So what is Pharmacognosy?

Today was the first class of Pharmacognosy & Herbal Pharmacy for Trimester 2 at ACNT. So I thought now is as good a time as any to look at this fascinating herbal science in more detail, and see why it is so important to being a good herbalist.

What Does Pharmacognosy Mean?

The word “pharmacognosy” was first coined by Johann Adam Schmidt in the “Lehrbuch der Materia Medica” (Textbook of Materia Medica) in 1811, and comes from the Greek:

pharmakon – drug or medicine

gignosco – knowledge

Culbreth summed it up as …

“the study of physical and chemical characteristics of drugs – the knowledge of selecting, recognising, and identifying true and false specimens by such characteristics.”¹

The photo at the top of this post is of an old Evans Pharmacognosy Recognition Kit at the Childers Pharmaceutical Museum in Queensland, which I have been fortunate enough to visit a couple of times. It shows the importance placed upon identification of herbal specimens.

A more recent definition of pharmacognosy from Heinrich et al …

“Pharmacognosy is the science of biogenic or nature-derived pharmaceuticals and poisons. It deals with all medicinal plants, including those yielding complex mixtures, which are used in the form of crude herbs or extracts (phytotherapy), pure compounds such as morphine, and foods having additional health benefits (nutraceuticals).”²

Pharmacognosy as part of Herbal Medicine

Whilst pharmacognosy is not therapeutics – and therefore does not directly teach how to prescribe herbal medicines in a clinical setting – the discipline helps improve the understanding and the quality of the medicines used by herbalists.

As such, a solid grounding in basic pharmacognosy is an essential component of herbal training. The NHAA guidelines on education clearly specify a minimum of 60hrs of training in herbal pharmacology and pharmacognosy, in recognition of the importance of this discipline.

What Pharmacognosy Isn’t

Pharmacognosy is not some boring or dead laboratory science. It exists to support the practical medicinal use of plants.

Pharmacognosy is more than just herbal pharmacology. Whilst the study of how herbal medicines work at a tissue or cellular level is part of it, it is by no means the sum total of pharmacognosy.

Why Learn Pharmacognosy?

1. It helps us recognise the plants we use in their natural forms and habitats.
   • The medicines we use are not some abstract entity, they are natural substances.
   • Herbalists have a responsibility to be able to recognise many of the medicines we use in their natural form, and to be able to collect and use these raw materials in the way nature intended.
2. It helps us employ our medicines in a more specific and more flexible manner.
   • Knowing that Harpagophytum procumbens (Devil’s Claw) is an anti-inflammatory is one thing. Knowing which inflammatory pathways in the body it affects and how, helps us use it specifically, so that we get the best results in our patients.
3. It helps us make informed judgements about the quality of our medicines.
   • Quality is unfortunately used as catch-phrase in our society. However like anything, herbal medicines are subject to quality issues, which directly impact upon both efficacy and safety.
   • It is the responsibility of the herbalist to understand the issues around herbal quality in order to give their patients the best medicine possible.

Pharmacognosy at ACNT

One of my missions at ACNT was to ensure that pharmacognosy wasn’t just an afterthought, and that students were exposed to something more akin to real pharmacognosy. Whilst I have been teaching pharmacognosy at a number of private colleges and a university for around 15 years, the majority of courses have focused on just phytopharmacology.

The subject at ACNT is called Pharmacognosy & Herbal Pharmacy, and combines …

• phytochemistry
• phytopharmacology
• botany and medicinal plant identification
• herbal manufacturing (herbal pharmacy)

… into one coherent subject. Whilst there is no lab work (something which is difficult to do at Advanced Diploma level), there is a lot of practical work looking at the plants we use in their natural form, and practicals in manufacturing as well. This is combined with solid and clinically relevant training in phytopharmacology, and makes it a rewarding subject to teach.

To wrap up, a quote from one of my favourite historical figures, John Uri Lloyd …

“Taste, odor, physical condition, all that experience in qualities adds to knowledge through our senses, is a part of the work of the pharmacognosist. It is not enough that by means of the microscope the fact be demonstrated that the drug is true to name, the qualified pharmacist must be able to establish whether that drug is suitable to make a reliable preparation. It may be correctly named and yet worthless.”³

 

References

1. Culbreth DMR, 1903. A Manual of Materia Medicine and Pharmacology. Lea Brothers & Co, Philadelphia.
2. Heirich M, Barnes J, et al, 2004. Fundamentals of Pharmacognosy & Phytotherapy. Churchill Livingstone.
3. Ellingwood F, 1919. American Materia Medica, Therapeutics and Pharmacognosy. Eclectic Medical Publications.