Secondary Metabolism Primary & Secondary metabolites Primary Metabolites: Secondary Metabolites: Sugar, starch, citric acid, Vitamines Pectins & algins (food additives) Phenolic compounds (coffee, vine, incense, perfumes) protein (seeds of Fabaeceae) Terpenoid compounds plant fatty oils (nuts, corn, (lemon scent, anis taste, bitter sesame, peanuts, sunflower, rape) taste of hops, tonic water, color cellulose (cotton, fiber, wood) Amines (smell of fish, algae, ) Alkaloids (coffeine etc.) Glycosides (Sinigrin from mustard, allicin from garlic, PEA in chocolate) Doctrine of Signatures The doctrine of signatures states that herbs that resemble various parts of the body can be used to treat ailments of that part of the body. Examples include the plants liverwort; snakeroot: an antidote for snake venom; lungwort; bloodroot; toothwort; and wormwood, to expel intestinal parasites. A theological justification was “The Almighty must have set his sign upon the various means of curing disease which he provided”. However some version of the doctrine exists also among Asians & Native Americans. Medicinal plants based on the "Doctrine of Signatures" in Porta's Phytognomonica. Plants for scaly diseases include pine cones, thistles, catkins, and lily bulbs. The snake and fish were added to show scaly skin. Doctrine of Signatures The doctrine of signatures was described in the book “Phytognomica” by Philippus, Aureolus Theophrastus Bombastus von Hohenhein called Paracelsus. It provided many of the common names for plants St Johns Wort Hypericum perfor : holes in the leaf indicate use for cuts (Paracelsus) liverwort; Hepatica heals liver diseases snakeroot Ageratina altissima in the Asters contains toxin tremetol (milk sicknes) helps against snake venom lungwort; Pulmonaria spotted leaves excellent remedy for tuberculosis bloodroot; Sanguinaria canadensis wormwood Artemisia absinthum was used to expel intestinal parasites. Feverfew Chrysanthemum parthenium was used accordingly Eyebright Euphrasia officinalis was excellent remedy for sore eyes Toothwort Lathrea squamaria was used together with pine cones to fight toothaches is a carnivorous chlorophyll-free plant Clelandine Chelidonium major has yellow juice against jaundice No doctrine but signatures Î Plants have glands Clear giveaways = signatures = anatomical clues that plants have sequestered lots of active compounds Î glandular trichomes, lacticifers, idioblasts, resin canals, floral & extrafloral nectaries Anatomical signatures Î glandular hairs Clear giveaways = signatures = anatomical clues that plants have sequestered lots of active compounds Î (1) glandular trichomes, (2) lacticifers, idioblasts,(3) resin canals, (4) floral & extrafloral nectaries Trichomes or hairs are fine outgrowths or appendages on Examples are hairs, glandular hairs, scales, and papillae. Drosera leaf Coleus leaf Cross section through stem of Digitalis Leaf surface trichomes (Salvia divinorum). The upper leaf surface contains numerous or foxglove plant shows glandular hair. multicellular, glandular and non-glandular trichomes (hairs). Stinging Hairs For a long time we did not know what caused the stinging sensation of Urtica dioica? It was first shown that formic acid was inside the hairs but that alone does not cause such effects! pict Urtica dioica is harmless when compared with tropical nettles like Urtica stimulans (Java) & Urtica crenulata (India) & the worst Urtica urentissima (Timor) which also cause skin irritations but in addition affect the nervous system in the area with paralytic cramps & permanent damage to nerves. Dogs refuse to search for game after experiencing the burning sensation of nettels, geese seem to be insensitive, larvae of some butterfly too There are other plant families with stinging hairs Hydrophyllaeceae Wigandia urens , Euphorbiaceae Jatropha urens have stinging hairs while many members of the Urticaeceae (glass plants, hops) have none. Other plants like Primula obconica cause dermatitis Mimicry of nettle leaves by dead nettels alias Lamium species Secrets of Secretion of glandular hairs Glandular Trichomes are modified epidermal hairs and cover leaves, stems & the calyx in the Labiatae. Secretory cells are emanations that are either attached to a stalk or are sessile = attached to a basal cell in the epidermis. We find them in basil Ocimum basilicum, lavender Lavandula spp. Majoram & oregano Origanum spp., mint Mentha spp. & thyme Thymus spp. Also other families contain glandular hairs like hops Lupus humulus in Cannabinaeceae, source: Secretory structures of aromatic and medicinal plants by KP & TG Svoboda Bastyr Library QK 725.S92.2002 Spices and perfumes – Labiatea or mint family Mints have asymmetric, bilabiate (two-lipped) flowers, often in in axial nodes, square stems and opposite, fragrant leaves Rosemary (Rosmarinus officinalis), Thyme (Thymus vulgaris) antiseptic; Oregano (Origanum vulgare), Majoram (Origanum sp); Basil (Ocimum basilicum) Chatreuse; Sage (Salvia officinalis) stuffing, Peppermint (Mentha piperita); spearmint (Mentha spicata) Picture of leaf glands Secrets of secretory hairs Glandular Trichomes are modified epidermal hairs and cover leaves, stems & the calyx in the Labiatae. Secretory cells are emanations that are either attached to a stalk or are sessile = attached to a basal cell in the epidermis. We find them in basil Ocimum basilicum, lavender Lavandula spp. Majoram & oregano Origanum spp., mint Mentha spp. & thyme Thymus spp. Citrus family Pressurized vacuoles with essential oils protect citrus fruits. Interior of these fruits is isolated by thick cuticle and pectin layer. Secrets of Secretion of Essential oils Secretory cavities are spherical intercellular spaces that are lined with one or more layers of secretory cells. These cavities are found in the peel of Citrus fruits where they appear irregularly as oblate to spherical in the pericarp, in the flavedo (yellow colored part). source: Secretory structures of aromatic and medicinal plants by KP & TG Svoboda Bastyr Library QK 725.S92.2002 Secrets of Secretion of Essential oils Secretory cavities are spherical intercellular spaces that are lined with one or more layers of secretory cells. These cavities are found in the peel of Citrus fruits where they appear irregularly as oblate to spherical in the pericarp, in the flavedo (yellow colored part). Large secretory cavities are found in the flower buds of cloves Szygium aromaticum, the fruit walls of Pimenta dioica, the bark of myrrh Commiphora, benzoin Styrax and frankincense Boswellia and in the leaves of Eucalyptus spp. source: Secretory structures of aromatic and medicinal plants by KP & TG Svoboda Bastyr Library QK 725.S92.2002 Spices and perfumes – Apiacea or carrot/parsley family Umbelliferae: umbel as inflorescense; flat-topped clusters of flowers Parsley (Petrosselinum crispum) leaf; dill (Anethum graveolens) leaf; cilantro (Coriandrum sativum) leaf and fruit (coriander spice) Simple Secretory Cells Simple secretory cells occur in the leaf parenchyma of lemongrass Andropogon spp. , bayleaf Laurus nobilis, citronella Cymbopogon spp. & patchouli Pogostemon patchouli, in the seeds of cardamon Eletteria cardamonum, the rhizome of ginger Zingiber offic. & turmeric Curcuma longa & the fruit walls of chillies Capsicum annuum, in the embryo of of nutmeg Myristica fragrans, the bark of cinnamon Cassia angustifolia & Cinnamonum zeylandicum, root of Valeriana offic. source: Secretory structures of aromatic and medicinal plants by KP & TG Svoboda Bastyr Library QK 725.S92.2002 Anatomical signatures Î “Plants have idioblasts” Clear giveaways = signatures = anatomical clues that plants have sequestered lots of active compounds Î (1) glandular trichomes, (2) lacticifers, idioblasts,(3) resin canals, (4) floral & extrafloral nectaries Idioblasts are isolated cells which differ from neighboring plant cells by containing non-living substances. They store starch, excretory materials, pigments and minerals and can contain Ca oxalate raphides emerge from oil, latex, gum, resin, tannin or pigments irritated idioblasts etc. Some can contain mineral crystals such as acrid tasting and poisonous calcium oxalate or silica. Idioblasts are divided into three main categories: excretory, tracheoid and sclerenchymatous. When the end of the idioblast is broken the crystals or other substance is Cross sections of petals of various plants ejected by internal water pressure showing idioblasts around the vascular ring. Secrets of simple Secretion Epidermal cells. Many flowers lack glandular hairs and exude their essential oils from simple epidermal cells through the cuticle to the outside. This primitive mechanism is normally associated with very low yield of essential oils. It occurs in rose petals Rosa spp. , Acacia petals & those of jasmine Jasminum spp. source: Secretory structures of aromatic and medicinal plants by KP & TG Svoboda Bastyr Library QK 725.S92.2002 Secrets of Secretions Nectar is a sugar-rich liquid produced by plants in glands called nectaries. Nectaries are either within the flowers (Î floral nectaries)., or they are outside (Î extrafloral nectaries). In both cases they provide a nutrient source to animal mutualists. Floral nectaries are located at the bottom of the perianth, forcing pollinators to brush the flower's reproductive structures, the anthers and pistils. Extrafloral nectaries are located on the leaf petioles, mid-rib or leaf margin. Extrafloral nectaries can be found on species belonging to (amongst others) the genera Salix, Prunus (cherries)