SB Medicinal Garden
Herbalism, or phytotherapy, is the use of plants or plant extracts for medicinal purposes. Plants have been the basis for medical treatments throughout much of human history and until the 17th century, they were the main component of medicinal practice. Since that time, plants have mainly been replaced by synthetic compounds however they are still used extensively in some countries, such as China and India, and plant extracts are still used within certain modern medicines. Many Asian countries rely heavily on high-value medicinal plants for cosmetic, nutraceutical, and pharmaceutical industries. However, within these countries, focus is more on prevention rather than treatment.
With a recent increase in the use of dietary supplements derived from plants, there is renewed interest in the role of plants in health care. In addition to this, traditional herbal remedies have been gaining interest due to accessibility, affordability, safety and low environmental impact. The pharmaceutical industry commenced in apothecary shops in Europe during the 19th century using plant extracts including morphine and quinine. Many other medicinal plants and compounds have been identified using ethnobotany; the study of plants used by indigenous people.
The Sutton Bonington Medicinal Garden showcases a subset of plants that have been used for medicinal purposes. Each of the three raised beds showcase plants that are used to treat specific ailments, grouped into a cold and flu bed; mental health and improved sleep plus a miscellaneous bed which includes plants that treat a variety of other ailments. The images below will take you to an overview of each bed or alternatively, search the medicinal plant database:
DISCLAIMER: This site was not written by a medical professional. Check with your doctor if you have any existing medications and illnesses, are under the age of 18 or are pregnant or nursing before taking any herbal remedy. Medicinal plants and the active ingredients they contain may interact with your body in the same way that modern medicines do and/ or may interact with any medication you may be taking. Long-term use of herbs can also affect the way your body absorbs iron and other minerals. Similarly, if you are allergic to any known plants, seek confirmation that any herbal remedy may not also induce the same response, particularly if the plant belongs to the same family as the known allergen. Even natural-derived products can be harmful, can contain contamination and, in extreme cases, can cause overdoses.
Numerous flowers, fruits, herbs, and vegetables have been found to contain powerful antifungal, antibacterial, antimicrobial, and antiviral properties. They also contain important nutrients, such as antioxidants, vitamins, and a host of phytochemicals that help to boost the immune system. In addition, all plants produce chemical compounds during their metabolism; called phytochemicals. A subsection of these- the secondary metabolites- are found in some species where they carry out a number of functions. These include toxins to repel or deter pests and herbivores, signalling molecules or compounds that attract pollinators. However, some of these secondary metabolites also have therapeutic effects on humans and have been extensively used in traditional medicine as well as refined to produce drugs used in modern medicine. Common drugs derived from plants include aspirin from the bark of the willow tree plus opium from poppies providing pain relief; digoxin or digitalis from the foxglove for the treatment of heart conditions; and quinine from the bark of the cinchona tree for the treatment of malaria.
Because each plant contains many different phytochemicals, the effect of using the whole plant for medicine is uncertain due to unknown potential reactions between the different phytochemicals. Modern knowledge of medicinal plants is categorised in the Medicinal Plant Transcriptomics Database, which provides a sequence reference for the transcriptome of numerous medicinal plant species. At least 12,000 such compounds have been isolated so far; a number estimated to be less than 10% of the total. These compounds vary in their composition and action, but most are from the four major biochemical classes: alkaloids, glycosides, polyphenols and terpenes.
Alkaloids are bitter tasting chemicals that are often toxic. They have multiple modes of action and are common for both recreational and pharmaceutical drugs. Examples include atropine from nightshade to treat low heart rate; galantamine from daffodils for the treatment of Alzheimer’s; morphine from the opium poppy; vincristine and vinblastine from the periwinkle (Catharanthus roseus and other Vinca plants) used in anti-cancer drugs including chemotherapy treatment; nicotine from tobacco; caffeine from coffee plants; and cocaine from Coca plants.
Gylcosides with medicinal properties can be split into two main groups. Anthraquinone glycosides are found in plants including rhubarb, Alexandrian senna, cascara and Aloe. These are commonly used for plant-based laxatives. In comparison, the cardiac glycosides (including digoxin and digitoxin) are found in plants including foxglove and lily of the valley, and support the heart as well as acting as a diuretic (i.e. promotes the production of urine).
Polyphenols are widespread in plants with diverse roles, usually related to defence against pests and disease. They include plants such as fennel, anise, angelica and kudzu which contain compounds that mimic hormones, termed phytoestrogens, used for the treatment of gynaecological disorders including menstrual and menopausal problems plus fertility. Some polyphenolic extracts are sold as dietary supplements and cosmetics including olives, grape seeds and maritime pine bark.
Terpenes and terpenoids are also widespread in medicinal plants and resinous plants including conifers where they mainly function to repel herbivores. They are highly aromatic and thus their scent is often beneficial in essential oils, aromatherapy or cosmetics as seen for rose and lavender. Some terpenes also have antiseptic and antifungal properties such as thymol, the essential oil obtained from the common thyme (Thymus vulgaris).
Preparation of Medicinal Plants
Medicinal plants are often tough or fibrous, thus requiring preparation prior to use. Common preparation methods can be grouped into the following:
Plant parts are steeped in boiling water for a short period of time to make a tea.
Plant parts are simmered in boiling water for a longer period of time.
Plant parts are dissolved in a water and alcohol solution. They may be left for a long period of time.
Plant parts are added to a sugar-water or honey-water mixture.
Dried plant parts are ground into a powder, traditionally using a mortar and pestle.
Essential plant fragrance is added to alcohol.
Fresh or dried plant parts are applied topically with moist heat.
Powdered, dried or fresh plant parts are added to an oily substance such as lard, petroleum jelly or olive oil, plus are often combined with beeswax so that they can be applied topically.
Once the compound responsible for medicinal action is known, it can be directly extracted by the plant or synthesised chemically to produce the pure chemical compound. When the structure of the phytochemical is complex, extraction from a plant may be preferrable to synthesis. For more traditional approaches to the use of medicinal plants, see details given in the plant database.
Whilst the modern drug industry often uses chemically produced compounds, during the period 1981-2010, over 50 % of small molecule approved drugs were either directly derived or inspired by natural products. Over a similar period, 65 % of small molecule drugs approved for cancer treatment originate from natural products.
WARNING: By 2007, clinical trials indicate that beneficial results only occur in 16% of herbal remedies; phytochemical evidence only occurs in 20% of remedies; and 12% of remedies have not been studied scientifically at all. As of 2015, the majority of products derived from medicinal plants had not been tested for efficacy and safety. Marketed products I many developing countries were found to be of uneven quality, sometimes containing dangerous contaminants. In most countries, there is little regulation surrounding the use of medicinal plants. However, the World Health Organisation coordinates a network called the International Regulatory Cooperation for Herbal Medicines to encourage their safe and appropriate use. In 2015, only 20% of countries had agencies regulating the use of medicinal plants; half had limited regulatory capacity and 30% of countries had no regulation at all.
Threats to Medicinal Plants
Similar to many organisms, medicinal plants face a number of threats including climate change, habitat destruction and unsustainable harvesting by humans to meet market demand. For example, there is evidence that climate change is causing noticeable effects on the life cycle and distribution of many plant species. This can arise for numerous reasons including changes in temperature and precipitation, increases in pests, pathogens and herbivores plus the disruption to commensal relationships. Not only do these features influence the distribution of medicinal plants, but they may also alter their biochemical composition, including that of the phytochemicals that convey medicinal properties. Therefore, changes to the abiotic and biotic environment in which the plants are grown could also affect the quality and safety of the medicinal products derived from them.
A recent study estimates that 600 plant species have gone extinct within the last 250 years and it is likely that some species will become extinct before they are formally recognised. Of these species, it is possible that plants with potential medicinal properties are also being lost. A report published by the Royal Botanic Gardens, Kew in 2020 identified 723 known medicinal plants that are at risk of extinction, partly as a result of unsustainable harvesting.