Rebuttal to Journal of Medicinal Chemistry Article on Curcumin

by Ajay Goel, PhD

The Concern

The Journal of Medicinal Chemistry published an article in January 2017 entitled “The Essential Medicinal Chemistry of Curcumin: Miniperspective.”¹ The authors offer an overview on the clinical trials and drug development effort regarding curcumin and state a number of conclusions and opinions they draw based on their personal interpretation of previous research.

The media has reacted with only a superficial understanding of this scientific article, which has led to confusion and misinformation about this extremely beneficial botanical, including mainstream media stories condemning curcumin’s medical promise. Let’s take a moment to look more deeply at the facts.

What is Curcumin?

Turmeric contains the compound curcumin. About two to five percent of turmeric is curcumin. Curcumin is extracted from turmeric to deliver a more concentrated dose.

Curcumin is the primary member of a family of compounds called curcuminoids, which also includes demethoxycurcumin and bisdemethoxycurcumin. Although it is not technically correct, in common language curcumin is often used to refer to the full family of curcuminoids. Full spectrum, natural “curcumin” supplements contain all 3 compounds from the curcuminoid family. The authors of this article state they are exploring curcumin only—meaning a single curcuminoid removed from its family.

The Claims

The authors state, “This miniperspective will not attempt to address the potential therapeutic effects of even more complex turmeric extracts or preparations thereof but instead focuses on the reported utility of the chemical structure of the major constituent of these extracts: curcumin.”

Many people are confused by this and have taken the claims more generally to mean that all curcumin is ineffective.

Some of the statements are indeed true:

• Curcumin is hard to absorb.

• Curcumin is not very stable.

• Curcumin is not very water soluble.

• There is a multitude of curcumin raw material, and it can differ significantly.

That is why it is important to use a consistent, high quality, enhanced absorption curcumin preparation that has been proven in multiple human clinical trials. Absorption, safety, and efficacy should be demonstrated in peer-reviewed journals.

Some of the statements are questionable:

• In vitro results (meaning tests outside a living system) are not borne out in in vivo (meaning living systems) results.

• No double-blinded, placebo-controlled clinical trial of curcumin has been successful.

This is puzzling indeed. The authors do not indicate if they mean synthetically isolated curcumin as a curcuminoid, or full spectrum natural curcumin. If they are referring to curcumin as a family of compounds, which most people do, it is not true. In the electronic database of the National Institutes of Health (NIH), available at PubMed.gov, there are well over 9,000 published studies on curcumin; and if you just look at human, double-blind, placebo-controlled trials, there are more than 80—the vast majority of which use enhanced absorption curcumin. I myself have been involved in several published trials and have firsthand experience of curcumin’s effectiveness in a variety of diseases. One trial in which I participated found that curcumin performed as well as a prescription drug for rheumatoid arthritis. There are many other successful studies, too.

Additionally, I have done research on cancer, in which the in vitro results were subsequently demonstrated to be true when carried out in a living organism (in vivo).

Conclusion

One of the stated reasons for this article was to explore the likelihood of curcumin as a drug candidate, with the initial conclusion being that curcumin is not a good candidate as there is not a straightforward way to create an analog for a specific therapeutic effect. It is my opinion that curcumin cannot be reduced to a few chemical structures that behave in a singular fashion. There is a vast array of physical targets that are touched by the natural compounds in curcumin that cannot be duplicated by a synthetic drug.

My own scientific research, and the research of other esteemed scientists around the world, has confirmed that curcumin is a powerful and clinically documented intervention that has provided health benefits to hundreds of thousands of people around the world.

Published Curcumin Research Fact Sheet

All statistics pulled from the electronic database of the National Institutes of Health (NIH) Institutes of Medicine (IOM) PubMed (PubMed.gov) the week of January 30, 2017:

• Studies mentioning curcumin: 9,784;

• Studies on curcumin and cancer: 3,718;

• Examples of types of cancer investigated: Lung, colon, colorectal, breast, liver, prostate, brain, kidney, leukemia, lymphoma, uterine, ovarian, pancreatic, bone, skin (melanoma and squamous cell carcinoma), eye, oral, testicular, cervical, thyroid, and more rare cancers as well;

• Human, double-blind, placebo-controlled clinical trials: 60+;

• Other human studies, combining single-blind and non-placebo controlled: >300;

• Human clinical trials using curcumin with other medications or in comparison to other medications: >25;

• Curcumin animal studies: 2247.

Curcumin Research Currently in Process

According to the electronic database of clinical trials registered with the National Institutes of Health (NIH) at ClinicalTrials.gov, there are currently 142 human clinical trials in progress. Topics include asthma, diabetes, pre-cancer cervical lesions, colon cancer, schizophrenia, advanced pancreatic cancer, breast cancer radiation therapy dermatitis, pediatric ulcerative colitis, polycystic kidney disease, oral lichen planus, adult cystic fibrosis, and more than 125 others.

Selected Quotes from Published Human Studies

• “To date, over 100 different clinical trials have been completed with curcumin, which clearly show its safety, tolerability and its effectiveness against various chronic diseases in humans.”²

• “We conclude that there is supporting evidence that curcumin administration reduces depressive symptoms in patients with major depression.”³

• “In conclusion, curcumin was demonstrated to be effective as an adjuvant therapy for the treatment of psoriasis vulgaris and to significantly reduce serum levels of IL-22.”⁴

• “Curcuminoids were safe and well-tolerated throughout the trial. Short-term adjunctive therapy with curcuminoids can suppress systemic inflammation in patients suffering from SM-induced chronic pulmonary complications.”⁵

• “The results from this 8-week randomized study in patients with active RA provide evidence that curcumin is safe, and has a significant efficacy in improving the DAS and ACR scores in patients with mild or moderate RA, when given alone or in combination with diclofenac sodium.”⁶

• “This study provides first clinical evidence that curcumin may be used as an effective and safe modality for treatment in patients with MDD without concurrent suicidal ideation or other psychotic disorders.”⁷

• “Curcumin was found to be equivalent to fluoxetine in terms of change in HAM-D17 score from baseline after six weeks of treatment.”⁷

References

1. Nelson KM, et al. The Essential Medicinal Chemistry of Curcumin: Miniperspective. J Medicinal Chem. 017;60 (5): 1620–1637.

2. Kunnumakkara AB, et al. Curcumin, the Golden Nutraceutical: Multitargeting for Multiple Chronic Diseases. British Journal of Pharmacology. 2016 Sep 17.

3. Al-Karawi D, et a;. The Role of Curcumin Administration in Patients with Major Depressive Disorder: Mini Meta-Analysis of Clinical Trials. Phytotherapy Research. 2016 Feb;30(2):175-83.

4. Antiga E, et al. Oral Curcumin Is Effective as an Adjuvant Treatment and Is Able to Reduce IL-22 Serum Levels in Patients with Psoriasis Vulgaris. BioMed Research International. 2015;2015:283634.

5. Panahi Y, et al. Short-term Curcuminoid Supplementation for Chronic Pulmonary Complications due to Sulfur Mustard Intoxication: Positive Results of a Randomized Double-blind Placebo-controlled Trial. Drug Research (Stuttg). 2015 Nov;65(11):567-73.

6. Chandran B, Goel A. A Randomized, Pilot Study to Assess the Efficacy and Safety of Curcumin in Patients with Active Rheumatoid Arthritis. Phytotherapy Research. 2012 Nov;26(11):1719-25.

7. Sanmukhani J, et al. Efficacy and Safety of Curcumin in Major Depressive Disorder: A Randomized Controlled Trial. Phytotherapy Research. 2013;28(4):579-85.

BIO

Ajay Goel, PhD, is a professor and Director of Translational Genomics and Oncology, and Director of the Center for Gastrointestinal Research at the Baylor Scott & White Research Institute, Baylor University Medical Center in Dallas, Texas. He is one of the top scientists in the world investigating botanical interventions.

Dr. Goel has spent more than 20 years researching cancer and has been the lead author or contributor to over 225 scientific articles published in peer-reviewed international journals and several book chapters. He is also the author of the recently published book Curcumin: Nature’s Answer to Cancer and Other Chronic Diseases.