Clinical trials using silymarin have offered support that milk thistle (Silbum marianum) can protect the liver in acute and chronic hepatitis, alcohol related liver disease and liver damage from toxic compounds including death cap mushroom.
A popular form of milk thistle is a form known as a tincture. Recently the scientific literature has suggested variability in the content of milk thistle phytochemicals in different extracts.
Silymarin is considered one of the more active compounds in milk thistle and is often quantified in milk thistle products.
The purpose of this study published in the journal Herbal Medicine was to quantify silymarin in different commercially available milk thistle alcohol tincture.
Here are the details of the study
– Milk thistle (Silybum marianum) tinctures were purchased from commercial sources.
– An HPLC-UV method was developed to quantify silymarin in each product
Here are the main results
– 11 Products were tested and only 4 had detected Silymarin
– Tinctures made with 70% alcohol had higher silymarin content 18.37 mg/mL.
– Tinctures made with 51% alcohol had a silymarin content of silymarin of 4.75 mg/mL
– Tinctures made with 25% alcohol did not have detectable levels of silymarin (i.e. 0%)
– Several phytochemicals were identified in the different products that included:
- Taxifolin
- Silybin A and B
- Isosilybin A and B
- Silychristin
- Isosilychristin
- Silydianin
Here is what the authors had to say
Despite their popularity as an herbal medicine, Silybum marianum tinctures may provide an unsuitable dosage of silymarin unless standardized to the recommended silymarin concentrations (mg/mL).
And
extraction processes of silymarin involving less than 45% of alcohol is unsuitable for therapeutic uses as the silymarin content was negligible.
And
To ensure effective treatment outcomes, the use of tinctures with a concentration ratio herb to liquid 1:1 (kg/L) and an alcoholic content of 70% is strongly recommended.
Take away message
The majority of clinical trials using Milk Thistle products have used products that contain at least 70% silymarin. If you are using an alcohol tincture of milk thistle you want to make sure you use a product that defines the percent of alcohol in the product.
Ideally, the amount of alcohol used to make the milk thistle tincture should be 70%. The product will also ideally have quantified the amount of silymarin in the product.
Reference
Pendry et al. Silymarin content in Silybum marianum extracts as a biomarker for the quality of commercial tinctures. Journal of Herbal Medicine. Volume 10, December 2017, Pages 31-36
His research on plant medicine has led to more than 45 publications and abstracts.This research has been presented at international meetings in the USA, France, Turkey, Peru, Israel, Austria, and Italy.
Categories: Antioxidant, Ask the Pharmacist, Dietary Supplements, Liver, Plant Extracts, Quality Control