Curcumin trial retraction latest in long line for retired researcher

Journal chief editors have cited 'inconsistencies in experimental rigour' concerning a curcumin anti-cancer trial, co-authored by a researcher with a history of multiple study retractions.

Retraction Watch highlight work involving Bharat Aggarwal, a retired scientist, who worked at the M.D. Anderson Cancer Center in Houston.

According to the blog, image duplication leading to concerns and issues about data and/or results were suggested as the reason for the retraction – Dr Aggarwal’s 19th in total.

Dr Aggarwal first came to the attention of ethics authorities after a report in the Houston Chronicle newspaper alleged he had altered images (apparently to plump up the data) in as many as 65 published papers. MD Anderson conducted an internal investigation of Dr Aggarwal.

Comments that appeared on the online journal club PubPeer pointed to Dr Aggarwal’s links to the Frontiers in Pharmacology journal’s editor Gautam Sethi as an ex-student and co-author in a series of Aggarwal's curcumin papers that later required corrections or retraction.

“Following publication, concerns were raised regarding the scientific validity of the article. An investigation was therefore conducted in accordance with our established procedures,” the retraction notice stated.

“Following provision of raw data by the authors, the Chief Editor concluded that aspects of the paper's conclusions and assertions were not sufficiently supported by the findings from the material provided.

“Namely that inconsistencies in experimental rigour preclude confirmation of the conclusion of the article.”

Curcumin anticancer potential

The chief editors of Pharmacology and the editor-in-chief of Frontiers approved the article’s retraction, as did the study’s authors.

The original article, published on the 17 December 2017 and entitled ‘Curcumin-Free Turmeric Exhibits Activity against Human HCT-116 Colon Tumor Xenograft: Comparison with Curcumin and Whole Turmeric,’ highlights the benefits of turmeric and curcumin in exhibiting anticancer potential.

The study also suggested a more effective efficacy at lower doses, with possibilities of curcumin-free turmeric (CFT) given at higher doses without loss in favourable activity.

Mice with colorectal cancer (CRC) xenografts given either 100 or 500 milligrams per kilogram (mg/kg) of curcumin, turmeric, and CFT preparations exhibited similar xenograft growth suppression.  

The University of Texas MD Anderson Cancer Center team also found the effect of CFT on suppression of tumour growth was dose-dependent.

500 mg/kg tended to be more effective than 100 mg/kg, with 100 mg/kg of curcumin or turmeric found to be more effective than 500 mg/kg. 

No cancer affiliation

In February this year, The University of Texas requested a cancer conference in Chennai, India to stop claiming it was a co-sponsor after one of the meeting’s organisers was revealed to be Bharat Aggarwal.

“In the past, MD Anderson has sponsored this conference through its Global Academic Program,” the centre said on Twitter.

“But this year, we’re not a sponsor. Our name and logo are being used without permission, and we’ve requested they be removed from promotional materials. Faculty involved in the event are doing so on their personal time.”