Preparation of Medicines from Plants

By January 28, 2019 April 17th, 2019 Articles

From the earliest times in human history plants have been the basis of agriculture and a source of food.

Over the ages certain plants were recognized as being poisonous and others as medicines for a variety of ailments.

The study of plants used as medicines is known as Pharmacognosy.

Pharmacists were trained in botany, the study of plants, plant chemistry and in Pharmacognosy. This is the basis of the preparation of medicines from plant material.

In the museum we have a wide collection of Pharmacognosy specimens and the medicinal extracts which were used in the pharmacies to fill the prescriptions from the doctors.

The Belladonna display illustrates one of the processes, known as percolation, used to extract the active component from the plant. This is done on accordance with the method and standard prescribed in the British Pharmacopeia for preparing the final product. This process was described as far back as 1809.

The history of the plant, Belladonna is fascinating. The botanical name, Atropa Belladonna, is derived from the common name for the plant, the Deadly Nightshade, which has fatal results if ingested in sufficient quantities. In Greek mythology the span of life is represented by three faiths, Clotho who spun the thread of life, Lachesis who measured its length, and Atropos who wielded the cut of death with her shears, as illustrated in the display. Hence the name Atropa belladonna.

The three examples of dried Belladonna plant material in the display are from different sources. They have to be identified as complying with the description and standards in the Pharmacopeia. This involves microscopic examination and chemical tests to ensure that the material is genuine.

The Deadly Nightshade grows in Europe, the USA and in some countries in the east.

The active constituent is extracted by a process of percolation in 70% alcohol of Pharmacopeia standard.

The large percolator with a volume of 2 gallons was made in England in the late 1800’s to a specification dated 1874. The smaller porcelain percolators were used in pharmacies for smaller quantities.

The alcoholic extract contains the active medicinal alkaloid. The concentration is determined by chemical analysis and various preparations can then be made from the standardised material. The tincture is specified to contain 0, 03% of the active alkaloid.

The Martindale, a source of the most comprehensive medicine information, lists 29 preparations which can be made from Belladonna by the methods described in the Pharmacopeia.

It is used as sedative, muscle relaxant and to check excessive excretions.

by Ray Pogir