Salix Alba Lecture Notes Vocabulary

White Willow (Salix alba)

Morphology and Introduction

  • Salix alba (S. alba) is a medium-sized deciduous tree.
  • It can reach a height of 10 to 25 meters.
  • It is known as "White willow" due to the silky hairs present on its leaves.
  • Classification:
    • Class: Magnoliopsida
    • Order: Malpighiales
    • Family: Salicaceae
  • Contains a glycoside called Salicin.
  • The bark and leaves are used to treat inflammation and as an analgesic.

Range

  • Native to Northwest Asia, North Africa, and Europe.
  • Introduced to Australia, North America, and South America.
  • S. alba can be found in wet or poorly drained soils.
  • It can tolerate maritime exposure and atmospheric pollution.

Historical Medical Uses

  • Historical use of willow (Salix sp.) bark dates back 6,000 years.
  • Early Civilizations:
    • Babylonians used willow tree extracts to treat common fever, pain, and inflammation.
    • Egyptians used willow leaves to treat inflammatory conditions.
      • The willow was listed in the Eber Papyrus as an herbal remedy.

Historical Medical Uses (Continued)

  • Chinese and Greek civilizations:
    • Chinese used willow shoots for centuries to treat rheumatic fever and colds.
    • Greek physician, Hippocrates, recommended chewing willow bark to patients experiencing high fever and pain.
    • Dioscorides, another Greek physician, prescribed willow bark to reduce the symptoms of inflammation.

From Salicin to Aspirin

  • Salicin is a glycoside found in willow bark and leaves.
  • Salicin was first crystallized in 1829 by Henri Leroux.
  • In 1835, Raffaele Pirra synthesized Salicylic acid from Salicin.
  • In 1860, Kolb and Lautemann achieved small-scale chemical synthesis, leading to industrial production of Salicylic acid.
  • Salicylic acid irritated the stomach, so a safer chemical compound was created by acetylating salicylic acid.
  • Felix Hoffman developed acetylsalicylic acid in 1897.
    • This acid is the main ingredient of Aspirin.

Modern Time – Phytoremediation Potential

  • Phytoremediation: Process that uses plants to remove, degrade, or contain pollutants in soil, water, or air.
  • Studies have shown that Salix alba has potential in phytoremediation.

Phytoremediation Potential - Water

  • Study on the growth of S. alba and the absorption of heavy metals (Na, Co, Fe, and Mn) in industrial contaminated water.
  • Seedlings were watered with industrial wastewater. S. alba showed symptoms related to the toxicity of metal ions and root browning.
  • Roots of S. alba acted as a trap organ, limiting the toxicity of the heavy metals and improving tolerance.
  • Concentration of toxic ions in treated water were significantly lower compared to contaminated water.
  • Effectiveness ranged from 13% to 99%, with S. alba showing a prefer order of accumulation: Na < Co < Mn < Fe.

Phytoremediation Potential - Soil

  • Study about S. alba's potential for accumulation of heavy metals in soil.
  • Soil where S. alba was planted had traces of heavy metals (Cd, Cu, Ni, Cr, Pb).
  • After two years, seedlings were cut and soil samples taken.
  • Soil showed significantly lower heavy metal concentration in soils with S. alba present.
  • S. alba showed to be a hyperaccumulator of heavy metals.
  • Roots were the organ with the greatest ability of accumulation.
  • Some genotypes showed better accumulation of certain metals, like Cd and Cr.

Conclusion

  • S. alba has important historic uses for treating inflammatory issues, fever, and pain.
  • This historical use helped with the extraction of Salicin, which later led to the creation of Aspirin.
  • S. alba has shown high phytoremediation potential, showing potential in the extraction of heavy metals in water and soil.
  • S. alba can be used in Superfund sites, as well as in industrial heavy areas.
  • S. alba can respond and adapt to the pollution, and some genotypes are better in absorbing certain metals than others.

References

  • 1) Bartnik, M. & Facey, P.C. (2017) Chapter 8 – Glycosides, Pharmacognosy. Academic Press. Chapter 8, 101-161.
  • 2) Bousbih, M., Lamhamedi, M. S., Abassi, M., Khasa, D. P., & Béjaoui, Z. (2023). Potential Use of Two Forest Species (Salix alba and Casuarina glauca) in the Rhizofiltration of Heavy-Metal-Contaminated Industrial Wastewater. Forests, 14(3), 654-.
  • 3) Burge, S., & Oakeley, H. (2023). Salix alba: The source of salicylic acid. Filipendula ulmaria: The source of aspirin. Gaultheria procumbens: The source of methyl salicylate. In Modern Medicines from Plants (1st ed., Vol. 1, pp. 280–292). CRC Press.
  • 4) Mahdi, J. G., Mahdi, A. J., & Bowen, I. D. (2006). The historical analysis of aspirin discovery, its relation to the willow tree and antiproliferative and anticancer potential. Cell Proliferation, 39(2), 147–155.
  • 5) Urošević, J., Stanković, D., Jokanović, D., Trivan, G., Rodzkin, A., Jović, Đ., & Jovanović, F. (2024). Phytoremediation Potential of Different Genotypes of Salix alba and S. viminalis. Plants (Basel), 13(5), 735-.
  • 6) WFO (2025): Salix alba L. Published on the Internet; http://www.worldfloraonline.org/taxon/wfo-0000929085. Accessed on: 19 Apr 2025
  • 7) Salix alba L. in GBIF Secretariat (2023). GBIF Backbone Taxonomy. Checklist dataset https://doi.org/10.15468/39omei accessed via GBIF.org on 2025-04-19.