Plant allergens are described in detail.

1. ALLERGENS
By
Dr. S.T.V.Raghavamma

2. • An allergen is a type of antigen that produces an
abnormally vigorous immune response in which
the immune system fights off a perceived threat
that would otherwise be harmless to the body.
Such reactions are called allergies.
• an allergen is an antigen that is capable of
stimulating a type-I hypersensitivity reaction
in atopic individuals through Immunoglobulin
E (IgE) responses
• Allergen can be transmitted by direct skin
contact, by airborne pollens, smoke and dried
plant particles.

3. • Plant allergens are:
• 1. latex
• Wood
• Plant pollens (hay fever)
• Grass : ryegrass, timothy- grass
• Weeds: ragweed, plantago, nettle, Artemisia
vulgaris, chenopodium album, sorrel.
• Trees: birch, alder, hazel, hornbeam, Aesculus,
willow, poplar, plantanus, tilia etc.

4. • 1. Timothy-grass (Phleum pratense)
• an abundant perennial grass native to most of Europe except for
the Mediterranean region. It is also known simply
as timothy, meadow cat's-tail or common cat's tail.
• It is a member of the genus Phleum, consisting of about 15 species
of annual and perennial grasses.
• Its pollen is a common allergen;
• it has recently been used in small amounts as part of a new hay
fever vaccine Grazax, which is designed to recondition the body's
immune system so it no longer responds to pollen.

5. 2. Dactylis glomerata
• another important cause of allergic reactions in man
 Dactylis glomerata, also known as cock's-foot, orchard grass,
or cat grass is a common species of grass in the genus Dactylis.
• native throughout most of Europe, temperate Asia, and
northern Africa

6. 3. Lolium perenne,
• common name perennial ryegrass, English ryegrass, winter
ryegrass, or ray grass,
• Family: Poaceae.
• It is native to Europe, Asia and northern Africa, but is widely
cultivated and naturalised around the world.

7. 4. Urtica dioica
• Known as common nettle, stinging nettle (although not all plants of
this species sting) or nettle leaf, or just a nettle or stinger,
• herbaceous perennial flowering plant
• Family: Urticaceae
• Originally native to Europe, much of temperate Asia and western
North Africa. it is now found worldwide

8. 5. Plantago spp.
• Plantago is a genus of about 200 species of small, inconspicuous
plants
• commonly called plantains or fleaworts.
• The common name plantain is shared with the unrelated cooking
plantain a kind of banana.
• Family: Plantaginaceae
• Most are herbaceous plants, though a few are subshrubs growing
to 60 cm (24 in) tall

9. 6. Artemisia vulgaris (common mugwort)
• one of several species in the genus Artemisia commonly known
as mugwort
• This species is also occasionally known as riverside wormwood,
felon herb, chrysanthemum weed, wild wormwood, old Uncle
Henry, sailor's tobacco, naughty man, old man or St. John's
plant
• Mugworts have been used medicinally and as culinary herbs.

10. 7. Ragweeds
• flowering plants in the genus Ambrosia in the aster
• Family: Asteraceae
• common names include
Bursages and burrobrushe
• pollen is notorious for causing
allergic reactions in humans,
specifically allergic rhiniti

11. 8.Cladosporium herbarum
• common fungus found worldwide in organic and inorganic
matter.
• It is distributed in the air,
• It can grow over a wide range of temperatures including very cold
environments, giving it the ability to grow on refrigerated meat
and form "black spots”.
• an important exacerbant of asthma and hay fever

12. 9. Porobolomyces roseus
• common ballistoconidium-forming yeast species and
• occurs in many different habitats, but most frequently
in the phyllosphere

13. 10. Lycopodium
• (frm Greek lukos, wolf and podion, diminutive of pous, foot) is
a genus of clubmosses, also known as ground pines or creeping
cedar.
• family: Lycopodiaceae
• Lycopodium powder is also
used to determine the
molecular size of oleic acid
• spores will cause dermatitis and
Asthma
• it adheres to serous surfaces
and granulomas.
• Used as dusting powder for
Nonlubricated condoms

14. 11. Toxicodendron radicans,
• commonly known as eastern poison ivy or poison ivy, is a
• poisonous Asian and Eastern North American flowering plant that
is well-known for causing urushiol-induced contact dermatitis,
an itchy, irritating, and sometimes painful rash, in most people
who touch it.
• The rash is caused by urushiol, a clear liquid compound in the
plant's sap.
• family (Anacardiaceae)

15. • Urushiol is an oily mixture of organic compounds alkenyl
polyphenols with allergenic properties found in plants of
the family Anacardiaceae,
• especially Toxicodendron spp. (e.g., poison oak, Chinese lacquer
tree, poison ivy, poison sumac )and also in parts of the mango tree.
• The name urushiol is derived from the Japanese word for the
lacquer tree, Toxicodendron vernicifluum.
• the oxidation and polymerization of urushiol in the tree's sap in the
presence of moisture allows it to form a hard lacquer, which is
used to produce traditional Chinese, Korean and
Japanese lacquerware.

16. • Urushiol
• R= C15 aliphatic side chain for poison ivy:
• R= C 17 aliphatic side chain for poison oak
• R = (CH2)14CH3 or
R = (CH2)7CH=CH(CH2)5CH3 or
R = (CH2)7CH=CHCH2CH=CH(CH2)2CH3 or
R = (CH2)7CH=CHCH2CH=CHCH=CHCH3 or
R = (CH2)7CH=CHCH2CH=CHCH2CH=CH2and others

17. Pharmacological action:
• Compound undergoes oxidation to quinone which binds
covalently to protein nucleophile resulting in an
antigenic complex.

18. • Lacquer -Used in wood finishing was derived from
R .vernicifera. This caused harmful effects in crafts men.
• Ginkgo biloba, trichomes of Phacelia have similar compound.

19. 12. Sesquiterpene lactones:
• found in Compositae, Lauraceae, and Magnoliaceae and
Liverwort (frullania), Asteraceae family-(AKA daisy, aster or
sunflower family
• Parthenium histosporous – pseudoguanolide parthenium-
weed causing public health problems.
• Chrysanthemum
• Ruta graveolens
• Dieffenbachia seguine
• All these cause irritation by introducing irritant into the tissues
by abrasion through punctures caused by the acicular crystals
of calcium oxalate in idioblasts.