PLANT OF THE DAY brings you easy to digest information exploring science backed plants for health and medicine. Written by scientists, it aims to increase understanding of how effective plant medicine is as well as encourage simple dietary interventions to increase health and prevent disease. Plant of the day promotes the scientific research on select plant medicines and thereby helps bridge the gap between the worlds of plant medicine and general medicine.
DID YOU KNOW? While you can take, for example, a cup of chamomile tea to aid relaxation and sleep anytime, to treat a condition with a plant medicine it is important to take the correct dose and prescription for your individual needs – and in that case always first consult a NIMH medical herbalist and inform your healthcare provider before giving to a child, if you are pregnant, have any medical condition or are taking any medication.
Immune, respiratory and antimicrobial plant medicines – Thyme
Photography by David Taylor
Supporting immunity
Our innate immunity provides the initial response against pathogens like viruses and is a complex network that includes the inflammatory response. Inflammation response to infection involves mobilising inflammatory markers. These markers increase the presence of immune modulating cells, like white blood cells (also called leukocytes). And it’s the regulation of the initiation and extent of neutrophil (a type of leukocyte) and influx of cells such as lymphocytes (which produce antibodies) during inflammation that can determine both the success of pathogen elimination and the level of resulting tissue damage.
The respiratory system is particularly susceptible to oxidative-stress injury because of the large surface area associated with gas exchange. Oxidative stress injury includes damage to lung tissue, mucus hypersecretion, oedema of the bronchial wall, broncho-constriction and inflammation.
Among many approaches to supporting the immune system, inflammatory responses and respiratory function, are a range of effective plant medicines.
We can also help boost our innate immunity by simple lifestyle changes such as eating a rainbow diet, exercising to help lymphatic circulation (a crucial part of our immune response), getting outdoors daily to boost vitamin D, relaxing to prevent chronic stress and ensuring we rest and sleep well.
Supporting immunity with aromatic plants
Different plant medicines are used to support immunity and treat respiratory disorder in different parts of the globe, such as elder berry in Europe, echinacea in North America, and astragalus in Asia. We shall be exploring some of these in upcoming blogs. Aromatic plants though have a key role to play due to their essential or volatile oil. Volatile oils, as their name suggests, are the concentrated volatile ‘aromatic’ part of the plant (normally about 1-2% of a plant). You will be familiar with the scent of one of their active chemicals, camphor, inhaled from vapour rubs and present in eucalyptus and other aromatic plants.
Over the last 5 years studies on antibacterial, antiviral and antifungal volatile oils has more than tripled. Annual production of thyme essential oil alone (from several Thymus species) is estimated at 30 tonnes (with a value of around £1.2 million) and it is used in perfumes, cosmetics and widely in the food industry for flavour and improving shelf life by slowing oxidation and decreasing colour changes.
Essential oils and their chemical ingredients, have a long list of preventative actions (termed ‘anti-‘). They have been shown to be expectorant but also, anti-spasmodic, anti-tussive (cough), anti-histamine, anti-bacterial, anti-viral (including bay Laurus nobilis against SARS corona virus), anti-fungal and anti-oxidative and anti-inflammatory (by several mechanisms). Essential oils with anti-inflammatory activity act to reduce swelling and edema associated with respiratory infections and so reducing symptoms like wheezing, congestion and difficulty breathing. A combination of essential oils can act on different pathways to treat respiratory infection and on various levels.
The aromatic herb thyme is used as a plant medicine for inflammatory diseases and several studies show it contains valuable components to help treat respiratory disease by a number of different mechanisms. It is also antimicrobial and antiviral. Thyme is an aromatic plant and both extracts of the whole herb and its volatile oil have been shown active.
A brief profile of thyme extracted from Grow Your Own Physic Garden
Scientific sources
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Büechi S, Vögelin R, von Eiff MM, Ramos M, Melzer J. Open trial to assess aspects of safety and efficacy of a combined herbal cough syrup with ivy and thyme. Forsch Komplementarmed Klass Naturheilkd. 2005;12(6):328–332. doi:10.1159/000088934
Büechi S, Vögelin R, von Eiff MM, Ramos M, Melzer J. Open trial to assess aspects of safety and efficacy of a combined herbal cough syrup with ivy and thyme. Forsch Komplementarmed Klass Naturheilkd. 2005;12(6):328–332. doi:10.1159/000088934
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Sharifi-Rad J, Salehi B, Schnitzler P, et al. Susceptibility of herpes simplex virus type 1 to monoterpenes thymol, carvacrol, p-cymene and essential oils of Sinapis arvensis L., Lallemantia royleana Benth. and Pulicaria vulgaris Gaertn. Cell Mol Biol (Noisy-le-grand). 2017;63(8):42–47. Published 2017 Aug 30. doi:10.14715/cmb/2017.63.8.10
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