Categories:Health Conditions/cardiovascular, immune, eye; Herbal Ingredients; Business Strategies/quality control; Manufacturing/lab testing & methods
How ironic that an herbal extract known to support eye health fails to effectively reach consumers when companies receiving the botanical material for manufacturing turn a blind eye to adulterated supply. This is the case with bilberry, an herbal remedy dominating the natural health market for age-related macular degeneration (AMD), a leading cause of blindness in older people.
Also known as the European blueberry, bilberry (Vaccinium myrtillus) is related to blueberry but grows in single or paired formation, rather than as clusters. Another difference is bilberry flesh is a much darker red and purple than blueberries. This indicates greater anthocyanin content, the purported key to bilberry's health benefits.
Concentrating on this anthocyanin content, scientists created a standardized extract containing 25-percent anthocyanins; this is the bilberry used in many trials on ocular health, microcirculation, vascular integrity, intestinal problems, and both kidney and liver damage.
As with other botanical extracts, the standard is based on the first quality extract to the market. The first bilberry extract came from Indena in the early 1970s, utilizing the standardized method of Ultraviolet-visible (UV-VIS) spectrophotometry and reporting 25-percent anthocyanidin content on the Certificate of Analysis (C of A), as a requested specification. Christian Artaria, Indena, noted this method and reference value were subsequently adopted by the Italian Pharmacopeia and became the standard method and the reference value to describe the “quality” of a bilberry extract in the market.
According to Anthony Jacobs, BerryPharma (formerly Artemis International Europe), "25 percent is what historically could be extracted, on average, from Scandinavian Blueberries." He noted, "It would not be possible to economically reach this figure with Canadian blueberries. Most berries have quite unique and different anthocyanin profiles, and different anthocyanins have different modes of action when absorbed." Noting bilberry is unique due to the large number of different anthocyanins present in the fruit—at least 20 types—Jacobs said some of these compounds are thought to explain the anti-inflammatory benefits of bilberry intake and supplementation, as is also, perhaps, the resveratrol naturally present in the fruit's skin.
This level of concentration (100:1), coupled with the process used to manufacture a consistent, high-quality extract, have made bilberry one of the most expensive botanical extracts on the natural products market.
Jacobs said adulteration is highly profitable for cheats. "In the case of bilberry 25-percent, the price ranges from $660 (US) to $800; if you can adulterate with pigment or mulberry or black rice husks, you can bring the cost down to $50 and it is then typically sold for less than $400," he explained. "The business-to-business customer thinks that they have a bargain. However, lower prices resulted in many large contracts changing suppliers, consumer products had no active compounds, and consumers also stopped buying bilberry products—adulteration destroys the consumer repurchase chain."
The adulteration of bilberry came to the forefront in a big way in 2007, after Australian company MediHerb tested some bilberry extract it received from a supplier. Initial simple spectrometry tests showed the material met anthocyanin spec, but further analysis revealed the product was likely not entirely bilberry.
Researchers from MediHerb and several chemistry researchers from Australian universities compared a bilberry extract (claimed to be 25-percent anthocyanin) from a Chinese supplier to a reference sample (J Agric Food Chem. 2006;54(19):7378-82), using UV-VIS spectrometry as well as more advanced tests such as high-performance liquid chromatography (HPLC-DAD), UV-spectral comparison and liquid chromatography/mass spectrometry (LC/MS); they also profiled with HPTLC (high-performance thin layer chromatography).
They discovered the Chinese sample nearly matched the reference sample (as MirtoSelect, from Indena) for anthocyanins by the UV-VIS test. However, the more advanced tests revealed a more sinister differentiation. HPLC fingerprinting showed inconsistent peaks when comparing the two samples, and HPTLC started to uncover the adulterant as amaranth, a chemical red dye. Then, LC/MS appeared to definitively link the suspected fake compound in the Chinese extract to an amaranth sample.
In the end, the researchers stated the level of adulteration of bilberry extract's anthocyanin content has become sophisticated. Existing pharmacopeia testing requirements using only UV-VIS showed both samples to be similar, but only advanced testing revealed the truth behind the adulteration. The scientists, therefore, recommended companies employ advanced chromatography testing to ensure the quality and integrity of bilberry 25-percent extracts from suppliers, despite any guarantees or C of As.
Jacobs suggested supplying both a C of A and HPLC fingerprint with each shipment is a good starting place for ensuring quality bilberry extract. It advised industry manufacturers to request this basic information from suppliers, which they could then independently compare this fingerprint to a true bilberry reference fingerprint to determine if there are any adulterants present. "You will notice that reputable suppliers of bilberry have adopted this approach with their customers," he said.
Mike Barnhart, president of Veritol, a contract manufacturer of bilberry 25-percent extract, noted the high cost of bilberry and demand in the market will continue to tempt cheats into attempting adulteration. "However, enhanced understanding of bilberry chromatograms by experienced HPLC operators is generally enough to warrant further investigation if unusual patterns or lack of peak formation occur during a routine analysis."
Artaria confirmed the test methods are relatively easy to implement, but added the problem is more of ethics, regulation and enforcement. "In many markets there is no obligation for a manufacturer to analyze each batch of ingredient received," he said. "Manufacturers also make an assumption that the C of A provided with the bilberry extract is correct and true. These factors make it very difficult to uncover adulteration problems and correct them."