bases of tRNA. Results obtained from infrared and CD studies suggest that epirubicin complexation with tRNA does not result in any conformational change in tRNA structure. Binding constant (2.1 × 10³ M^-1) calculated from the absorbance data illustrates that epirubicin has a weak interaction with tRNA molecule. These spectroscopic results like the binding site of epirubicin and binding energy of epirubicin-tRNA complex were also verified by the molecular docking. Results of the present study provide information that aids in the development of efficient RNA targeted drugs from the existing drugs by certain chemical modification in their structure resulting in lesser side effects and better efficacy.Communicated by Ramaswamy H. Sarma.

A comprehensive review of the pharmacological potential of Crocus sativus and its bioactive apocarotenoids

Crocus sativus is an herbaceous plant that belongs to family Iridaceae. It is commonly known as saffron and has been used for medicinal purposes since many centuries in India and other parts of the world. Saffron of commercial importance comprises of dried stigmas of the plant and is rich in flavonoids, vitamins, and carotenoids. Carotenoids represent the main components of saffron and their cleavage results in the formation of apocarotenoids such as crocin, picrocrocin, and safranal. Studies conducted during the past two decades have revealed the immense therapeutic potential of saffron. Most of the therapeutic properties are due to the presence of unique apocarotenoids having strong free radical scavenging activity. The mode of action of these apocarotenoids could be: modulatory effects on detoxifying enzymes involved in combating oxidative stress, decreasing telomerase activity, increased the proapoptotic effect, inhibition of DNA, RNA and protein synthesis, and by a strong binding capacity of crocetin with tRNA. The present review focuses on the therapeutic role of saffron and its bio oxidative cleavage products and also highlights the possible molecular mechanism of action. The findings reported in this review describes the wide range of applications of saffron and attributes its free radical scavenging nature the main property which makes this spice a potent chemotherapeutic agent for the treatment of various diseases.

Anti-tumor effects of crocetin and related molecular targets

Natural products have gained a wide popularity as chemopreventive and anti-cancer agents owing to their multi-mechanistic mode of action, availability and synergism with several conventional chemotherapeutic agents. Crocetin is a carotenoid compound isolated from the stigma of Crocus sativus L. (saffron). Crocetin has shown promising effects as an anti-tumor agent in animal models and cell culture systems. Crocetin retards the growth of cancer cells via inhibiting nucleic acid synthesis, enhancing anti-oxidative system, and inducing apoptosis and differentiation pathways. The present review outlines natural sources of crocetin, and its pharmacokinetic and pharmacological properties relevant to the prevention and treatment of cancer. Also, we discuss molecular targets underlying the putative anti-tumor effects of crocetin.

Saffron: a natural product with potential pharmaceutical applications

OBJECTIVES

Recently, a great deal of interest has been developed to isolate and investigate novel bioactive components from natural resources with health beneficial effects. Saffron is the dried stigma of Crocus sativus L. and has been used for centuries in traditional medicine mainly for its healing properties, as well as for the treatment of various pathological conditions. Objectives of the present review are to unravel its therapeutic properties and investigate the potential applications of saffron in contemporary therapy of a wide spectrum of diseases and summarize previous and current evidence regarding the biological/pharmacological activities of saffron and its active ingredients and their possible therapeutic uses.

KEY FINDINGS

Recent phytochemistry and pharmacological experiments have indicated that crocin and safranal, the major active ingredients of saffron, exert important actions, such as antioxidant, anti-tumor, anti-diabetic, anti-inflammatory and anti-atherosclerotic. Unfortunately, the vast majority of those data derive from in vitro studies, whereas a limited number of in vivo experiments support the aforementioned effects. In addition to studies with mechanistic implications, very few clinical trials provide preliminary evidence of saffron potentiality to alleviate depression and increase cognitive function in patients with Alzheimer's disease.

SUMMARY

The history and structural features of saffron constituents are given in the first part of the review, followed by a comprehensive and critical presentation of the published preclinical and clinical studies and review papers on the pharmacology and possible therapeutic uses of saffron and its main active components crocin and safranal.

Proposed cytotoxic mechanisms of the saffron carotenoids crocin and crocetin on cancer cell lines

We investigated the cytotoxic activities of crocin and crocetin, 2 major carotenoids isolated from the stigma of Crocus sativus (saffron), on 5 human cancer cell lines and proposed their possible anticancer mechanisms. Crocetin, a glycosylated carotenoid, showed approximately 5- to 18-fold higher cytotoxicity than crocin, a carboxylic carotenoid (IC50 of 0.16–0.61 mmol/L for crocetin vs. 2.0–5.5 mmol/L for crocin). This suggests that structural differences account for the different efficacies between them. Fluorescence-activated cell sorting (FACS) analysis showed that crocetin induced a significant level of cellular reactive oxygen species (ROS) in HeLa cells, whereas crocin did not. This ROS induction supported the cytotoxicity of crocetin, but not of crocin. A significant activation of nuclear factor erythroid 2-related factor 2 (Nrf2) was observed in both HeLa cells treated with crocin and crocetin: a 3.0-fold increase by 1 mmol/L crocetin and a 1.6-fold increase by 0.8 mmol/L crocin compared to the control. Furthermore, both crocetin and crocin reduced the protein expression of lactate dehydrogenase A (LDHA), one of the targets for chemoprevention in cancer cells, by 34.2% and 10.5%, respectively, compared to the control in HeLa cells. These findings suggest that crocetin and crocin have different mechanisms for their observed cytotoxicity in cancer cell lines.

Anticancer Effect and Molecular Targets of Saffron Carotenoids

Saffron carotenoids, crocin and crocetin, have shown anticancer activity in various animal models of cancer and against different cancerous cell lines. The radical scavenging property and activation of antioxidant defense system are two well-known characteristics of these compounds. However, the results of the studies indicated other mechanisms could also be involved in this function. Insights into various molecular mechanisms of action for crocin and crocetin have been obtained in recent years. The results indicated that despite the structural similarity of crocin and crocetin, their anticancer effects may exert through different mechanisms. Particular interest concerns the ROS-dependent signaling pathways of crocetin. Saffron compounds are safe and may provide inexpensive therapy for treating cancer. They also have protective potential in targeting other disorders including diabetes, Alzheimer's and cardiovascular disease, cognitive deficits, ischemia-induced retinal damage, and many other diseases.

Saffron as a source of novel acetylcholinesterase inhibitors: molecular docking and in vitro enzymatic studies

Inhibitors of acetylcholine breakdown by acetylcholinesterase (AChE) constitute the main therapeutic modality for Alzheimer's disease. In the search for natural products with inhibitory action on AChE, this study investigated the activity of saffron extract and its constituents by in vitro enzymatic and molecular docking studies. Saffron has been used in traditional medicine against Alzheimer's disease. Saffron extract showed moderate AChE inhibitory activity (up to 30%), but IC(50) values of crocetin, dimethylcrocetin, and safranal were 96.33, 107.1, and 21.09 μM, respectively. Kinetic analysis showed mixed-type inhibition, which was verified by in silico docking studies. Safranal interacts only with the binding site of the AChE, but crocetin and dimethylcrocetin bind simultaneously to the catalytic and peripheral anionic sites. These results reinforce previous findings about the beneficial action of saffron against Alzheimer's disease and may be of value for the development of novel therapeutic agents based on carotenoid-based dual binding inhibitors.

Crocetin: an agent derived from saffron for prevention and therapy for cancer

Cancer is one of the leading causes of death in the United States and accounts for approximately 8 million deaths per year worldwide. Although there is an increasing number of therapeutic options available for patients with cancer, their efficacy is time-limited and non-curative. Approximately 50-60% cancer patients in the United States utilize agents derived from different parts of plants or nutrients (complementary and alternative medicine), exclusively or concurrently with traditional therapeutic regime such as chemotherapy and/or radiation therapy. The need for new drugs has prompted studies evaluating possible anti-cancer agents in fruits, vegetables, herbs and spices. Saffron, a spice and a food colorant present in the dry stigmas of the plant Crocus sativus L., has been used as an herbal remedy for various ailments including cancer by the ancient Arabian, Indian and Chinese cultures. Crocetin, an important carotenoid constituent of saffron, has shown significant potential as an anti-tumor agent in animal models and cell culture systems. Crocetin affects the growth of cancer cells by inhibiting nucleic acid synthesis, enhancing anti-oxidative system, inducing apoptosis and hindering growth factor signaling pathways. This review discusses the studies on cancer preventive potential of crocetin and its future use as an anticancer agent.

Crocetin induces cytotoxicity and enhances vincristine-induced cancer cell death via p53-dependent and -independent mechanisms

AIM

To investigate the anticancer effect of crocetin, a major ingredient in saffron, and its underlying mechanisms.

METHODS

Cervical cancer cell line HeLa, non-small cell lung cancer cell line A549 and ovarian cancer cell line SKOV3 were treated with crocetin alone or in combination with vincristine. Cell proliferation was examined using MTT assay. Cell cycle distribution and sub-G(1) fraction were analyzed using flow cytometric analysis after propidium iodide staining. Apoptosis was detected using the Annexin V-FITC Apoptosis Detection Kit with flow cytometry. Cell death was measured based on the release of lactate dehydrogenase (LDH). The expression levels of p53 and p21(WAF1/Cip1) as well as caspase activation were examined using Western blot analysis.

RESULTS

Treatment of the 3 types of cancer cells with crocetin (60-240 μmol/L) for 48 h significantly inhibited their proliferation in a concentration-dependent manner. Crocetin (240 μmol/L) significantly induced cell cycle arrest through p53-dependent and -independent mechanisms accompanied with p21(WAF1/Cip1) induction. Crocetin (120-240 μmol/L) caused cytotoxicity in the 3 types of cancer cells by enhancing apoptosis in a time-dependent manner. In the 3 types of cancer cells, crocetin (60 μmol/L) significantly enhanced the cytotoxicity induced by vincristine (1 μmol/L). Furthermore, this synergistic effect was also detected in the vincristine-resistant breast cancer cell line MCF-7/VCR.

CONCLUSION

Ccrocetin is a potential anticancer agent, which may be used as a chemotherapeutic drug or as a chemosensitizer for vincristine.

A new validated SPE-HPLC method for monitoring crocetin in human plasma--application after saffron tea consumption

Saffron (stigmas of Crocus sativus L.) is a well-known spice with many attributed therapeutic uses throughout centuries. Although studies have demonstrated that crocetin and crocins from saffron have various biological functions, issues concerning the route and way of saffron administration, the absorption and metabolism of saffron carotenoids in humans have not been answered yet. In the present study, an isocratic reversed-phase liquid chromatographic method was developed and validated for the determination of crocetin in plasma. Samples were pre-treated by solid phase extraction (recoveries >72%) and were chromatographed on a Luna C-18 column (4.6mm×250mm, 5μm) with a mobile phase consisting of methanol-water-trifluoroacetic acid (75.0:24.5:0.5, v/v/v) at a flow rate of 1.0mLmin(-1). The HPLC method developed resulted in sharp peaks at 10.7 (trans-crocetin) and 18.6min (cis-crocetin), whereas the calibration curve of total crocetin in plasma displayed a good linearity for concentrations of 0.020-20μM (R(2)=0.999). Specificity, precision, accuracy and stability were studied with spiked plasma samples and were acceptable. The developed method was applied to the determination of crocetin levels in plasma of four healthy human volunteers before and after consumption of one cup of saffron tea (200mg of saffron in 80°C water for 5min). Results showed that the concentration of crocetin was high after 2h (1.24-3.67μM) and still determined after 24h (0.10-0.24). Interestingly, the percentage of the cis-isomer ranges from 25 to 50%, suggesting in vivo isomerization.

Further examination of antiradical properties of Crocus sativus stigmas extract rich in crocins

Data for antiradical properties of saffron extract and its bioactive constituents (crocins, crocetin) are limited and poorly discussed in comparison with those of extracts containing potent scavengers. Further examination was sought using the Folin-Ciocalteu (F-C) reagent and various free radical species produced in cell-free or cell model systems. Oregano and turmeric methanol extracts, rich in well established scavengers, and also crocetin, rosmarinic acid, and curcumin, representing the major types of constituents in the three studied extracts, were used as "reference". On the same weight basis, saffron extract activity was found to be rather negligible in all cell-free systems with regard to that found for reference ones. On the contrary, in the human monocyte system, saffron extracts or free crocetin were found to reduce ROS production as effectively as the phenolic antioxidants. Our findings point out that saffron extracts exhibit a remarkable intracellular antioxidant activity that cannot be revealed using assays repeatedly applied to the evaluation of phenolic-type antioxidants.