Understand the specified amount of botanical extract

Förstå angiven mängd av botaniska extrakt

Introduction

In the manufacturing of dietary supplements, Good Manufacturing Practices (cGMP) play a central role in ensuring product quality. A crucial part of this is establishing and verifying specifications for ingredients, especially botanical extracts. However, there is an area that often leads to misunderstanding and confusion: plant-to-extract ratios. This article aims to clarify what plant-to-extract ratios mean and their relevance for quality control and product labeling.

What are Plant-to-Extract Ratios?

"Plant-to-extract ratios" represent the amount of plant material required to produce a certain amount of extract. It is a measure of the yield from the raw material and indicates the strength of the extract. A common misconception is that a higher ratio would mean a stronger extract. However, this is not always the case, as the ratio is also influenced by factors such as the quality of the raw material, the type of solvent used, and the parameters of the extraction process.

Botanical Extracts: Types and Forms

Botanical extracts can be divided into different types based on their physical form, as shown in Table 1 below:

Extract Type Extract Form Definition Examples of USP Monographs
Fluid Extract Liquid A liquid extract containing aqueous ethanol as a solvent or preservative, where each 1 ml contains extract from 1 g of dry material. Garlic Extract
Tincture Liquid A liquid extract prepared with ethanol or hydroalcoholic mixtures by maceration or percolation. Rhodiola Tincture, Valerian Tincture
Soft Extracts & Oleoresins Semisolid or viscous Extracts with a consistency between liquid and dry, often due to incomplete evaporation of solvents or natural water content. Capsicum Oleoresin (Chilli extract)
Dry Extract Solid Dry extracts are solid articles, such as powders, flakes, or granules, prepared by evaporating the solvent used in production. Guarana Seed Extract (dry)

Standardization of Botanical Extracts

To ensure consistent quality and efficacy of botanical extracts, standardization is used. This involves controlling and optimizing production processes to minimize natural variation in the raw material and ensure that the extract contains a defined amount of active or marker compounds. Examples of standardized extracts include senna extract, which is standardized to a specific content of sennosides, and milk thistle extract, which is standardized for silymarin.

Challenges with Plant-to-Extract Ratios

One of the biggest challenges with using plant-to-extract ratios as a measure of extract strength is the variation in extractive content in different plant materials. For example, the same plant, depending on its origin and processing, can yield different amounts even under identical extraction conditions. This means that the ratios can vary from batch to batch, which complicates comparisons between products.

Labeling of Plant-to-Extract Ratios

In many countries, it is required to state plant-to-extract ratios on the product label, especially to help consumers and regulatory authorities understand the strength and quality of the product. An example of correct labeling according to the European Medicines Agency (EMA) is shown in Table 2 below:

Ingredient Finished Product (Capsule)
Dry extract from valerian root Amount of dry extract (genuine herbal preparation and other excipients) in the herbal medicine: 200 mg/capsule
Amount of genuine extract: 80% genuine extract DER genuine: 3–6:1
Other excipients: 20% Label: Each capsule contains 160 mg extract (as dry extract) from Valeriana officinalis L s.l., radix

Conclusion

Plant-to-extract ratios are an important component in the description of botanical extracts, but they should be used with caution. For these ratios to provide a fair picture of the extract's quality and strength, it is crucial to also consider the entire composition of the extract, including added excipients and extraction methods. By understanding and correctly using plant-to-extract ratios, manufacturers can improve the accuracy of their product labeling and support consumers in their decision-making.

Source: National Library of Medicine