S2 l9 10 pro inflammatory plants
This presentation is the property of its rightful owner.
Sponsored Links
1 / 24

S2 L9-10 Pro-inflammatory plants PowerPoint PPT Presentation


  • 93 Views
  • Uploaded on
  • Presentation posted in: General

S2 L9-10 Pro-inflammatory plants. Anna Drew. Plants producing dermatitis…. = environmental toxicology not pollen allergy Can result from contact with living, damaged or processed plant material Hazardous in Industry: timber, cosmetic/perfume, paint/varnish Environment: walks, gardening

Download Presentation

S2 L9-10 Pro-inflammatory plants

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


S2 l9 10 pro inflammatory plants

S2 L9-10 Pro-inflammatory plants

Anna Drew


Plants producing dermatitis

Plants producing dermatitis….

  • = environmental toxicology

    • not pollen allergy

  • Can result from contact with living, damaged or processed plant material

  • Hazardous in

    • Industry: timber, cosmetic/perfume, paint/varnish

    • Environment: walks, gardening

    • Veterinary: grazing or domestic

      • mouth areas inflammed, balding

      • scouring – severe diarrhoea – food not utilised properly

  • Main clinical problem

    • identify cause and remove

  • Treatment

    • topical corticosteroids

  • Dermatitis

    • itching -> scratching -> pain

      • oedema with blisters that weep. If break can get 2y infection

      • OR hyperplasia (thickening) of skin. Dries and breaks


  • Plants producing contact dermatitis can be classified into 5 groups

    Plants producing contact dermatitis can be classified into 5 groups:

    • Mechanical irritants

    • Stinging nettles

    • Phototoxic compounds

    • Allergenic substances

    • Direct or primary irritants

    Ref: Evans FJ, Schmidt RJ. Plants and plant products that induce contact dermatitis. Planta Medica 1980: 38(4)


    Mechanical irritants

    Mechanical irritants

    • Caused by:

      • Easily detachable rough hairs or bristles on surface of the plant

        • break off into skin when touched

        • move around the in the skin causing irritation

      • or acicular calcium oxalate crystals produced onto plant surface

    • Found in:

      • Boroginaceae - Borago, Echium, Pentaglottis, Pulmonaria, Symphytum

        • Covered with coarse stiff trichomes

        • highly lignified or produce silica around the hair

  • Cornaceae - Cornus sanguinea

    • T shaped trichomes

  • Malpighiaceae – Malpighia urens

  • Barley (awns) and other cereal grasses

  • Cactaceae - Opunta ficus-indica, Opunta cochinillifera (prickly pears)

  • Narcissus (daffodil), Hyacinthus (hyacinth family)

    • secrete CaOx onto bulb surface

    • -> daffodil itch, lily rash which wears off in 12-12 hours


  • Stinging nettles

    Stinging nettles

    • Caused by:

      • a defensive trichome which they have evolved

        • combination of a spring release mechanism + hypodermic syringe

        • silica (glass) or calcium oxalate tip on surface

        • when touched tip breaks triggering basal pump mechanism which releases small amount of toxin into the skin

        • (equiv to muscles or contractile tissue!)

    wound hollow tube

    tip


    S2 l9 10 pro inflammatory plants

    • Causes: mild -> very irritant dermatitis, even death

      • Australia/India

        • further evolved with enormous hairs to kill animals

      • UK

        • only one species Urtica dioica

        • some plants mimic it but do not sting

        • varies in form according to nutrient value of soil

    Tragia involucrata


    S2 l9 10 pro inflammatory plants

    • Composition of poison:

      • protein peptide material

        • large molecule – unusual

        • when dried it denatures

        • got poison out by dipping leaf in liquid nitrogen and brushing off trichomes onto paper

        • has properties in common with acetylcholine, histamine, 5-HT

    • Found in: (over 50 species)

      • Urticaceae - Urtica, Giardinia, Gyrotaenia, Laportea, Obetia

      • Euphorbiaceae - Acidoton, Cnesmone, Tragia

        • (Tragia involucrata – Indian species)

    • Loasaceae - Loasa, Evertesia, Eucnide

    • Hydrophyllaceae - Wigandia

      • lethal ones

  • Leguminosae - Mucuna pruriens and other Mucuna sp.

    • trichomes on seed pods

    • mucunain, a proteinase, on surface responsible for pruritus and mechanical effect for dermatitis


  • Phytotoxic substances

    Phytotoxic substances

    • Caused by:

      • Furanocoumarins (coumarin family)

        • harmless – animals and humans can eat plants

        • veterinary problem

          • photoactivated on skin -> sunburn effect

          • red inflammation peels to leave brown pigmented areas

          • around muzzle, hair falls out, look in poor condition

      • Photoactivated form binds to epidermal DNA and ribosomal RNA

        • -> pigment


    S2 l9 10 pro inflammatory plants

    1/3 as active

    • Found in:

      • Umbellifereae – Heracleum mantegazzanium, Pastinacea sativa

      • Rutaceae – Dictamnus albus, Phebalium argentium

      • Leguminosae – Psoralea sp.

      • Moraceae – Ficus carica

      • Rosaceae

    ¼ as active

    6x as active


    Contact allergens

    Contact allergens

    • Most common form of plant dermatitis

      = allergenic eczematous contact dermatitis

      • dry scaly erythema -> severe papular/vescicular inflammation with oedema

    • 1st exposure -> sensitisation (eg 6-25 days)

    • 2nd exposure -> dermatitis (eg 24 hours)

      • degree depends on exposure dose

      • hard to diagnose (patch testing)

      • population variability: genetically determined (race, gender)

      • cross sensitization between plants

        • compounds of same basic chemical structure can cause reaction

        • elictors – may not be allergenic themselves


    Sri lanka

    Sri Lanka

    • Kandy - plant dermatitis accounted for one third of cases

    • Clinic incidence affected by:

      • industrial development of the area

      • pattern of employment

      • interest the dermatologist takes in contact dermatitis

    Ref: Perera WDH. Special problems and perspectives from Sri Lanka. In: See Ket Ng, Chee Leok Goh (Eds). The Principles and Practice of Contact and Occupational Dermatology in the Asia-Pacific Region. World Scientific, 2001


    Groups of compounds

    Groups of compounds:

    • URUSHIOLS = Poison ivy toxins

      • typical allergenic compounds

        • simple molecules (low MWt, haptens)

        • homologous long chain phenolics

      • R1 and R3 can be -H, -OH or -COOH

      • R2 can be C9 -> C19 saturated or unsaturated

        • lipid soluble and will penetrate skin and phenolic groups burn

        • mechanism of action unknown (direct irritation, allergenic or inflammation)

      • hard to separate compounds (need GLC) but all work

      • cross sensitization takes place


    S2 l9 10 pro inflammatory plants

    • 150 derivatives have been found in:

      • Anacardiaceae

        • Toxicodendron (poison ivy)

        • Pentaspadon

        • Semecarpus (5 species in SL)

          • medium-sized forest trees found in the wet zone

          • -> itchy vesicular dermatitis in sensitized individuals

          • streaks of vesicles correspond to points of contact (face, exposed areas) with the plant

          • reactions often severe requiring treatment with systemic steroids

        • Mangifera indica (mango tree)

          • -> allergic contact dermatitis

          • from contact with stem, leaves, skin of unripe fruit

          • seen on lips and around mouth

          • climbing a tree can produce dermatitis all over body

        • Anacardium occidentale (cashew nut tree)

          • -> allergic contact dermatitis

          • from handling fruit, nut and also from cashew nut oil

      • Ginkgoaceae - Ginkgo biloba (fruit pulp)

      • Protaceae - Persiana


    S2 l9 10 pro inflammatory plants

    • SESQUITERPENE LACTONES

      • Mainly found in Compositae

        • Allergenic ones also found in: Jubilaceae, Lauraceae

      • Concentrated in pollen and trichomes

        • distributed by wind over large areas in spring

        • distinct from hayfever caused by protein constituents in pollen exine

      • 250+ characterised - 4 main types structurally:

        • All essentially have C15 hydrocarbon nuclei

        • Not all tested on humans (~50)

        • γ-lactone and α-methylene group -> effect

    guaiane

    pseudoguaiane

    eudesmane

    germacrane


    S2 l9 10 pro inflammatory plants

    * widely distributed

    • Found in:

      • Compositae

        • Ambrosia

        • Artemisia*

        • Chrysanthemum*

        • Eupatorium*

        • Helenium

        • Iva

        • Parthenium eg Tanacetum parthenium (feverfew)

      • Jubilaceae

        • Fruillania

      • Lauraceae

        • Laurus

    Parthenolide


    S2 l9 10 pro inflammatory plants

    • OTHER

      • Occupational hazards mainly in timber industry (sawing -> dusts)

        (1) Quinones

        • in heartwood are responsible

        • Found in:

          • Primulaceae – Primula obconica

    Primin

    Mansenone

    Larchol


    S2 l9 10 pro inflammatory plants

    (2)

    • Not present in the plant under normal circumstances

    • Formed when plant injured by hydrolysis of tuliposide A -> tulipalin A (enzyme β-glucosidase)

    • = allergenic material (phytoalexin)

    • Found in:

      • Liliaceae and related families

        • Tulipa, Erythronium, Alstroemeria

          (3) Volatile oils

    • low allergenic sensitizing potential

      (4) Many miscellaneous compounds


    Primary irritants

    Primary irritants

    • Largest group of all

    • Cause most damage

    • End up in all kinds of cosmetics, perfumes, soaps, eye makeup – dermatitis common

    • Burn directly (1st and every exposure)

      • can be widespread

        -> severe erythema, itching, flaking etc

    • Have diverse structures

    • Not all mechanisms understood

      • phorbol esters from croton (Euphorbiaceae) best understood

        • activate protein kinase C – inflammation pathway

      • some simply acids or phenols which burn

    • Time for reaction depends on lipid solubility

      • volatile oils worse

      • may induce irritation and malignancy at a later stage


    S2 l9 10 pro inflammatory plants

    • Capsaicins & ginger group

      • Capsaicin = irritant principle found in red pepper family

        • Solanaceae - Capsicum minimum, C.fructescens

        • burning effect on membranes throughout GI tract (curry ingredients)

        • externally -> erythema, no blistering

      • Gingerols, shagaols

        • Zingiberaceae – Zingiber officinalis

        • also capsaicin-like compounds -> rubefacient

      • Uses:

        • Go into “deep heat” products – paraffin-based creams for massage, counterirritants to increase blood flow to damaged muscle

        • Itching powders (mechanical trichome) or chemical irritants

        • Some foods


    S2 l9 10 pro inflammatory plants

    Capsaicin

    • Electron dense centre with lipid side chain

      • lipophilic, will penetrate cells easily

    Shogaol

    The gingerols


    S2 l9 10 pro inflammatory plants

    • Volatile oils

      • Thought to be phenols present if they burnt

      • Now realise terpinoids present

      • Affect certain types of smooth muscle -> spasm (contraction)

      • Mechanism unknown – may block Ca2+ channel

      • Uses: antibacterial, indigestion preparations

      • Two groups: aromatics, terpinoids

      • Beware: cajaput, clove, eucalyptus, nutmeg, pumilopine, rosemary, thyme, terpentine

    Eugenol

    Safrole

    Limonene

    α-pinene


    S2 l9 10 pro inflammatory plants

    • Proteolytic enzymes

      • Found in the sap of some plants:

        • Papain – Carica sp.

        • Ficia – Ficus sp.

        • Bromelain – Ananus sp.

        • Nepenthin -Nepenthus sp.

          • Eg pitcher plant – insectivorous

            • insects attracted into modified leaf structure

            • contains sugary solution with proteolytic enzyme

            • Insects are a source of nitrogen

        • On skin -> digestion -> very painful dermatitis

        • Use: meat industry


    S2 l9 10 pro inflammatory plants

    • Sulphur glycosides

      • Irritant to mucous membranes

        • Eg Allium sp.

          • peeling an onion – eye watering (volatile substances)

          • when damaged enzymes convert sulphur glycosides ->

    • Mustards

      • when damaged glucosinolate glycoside -> isothiocyanates (enzyme myrosinase)

    propenyl sulphuric acid

    eg isothiocyanate


    S2 l9 10 pro inflammatory plants

    • Resins

      • Found in:

        • Berberidaceae

          • Podophyllum peltatum

          • Podophyllum hexandrum

      • Uses: to burn off worts, (antitumour properties)

    Podophyllotoxin


  • Login