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Chemical complexity in medicines: Herbal constituents vs pharmaceutical compounds

  • Rebecca Lazarou
    Rebecca Lazarou

    Rebecca Lazarou is our science advisor here at Herbal Reality. She is currently completing her PhD at Kew Gardens and UCL School of Pharmacy in the medicinal plants and fungi of Cyprus. She is the founder of Laz The Plant Scientist where she sells sustainably sourced herbal medicines she has formulated, and is also a board member for the McKenna Academy.

    She completed her degree in  Biomedical Science-Human Biology, always with the intention to study herbal medicines after. She then went on to study a master’s at UCL School of Pharmacy, in Medicinal Natural Products and Phytochemistry. Since then she has been a scientific researcher, editor for the academic Journal of Herbal Medicine, and pharmacology teacher at Betonica School of Herbal Medicine as well as other projects. Her career is an ecology of different disciplines spanning across medical science, ethnopharmacology, herbalism, holistic healthcare, cannabis and psychedelics.

    You can read more about her work at www.rebeccalazarou.com and follow her educational content on social media @laztheplantscientist.

  • 12:45 reading time (ish)
  • Evidence

Herbs contain an abundance of constituents that interact to produce an effect. Drugs are singular compounds targeted to specific receptors. How do they differ?

Pharmaceuticals vs herbs: What is the difference?

Chemical Complexity In Medicines Herbal Constituents Vs Pharmaceutical Compounds

Besides their difference in origin (synthetic vs natural), the main difference between pharmaceuticals and herbal medicines is their chemical complexity and composition. 

Pharmaceuticals are mostly single compounds, whereas herbal medicines are chemically complex with hundreds or thousands of molecules in each extract. It is precisely this chemical abundance and diversity that offers many of the medicinal virtues of herbs, but more on this later. 

Wider differences in the philosophies and treatment protocols within the different doctrines of allopathic medicine and herbalism also exist and account for disparity between practices. Our series on herbal formulations shares some insights on different herbal medical systems.

Reductionist science

Reductionist science is a way of explaining and studying complex systems by breaking things down into small parts and investigating the separate parts. This helps us understand how things work, and can be fantastically helpful, but like any tool, it has its limits. 

The approach of reductionist science, for example, in the study of heart anatomy and pathology, would be to focus investigations into the intricate component parts. From the level of the cardiovascular system, to the organ, tissue, and cells, e.g. cardiomyocytes, fibroblasts or pericytes. Then, the mechanisms within those cells at the level of the proteins, such as enzymes and receptors, would be further researched to understand how they work. 

Pharmaceutical companies then find singular compounds to stimulate/block these receptors and processes, which have an effect on the body and can be used for medicine. Typically, this molecule is then patented and sold for profit. The drive for drug discovery continues, and oftentimes pharmaceutical companies explore traditional medicine resources to find new compounds to isolate and purify in a process called bioprospecting. 

Humans have been using medicines from nature for thousands of years, but in the 1800s this began to change due to rapid advances in chemistry (1). The sourcing of medicine shifted from whole plant extracts to single isolated compounds. This led to significant developments, like morphine from poppy (Papaver somniferum) in the early 1800s and salicin from willow bark, which was used to synthesise acetylsalicylic acid — aspirin (2). Since then, the pharmaceutically-motivated medical system has been centred around finding “silver bullets” to cure diseases, which has come with both its benefits and limitations.

What are the benefits and limitations of isolating compounds?

Herbal quality and safety: What to know before you buy

There are some benefits to using isolated compounds, for example, pharmaceutical drugs can have a faster onset of action and greater potency (a smaller quantity has a greater effect). The use of isolated compounds also allows for greater precision with dosing, where the exact measure of the bioactive compound is known and administered. In plants, the concentration of active constituents in an extract can vary owing to a multitude of factors — environmental conditions, soil health, time of harvest, biodiversity etc. 

However, the use of isolated compounds as medicine is often associated with a higher incidence of side effects. The integrative use of herbs in conjunction with pharmaceutical agents can help to mitigate these effects (3). 

Research that has isolated compounds has also facilitated understanding of which plant constituents are active and contribute to a plant’s medicinal effects. From this work, marker compounds have been identified which allow for the standardisation of whole plant extracts, which mitigates the aforementioned variability and is a means to uphold quality and safety of products in the herbal industry by meeting pharmacopoeial standards. 

Scientific research has increasingly recognised the limitations of using single compounds for treatment. Whilst this approach is very popular in modern drug discovery, many complex diseases (such as cancer, degenerative disorders and inflammatory conditions) have limited success with treatment with single compounds, as the mechanisms underpinning the pathophysiology of the disease are so multifaceted (4). In this understanding, increasingly scientists are investigating multi-targeted molecules in the search for more effective medicine (5).

Rebecca Lazarou

Rebecca Lazarou is our science advisor here at Herbal Reality. She is currently completing her PhD at Kew Gardens and UCL School of Pharmacy in the medicinal plants and fungi of Cyprus. She is the... Read more

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