Bubbling hookah smoke through heat-solubilized curcumin/turmeric and incorporation of the curry spice as an additive or filter in cigarettes to minimize tobacco smoke-related toxicants

Curcumin Preparations Can Improve Flow-Mediated Dilation and Endothelial Function: A Meta-Analysis

INTRODUCTION

Endothelial dysfunction is an early marker of atherosclerosis. Flow-mediated dilation (FMD), measured by ultrasonography, is used to noninvasively assess endothelial dysfunction. Preparations of curcumin, a naturally occurring pigment found in turmeric, may improve FMD and thus endothelial dysfunction. We did a systematic review and meta-analysis to analyze the effect of curcumin preparations on endothelial dysfunction.

METHODS

Five randomized clinical trials met the inclusion criteria for meta-analysis. The primary outcome was an improvement in FMD, as measured at brachial artery, after supplementations with curcumin preparations compared to the control group. Standardized mean difference and Hedges' g were used for effect size (ES) measurement. An ES of 0.2-0.5 is considered small, 0.5-0.8 is medium, and more than 0.8 is large. Publication bias was studied too.

RESULTS

We found supplementation with curcumin preparations had an overall ES (standard difference in means) of 1.379 (95% CI 0.485-2.274, p = 0.003) on FMD. The overall Hedges' g was 1.353 (95% CI 0.47-2.235, p = 0.03). This analysis suggests a positive and large ES of curcumin preparations on FMD using a random effect model. Smokers had a smaller increase in FMD compared to nonsmokers (ES 0.379 vs. 1.639, p = 0.034).

CONCLUSION

This meta-analysis of 5 randomized clinical trials indicates a significant effect of curcumin preparations to increase the FMD compared to placebo and thus endothelial function. This effect is not strongly noticed in smokers.

Curcumin/Turmeric as an Environment-Friendly Protein Gel Stain

Curcumin, the main curcuminoid in food spice turmeric, is insoluble in water at room temperature. We showed that curcumin can be solubilized in water with the application of heat (100 °C). Here we demonstrate that heat-solubilized curcumin can serve as a nontoxic and environment-friendly fluorescent/colorimetric reversible protein stain. Curcumin, the yellow pigment found in the rhizomes of the perennial herb Curcuma longa (turmeric), is insoluble in aqueous solvents. However, heat solubilization in water renders 1.5% of curcumin soluble. Curcumin solubilized by ethanol or alkali is ineffective in staining proteins. Heat-solubilized curry spice turmeric also stains proteins. Staining is achieved in 30 min, with a sensitivity almost equaling that of Coomassie Brilliant Blue (CBB). Destaining is not required and excess curcumin/turmeric can be discarded into the sink. Binding of proteins by silver inhibits curcumin binding, suggesting similarity of protein binding by silver and curcumin. It costs $1.5-2.0 to stain a mini-gel with curcumin, while turmeric costs less than 0.005 cent. CBB staining/destaining costs about two cents. Curcumin/turmeric, thus, can serve as an ideal nontoxic protein stain.

Heat/Pressure Treatment with Detergents Significantly Increases Curcumin Solubility and Stability: Its Use as an Environment-Friendly Protein Gel Stain

Curcumin, the principal curcuminoid in the food spice turmeric, is insoluble in water at room temperature. We have previously solubilized curcumin in water with the application of heat (100 °C) and found that this solubilized curcumin could be used as a gel protein stain. However, heat solubilization in water solubilized only a small fraction of the curcuminoid (1.5%), making it relatively expensive to stain one gel ($1.5-2 per gel). Heat/pressure solubilization (121 °C/15 psi) helps increase the solubility of curcumin in water to only 5%. Therefore, we ventured into increasing curcumin solubility further by using detergents (Tween 20, Tween 80, or Triton X-100) combined with heat/pressure treatment. Curcumin solubilized with Tween 20, Tween 80 or Triton X-100 stained proteins efficiently as before. We could dramatically increase the solubility of curcumin by solubilizing in detergents such that we had to dilute the solubilized curcumin 1:100 with water to stain proteins. However, we had to use the soluble curcumin (extracted with heat/pressure alone) straight without dilution. Thus, the amount of curcumin solubilized with detergents was at least 100-fold, with 0.5% Tween 80 being the most efficient. Staining can be carried out in 30 min, and sensitivity of staining is similar or better than that obtained with Coomassie Brilliant Blue (CBB). It is unnecessary to destain the gel, and excess curcumin can be discarded into the sink, unlike CBB. Curcumin solubilized in Tween 20 has been found to be stable for a period of over 4 years. Therefore, curcumin solubilized in Tween 80 or Triton X-100 can serve as an efficient nontoxic and environment-friendly protein stain. Tween 80 has been used in cough syrups to make a colloidal suspension, and also in foods. Solubilizing curcumin with Tween 80 would be a useful alternative to increase curcumin bioavailability in clinical studies.

Spicy SDS-PAGE gels: curcumin/turmeric as an environment-friendly protein stain

Gel proteins are commonly stained with calorimetric/fluorescent dyes. Here, we demonstrate that heat-solubilized curcumin can serve as a nontoxic and environment-friendly fluorescent/colorimetric reversible protein stain. Curcumin, the yellow pigment found in the rhizomes of the perennial herb Curcuma longa (turmeric), is insoluble in aqueous solvents. However, heat (100°C) solubilization in water renders 1.5% of curcumin soluble. Curcumin solubilized by ethanol or alkali is ineffective in staining proteins. Heat solubilized curry spice turmeric stains proteins similarly. Staining is achieved in 30 min, with a sensitivity almost equaling that of Coomassie Brilliant Blue (CBB). Destaining is not required, and excess curcumin/turmeric can be discarded into the sink. Binding of proteins by silver inhibits curcumin binding, suggesting similarity of protein binding by silver and curcumin. It costs $1.5-2.0 to stain a mini-gel with curcumin, while turmeric costs less than 0.005 cent. CBB staining/destaining costs about 2 cents. However, CBB is toxic and its use necessitates specialized disposal efforts. Curcumin/turmeric, thus, can serve as an ideal nontoxic protein stain.

Heat-solubilized curry spice curcumin inhibits antibody-antigen interaction in in vitro studies: a possible therapy to alleviate autoimmune disorders

Chronic and complex autoimmune diseases, currently treated palliatively with immunosuppressives, require multi-targeted therapy for greater effectiveness. The naturally occurring polyphenol curcumin has emerged as a powerful "nutraceutical" that interacts with multiple targets to regress diseases safely and inexpensively. Up to 8 g/day of curcumin for 18 months was non-toxic to humans. However, curcumin's utility is limited by its aqueous insolubility. We have demonstrated a heat-mediated 12-fold increase in curcumin's aqueous solubility. Here, we show by SDS-PAGE and surface plasmon resonance that heat-solubilized curcumin binds to proteins. Based on this binding we hypothesized that heat-solubilized curcumin or turmeric would prevent autoantibody targeting of cognate autoantigens. Heat-solubilized curcumin/turmeric significantly decreased binding of autoantibodies from Sjögren's syndrome (up to 43/70%, respectively) and systemic lupus erythematosus (up to 52/70%, respectively) patients as well as an animal model of Sjögren's syndrome (up to 50/60%, respectively) to their cognate antigens. However, inhibition was not specific to autoimmunity. Heat-solubilized curcumin/turmeric also inhibited binding of commercial polyclonal anti-spectrin to spectrin (50/56%, respectively). Thus, we suggest that the multifaceted heat-solubilized curcumin can ameliorate autoimmune disorders. In addition, the non-toxic curcumin could serve as a new protein stain in SDS-PAGE even though it is less sensitive than the Coomassie system which involves toxic chemicals.