When It Comes To Herbal Medicines, Preparation Method Matters

Asking whether herbal medicines work is, superficially, a bit like asking if medicines work.

Which medicines? To have what effect? Upon whom? Under what circumstances?

We covered this a little here, by the way: Do Essential Oils Really Have Medicinal Properties?

The answer of course will tend to depend on many factors, but one thing that herbal medicines often lack, compared to industrial pharmaceuticals, is standardization.

And, as we’ll explore today, this goes beyond what dosage is included:

The curious case of the honeysuckle in the…

…water? Alcohol? Something else?

Researchers (Dr. Zheng Fu et al.)  investigated how different manufacturing methods affect the plant microRNA MIR2911 in honeysuckle, finding that traditional water decoction preserved both the RNA and its antiviral activity, whereas ethanol-based processing removed most of it.

For example, a common ethanol-based extraction process reduced MIR2911 levels in the final preparation by 93.6% compared with a traditional water decoction, and several commercially available honeysuckle products processed similarly contained little or no detectable MIR2911.

However, even in the case of water decoctions, adjusting the decoction to a mildly acidic pH before sterilization improved the RNA’s stability by a noteworthy amount, so there are still options in that regard too..

This is quite an important discovery, because herbal medicines have traditionally been evaluated by their small-molecule compounds, such as flavonoids, alkaloids, and terpenoids, because nucleic acids (like the microRNA being discussed here) were generally assumed to be too unstable to survive boiling, digestion, and absorption.

There were more things that made a difference that just the medium (water vs ethanol), too: unopened honeysuckle flower buds contained the highest MIR2911 levels, concentrations varied by production region, and oven drying preserved about 3.2x more MIR2911 than air drying.

Now, this is all specific to honeysuckle, and so these results don’t mean all herbal medicines depend on RNA or that MIR2911 is a universal quality marker, but they do how how quality-control systems based solely on chemical compounds can overlook things like biologically important RNA components, and how often, the ingredient is not the issue.

As the researchers themselves put it:

❝Some botanical medicines may contain not only chemical actives, but also information-bearing biological components whose fate depends on manufacturing. A process may preserve one layer of activity while unintentionally removing another.❞

You can read the paper itself, here: Extracellular RNA dimension in alternative medicine: processing–dependent integrity and bioactivity of honeysuckle miRNA MIR2911

Want to learn more?

For a much deeper dive into the science of herbal medicine, you might like this book we reviewed:

Encyclopedia Of Herbal Medicine – by Andrew Chevallier

Enjoy!