Updated AHP cranberry monograph includes tools to help stem tide of adulteration

Christian Krueger, PhD, is CEO of the company Complete Phytochemical Solutions and is also a research manager at the University of Wisconsin Madison. Dr Krueger, who helped write the constituents portions of the monograph, which was released by the American Herbal Pharmacopoeia​, has worked for a number of years on an analytical technique called MALDI-TOF that he has applied to cranberry.  He published his first paper on the technique more than 15 years ago and has refined the approach to help distinguish the proanthocyanidins in cranberry from those that occur in a number of other botanicals. This has been particularly difficult to do in the past, leading some suppliers in recent years to openly admit that from a chemical standpoint it was impossible to determine the ratios of constituents in mixed berry powders, or even to be 100% sure of the identity of those constituents. That being the case, the barn door was wide open to adulteration, something that Dr Krueger said he has confirmed within cranberry ingredients.

Not all PACs created equal​

“One of the big changes in the monograph is the introduction of the MALDI-TOF tool for the authentication of the principle bioactive components, those being the proanthocyanidins,” ​Dr Krueger told NutraIngredients-USA. “The tool allows us to distinguish between A-type and B-type linkages and to quantify the ratios between them.”​

MALDI-TOF stands for matrix-assisted laser desorption/ionization with time of flight mass spectrometry. The technique can take a more detailed look at the PACs in cranberry and other botanicals. Other chemical means can detect the presence of PACs, but can’t drill deeper than that, and just being able to in effect identify it as a horse is not enough in this case. You really need to know if it’s a black horse or a white horse. The primary health claim for cranberry PACs up to this point has been in urinary tract health for women, and you can’t saddle up just any horse to reach that goal. To quote the monograph:

“The primary compounds of interest in cranberry are anthocyanins and PAC oligomers of both A-type (with at least one set of two bonds between monomer units) and B-type (with all single interflavan bonds). Bacterial antiadhesion activity has been demonstrated for A-type PACs (Howell et al. 2005), with an effect of clinical relevance regarding cranberry’s putative beneficial affects on the genitourinary tract. PACs with only the B-type linkages have not demonstrated in vivo antiadhesion activity.”​

The monograph noted that these PACs exist in peanut skins, black bean skins, plums and mulberries. These adulterants have reportedly been mixed into cranberry extracts coming out of China and have shown up on the US market. This is not necessarily a safety concern, but does certainly constitute labeling fraud. PACs from these other sources may have health benefits of their own, but are not going to do what the cranberry label says they might.

“We have demonstrated our technique on cranberry, grape extracts and pomegranate. The technique is widely capable of detecting PACs from a variety of sources. Each plant has its own unique signature or fingerprint in the ratio of the A- and B-linkages,”​ Dr Krueger said.

Dr Krueger added that other key aspects of the updated monograph include the application of the 4-(Dimethylamino)cinnamaldehyde (DMAC) method, a type of colormetric assay, for the overall quantification of PACs and the inclusion of a butanol-HCL method to identify the insoluble PACs that are left over in the pressed cake after juice extraction. 

Suppliers on notice​

Stephen Lukawski, director of sales for cranberry ingredient supplier Fruit d’Or Nutraceuticals, a company that has worked with Dr Krueger in the past, said the new monograph should help put a stop to willful ignorance on the part of some suppliers.

“It’s ​going to change the landscape, not just for cranberry but for other botanicals. It’s up to us to protect the consumers’ health and safety because we are dealing with questions of adulteration and authenticity here. There are no excuses now for manufacturers to say they didn’t know about these analytical techniques,”​ he said.

Dr Krueger said it has been a long time coming to get the MALDI-TOF technique included as an officially recognized method. There were a few hurdles to clear to convince interested parties that MALDI-TOF’s time had come.

“I wouldn’t say it was a struggle, but there was serious education component that needed to go into this.  The only real hesitancy for inclusion is that this is not the most generalized tool. There are cheaper and more routine assays available but unfortunately they are just not good enough,”​ Dr Krueger said.

To order a copy of the new monograph, click here​.