Plant extracts - production and classification

How is the herbal extract obtained?

Extracts are plant extracts obtained from the plant material by extraction with a specific solvent - usually water or ethanol, as well as oils. They undergo concentration - and it is the degree of concentration that determines what type of extract we are dealing with. On this basis, a distinction is mainly made between dry extract (most commonly used in capsules), thick extract and liquid extract ^[1].

What plant parts are used to prepare extracts and oils?

Supplements based on plant extracts can be produced from flowers, leaves, fruits, cones, nevi or from seeds, rhizome or root or resin. Plant extracts are also prepared from the so-called 'herb', which corresponds to the above-ground parts of the plant. In the case of mushroom extracts, they can be made from the pericarp or mycelium.
The specific parts of the plant have their own effects. There may be completely different substances in the fruiting body than in the root. The part of the plant from which the extract is prepared sometimes also determines whether the extract is permitted for sale in a particular country - depending on the legislation there.

Safety of herbal supplements

Doubts and discussions related to the effects of herbal supplements. How to choose and use herbal products wisely?

The belief that natural substances are completely safe for the body is wrong. The undesirable effects of plant products are most often related to two issues:
intrinsic aspects, i.e. the effects of plant-based food supplements: taking too large portions; allergic reactions to a substance; interactions with medications taken;
external aspects concerning production: errors in plant identification, lack of good manufacturing practice, adulteration and substitution of herbal products, plant contamination, lack of standardisation ^{[2, 3, 4]}.

What factors may affect the safety of the use of plant raw materials in food supplements?

As food supplements belong to the group of food products, they do not need to be tested as thoroughly as medicinal products. Therefore, it is important to choose those from a proven manufacturer and with a well-known reputation. How can you recognise that a particular product is worth buying? First of all, it is important to pay attention to whether the company performs tests and makes the results available to its customers. This is valuable information testifying to the quality of the supplement - e.g. ensuring that the actual composition is consistent with that stated on the label.

What are the most common risks associated with choosing a plant-based food supplement?

• Incorrect identification of raw plant material.
  It is important to describe in detail the plant used to produce the supplement. This characterisation includes giving the correct Latin name (including genus and species), indicating the part of the plant that was used in production, and specifying in which processing form the product is present (e.g. extract, oil, juice, powder). It is also worth noting whether the supplement is standardised (i.e. whether it specifies the physiologically active substance content of the plant extract).
• Contamination or adulteration of raw material with the addition of another substance.
  For example, psychoactive substances, steroids or other undesirable ingredients have sometimes been found in food supplements. Such practices on the part of the manufacturer are not only unethical, but above all pose a risk to the health and life of consumers. The lack of information about the addition of specific substances in a supplement can result in undesirable interactions with other medicines taken.
• Contamination of raw material with another plant.
  Contamination of the product with another plant can result from a mistake during harvesting or misidentification of the species. This can happen at any stage of production, and the consequences of including an unsuitable raw material in a supplement can be difficult to predict for those taking it. This is why it is important to choose products of proven origin from a company that does not have a dubious reputation.
• Biological, chemical and physical product contamination.

Plant raw materials can be contaminated by failing to observe hygiene rules at the production, storage or packaging stage of the raw material, by using poor water quality in its cultivation or processing and by using inappropriate fertilisation methods. A European Commission regulation has set permissible levels for certain contaminants in food products - this includes microbiological contaminants, heavy metals, PAHs (polycyclic aromatic hydrocarbons) and pesticides ^[5].

What affects the quality of plant-based supplements?

It is not easy to assess the quality of herbal supplements unequivocally. Many factors influence their efficacy and safety. Among these are:

• the conditions under which the plants are grown (the phytochemicals present in herbal preparations vary according to climate, soil composition and growing region),
• cultivation methods (use of pesticides, fertilisers, proximity to other crops, industrial regions),
• the period during which the plants are harvested (their properties vary depending on the season in which they are harvested),
• the way in which the raw material is processed (the use of poor drying practices can result in elevated PAH levels),
• storage and transport conditions of the raw material,
• the use of specific parts of the plant (the properties of the product may vary depending on the use of roots, leaves, herb or fruit to make the product) ^{[2, 4]}.

Quality standards

There are various methods for determining the content of active substances in plant extracts. Among the most popular are standardisation (which is based, among other things, on pharmacopoeial standards) and DER (Drug Extract Ratio).

Pharmacopoeial standards

A pharmacopoeia - also referred to as a pharmacy code - is a document that defines the testing methods for medicinal products and the quality requirements for, among other things, the raw materials used to manufacture the product. A distinction is made between international and local pharmacy codes. Global pharmacopoeias include the American Pharmacopoeia, the European Pharmacopoeia and the British Pharmacopoeia.
For herbal products, the legal process for regulating legislation varies from country to country. Among other things, this is influenced by the fact that herbal preparations are rarely tested, and cultural issues are also of considerable importance. As relatively few supplements of this type have been tested for efficacy and safety, it is important to pay attention to the information provided by the manufacturer - a good quality supplement will have the relevant certificates and will meet international recommendations. The World Health Organisation (WHO) has prepared pharmacopoeial monographs setting out basic guidelines for herbal products ^{[2, 7]}.

The standardisation process - what does it involve?

Standardisation of raw plant material determines what is the minimum content of substances in plant extracts. It allows the active ingredients in the product to be identified and labelled and is considered one of the quality control techniques. For example, 200 mg of an extract standardised to contain 40% of the active substance indicates a minimum content of 80 mg (200 mg x 0.4 = 480 mg). The purity of herbs (i.e. their quality) is defined on the basis of the initial identification of the raw material and the determination of its physical, chemical and biological properties.

Interestingly, the process of eliminating undesirable components from extracts is also considered a form of standardisation. An example of so-called negative markers may be, for example, thujone contained in the sea-root ^[9].

It is worth knowing that the manufacture of food supplements does not involve the standardisation of the raw material into a specific biologically active compound. Whether a product undergoes this process depends solely on the manufacturer and the values that guide it ^[5].

DER - what does this abbreviation tell us?

Drug Extract Ratio (DER) is the ratio of raw material to extract - it indicates how much raw material was used to prepare the extract. This ratio is one of the most important criteria for determining the value of herbal preparations ^[10]. For example, a DER of 30:1 means that 30 parts of raw material (e.g. 30 grams) yielded 1 part (1 gram) of extract.

Quality from Osavi - naturally for your condition

When choosing a good quality plant-based food supplement, it is worth looking at the following aspects, among others :

• which parts of the plant the product was prepared from,
• how much raw material was used to prepare the extract (DER),
• what is the minimum content of the active substance (standardisation for substances with specific effects).

You will find this information on the labels of Osavi's Nature supplements. The set of carefully tested and high-quality products based on plant raw materials offers, among other things, support for good sleep and liver function or help to restore harmony in the body. Check out the power of nature in a safe version on yourself today.

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[2] Kumar V. & Kumar V. (2009). An overview of herbal medicine. Int. J. Ph. Sci, 1(1), 1-20.
[3] Zhang J. et .al. (2012). Quality of herbal medicines: challenges and solutions. Complementary therapies in medicine, 20(1-2), 100-106.
[4] Balekundri A., Mannur V. (2020). Quality control of the traditional herbs and herbal products: a review. Futur J Pharm Sci 6, 67 https://doi.org/10.1186/s43094-020-00091-5.
[5] Baraniak J. et. al. (2020). Istotne problemy związane z bezpieczeństwem surowców roślinnych obecnych w wybranych grupach suplementów diety.
[6] Dekalog suplementacji, Główny Inspektorat Sanitarny. Pobrano 16.05.2023 z https://www.gov.pl/web/gis/dekalog-suplementacji.
[7] Zhang J., Onakpoya I. J. Posadzki, P. & Eddouks M. (2015). The safety of herbal medicine: from prejudice to evidence. Evidence-Based Complementary and Alternative Medicine, 2015.
[8] Bauer R. (1998). Quality Criteria and Standardization of Phytopharmaceuticals: Can Acceptable Drug Standards Be Achieved?. Ther Innov Regul Sci 32, 101–110. https://doi.org/10.1177/009286159803200114.
[9] Monagas M et. al. (2022). Understanding plant to extract ratios in botanical extracts. Frontiers in Pharmacology, 13.
[10] Spriano D. et. al. (2006). The drug-extract-ratio of aqueous/ethanolic Harpagophyti radix extracts has to be revised. Planta Medica, 72(11), P_287.