Knowing something about the sources, formulations and quality verification protocols used by product manufacturers are all essential ways to ensure the herbs you are using in your practice are safe and of the best quality.
Therapeutic herbs are being used with increasing frequency for both companion and working animals. This means it’s important for veterinarians to know how to determine quality as they evaluate the various products on the marketplace for inclusion in their practices. Here’s a step-by-step procedure for helping to ensure the herbal products you’re using and recommending are safe and of high quality.
CONSIDER THE SOURCES
Herbal products all begin as plants, but can take very different paths before they reach the end user. Historically, herbalists worked with fresh or dried herbs, including roots, stems,
leaves, flowers, seeds, and fungi, which they often gathered themselves. They would administer them as tea, in an alcohol extract, or sometimes in food form.
In today’s marketplace, most large manufacturers work with dried and powdered herbs or herbal extracts delivered in drums, which they then encapsulate. Some manufacturers use more traditional methods, such as alcohol extraction of fresh herbs shipped to them overnight.
So the first question to ask a manufacturer is: do they work with the same suppliers year in and out, who can verify the origin, handling, and quality of the ingredients, or are they
buying whatever they can get the best price on from a variety of suppliers? If they are working with powders, ask if they are using any branded ingredients backed by clinical studies, because there are a lot of them on the market today.
UNDERSTAND HOW PRODUCTS ARE FORMULATED
Depending on the herb and its desired effects, different plant parts are used, since they may have very different effects, potencies, and sometimes toxicity levels.
For those new to herbs, it’s important to know that they usually work best in a formulation rather than as a single herb. Looking for a single herb to address a health condition is an allopathic view; however, a skillful formulation of herbs that synergistically complement the other ingredients creates a far more effective remedy, and is how most herbalists treat patients. This is why herbal products should be designed by trained herbalists.
VERIFY QUALITY
Manufacturers are required by law to confirm the identity of materials used in dietary supplements, but FDA guidelines are somewhat vague on what that means and how it should be done. Where and how a manufacturer has their products tested to meet these criteria creates a litmus test of sorts, which helps identify manufactures that are truly serious about quality, and those that are not.
For companies that work with fresh herbs to produce products made by trained and experienced herbalists, organoleptic (smell, taste, appearance) identification usually works fine. For the vast majority of manufacturers that work with powdered ingredients, rigorous testing by a highly competent lab is essential to confirming the high quality that carefully-sourced and meticulously-processed ingredients can achieve. A label on a bin of powder that looks like all the other powders in the warehouse is not sufficient proof of identity and quality.
You also have to be clear on what the lab is testing for, such as identity, purity, and potency. The lab needs to know what it’s testing for before it starts, and be equipped for the assignment. The proficiency of the lab is crucial, as not all labs are created equal.
Our own clients set specs, and we try to make sure they are getting what they asked for. If all they care about in their green tea powder is that the caffeine spec is met, they could be trading saw dust fortified with caffeine, and they are also probably not going to the best labs. Sometimes color can vary, and when botanicals are highly processed, they could be almost anything. Aspects of botanicals can vary from season to season and region
to region, which is why we test against several different verified reference materials when confirming identity.
TESTING METHODS MATTER
In deciding which test methods are best for a specific sample, expertise is essential in knowing which instruments and methods are appropriate.
There is a huge difference between methods appropriate for testing raw materials vs. finished products. You might use DNA, microscopy and or HPTLC and HPLC to identify your
raw ginger root for example. If it’s an extract, or a finished product with extracts in it, or one that is highly processed, then only HPTLC and HPLC can be used.
The point is, to get accurate results, you have to choose verified, accepted methods that are fit for the purpose. If and when newer technologies get to the point of being verified
and accepted by all relevant bodies, then and only then should they join the pantheon of tests we all rely on today.
The National Animal Supplement Council (NASC) has done a good job of setting standards for supplements used for animals, and can be a great resource.
We’re starting to see manufacturers make test results public, which will make it easier to identify those companies committed to rigorous product testing. We should all be asking
for that level of transparency.
EXPLAINING TESTING TOOLS
IDENTITY TESTING
High Performance Liquid Chromatography (HPLC) finger-printing is a useful and complementary technique used to assess the identity and quality of complex herbal blends and various ingredients from a marker compound perspective.
Chromatographic fingerprints give information that assists
manufacturing control and assures batch-to-batch conformity.
High Performance Thin-Layer Chromatography (HPTLC) assesses the identity and quality of botanicals and various ingredients. Many times the test is able to detect adulterants and contamination, such as the inclusion of incorrect plant parts, closely-related species, and unknowns. This technique is applicable to crude raw botanicals from powdered to whole form, extracts (powdered or liquid), and finished products/
blends. HPTLC is the preferred technique worldwide.
Microscopy is one of the oldest and still most effective techniques employed to assess identity and quality of botanicals. It is often able to detect adulterants and contamination, including fillers, extracts, and incorrect plant parts. This technique is applicable to crude raw botanical, from powdered to whole form, and is a preferred technique.
Composite Reference Botanicals (CRBs) are custom blends of verified botanicals from multiple sources and locations to support internal lab testing. Each component is internally
qualified and then combined to create a better representative sampling of the botanical versus any single reference botanical available on the market.
POTENCY TESTING
High Performance Liquid Chromatography (HPLC) and Ultra Performance Liquid Chromatography (UPLC) are used to separate, identify, and quantitate compounds. They
are considered the most powerful tools in analytical chemistry. HPLC/UPLC can be used to assess the purity of samples from a variety of matrices that can be dissolved in a liquid/solvent. In many situations, this testing is able to quantify compounds and adulterants at very low concentrations. HPLC/UPLC is applicable to the accurate quantitation of several types of chemical constituents of crude raw botanicals, from powdered to whole form, extracts (powdered or liquid) and finished products/blends, as well as all vitamins and amino acids. This is a preferred technique worldwide.
Gas Chromatography (GC) is a term used to describe the group of analytical separation techniques utilized to analyze volatile substances in the gas phase. In gas chromatography, the components of a sample are dissolved in a solvent and vaporized in order to separate the analytes by distributing the sample between two phases: a stationary phase and a mobile phase. The mobile phase is a chemically inert gas that serves to carry the molecules of the analyte through the heated column and then through the one of the various detectors used, where the separated compounds are identified by comparing with known compounds. This technique is the preferred method for the quantitation of the various components of fish oils, oils in general, or many essential/volatile oils of botanicals, as well as a wide variety of combustible compounds found in many different matrices.
Ultraviolet-visible Spectroscopy or Ultraviolet-visible Spectrophotometry (UV-Vis or UV/Vis) refers to absorption spectroscopy in the ultraviolet–visible region of the spectrum. This means it uses light in the visible and adjacent (near-UV and near-infrared) ranges. UV/Vis spectroscopy is routinely used in the quantitative determination of solutions of highly conjugated organic compounds, and biological macromolecules. It is also frequently used to quantitate organic compounds found in many natural products and dietary supplements. UV/VIS has the limitation of not being as specific or accurate as HPLC or GC, but can be a quick and easy way of quantitating compounds or groups of compounds for “process control” or when one needs a reproducible way of measuring the quality of any material, such as an extract or botanical, without the need for the specificity of more accurate techniques.
Wet Chemistry is analysis that is generally performed in the liquid phase, and contains many different types of methods, such as Titration, Gravimetric analysis, Moisture, pH, Specific Gravity, Loss on Drying, Ash, Environmental, and some Elemental analyses of samples. Generally, Wet Chemistry is sometimes used to analyze single components in samples to which the method is targeted, but due to the non-specific nature of Wet Chemistry methods it is frequently only able to measure larger groups/classes of compounds versus single markers, hence is not as accurate as HPLC or GC.
PURITY TESTING
Ultra-Performance Liquid Chromatography Triple Quadrupole Mass Spectrometry (UPLC-MS/MS) with Electrospray Ionization is used for multi-residue pesticide analysis due to its high selectivity and sensitivity. We developed and optimized a method using this technology for the determination of multiple pesticide residues in various samples matrices prepared by a QuEChERS extraction technique.
Atmospheric Pressure Gas Chromatography Triple Quadrupole Mass Spectrometry (APGC-MS/MS) is used with QuEChERS extracted samples for multiple residue pesticide analysis in numerous matrix-type samples. The APGC source is a “soft” ionization technique with reduced fragmentation, and a high level of matrix tolerance gives the sensitivity and specificity for pesticide residue compliance analysis.
Inductively Coupled Plasma Mass Spectrometry (ICP-MS) is used to determine heavy metals in botanicals and dietary supplements. Heavy metals, which are associated with
health risks, can be introduced in botanicals when grown in contaminated soil or during manufacturing processes. Microwave digested samples are analyzed using ICP-MS for
trace level analysis of these elemental impurities.
Headspace Gas Chromatography Triple Quadrupole Mass Spectrometry (HS-GC-MS/MS) identifies volatile organic compounds used or produced in the preparation of botanical extracts and dietary supplements. A method using HS-GC-MS/MS and GC-MS/MS for all Class 1 and Class 2 USP <467> Residual Solvents has been developed for dietary
supplement formulations.
