Quality Issues in Herbal Products

Do you know what you are buying?

The herbal market is quite rightly beginning to show a preference for liquid herbs. These should work more quickly and efficiently but they are also easier to store and measure. If you are buying dried herbs you may be happy to judge how fresh they are by the look and smell. Indeed these are the only quality criteria you can easily use. Unless you are a botanist and can identify that you are being offered the correct herb you must rely on the manufacturer of the product.

Use by dates are more important for dry herbs than liquids. Research carried out on Echinacea and Valerian has shown that in both these herbs the level of actives in the dried roots will decline by 50% if kept at room temperature for just 6 months from harvest. It is therefore really important that the dried herbs you buy are fresh. Even those that are just a year old could be providing very little benefit to your horse. This alone is sufficient reason to use ethanolic extracts which have a much longer shelf life and preserve the active components of the plant.

Although they are theoretically better liquids are presented in such a wide variety of forms that it can be hard to compare them in a meaningful manner. The universal preference of professional herbalists is the ethanolic extract. There is little doubt that this is be best form of extract, but in the horse world more of the liquids offered are in something else.(more) The most common is vinegar but glycerine and propionic acid are also used. Many liquid products also include other things that are really just padding, filling or flavouring. These include honey, aspartame, dextrose and cider vinegar.

Like dried herbs there can be huge variations in quality between liquids and regretfully most products don’t disclose sufficient information. The strength of extracts normally vary between 1 in 10 to 1 in 2. 1 in 2 being the strongest by a factor of 5. A 1 in 10 extract contains 100gms of herb extracted into 1 litre of liquid, whereas a 1 in 2 contains 500gm of herb in 1 litre. It is very disappointing that few if any manufacturers state the strength of extract, but it get’s worse. Some do not even know when you ring and ask. The strengths of the few ethanolic extracts available are generally 1:5 or weaker. There are one or two better quality products that are as strong as 1:3 or 1:2. (more)

The problem then is how to find out how much dry herb equivalent you are giving your horse. A crude way to compare products is by their strength. ie how much dry herb equivalent is in each litre or ml of product. If the label declares its strength it is easy to decide. If the product contains things other than just the extract how can you know?

It gets a bit more complicated. Methods of manufacture vary and even two products manufactured to the same apparent strength may not be the same. We have tested several Devil’s Claw products with interesting results. The principal marker compound in the plant is harpagoside and this can be easily identified by HPLC analysis. One case which graphically illustrated the difference between manufacturing techniques involved raw herb from the same batch of raw material. The end results showed that one of the resulting extracts had twice the level of harpagoside as the other.

This bar graph shows the harpagoside levels in four Devil’s Claw products available on the UK market. This clearly highlights the problem of strength and quality.

Although these tests were carried out on UK products a similar range of products is available in New Zealand and exactly the same principles apply.

Although the stronger extracts will be more expensive you should get better results and should get better value for money. It is important to realise that a good herbal extract will generally be dark brown in colour and strong often bitter tasting. Don’t fall into the trap of thinking that if you don’t like it nor will your horse. They have quite different tastes to us and their normal diets can be quite bitter.

Labelling is the most important. All the ingredients in the product should be listed on the outside so you can make an informed decision as to the contents and whether you want to feed it to your horse. Statutory regulations require you to declare a wide range of things on the label. Some are helpful but others are not. The information you really need is a complete list of the ingredients, the strength of extract or if the product is diluted with fillers the dry herb equivalent per ml of the product, and if necessary the part of the plant that is used.

When you buy herbs make sure that the information on the label is complete and if it isn’t ask the retailer or the manufacturer. Isn’t it time consumers put some pressure on manufacturers to declare more about their products ?