The role of turmerones on curcumin transportation and P-glycoprotein activities in intestinal Caco-2 cells

Plant-Based Products Originating from Serbia That Affect P-glycoprotein Activity

Our review paper evaluates the impact of plant-based products, primarily derived from plants from Serbia, on P-glycoprotein (P-gp) activity and their potential in modulating drug resistance in cancer therapy. We focus on the role and regulation of P-gp in cellular physiology and its significance in addressing multidrug resistance in cancer therapy. Additionally, we discuss the modulation of P-gp activity by 55 natural product drugs, including derivatives for some of them, based on our team's research findings since 2011. Specifically, we prospect into sesquiterpenoids from the genera Artemisia, Curcuma, Ferula, Inula, Petasites, and Celastrus; diterpenoids from the genera Salvia and Euphorbia; chalcones from the genera Piper, Glycyrrhiza, Cullen, Artemisia, and Humulus; riccardins from the genera Lunularia, Monoclea, Dumortiera, Plagiochila, and Primula; and diarylheptanoids from the genera Alnus and Curcuma. Through comprehensive analysis, we aim to highlight the potential of natural products mainly identified in plants from Serbia in influencing P-gp activity and overcoming drug resistance in cancer therapy, while also providing insights into future perspectives in this field.

Sexual dysfunction in dichlorvos-exposed male Wistar rat is ameliorated by curcumin and associated with the upregulation of testosterone

Dichlorvos is an organophosphate pesticide that is commonly used for agricultural and domestic control of pests and insects. Despite its usefulness, it exerts reproductive toxicity and induces male sexual dysfunction. On the other hand, curcumin has been reported to improve sexual dysfunction. However, till date, no study has reported the impact of curcumin on dichlorvos-induced sexual dysfunction. This study investigated the effect and associated mechanism of curcumin on dichlorvos-induced sexual dysfunction. Thirty-two male Wistar rats were randomized into four groups; the control (1 mL of olive oil), curcumin-treated (100 mg/kg), DDVP-treated (98.54 g/m3 of dichlorvos by inhalation), and DDVP + Curcumin-treated. Dichlorvos induced sexual dysfunction as depicted by reduced motivation to mate (8.38 ± 0.18 vs. 4.00 ± 0.33, P < 0.0001), prolonged latencies (46.63 ± 1.30 vs. 98.75 ± 1.32, P < 0.0001) and reduced frequencies of mount (14.88 ± 0.52 vs. 8.63 ± 0.38), intromission (9.38 ± 0.50 vs. 3.75 ± 0.31, P < 0.0001), and ejaculation (7.63 ± 0.38 vs. 1.50 ± 0.19, P < 0.0001). These findings were accompanied by suppression of hypothalamic-pituitary-testicular axis, evidenced by marked reductions in circulating FSH (60.00 ± 1.04 vs. 21.13 ± 0.52, P < 0.0001), LH (46.38 ± 1.38 vs. 19.00 ± 0.46, P < 0.0001), and testosterone (6.01 ± 0.50 vs. 0.74 ± 0.05, P < 0.0001). Nonetheless, the administration of curcumin in dichlorvos-exposed rats significantly attenuated dichlorvos-induced sexual dysfunction by improving the assessed indices of male sexual act. Also, curcumin significantly increased serum levels of FSH (21.13 ± 0.52 vs. 47.25 ± 0.10, P < 0.0001), LH (19.00 ± 0.46 vs. 43.00 ± 1.49), and testosterone (0.74 ± 0.05 vs. 3.98 ± 0.08, P < 0.0001). This study revealed that curcumin attenuated dichlorvos-induced sexual dysfunction by activating the hypothalamic-pituitary-testicular axis and upregulating circulating testosterone.

Novel Biphasic In Vitro Dissolution Method Correctly Predicts the Oral Bioavailability of Curcumin in Humans

In vitro dissolution methods correctly predicting in vivo bioavailability of compounds from complex mixtures are lacking. We therefore used data on the in vivo performance of bioavailability-improved curcumin formulations to implement an in vivo predictive dissolution method (BiPHa+). BiPHa+ was applied for the characterization of eight curcumin formulations previously studied in a strictly controlled pharmacokinetic human trial. During dissolution, the dissolved proportion of curcumin in the aqueous medium underwent a formulation-dependent reduction, whereas the proportion remained stable in the organic layer. Compared with conventional dissolution systems, BiPHa+ was superior in terms of in vivo-relevant formulation characterization. All formulations could be precisely categorized according to their bioavailability in humans. In vitro-in vivo relationships for each dissolution method were established, with BiPHa+ providing the highest degree of linearity (r2 = 0.9975). The BiPHa+ assay correctly predicted the bioavailability of curcuminoids from complex mixtures and provided mechanistic information about formulation-dependent release characteristics.

Natural Products as a Tool to Modulate the Activity and Expression of Multidrug Resistance Proteins of Intestinal Barrier

The role of intestinal barrier homeostasis in an individual’s general well-being has been widely addressed by the scientific community. Colorectal cancer is among the illnesses that most affect this biological barrier. While chemotherapy is the first choice to treat this type of cancer, multidrug resistance (MDR) is the major setback against the commonly used drugs, with the ATP-binding cassette transporters (ABC transporters) being the major players. The role of P-glycoprotein (P-gp), multidrug resistance protein 1 (MRP1), or breast cancer resistance protein (ABCG2) in the efflux of chemotherapeutic drugs is well described in cancer cells, highlighting these proteins as interesting druggable targets to reverse MDR, decrease drug dosage, and consequently undesired toxicity. Natural products, especially phytochemicals, have a wide diversity of chemical structures, and some particular classes, such as phenolic acids, flavonoids, or pentacyclic triterpenoids, have been reported as inhibitors of P-gp, MRP1, and ABCG2, being able to sensitize cancer cells to chemotherapy drugs. Nevertheless, ABC transporters play a vital role in the cell’s defense against xenobiotics, and some phytochemicals have also been shown to induce the transporters’ activity. A balance must be obtained between xenobiotic efflux in non-tumor cells and bioaccumulation of chemotherapy drugs in cancer cells, in which ABC transporters are essential and natural products play a pivotal role that must be further analyzed. This review summarizes the knowledge concerning the nomenclature and function of ABC-transporters, emphasizing their role in the intestinal barrier cells. In addition, it also focuses on the role of natural products commonly found in food products, e.g., phytochemicals, as modulators of ABC-transporter activity and expression, which are promising nutraceutical molecules to formulate new drug combinations to overcome multidrug resistance.

Brain Targeted Curcumin Loaded Turmeric Oil Microemulsion Protects Against Trimethyltin Induced Neurodegeneration in Adult Zebrafish: A Pharmacokinetic and Pharmacodynamic Insight

PURPOSE

Aromatic turmerone, a major constituent of turmeric oil, has been recently reported for proliferation of neural stem cell showing great potential for effective treatment in neurodegenerative disorders. However, its effect as oral brain targeted formulation for neuroprotection has not yet reported. The objective of the study was to investigate the pharmacokinetic of curcumin loaded turmeric oil microemulsion for brain targeting and probing the protective effect against trimethyltin induced neurodegeneration in adult zebrafish.

METHODS

Initially, in vivo plasma and brain pharmacokinetics was performed to determine improvement in relative bioavailability in rats followed by biodistribution and histopathological evaluation. Furthermore, the neuroprotective effect of the formulation was assessed in trimethyltin induced neurodegeneration model using adult zebrafish by behavioral analysis and biochemical analysis.

RESULTS

The in vivo plasma and brain pharmacokinetics showed 2-fold and 1.87-fold improvement respectively. Biodistribution study revealed significantly lower concentration in organs other than brain. Furthermore, curcumin microemulsion exhibited improved spatial memory by remembering the training and made correct choices after curcumin microemulsion treatment than other treatment groups. Histopathological evaluation confirmed neuroprotective effect on zebrafish brains. The biochemical analysis revealed reduced oxidative stress in curcumin microemulsion treated group.

CONCLUSIONS

Overall results showed a great potential of curcumin microemulsion for brain targeting in the effective treatment of neurological ailments.

Pharmacological Profile, Bioactivities, and Safety of Turmeric Oil

The pharmacological attributes of turmeric have been extensively described and frequently related to the action of curcuminoids. However, there is also scientific evidence of the contribution of turmeric oil. Since the oil does not contain curcuminoids in its composition, it is crucial to better understand the therapeutic role of other constituents in turmeric. The present review discusses the pharmacokinetics of turmeric oil, pointing to the potential application of its active molecules as therapeutic compounds. In addition, the bioactivities of turmeric oil and its safety in preclinical and clinical studies were revised. This literature-based research intends to provide an updated overview to promote further research on turmeric oil and its constituents.

Uptake and time-dependent subcellular localization of native and micellar curcumin in intestinal cells

Uptake into intestinal cells and intracellular distribution into metabolically competent organelles, such as the endoplasmic reticulum, are important processes potentially limiting the bioavailability of xenobiotics. The incorporation of curcumin into polysorbate 80 micelles improves its naturally low oral bioavailability in humans. Here, we investigated uptake and time-dependent localization of curcumin in intestinal cells when administered as native or micellar formulation. Differentiated Caco-2 cells were incubated with 200 μmol/L native or micellar curcumin for up to 180 min and cellular uptake was quantified. Intracellular curcumin was detected already after 30 min and did not differ significantly between formulations or over time. Subcellular localization of native and micellar curcumin in Caco-2 cells was studied by density gradient centrifugation. After 30 min, curcumin from both formulations was mainly associated with mitochondria and lysosomes, after 180 min native curcumin was associated with mitochondria and peroxisomes, micellar curcumin with peroxisomes only. Uptake and localization of native and micellar curcumin in intestinal cells do not differ significantly and consequently do not explain differences in bioavailability in humans. The temporary co-localization with lysosomes is in agreement with the previously proposed role of endocytosis in cellular uptake of curcumin and warrants further investigation.

Curcuma as an adjuvant in colorectal cancer treatment

Colorectal cancer (CRC) is the second leading cause of cancer death worldwide and mostly affects men. Around 20% of its incidence is by familiar disposition due to hereditary syndromes. The CRC treatment involves surgery and chemotherapy; however, the side effects of treatments and the fast emergence of drug resistance evidence the necessity to find more effective drugs. Curcumin is the main polyphenol pigment present in Curcuma longa, a plant widely used as healthy food with antioxidant properties. Curcumin has synergistic effects with antineoplastics such as 5-fluorouracil and oxaliplatin, as well anti-inflammatory drugs by inhibiting cyclooxygenase-2 and the Nuclear factor kappa B. Furthermore, curcumin shows anticancer properties by inhibition of the Wnt/β-catenin, Hedgehog, Notch, and the phosphatidylinositol-3-kinase (PI3K)/Akt and the mammalian target of rapamycin (mTOR) signaling pathways implicated in the progression of CRC. However, the consumption of pure curcumin is less suitable, as the absorption is poor, and the metabolism and excretion are high. Pharmacological formulations and essential oils of the plant improve the curcumin absorption, resulting in therapeutical dosages. Despite the evidence obtained in vitro and in vivo, clinical studies have not yet confirmed the therapeutic potential of curcumin against CRC. Here we reviewed the last scientific information that supports the consumption of curcumin as an adjuvant for CRC therapy.

The Inhibitory Activity of Curcumin on P-Glycoprotein and Its Uptake by and Efflux from LS180 Cells Is Not Affected by Its Galenic Formulation

The biological activities of curcumin in humans, including its antioxidative and anti-inflammatory functions, are limited by its naturally low bioavailability. Different formulation strategies have been developed, but the uptake of curcumin from these galenic formulations into and efflux from intestinal cells, which may be critical processes limiting bioavailability, have not been directly compared. Furthermore, little is known about their effect on P-glycoprotein activity, an important determinant of the pharmacokinetics of potentially co-administered drugs. P-glycoprotein activity was determined in LS180 cells, incubated with 30 or 60 µmol/L of curcumin in the form of seven different formulations or native curcuma extract for 1 h. All formulations inhibited P-glycoprotein activity at both concentrations. Curcumin uptake, after 1 h incubation of LS180 cells with the formulations (60 µmol/L), showed significant variability but no consistent effects. After 1 h pre-treatment with the formulations and further 8 h with curcumin-free medium, curcumin in cell culture supernatants, reflecting the efflux, differed between individual formulations, again without a clear effect. In conclusion, curcumin inhibits P-glycoprotein activity independently of its formulation. Its uptake by and efflux from intestinal cells was not significantly different between formulations, indicating that these processes are not important regulatory points for its bioavailability.

Increasing Post-Digestive Solubility of Curcumin Is the Most Successful Strategy to Improve its Oral Bioavailability: A Randomized Cross-Over Trial in Healthy Adults and In Vitro Bioaccessibility Experiments

SCOPE

Different mechanistic approaches to improve the low oral bioavailability of curcumin have been developed, but not yet directly compared in humans.

METHODS AND RESULTS

In a randomized, double-blind, cross-over trial with 12 healthy adults, the 24 h pharmacokinetics of a single dose of 207 mg curcumin is compared from the following formulations: native, liposomes, with turmeric oils, with adjuvants (including piperine), submicron-particles, phytosomes, γ-cyclodextrin complexes, and micelles. No free, but only conjugated curcumin is detected in all subjects. Compared to native curcumin, a significant increase in the area under the plasma concentration-time curve is observed for micellar curcumin (57-fold) and the curcumin-γ-cyclodextrin complex (30-fold) only. In vitro digestive stability, solubility, and micellization efficiency of micellar curcumin (100%, 80%, and 55%) and curcumin-γ-cyclodextrin complex (73%, 33%, and 23%) are higher compared to all other formulations (<72%, <8%, and <4%). The transport efficiencies through Caco-2 cell monolayers of curcumin from the digested mixed-micellar fractions did not differ significantly.

CONCLUSION

The improved oral bioavailability of micellar curcumin, and to a lesser extent of γ-cyclodextrin curcumin complexes, appears to be facilitated by increased post-digestive stability and solubility, whereas strategies targeting post-absorptive processes, including inhibition of biotransformation, appear ineffective.

Improving Curcumin Bioavailability: Current Strategies and Future Perspectives

Curcumin possesses a plethora of interesting pharmacological effects. Unfortunately, it is also characterized by problematic drug delivery and scarce bioavailability, representing the main problem related to the use of this compound. Poor absorption, fast metabolism, and rapid systemic clearance are the most important factors contributing to low curcumin levels in plasma and tissues. Accordingly, to overcome these issues, numerous strategies have been proposed and are investigated in this article. Due to advances in the drug delivery field, we describe here the most promising strategies for increasing curcumin bioavailability, including the use of adjuvant, complexed/encapsulated curcumin, specific curcumin formulations, and curcumin nanoparticles. We analyze current strategies, already available in the market, and the most advanced technologies that can offer a future perspective for effective curcumin formulations. We focus the attention on the effectiveness of curcumin-based formulations in clinical trials, providing a comprehensive summary. Clinical trial results, employing various delivery methods for curcumin, showed that improved bioavailability corresponds to increased therapeutic efficacy. Furthermore, advances in the field of nanoparticles hold great promise for developing curcumin-based complexes as effective therapeutic agents. Summarizing, suitable delivery methods for this polyphenol will ensure the possibility of using curcumin-derived formulations in clinical practice as preventive and disease-modifying therapeutics.

Antimetastatic Effects of Curcumin in Oral and Gastrointestinal Cancers

Gastrointestinal (GI) cancers are known as frequently occurred solid malignant tumors that can cause the high rate mortality in the world. Metastasis is a significant destructive feature of tumoral cells, which directly correlates with decreased prognosis and survival. Curcumin, which is found in turmeric, has been identified as a potent therapeutic natural bioactive compound (Curcuma longa). It has been traditionally applied for centuries to treat different diseases, and it has shown efficacy for its anticancer properties. Numerous studies have revealed that curcumin inhibits migration and metastasis of GI cancer cells by modulating various genes and proteins, i.e., growth factors, inflammatory cytokines and their receptors, different types of enzymes, caspases, cell adhesion molecules, and cell cycle proteins. Herein, we summarized the antimetastatic effects of curcumin in GI cancers, including pancreatic cancer, gastric cancer, colorectal cancer, oral cancer, and esophageal cancer.

The enhanced bioavailability of free curcumin and bioactive-metabolite tetrahydrocurcumin from a dispersible, oleoresin-based turmeric formulation

BACKGROUND

Curcuminoids have been widely studied for human health and disease applications, yet bioavailability remains a hurdle to actualizing all the benefits ascribed to them. The lack of standardization in analysis method, confusion about what constitutes an ideal analyte, and conflicting thoughts around dosing strategies have made it difficult to draw parity between bioavailability and bioactivity and establish a baseline for formulation comparisons.

METHODS

This randomized double-blinded, 2-way cross over, single oral dose, comparative bioavailability study differentially evaluates curcumin at the time of its absorption and along various biotransformation pathways, to include free curcumin, the readily usable form of curcumin; individual and composite totals of curcumin and its analogues as exogenously cleaved conjugates, for example, total curcumin, total demethoxycurcumin (DMC), total bisdemethoxycurcumin (BDMC), and total curcuminoids respectively; and the bioactive metabolite of curcumin, total tetrahydrocurcumin (THC). As a primary study objective, the relative bioavailability of CURCUGEN, a novel dispersible, 50% curcuminoids-concentrated turmeric extract was compared to the standard curcumin reference product, curcuminoids 95% standardized extract (C-95), using the maximum concentration (Cmax), and area under the curve (AUC0-t) of free curcumin, total curcumin, total DMC, total BDMC and the curcumin active metabolite, as total THC.

RESULTS

The evaluation of free curcumin demonstrated that the Cmax and AUC0-t of the CURCUGEN was 16.1 times and 39 times higher than the Cmax and AUC0-t of C-95. Furthermore, total curcumin, total DMC, total BDMC, and total curcuminoids resulted in AUC0-t of the CURCUGEN at 49.5-, 43.5-, 46.8-, and 52.5-fold higher than C-95, respectively. The relative bioavailability of CURCUGEN for total THC was found to be 31 times higher when compared to C-95.

CONCLUSION

As the first human pharmacokinetics study to apply best-practice recommendations and pharmaceutically-aligned guidance in the comprehensive evaluation of a novel curcuminoids formulation, we have established the novelty of said formulation while better standardizing for the common variances and discrepancies between curcuminoids and their derivatives in the literature and commercial marketing, alike.

Dual-Acting Zeta-Potential-Changing Micelles for Optimal Mucus Diffusion and Enhanced Cellular Uptake after Oral Delivery

Context: Overcoming the intestinal mucosal barrier can be a challenge in drug delivery. Nanoemulsions with negative zeta potentials can effectively permeate the mucus layer, but those with positive zeta potentials are better taken up by cells; a nanoemulsion with capricious zeta potential from negative to positive can achieve both good permeation and high uptake. Objective: This study aimed to develop dual-acting zeta-potential-amphoteric micelles enabling optimal muco-permeation and enhancement of cellular uptake. Methods: A micellar pre-concentrate was prepared from 15% Labrasol, 15% Kolliphor EL, 30% Kolliphor RH 40, and 40% dimethylsulfoxide. The micellar pre-concentrate was loaded with anionic stearic acid (SA), forming ionic complexes with cationic polymers at a ratio of 25:1 with Eudragit RS 100 and Eudragit RL 100. Blank micelles and those containing complexes were separately diluted in physiological buffers and examined for their droplet sizes, polydispersity indices (PDIs), zeta potentials, and cytotoxicity. The SA release from the micellar complexes was evaluated in 0.1 mM phosphate buffer (pH 6.8) containing 0.001% fluorescein, thereby enabling an instant decrease in fluorescence. Finally, the micelles were loaded with the model drug fluorescein diacetate (FDA) and evaluated for their muco-permeation behavior and cellular uptake. Results: The micellar dilutions formed micelles at the critical micelle concentration (CMC) of 312 µg/mL and showed a uniform average droplet size of 14.2 nm, with a PDI < 0.1. Micellar dilutions were non-cytotoxic when used at 1:100 in a physiological medium. Micelles loaded with ionic complexes achieved a sustained release of 95.5 ± 3.7% of the SA in 180 min. Moreover, the zeta potential of the complex-loaded micelles shifted from −5.4 to +1.8 mV, whereas the blank micelles showed a stabilized zeta potential of −10 mV. Furthermore, the negatively charged blank and complex-loaded micelles exhibited comparable muco-permeation, with an overall average of 58.2 ± 3.7% diffusion of FDA. The complex-loaded micellar droplets, however, provided a significantly higher cellular uptake of the model drug FDA (2.2-fold, p ≤ 0.01) Conclusion: Due to undergoing a shift in zeta potential, the modified micelles significantly enhanced cellular uptake while preserving mucus-permeating properties.

A Randomized, Placebo-Controlled Study to Evaluate the Effect of Bio-Enhanced Turmeric Formulation on Radiation-Induced Oral Mucositis

INTRODUCTION

Oral mucositis is the most common toxicity of chemoradiotherapy treatment of head and neck cancers. The present study was performed to evaluate the effect of a researched turmeric formulation on oral mucositis in patients receiving chemoradiotherapy for oral cancer.

METHODS

This randomized double-blinded placebo-controlled trial included 60 patients with oral cancer who had undergone radical surgery. Patients were equally randomized into 3 arms. Bio-enhanced turmeric formulation (BTF) capsules (low dose [1 g/day] or high dose [1.5 g/day]) or placebo was administered daily for 6 weeks with concurrent chemoradiotherapy. Study endpoints included the impact of the treatment on chemoradiotherapy-induced oral mucositis along with dysphagia, oral pain, dermatitis, and weight loss.

RESULTS

The incidence of grade 3 toxicity of oral mucositis, oral pain, dysphagia, and dermatitis was significantly lower in patients who received BTF than placebo. Twenty-five and 20% patients in BTF 1 g/day (p = 0.011) and 1.5 g/day (p = 0.004) arms, respectively, developed grade 3 oral mucositis compared to 65% patients in the placebo arm. Thirty-five and 30% patients in BTF 1 g/day (p = 0.027) and 1.5 g/day (p = 0.011) arms, respectively, developed grade 3 oral pain compared to 70% patients in the placebo arm. Twenty-five and 20% patients in BTF 1 g/day (p = 0.025) and 1.5 g/day (p = 0.010) arms, respectively, developed grade 3 dysphagia compared to 60% patients in the placebo arm. Ten and 5% patients in BTF 1 g/day (p = 0.114) and 1.5 g/day (p = 0.037) arms. respectively, developed grade 3 dermatitis compared to 30% patients in the placebo arm. Patients under BTF supplementation experienced significantly less weight loss and greater compliance with treatment than placebo.

CONCLUSION

BTF (BCM-95®) can significantly reduce chemoradiotherapy-induced severe oral mucositis, dysphagia, oral pain, and dermatitis in oral cancer patients.

TRIAL REGISTRATION

Clinical Trials Registry, India (Registration No. CTRI) (CTRI/2015/12/006413 dated December 4, 2015).

The effect of curcumin and zinc co-supplementation on glycemic parameters in overweight or obese prediabetic subjects: A phase 2 randomized, placebo-controlled trial with a multi-arm, parallel-group design

Management of prediabetes is a critical step to prevent type-2 diabetes. Curcumin and zinc have been studied as an antioxidant, antiinflammatory, and antidiabetic agents. In this clinical trial, 84 subjects were randomized into curcumin (500 mg), zinc (30 mg), zinc and curcumin, and placebo groups for 90 days. At the baseline and the end of the study, the outcomes (fasting plasma glucose (FPG), 2-hour postprandial glucose (2hpp), HbA₁ C, insulin, insulin sensitivity (IS), insulin resistance (IR), β-cell function (BCF), weight, body mass index (BMI), dietary intake, and physical activity (PA)) were measured. A hypocaloric diet and PA were recommended for all subjects. In total, 82 subjects completed the study. After the intervention, dietary intake, PA, weight, and BCF% did not show a significant difference among the groups. However, subjects taking only zinc and zinc and curcumin groups experienced decreased BMI compared to the placebo (p = .01 and .007, respectively). The three treated groups had improved FPG (p = .01), 2hpp (p = .003), HbA1C (p = .004), insulin (p = .001), IS% (p = .001), and IR (p < .001) compared to the placebo. Based on these results, zinc and curcumin supplementation exerted a beneficial effect on several key glycemic parameters.

Detection of Biological Activity of Curcuma longa Methanol Extract and Its Antibacterial effect on Staphylococcus aureus

Plants are known to possess enormous profound benefits, which if well incorporated in daily living have the potential to influence our health in ways unexpected. Significant progress has been made concerning the anti-oxidative and anti-cancerous effect of bioactive components in food products, worthy of note in the curcuminoids derived from turmeric (Curcuma longa) rhizomes. Therefore, to this end, this research aims to describe succinctly the phytocomponents, antioxidant activity and anti-microbial activity of turmeric methanol extract. The zones of inhibition were measured after plating on a Mueller Hinton agar plate and compared to the standards penicillin G and chloramphenicol. Chloramphenicol used as a positive control was found to be most effective on Staphylococcus aureus while Curcuma longa methanol extract and penicillin G were found to have the same microbial inhibition due to the negative control. Compared to the IC50 values of Ascorbic acid which was 5 mg/ ml, Curcuma longa methanol extract had a lower IC50 value is 3.2 mg/ml which according to previous literature is a good one given that lower IC50 values indicate great antioxidant activity. It was gathered by the observation that the qualitative extraction of Curcuma longa using methanol shows the presence of varying chemical components such as AR-tumerone, arachinsaeure, alpha-tumerone amongst others. Research data suggest that ar-turmerone has the potential to promote the positive and negative proliferation of tumor cell lines. As a result, Curcuma longa has high potential to be developed into an antibiotic against Methicillin-resistant Staphylococcus aureus and other clinically important bacterial strains in future.

Medicinal Plants and Mushrooms with Immunomodulatory and Anticancer Properties-A Review on Hong Kong's Experience

The immune modulating effects of selected herbs deserve careful studies to gain evidence-based support for their further development. We have been working hard on many items of medicinal herbs to gain insight into their immunomodulatory effects relevant to cancer treatment in particular, while infection control is not excluded. Nine of them have been selected to give the results of our exploration on their biological, particularly immunomodulatory activities. Since Hong Kong people especially favor one medicinal mushroom, viz. Coriolus versicolor, a number of clinical trials using Coriolus for cancer-related studies are included in this review. While immune modulation platforms are being built for relevant studies, a brief account on the research targets and related procedures are given.

Bioavailable turmeric extract for knee osteoarthritis: a randomized, non-inferiority trial versus paracetamol

BACKGROUND

To compare the efficacy and safety of bioavailable turmeric extract versus paracetamol in patients with knee osteoarthritis (OA).

METHODS

In this randomized, non-inferiority, controlled clinical study, patients of knee OA were randomized to receive bioavailable turmeric extract (BCM-95®) 500 mg capsule two times daily or paracetamol 650 mg tablet three times daily for 6 weeks. The primary outcome measure was Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain subscale. The secondary outcome measures were WOMAC total, WOMAC stiffness, and WOMAC physical function scores. Responder analysis of individual patients at different levels (≥ 20%, ≥ 50%, and ≥ 70%) for WOMAC score was calculated. TNF alpha and CRP levels were evaluated and adverse events (AE) were also recorded.

RESULTS

Seventy-one and seventy-three knee OA patients, respectively in bioavailable turmeric extract and paracetamol groups, completed the study. Non-inferiority (equivalence) test showed that WOMAC scores were equivalent in both the groups (p value < 0.05) in all the domains within the equivalence limit defined by effect size (Cohen's d) of 0.5 whereas CRP and TNF-α were better reduced with turmeric extract than paracetamol. After 6 weeks of treatment, WOMAC total score, pain, stiffness, and function scores got a significant improvement of 23.59, 32.09, 28.5, and 20.25% respectively with turmeric extract. In the turmeric extract group, 18% of patients got more than 50% improvement and 3% of patients got more than 70% improvement in WOMAC pain and function/stiffness score and none of the patients in the paracetamol group met the criteria. CRP and TNF-α got significantly reduced (37.21 and 74.81% respectively) in the turmeric extract group. Adverse events reported were mild and comparatively less in the turmeric extract group (5.48%) than in the paracetamol group (12.68%).

CONCLUSION

The results of the study suggest that bioavailable turmeric extract is as effective as paracetamol in reducing pain and other symptoms of knee osteoarthritis and found to be safe and more effective in reducing CRP and TNF-α.

TRIAL REGISTRATION

Clinical Trials Registry - India CTRI/2017/02/007962 . Registered on 27 February 2017.

Neuroprotective Effect of Turmeric Extract in Combination with Its Essential Oil and Enhanced Brain Bioavailability in an Animal Model

Purpose

The study evaluated the neuroprotective effect and pharmacokinetic profile of turmeric extract and their metabolites in the blood and brain in an aluminum-induced neurotoxic animal model.

Methods

Swiss albino mice received turmeric extract (TE), TE-essential oil combination (TE+EO) at doses of 25 and 50 mg/kg/day orally, vehicle (control), and a positive control group. Neurotoxicity was induced by injecting aluminum chloride (40 mg/kg/day, i.p.), and the effect of the intervention was studied for 45 days. The pharmacokinetic and behavioral biochemical markers of brain function and brain histopathological changes were evaluated.

Results

The AUC 0-t showed a 30.1 and 54.2 times higher free curcumin concentration in plasma with 25 mg/kg and 50 mg/kg of TE+EO vs. TE, respectively. The concentration of free curcumin in the brain was 11.01 and 13.71-fold higher for 25 mg/kg and 50 mg/kg of TE+EO vs. TE, respectively. Aluminum impairs spatial learning and memory, which was significantly reversed with TE+EO by 28.6% (25 mg/kg) and 39.4% (50 mg/kg). In the elevated plus maze test, 44.8% (25 mg/kg) and 67.1% (50 mg/kg) improvements were observed. A significant reduction in aluminum-induced lipid peroxidation was observed. Also, the levels of glutathione, acetylcholinesterase, and catalase were improved with TE+EO. Damage to the hippocampal pyramidal cells was averted with TE+EO.

Conclusion

The neuroprotective and antioxidant response confirms the benefits of TE+EO against aluminum-induced neurotoxicity. The presence of free curcumin and its metabolites in the brain and plasma establishes its improved bioavailability and tissue distribution. Therefore, the benefits of TE+EO could be harnessed in neurodegenerative diseases.

Curcuma longa L. Rhizome Essential Oil from Extraction to Its Agri-Food Applications. A Review

Curcuma longa L. rhizome essential oil is a valuable product in pharmaceutical industry due to its wide beneficial health effects. Novel applications in the agri-food industry where more sustainable extraction processes are required currently and safer substances are claimed for the consumer are being investigated. This review provides information regarding the conventional and recent extraction methods of C. longa rhizome oil, their characteristics and suitability to be applied at the industrial scale. In addition, variations in the chemical composition of C. longa rhizome and leaf essential oils regarding intrinsic and extrinsic factors and extraction methods are also analysed in order to select the most proper to obtain the most efficient activity. Finally, the potential applications of C. longa rhizome oil in the agri-food industry, such as antimicrobial, weedicide and a food preservative agent, are included. Regarding the data, C. longa rhizome essential oil may play a special role in the agri-food industry; however, further research to determine the application threshold so as not to damage crops or affect the organoleptic properties of food products, as well as efficient encapsulation techniques, are necessary for its implementation in global agriculture.

Investigating Curcumin/Intestinal Epithelium Interaction in a Millifluidic Bioreactor

Multidrug resistance is still an obstacle for chemotherapeutic treatments. One of the proteins involved in this phenomenon is the P-glycoprotein, P-gp, which is known to be responsible for the efflux of therapeutic substances from the cell cytoplasm. To date, the identification of a drug that can efficiently inhibit P-gp activity remains a challenge, nevertheless some studies have identified natural compounds suitable for that purpose. Amongst them, curcumin has shown an inhibitory effect on the protein in in vitro studies using Caco-2 cells. To understand if flow can modulate the influence of curcumin on the protein's activity, we studied the uptake of a P-gp substrate under static and dynamic conditions. Caco-2 cells were cultured in bioreactors and in Transwells and the basolateral transport of rhodamine-123 was assessed in the two systems as a function of the P-gp activity. Experiments were performed with and without pre-treatment of the cells with an extract of curcumin or an arylmethyloxy-phenyl derivative to evaluate the inhibitory effect of the natural substance with respect to a synthetic compound. The results indicated that the P-gp activity of the cells cultured in the bioreactors was intrinsically lower, and that the effect of both natural and synthetic inhibitors was up modulated by the presence of flow. Our study underlies the fact that the use of more sophisticated and physiologically relevant in vitro models can bring new insights on the therapeutic effects of natural substances such as curcumin.

Efficacy and safety of combination of curcuminoid complex and diclofenac versus diclofenac in knee osteoarthritis: A randomized trial

BACKGROUND

To compare the efficacy and safety of combination of curcuminoid complex and diclofenac vs diclofenac alone in the treatment of knee osteoarthritis (OA).

METHODS

In this randomized trial, 140 patients of knee OA received either curcuminoid complex 500 mg (BCM-95) with diclofenac 50 mg 2 times daily or diclofenac 50 mg alone 2 times daily for 28 days. Patients were assessed at baseline, day 14 and day 28. Primary efficacy measures were Knee injury and OA outcome score (KOOS) subscale at day 14 and day 28. Anti-ulcer effect and patient-physician's global assessment of therapy at day 28 were included as secondary endpoints. Safety after treatment was evaluated by recording adverse events and laboratory investigations.

RESULTS

Both treatment groups showed improvement in primary endpoints at each evaluation visit. Patients receiving curcuminoid complex plus diclofenac showed significantly superior improvement in KOOS subscales, viz. pain and quality of life at each study visit (P < .001) when compared to diclofenac. Less number of patients required rescue analgesics in curcuminoid complex plus diclofenac group (3%) compared to diclofenac group (17%). The number of patients who required histamine 2 (H2) blockers was significantly less in curcuminoid complex plus diclofenac group compared to diclofenac group (6% vs 28%, respectively; P < .001). Adverse effects were significantly less in curcuminoid complex plus diclofenac group (13% vs 38% in diclofenac group; P < .001). Patient's and physician's global assessment of therapy favored curcuminoid complex plus diclofenac than diclofenac.

CONCLUSION

Combination of curcuminoid complex and diclofenac showed a greater improvement in pain and functional capacity with better tolerability and could be a better alternative treatment option in symptomatic management of knee OA.

TRIAL REGISTRATION

ISRCTN, ISRCTN10074826.

Target and Nontarget Toxicity of Cassia fistula Fruit Extract Against Culex pipiens (Diptera: Culicidae), Lung Cells (BEAS-2B) and Zebrafish (Danio rerio) Embryos

Mosquitoes transmit serious diseases, which threaten humans and severely affect livestock. The half-lethal concentration (LC50) was calculated by log probit analysis. The LC50 and LC90 values of larvicidal activity of Cassia fistula Linn. hexane-methanol soluble fraction (HMSF) after 24 h of exposure were 21.04 and 34.68 µg/ml, respectively. The LC50 values after 24 h of exposure were 84.09 µg/ml and 108.08 µg/ml for chloroform-methanol soluble fraction (CMSF) and ethyl acetate-methanol soluble fraction (EMSF) respectively. The percent hatchability of eggs exposed to the hexane extract was 90 ± 5.0, 68.33 ± 7.6, 46.6 ± 11.5, 10 ± 0.0, and 0 ± 0.0% at 10, 20, 40, 60, and 80 ppm, respectively. The pupicidal activity of the hexane extract at 40 µg/ml was 0.0%. The LC50 value of adulticidal activity of the hexane extract was 12.8 mg/test tube. The biosafety of the hexane extract was assessed in nontarget organisms, i.e., zebrafish (Danio rerio) embryos and normal lung cells (BEAS-2B). The hexane extract of C. fistula was well tolerated by zebrafish embryos, and no mortality or toxicity was found in the embryos exposed to the highest tested concentration of 300 µg/ml. Similarly, all the concentrations tested against the normal lung cells (BEAS-2B) showed more than 95% survival. The gas chromatography-mass spectroscopy analysis identified 12 compounds, and 2-methyl hexanoic acid and 2-methyl butanoic acid were the major compounds identified in the hexane extract. The larvicidal activity of C. fistula extracts will help in the development of natural substitutes for vector management of mosquito populations.

Role of turmeric extract in minimising mucositis in patients receiving radiotherapy for head and neck squamous cell cancer: a randomised, placebo-controlled trial

OBJECTIVE

To determine the role of turmeric extract in reducing mucositis in patients undergoing radiotherapy for head and neck cancer.

METHODS

Sixty-one patients who underwent radiotherapy were included in the study and randomised into groups A and B. Patients in group A received 500 mg of turmeric extract (BCM-95) thrice daily, while patients in group B received placebo until radiotherapy completion. All patients were assessed for oral mucositis on a weekly basis during treatment and two months post-treatment using the National Cancer Institute Common Terminology Criteria for Adverse Events and World Health Organization criteria.

RESULTS

Both groups had a similar grade of mucositis in first two weeks of treatment. The severity of mucositis was progressive in the control group, with four patients developing grade 3 mucositis by week four. In group A, however, the majority of patients (73.3 per cent) had grade 1 mucositis after four weeks of treatment. The difference was statistically significant from the third week onwards (p < 0.001).

CONCLUSION

Turmeric extract reduces the incidence and severity of radiation-induced mucositis, which can benefit patients undergoing radiation for head and neck cancer.

Untargeted UPLC-MS metabolomics reveals multiple changes of urine composition in healthy adult volunteers after consumption of curcuma longa L. extract

Curcuma longa L. is used as food supplement to prevent diseases, although limited studies have been performed on healthy subjects up to now. In the present work, an untargeted UPLC-MS metabolomics approach was applied to study the changes of 24-hours urinary composition on healthy volunteers due to a 28-days daily consumption of a dried C. longa extract containing a standardized amount of curcuminoids. Changes in the excretion of different metabolites were observed after supplementation. Curcumin and two metabolic derivatives (hexahydrocurcumin and dihydrocurcumin) were detected in urine, indicating the absorption of the main curcuminoid from the extract and its further metabolism by liver and gut microbiota. For the first time ar-turmerone, the main apolar constituent of curcuma, was detected in urine in intact form, and its presence was confirmed by a targeted GC-MS analysis. The increase of tetranor-PGJM and tetranor-PGDM, two prostaglandin-D2 metabolites, was observed, being related to the anti-inflammatory effect exerted by curcuma. The variation of the amounts of HPAG, PAG, proline-betaine and hydroxyphenyllactic acid indicate that the supplementation induced changes to the activity of gut microbiota. Finally, the reduced excretion of niacin metabolites (nicotinuric acid, trigonelline and 2PY) and medium- and short-chain acylcarnitines suggests that curcuma could induce the mitochondrial β-oxidation of fatty acids for energy production in healthy subjects. Overall, the results indicate that a prolonged daily consumption of a dried curcuma extract exerts multiple effects on healthy subjects, furthermore they show the opportunity offered by untargeted metabolomics for the study of the bioactivity of natural extracts in healthy human volunteers.

The differential cellular uptake of curcuminoids in vitro depends dominantly on albumin interaction

BACKGROUND

Curcuminoids, mainly present in the plant rhizomes of turmeric (Curcuma longa), consist of mainly three forms (curcumin (CUR), bisdemethoxycurcumin (BDMC) and demethoxycurcumin (DMC)). It has been reported that different forms of curcuminoids possess different biological activities. However, the mechanisms associated with these differences are not well-understood. Recently, our laboratory found differences in the cellular uptake of these curcuminoids. Therefore, it has been inferred that these differences contribute to the different biological activities.

PURPOSE

In this study, we investigated the mechanisms of differential cellular uptake of these curcuminoids.

METHOD

Based on our previous study, we hypothesized the differential cellular uptake is caused by (I) polarity, (II) transporters, (III) metabolism rate of curcuminoids and (IV) medium components. These four hypotheses were each investigated by (I) neutralizing the polarities of curcuminoids by encapsulation into poly(lactic-co-glycolic) acid nanoparticles (PLGA-NPs), (II) inhibition of polyphenol-related absorption transporters, (III) analysis of the cellular curcuminoids and their metabolites by liquid chromatography-tandem mass spectrometry (LC-MS/MS) and (IV) use of different mediums in cell study.

RESULTS

The differential cellular uptake was not affected by (I-III). However, when investigating (IV), not only CUR but also BDMC and DMC were incorporated into cells when serum free media was used. Furthermore, when we used the serum free medium containing bovine serum albumin (BSA), only CUR was taken up but BDMC and DMC were not. Therefore, we identified that the differential cellular uptake of curcuminoids is caused by the medium components, especially BSA. Also, the fluorescence quenching study suggested that differential cellular uptake is due to the different interaction between BSA and each curcuminoid.

CONCLUSION

The differential cellular uptake of curcuminoids was caused by the different interaction between curcuminoids and BSA. The results from this study might give clues on the mechanisms by which curcuminoids exhibit different physiological activities.

Safety and efficacy of curcumin versus diclofenac in knee osteoarthritis: a randomized open-label parallel-arm study

Background

The purpose of this study was to compare the efficacy and safety of curcumin with those of diclofenac in the treatment of knee osteoarthritis (OA).

Methods

In this randomized, open-label, parallel, active controlled clinical study, 139 patients with knee OA were randomly assigned to receive either a curcumin 500-mg (BCM-95^®) capsule three times daily or a diclofenac 50-mg tablet two times daily for 28 days. Patients underwent assessment at baseline and days 7, 14, and 28. The main outcome measure was severity of pain using visual analogue scale score at days 14 and 28. Knee Injury and Osteoarthritis Outcome Score (KOOS) (at days 14 and 28), anti-flatulent effect (at day 7), anti-ulcer effect, weight-lowering effect, and patient’s and physician’s global assessment of therapy at day 28 were included as secondary outcome measures. Safety after treatment was evaluated by recording adverse events and laboratory investigation.

Results

At days 14 and 28, patients receiving curcumin showed similar improvement in severity of pain and KOOS scale when compared with diclofenac, and the difference was not statistically significant. At day 7, the patients who received curcumin experienced a significantly greater reduction in the number of episodes of flatulence compared with diclofenac (P <0.01). At day 28, a weight-lowering effect (P <0.01) and anti-ulcer effect (P <0.01) of curcumin were observed. None of the patients required H2 blockers in the curcumin group, and 19 patients required H2 blockers in the diclofenac group (0% versus 28%, respectively; P <0.01). Adverse effects were significantly less in the curcumin group (13% versus 38% in the diclofenac group; P <0.01). Patient’s and physician’s global assessment of therapy was similar in the two treatment groups.

Conclusion

Curcumin has similar efficacy to diclofenac but demonstrated better tolerance among patients with knee OA. Curcumin can be an alternative treatment option in the patients with knee OA who are intolerant to the side effects of non-steroidal anti-inflammatory drugs.

Trial registration

ISRCTN, ISRCTN10074826. Registered 21 November 2017 - Retrospectively registered.

Non-Curcuminoids from Turmeric and Their Potential in Cancer Therapy and Anticancer Drug Delivery Formulations

Over the past decades curcuminoids have been extensively studied for their biological activities such as antiulcer, antifibrotic, antiviral, antibacterial, antiprotozoal, antimutagenic, antifertility, antidiabetic, anticoagulant, antivenom, antioxidant, antihypotensive, antihypocholesteremic, and anticancer activities. With the perception of limited toxicity and cost, these compounds forms an integral part of cancer research and is well established as a potential anticancer agent. However, only few studies have focused on the other bioactive molecules of turmeric, known as non-curcuminoids, which are also equally potent as curcuminoids. This review aims to explore the comprehensive potency including the identification, physicochemical properties, and anticancer mechanism inclusive of molecular docking studies of non-curcuminoids such as turmerones, elemene, furanodiene (FN), bisacurone, germacrone, calebin A (CA), curdione, and cyclocurcumin. An insight into the clinical studies of these curcumin-free compounds are also discussed which provides ample evidence that favors the therapeutic potential of these compounds. Like curcuminoids, limited solubility and bioavailability are the most fragile domain, which circumscribe further applications of these compounds. Thus, this review credits the encapsulation of non-curcuminoid components in diverse drug delivery systems such as co-crystals, solid lipid nanoparticles, liposomes, microspheres, polar-non-polar sandwich (PNS) technology, which help abolish their shortcomings and flaunt their ostentatious benefits as anticancer activities.

Food matrix and co-presence of turmeric compounds influence bioavailability of curcumin in healthy humans

Turmeric enhances curcumin bioavailability in healthy men.

Overcoming P-Glycoprotein-Mediated Multidrug Resistance in Colorectal Cancer: Potential Reversal Agents among Herbal Medicines

OBJECTIVES

Multidrug resistance (MDR) is the major reason for the failure of chemotherapy in colorectal cancer (CRC), and the primary determinant of MDR in CRC patients is active drug efflux owing to overexpression of P-glycoprotein (P-gp) in cancer tissues. Despite research efforts to overcome P-gp-mediated drug efflux, the high toxicity of P-gp inhibitors has been a major obstacle for the clinical use of these agents. The aim of this study was to review the literature for potential P-gp reversal agents among traditional herbal medicines, which offer the advantages of safety and potential synergetic effects in CRC chemotherapy.

METHODS

We searched ten databases including 3 English databases, 1 Chinese medical database, and 6 Korean medical databases up to July 2018 and included in vivo and in vitro studies evaluating the effects of herbal medicines as P-gp reversal agents in CRC.

RESULTS

A total of 28 potentially related studies were identified and 16 articles were included. Involving 3 studies about Salvia miltiorrhiza and 2 studies about Curcuma longa, finally we found 14 kinds of traditional herbal medicines-Salvia miltiorrhiza, Curcuma longa, Sinomenium acutum, Stephania tetrandra, Bufo gargarizans, Coptis japonica, Piper nigrum and Piper longum, Hedyotis diffusa, Schisandra chinensis, Glycyrrhiza glabra, Glycyrrhiza inflate, Daphne genkwa, Stemona tuberosa Lour, and Andrographis paniculata-as showing efficacy as P-gp inhibitors in anticancer drug-resistant CRC cells in vitro and in vivo.

CONCLUSIONS

This brief account provides insight into the relationship between P-gp and CRC. Further studies on herbal medicines with demonstrated effects against P-gp overexpression will aid in improving the efficacy of chemotherapy in CRC.

Turmeric extract, with absorbable curcumin, has potent anti-metastatic effect in vitro and in vivo

BACKGROUND

Curcumin, a well-studied component in turmeric, exhibits potent antitumor effects in colorectal cancer. Previous studies showed that turmerones raised the accumulation of curcumin inside colonic cells, and curcumin present in turmeric ethanolic extract had enhanced anti-tumor activities in mice. Metastasis accounts for more than 90% colorectal cancer deaths. However, the anti-metastatic effect of turmeric extract on colorectal cancer is still unknown.

METHODS

In the present study, colony formation, scratch, transwell and Western blot were used to assess colony formation, motility, migration and underlying mechanisms in vitro, respectively. Anti-tumor and anti-metastatic effects in vivo were investigated using an orthotopic xenograft model.

RESULTS

Turmeric extract exhibited cytotoxic effect, inhibited colony formation, decreased cell motility, migration and epithelial-mesenchymal transitions through regulating multiple pathways including cofilin, FAK/p-Src, AKT, Erk and STAT3 signaling pathways in murine colorectal cancer cells. Furthermore, turmeric extract at 200 mg/kg could decrease colon tumor burden and inhibit liver and lung metastasis in vivo. Treatment of turmeric extract enhanced immunity through T cell stimulation, changed tumor microenvironment, exerted anti-metastatic effects which were shown for the first time in pre-clinical colorectal cancer models. The decrease of immunity after FOLFOX treatment was also firstly demonstrated in mouse model.

CONCLUSIONS

Turmeric extract was demonstrated for the first time for its anti-tumor and anti-metastatic effects in both colorectal cancer cells and orthotopic mouse model through regulation of multiple targets. These findings strongly suggested the promising use of turmeric extract as chemopreventive or chemotherapeutic agent for colorectal cancer patients with metastasis.

Effects of curcumin consumption on human chronic diseases: A narrative review of the most recent clinical data

Numerous clinical trials have investigated the potential beneficial effects of curcumin supplementation against several human chronic diseases. Up to now, it has been claimed that curcumin consumption may exert beneficial effects against several chronic diseases by promoting human health and preventing diseases. In this aspect, the present review aims to critically collect and in-depth summarize the most recent, well-designed clinical studies evaluating the potential beneficial effects of curcumin consumption on human health promotion and disease prevention. According to recent and well-designed clinical studies, curcumin consumption may benefit against obesity, metabolic syndrome, and diabetes. Moreover, curcumin consumption seems to exert a positive effect on people suffering from various types of cancer, fatty liver disease, depression, arthritis, skin diseases, gut inflammation, and symptoms of premenstrual syndrome. Due to the strong heterogeneity among the clinical studies concerning the exact effective curcumin dose and formulation, as well as the recommended treatment duration for each chronic disease, no precise and definitive conclusions could be drawn. Further large-scale prospective studies are strongly recommended, being well-designed as far as follow-up times, dosage, formulation, and duration of curcumin supplementation are concerned. Moreover, potential confounders in each specific chronic disease should carefully be taken into account in future studies.

Curcumin as a clinically-promising anti-cancer agent: pharmacokinetics and drug interactions

INTRODUCTION

Curcumin has been extensively studied for its anti-cancer properties. While a diverse array of in vitro and preclinical research support the prospect of curcumin use as an anti-cancer therapeutic, most human studies have failed to meet the intended clinical expectation. Poor systemic availability of orally-administered curcumin may account for this disparity. Areas covered: This descriptive review aims to concisely summarise available clinical studies investigating curcumin pharmacokinetics when administered in different formulations. A critical analysis of pharmacokinetic- and pharmacodynamic-based interactions of curcumin with concomitantly administered drugs is also provided. Expert opinion: The encouraging clinical results of curcumin administration are currently limited to people with colorectal cancer, given that sufficient curcumin concentrations persist in colonic mucosa. Higher parent curcumin systemic exposure, which can be achieved by several newer formulations, has important implications for optimal treatment of cancers other than those in gastrointestinal tract. Curcumin-drug pharmacokinetic interactions are also almost exclusively in the enterocytes, owing to extensive first pass metabolism and poor curcumin bioavailability. Greater scope of these interactions, i.e. modulation of the systemic elimination of co-administered drugs, may be expected from more-bioavailable curcumin formulations. Further studies are still warranted, especially with newer formulations to support the inclusion of curcumin in cancer therapy regimens.

Essential turmeric oils enhance anti-inflammatory efficacy of curcumin in dextran sulfate sodium-induced colitis

Turmeric has been used as a medicinal herb for thousands of years for treatment of various disorders. Although curcumin is the most studied active constituents of turmeric, accumulating evidence suggests that other components of turmeric have additional anti-inflammatory and anti-tumorigenic properties. Herein, we investigated anti-inflammatory efficacy and associated gene expression alterations of a specific, curcumin preparation containing essential turmeric oils (ETO-curcumin) in comparison to standard curcumin at three specific doses (0, 5, 25 or 50 mg/kg), in an animal model of dextran sodium sulfate (DSS)-induced colitis. The present study showed that both ETO and standard curcumin treatments provided protection against DSS-induced inflammation. However, ETO-curcumin improved disease activity index (DAI) dose-dependently, while the anti-inflammatory efficacy of standard curcumin remained constant, suggesting that ETO-curcumin may provide superior anti-inflammatory efficacy compared to standard curcumin. Gene expression analysis revealed that anti-inflammatory cytokines including IL-10 and IL-11 as well as FOXP3 were upregulated in the colon by ETO-curcumin. Collectively, these findings suggest that the combined treatment of curcumin and essential turmeric oils provides superior protection from DSS-induced colitis than curcumin alone, highlighting the anti-inflammatory potential of turmeric.

Complementary and alternative medicine use among cancer patients in Palestine with special reference to safety-related concerns

ETHNOPHARMACOLOGICAL RELEVANCE

The use of CAM including herbal medicine as the most preferred CAM modality, among cancer patients who are taking prescription medications has shown to be highly prevalent worldwide as well as in several Middle Eastern countries, with a high percentage of the patients do not disclose their CAM use to treating physician.

AIM OF THE STUDY

The current study aimed to evaluate the patterns of CAM use among two cohorts of cancer patients in Palestine over a three-year period, and to identify socio-demographic factors that are associated with CAM use.

MATERIALS AND METHODS

Across-sectional survey of patients attending outpatient cancer clinics. The method was based on a semi-structured questionnaire. In order to identify safety-related concerns associated with the products listed, a literature search was conducted using different databases (PubMed, Micromedex, AltMedDex, and the Natural Medicine Comprehensive Database).

RESULTS

In 472 cancer patients including 372 of the 2011 cohort; and 100 of the 2014 cohort, the overall prevalence of CAM use was 69.5%. CAM users were more likely to be ≤65 years old, village resident, being in the midst of chemotherapy, to have high interest spiritual quest, and to have no other chronic diseases. A significant number of CAM users reported using herbal preparations (98.3%, and 89.6% in the two study cohorts, respectively). In the current study, a total of 40 plant taxa belonging to 23 botanical families were reported by ≥3 cancer patients in the two cohort groups. The top most commonly used plant in the 2011 cohort group was Arum palaestinum (43.5%), while Ephedra foeminea emerged as the top most commonly utilized plant (from 0.0% in 2011 to 55.2% in the 2014 cohort), mainly due to a recent publicizing and portraying of the plant in the local media as an effective cancer herbal remedy. Safety-related concerns were associated with 33 (82.5%) herbs, including herb-drug interactions with altered pharmacokinetics (8, 20% herbs), direct toxic effects (16, 40% herbs), and increased in vitro response of cancer cells to chemotherapy (30, 75% herbs).

CONCLUSIONS

CAM use, especially herbal medicine in cancer is highly prevalent in Palestine. This study has demonstrated the role of the media on the emergence of new CAM herbal therapies among cancer patients in Palestine, and discussed its potential implications on patients and for oncologists who are treating them. Some of the most widely used herbal medicines by cancer patients in the present work are known to interact with conventional anticancer drugs. Hence, the disclosure of the use of herbal remedies by patients to health professionals with sufficient training in CAM use is important for the later in order to assess whether there are any possible herbal drug interactions and/or harmful drug reactions.

Combined therapy using bevacizumab and turmeric ethanolic extract (with absorbable curcumin) exhibited beneficial efficacy in colon cancer mice

Turmeric is commonly used as a medicinal herb and dietary supplement. Its active ingredient, curcumin, has been shown to possess antitumor effects in colorectal cancer patients. However, poor absorption of curcumin in intestine impedes its wide clinical application. Our previous findings showed that the presence of turmerones increased the accumulation of curcumin inside colonic cells. Hence, we hypothesized that curcumin with turmerones or present in turmeric ethanolic extract would augment its anti-tumor activities in tumor-bearing mice. The pharmacokinetics of curcumin in different preparations (containing same amount of curcumin) were studied in mice. The anti-tumor efficacies of curcumin or turmeric extract (with absorbable curcumin) in combination with bevacizumab were further investigated in HT29 colon tumor-bearing mice. Pharmacokinetic results showed that the plasma curcumin level of turmeric extract-fed mice was the highest, suggesting turmeric extract had the best bioavailability of curcumin. Besides, combined turmeric extract plus bevacizumab treatment significantly inhibited the tumor growth. Such inhibitory effects were stronger than those of curcumin plus bevacizumab or bevacizumab alone and were comparable with those of 5-fluorouracil+leucovorin+oxaliplatin (FOLFOX) plus bevacizumab. Notably, there was no observable side effect induced by turmeric extract treatment while significant side effects were found in FOLFOX-treated mice. In conclusion, combination of turmeric extract with bevacizumab possessed potent anti-tumor effects without observable side effects, strongly suggesting the adjuvant use of turmeric extract in colorectal cancer therapy. Our current findings warrant the confirmation regarding the benefits arising from the combined use of bevacizumab and turmeric in colorectal cancer patients in the near future.

Polymeric nanoassemblies entrapping curcumin overcome multidrug resistance in ovarian cancer

The increasing emergence of multidrug-resistant (MDR) cells presents a challenge to effective cancer therapy. Curcumin (CUR) has multifunctional anticancer properties, but its clinical use has been limited by poor solubility. We developed biodegradable polymeric micelles entrapping CUR in order to improve its antitumor activity and to explore whether it could treat MDR cells. This delivery system produced small micelles with a high encapsulation efficiency, good stability, and slow release of CUR. CUR micelles showed cytotoxic effects in wild-type drug-sensitive A2780s and in paclitaxel-resistant A2780t ovarian adenocarcinoma cells. The concentration of free CUR that reduced cell viability by 50% (IC50) was 1.5 fold and 1.2 fold higher than that of CUR micelles in A2780s and A2780t cells, respectively. Cellular uptake studies indicated that delivery by micelles improved CUR uptake into both cell lines. Cell cycle analysis suggested that CUR micelles induced apoptosis and enhanced G2/M arrest. Overall, CUR micelles may provide a novel strategy to improve the clinical management of MDR ovarian cancer.

Glyceollin transport, metabolism, and effects on p-glycoprotein function in Caco-2 cells

Glyceollins are phytoalexins produced in soybeans from their isoflavone precursor daidzein. Their impressive anticancer and glucose normalization effects in rodents have generated interest in their therapeutic potential. The aim of the present studies was to begin to understand glyceollin intestinal transport and metabolism, and their potential effects on P-glycoprotein (Pgp) in Caco-2 cells. At 10 and 25 μM, glyceollin permeability was 2.4±0.16×10(-4) cm/sec and 2.1±0.15×10(-4) cm/sec, respectively, in the absorptive direction. Basolateral to apical permeability at 25 μM was 1.6±0.10×10(-4) cm/sec. Results suggest high absorption potential of glyceollin by a passive-diffusion-dominated mechanism. A sulfate conjugate at the phenolic hydroxyl position was observed following exposure to Caco-2 cells. In contrast to verapamil inhibition of the net secretory permeability of rhodamine 123 (R123) and its enhancement of calcein AM uptake into Caco-2 cells, neither glyceollin nor genistein inhibited Pgp (MDR1; ABCB1) up to 300 μM. There was no significant change in MDR1 mRNA expression, Pgp protein expression, or R123 transport in cells exposed to glyceollin or genistein for 24 h up to 100 μM. Collectively, these results suggest that glyceollin has the potential to be well absorbed, but that, similar to the isoflavone genistein, its absorption may be reduced substantially by intestinal metabolism; further, they indicate that glyceollin does not appear to alter Pgp function in Caco-2 cells.

Metabolic profiling of Zingiber zerumbet following Pythium myriotylum infection: investigations on the defensive role of the principal secondary metabolite, zerumbone

Induced biosynthesis of bioactive secondary metabolites constitutes one of the mechanisms of plant basal innate immunity to fungal infection. Metabolic changes were studied in rhizomes of Zingiber zerumbet, a wild congener of ginger, after infection with soft rot-causative necrotrophic phytopathogen, Pythium myriotylum, by gas chromatography-mass spectrometry (GC-MS) analysis. Infection triggered a considerable alteration in the relative content of zerumbone and α-caryophyllene (humulene) with enhancement in zerumbone content (81.59%) and that of α-caryophyllene (11.91%) compared to 9.97 and 1.11%, respectively, in uninfected rhizomes. While zerumbone is the principal secondary metabolite in Z. zerumbet, α-caryophyllene is its immediate precursor. Principal component analysis (PCA) identified the correlations between metabolite changes in Z. zerumbet rhizomes and P. myriotylum infection. Radial diffusion assay with zerumbone indicated a concentration-dependent P. myriotylum growth inhibition with 93.75% inhibition observed at 700 μg and 50% maximal effective concentration (EC50) value of 206 μg. Scanning electron microscopy (SEM) analysis revealed that the mechanistic basis of zerumbone's antagonistic action on P. myriotylum growth involved the induction of aberrant morphology including severe hyphal deformities and membrane disruption. Results are discussed highlighting the critical role played by sesquiterpenoid zerumbone in affording resistance in Z. zerumbet and could expedite the development of appropriate strategies for biocontrol of Pythium spp., thus reducing the usage of broad-spectrum fungicides.

The molecular basis for the pharmacokinetics and pharmacodynamics of curcumin and its metabolites in relation to cancer

This review addresses the oncopharmacological properties of curcumin at the molecular level. First, the interactions between curcumin and its molecular targets are addressed on the basis of curcumin's distinct chemical properties, which include H-bond donating and accepting capacity of the β-dicarbonyl moiety and the phenylic hydroxyl groups, H-bond accepting capacity of the methoxy ethers, multivalent metal and nonmetal cation binding properties, high partition coefficient, rotamerization around multiple C-C bonds, and the ability to act as a Michael acceptor. Next, the in vitro chemical stability of curcumin is elaborated in the context of its susceptibility to photochemical and chemical modification and degradation (e.g., alkaline hydrolysis). Specific modification and degradatory pathways are provided, which mainly entail radical-based intermediates, and the in vitro catabolites are identified. The implications of curcumin's (photo)chemical instability are addressed in light of pharmaceutical curcumin preparations, the use of curcumin analogues, and implementation of nanoparticulate drug delivery systems. Furthermore, the pharmacokinetics of curcumin and its most important degradation products are detailed in light of curcumin's poor bioavailability. Particular emphasis is placed on xenobiotic phase I and II metabolism as well as excretion of curcumin in the intestines (first pass), the liver (second pass), and other organs in addition to the pharmacokinetics of curcumin metabolites and their systemic clearance. Lastly, a summary is provided of the clinical pharmacodynamics of curcumin followed by a detailed account of curcumin's direct molecular targets, whereby the phenotypical/biological changes induced in cancer cells upon completion of the curcumin-triggered signaling cascade(s) are addressed in the framework of the hallmarks of cancer. The direct molecular targets include the ErbB family of receptors, protein kinase C, enzymes involved in prostaglandin synthesis, vitamin D receptor, and DNA.

Curcumin-loaded nanoparticles induce apoptotic cell death through regulation of the function of MDR1 and reactive oxygen species in cisplatin-resistant CAR human oral cancer cells

Curcumin is a polyphenolic compound which possesses anticancer potential. It has been shown to induce cell death in a variety of cancer cells, however, its effect on CAL27‑cisplatin-resistant human oral cancer cells (CAR cells) has not been elucidated to date. The low water solubility of curcumin which leads to poor bioavailability, however, has been highlighted as a major limiting factor. In this study, we utilized water-soluble PLGA curcumin nanoparticles (Cur-NPs), and investigated the effects of Cur-NPs on CAR cells. The results showed Cur-NPs induced apoptosis in CAR cells but exhibited low cytotoxicity to normal human gingival fibroblasts (HGFs) and normal human oral keratinocytes (OKs). Cur-NPs triggered DNA concentration, fragmentation and subsequent apoptosis. Compared to untreated CAR cells, a more detectable amount of Calcein-AM accumulation was found inside the treated CAR cells. Cur-NPs suppressed the protein and mRNA expression levels of MDR1. Both the activity and the expression levels of caspase-3 and caspase-9 were elevated in the treated CAR cells. The Cur-NP-triggered apoptosis was blocked by specific inhibitors of pan-caspase (z-VAD-fmk), caspase-3 (z-DEVD-fmk), caspase-9 (z-LEHD-fmk) and antioxidant agent (N-acetylcysteine; NAC). Cur-NPs increased reactive oxygen species (ROS) production, upregulated the protein expression levels of cleaved caspase-3/caspase-9, cytochrome c, Apaf-1, AIF, Bax and downregulated the protein levels of Bcl-2. Our results suggest that Cur-NPs triggered the intrinsic apoptotic pathway through regulating the function of multiple drug resistance protein 1 (MDR1) and the production of reactive oxygen species (ROS) in CAR cells. Cur-NPs could be potentially efficacious in the treatment of cisplatin-resistant human oral cancer.

Curcumin-free turmeric exhibits anti-inflammatory and anticancer activities: Identification of novel components of turmeric

Turmeric, a dried powder derived from the rhizome of Curcuma longa, has been used for centuries in certain parts of the world and has been linked to numerous biological activities including antioxidant, anti-inflammatory, anticancer, antigrowth, anti-arthritic, anti-atherosclerotic, antidepressant, anti-aging, antidiabetic, antimicrobial, wound healing, and memory-enhancing activities. One component of turmeric is curcumin, which has been extensively studied, as indicated by more than 5600 citations, most of which have appeared within the past decade. Recent research has identified numerous chemical entities from turmeric other than curcumin. It is unclear whether all of the activities ascribed to turmeric are due to curcumin or whether other compounds in turmeric can manifest these activities uniquely, additively, or synergistically with curcumin. However, studies have indicated that turmeric oil, present in turmeric, can enhance the bioavailability of curcumin. Studies over the past decade have indicated that curcumin-free turmeric (CFT) components possess numerous biological activities including anti-inflammatory, anticancer, and antidiabetic activities. Elemene derived from turmeric is approved in China for the treatment of cancer. The current review focuses on the anticancer and anti-inflammatory activities exhibited by CFT and by some individual components of turmeric, including turmerin, turmerone, elemene, furanodiene, curdione, bisacurone, cyclocurcumin, calebin A, and germacrone.

Prevention and Treatment of Colorectal Cancer by Natural Agents From Mother Nature

Colorectal cancer (CRC) is the third most commonly diagnosed cancer in the United States after cancers of the lung and the breast/prostate. While the incidence of CRC in the United States is among the highest in the world (approximately 52/100,000), its incidence in countries in India is among the lowest (approximately 7/100,000), suggesting that lifestyle factors may play a role in development of the disease. Whereas obesity, excessive alcohol consumption, a high-calorie diet, and a lack of physical activity promote this cancer, evidence indicates that foods containing folates, selenium, Vitamin D, dietary fiber, garlic, milk, calcium, spices, vegetables, and fruits are protective against CRC in humans. Numerous agents from "mother nature" (also called "nutraceuticals,") that have potential to both prevent and treat CRC have been identified. The most significant discoveries relate to compounds such as cardamonin, celastrol, curcumin, deguelin, diosgenin, thymoquinone, tocotrienol, ursolic acid, and zerumbone. Unlike pharmaceutical drugs, these agents modulate multiple targets, including transcription factors, growth factors, tumor cell survival factors, inflammatory pathways, and invasion and angiogenesis linked closely to CRC. We describe the potential of these dietary agents to suppress the growth of human CRC cells in culture and to inhibit tumor growth in animal models. We also describe clinical trials in which these agents have been tested for efficacy in humans. Because of their safety and affordability, these nutraceuticals provide a novel opportunity for treatment of CRC, an "old age" disease with an "age old" solution.

Intestinal absorption and bioavailability of traditional Chinese medicines: a review of recent experimental progress and implication for quality control

Objectives

Experimental studies on the pharmacokinetics of traditional Chinese medicines (TCMs) have achieved great progress in recent years. This review aims to summarize the progress made on intestinal absorption and bioavailability of TCMs, and proposes the application of intestinal absorption assays as new tools for the quality and safety control of these medicines.

Key findings

Since only the absorbed constituents may produce possible therapeutic effect (except those that directly target the digestive tract), intestinal absorption is of utmost importance for the drug action of TCMs, which are usually taken orally. Meanwhile, complicated drug interactions may occur among the multiple ingredients in a herbal mixture. In this regard, the intestinal permeability assays not only provide useful pharmacokinetic data of TCMs, but have potential applications for quality and safety control. Moreover, knockout animals, 2/4/A1 in-vitro cell model and physiologically-based in-silico models based on the online TCM database can be quite useful for the prediction of absorption and bioavailability of TCMs.

Summary

A variety of in-vivo, in-vitro, in-situ and in-silico models for predicting the intestinal absorption and bioavailability can be applied to study the herbal interactions and screen appropriate biomarkers for the quality and safety control of TCMs.