EFFECTS OF HUMAN POLLUTANTS ON PLANTS: THE CASE OF RIBWORT

ribwortRibwort (narrow leaved plantain) is commonly seen in pastures, lawns and street verges, and once positively identified, is rarely forgotten. One of the most useful and endemic “weeds”, its young fresh leaves have been used for centuries as a healing ointment and treatment for slow healing wounds, bites and haemorrhoids, by people from many different parts of the world.

Seed husks of its botanical relative Plantago ovata (commonly known as Psyllium seed), are used as a bulking laxative and for digestive health.

The other main application of Ribwort leaves, is to improve the health and function of the mucous membranes in the respiratory tract. A particular characteristic of this plant, when harvested and prepared in the optimal way, and applied or taken in sufficient doses, is its gentle nurturing and nutritive, but also protective barrier effects on delicate mucous membranes of the nasal passage and other sensitive skin areas of the body. These mucous membranes help protect the sinuses and bronchial tract from invading micro-organisms and other insults, and foods and herbs that optimise their function, can help protect against and manage a wide range of upper respiratory tract conditions.

The diverse phytochemistry of ribwort, which includes polysaccharide hydrocolloids (mucilaginous compounds), phenylethinoid glycosides, flavonoids, coumarins, cinnamic and other phenolic acids, contributes to its anti-inflammatory, antioxidant and antimicrobial activities. This combination of herbal actions makes it a valuable addition to the treatment of inflamed sinuses, catarrh or blocked noses. Research has also found ribwort in large doses to be comparable or superior to the drugs ranitidine and misopristol, in an animal model of peptic ulcer (1).

 

Human influences on the health of this plant

As a common and fairly fast growing plant, ribwort is one of a number of plant species being studied by plant and environmental scientists, for the effects of pollutants on its health and physiology. Recent studies have found ribwort grown near mines, smelting plants and other contaminated areas, accumulates high levels of cadmium, lead and other heavy metals(2-4). Heavy metal contamination of ribwort, dandelion and birch growing in urban areas of Poland with considerable air and soil pollution, has also been shown to be high(5).

In animal farming, anthelmintics (anti-worming drugs) are regularly applied to control gastrointestinal nematodes, and these are excreted from animals into pastures and the wider environment. Along with other drugs such as antibiotics, anthelmintics have become one of a new class of micro-pollutants that disturb the environment. The anthelmintic drugs albenazole, flubendazole and flenbendazole for example, widely used in conventional animal farming, are taken up by and metabolised by ribwort. However, they also produce, in the plant, a significant increase in concentrations of proline (a well-known stress marker), and activities of several antioxidant enzymes. This suggests a possible risk of oxidative damage in this and other plants influenced by these drugs, and is a growing cause of concern(6,7).

Anthelmintic drugs excreted into pastures and taken up by plants also have the potential to impede seed germination negatively, thus affecting affect the regeneration of ribwort and other plants(8).

These studies reinforce the sensitivity of ribwort and other plants to environmental contaminants as a result of human activity, in this case mining, city air pollution, and conventional animal farming. As we are only beginning to discover such delicate links between environmental pollutants and plant health, the importance of growing this plant (and probably numerous others) in certified organic soil as opposed to purchasing it from non-organic, so-called ‘wildcrafted’ or trade broker sources, is highlighted.

Refs:

  1. Melese E et al. Evaluation of the antipeptic ulcer activity of the leaf extract of Plantago lanceolata L. in rodents. Phytother Res. 2011 Aug;25(8):1174-80. doi: 10.1002/ptr.3411. Epub 2011 Feb 7.
  2. Tamás J, Kovács A.Vegetation pattern and heavy metal accumulation at a mine tailing at Gyöngyösoroszi, hungary. Z Naturforsch C. 2005 Mar-Apr;60(3-4):362-7.
  3. Tinkov AA et al. Comparative Analysis of the Trace Element Content of the Leaves and Roots of Three Plantago Species. Biol Trace Elem Res. 2016 Sep;173(1):225-30.
  4. Drava G et al.Trace elements in Plantago lanceolata L., a plant used for herbal and food preparations: new data and literature review. Environ Sci Pollut Res Int. 2019 Jan;26(3):2305-2313.
  5. Nadgórska-Socha A. Air pollution tolerance index and heavy metal bioaccumulation in selected plant species from urban biotopes. Chemosphere. 2017 Sep;183:471-482.
  6. Stuchlíková Raisová L et al. Evaluation of drug uptake and deactivation in plant: Fate of albendazole in ribwort plantain (Plantago lanceolata) cells and regenerants. Ecotoxicol Environ Saf. 2017 Jul;141:37-42.
  7. Stuchlíková LR et al, Biotransformation of flubendazole and fenbendazole and their effects in the ribwort plantain (Plantago lanceolata). Ecotoxicol Environ Saf. 2018 Jan;147:681-687.
  8. Eichberg C et al. The Anthelmintic Ingredient Moxidectin Negatively Affects Seed Germination of Three Temperate Grassland Species. PLoS One. 2016 Nov 15;11(11): e0166366. doi: 10.1371/journal.pone.0166366. eCollection 2016.
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