Parthenin: A toxin from Parthenium weed
Parthenin is a sesquiterpene lactone toxin produced by parthenium weed
Parthenium hysterophorus L. (Asteraceae) is considered to be one of the worst invasive weeds currently known. This is a weed of global significance as is poses severe health risks to both human and animal. It is responsible for dermatitis, asthma and bronchitis, and agricultural losses, as well as a great problem for biodiversity. Parthenium weed can grow in most soil types but it is most dominant in alkaline, clay soil . Apart from parthenium it has many local names such as bitter weed, carrot weed and chatak chandni. In Pakistan and India, the small white flowers from this weed are used in flower bouquets but skin specialists and dermatologists warn not to buy such a bouquet.
The sesquiterpene lactone parthenin (Figure 1) is the main secondary metabolite of Parthenium hysterophorus L. . Chemical analysis of parthenium has indicated that all parts, including trichomes and pollen, contain parthenin . Persons exposed to the plant for prolonged periods develop symptoms such as skin inflammation, eczema, asthma, allergic rhinitis, hay fever, black spots, burning and blisters around eyes. Exposure to P. hysterophorus pollens causes allergic bronchitis . The inhalation of pollen through inhalation can cause allergic trinities and speed up the development of bronchitis or asthma .
Leaching of the toxin from parthenium during rainfall event appears to be unlikely . We have lack of understanding regarding its fate and dynamics in soil. Regarding the biodegradation of the parthenin in the soil, no studies are available. However, in the aquatic environment, the phytotoxicity of parthenin is gradually lost in approximately 30 days under outdoor conditions, reducing the potency of the lethal dose .
Figure 1. Chemical structure of parthenin 
Apart from its toxic effects, it has some beneficial aspects too. It can be used as animal feed due to high potash, oxalic acids and protein content. Parthenin also exhibits significant anticancer properties .
CAS No: 508-59-8
Note: Check you flower bouquet for parthenium before buying it.
 M. Kaur, N.K. Aggarwal, V. Kumar & R. Dhiman (2014). Effects and Management of Parthenium hysterophorus: A weed of Global Significance. Hindawi Publishing Corporation,
Volume 2014, Article ID 368647, 12 pages. http://dx.doi.org/10.1155/2014/368647
 S. Patel (2011). Harmful and beneficial aspects of parthenium hysterophorus an update. 3 Biotech (2011) 1:1–9 DOI 10.1007/s13205-011-0007-7.
 T.P. Khaket, H. Aggarwal, D. Jodha, S. Dhanda & J. Singh (2015). Parthenium hysterophorus in Current Scenario: A Toxic Weed with Industrial, Agricultural and Medicinal Applications. Journal of Plant Sciences 10 (2): 42-53, 2015. ISSN 1816-4951 / DOI: 10.3923/jps.2015.42.53.
 S. Datta & D.B. Saxena (2001). Pesticidal properties of parthenin (from Parthenium hysterophorus) and related compounds. Pest Management Sci 57:95–101 (2001).
 S.S. Tessema & A.M. Tura (2018). Allelopathic property of Parthenin on seed germination and seedling growth of wheat (Triticum aestivum) and barley (Hordeum vulgare). International Journal of Chemical and Biochemical Sciences, IJCBS, 14(2018):23-27.
 Pandey, D.K. Phytotoxicity of sesquiterpene lactone parthenin on aquatic weeds. J Chem Ecol 22, 151–160 (1996). https://doi.org/10.1007/BF02040206
 Chemical Structure: http://www.chemspider.com/Chemical-Structure.390756.html
Parthenium Figures: https://www.cabi.org/isc/datasheet/45573
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