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• When have you used herbal/plant medicine?

  • Rub dock leaf on a nettle sting
  • Aloe vera on sunburn
  • Evening primrose oil
• Many medicines are from plants and herbs
• Records of plant-based medicines go back thousands of years
• Some plant-based medicines have only folklore evidence, others have scientific evidence
• Scientists are still looking at plants for new medicines
• Primrose


  Early spring flower, first aid leaves made to ointment to heal wounds
• Foxglove


  Poisonous, used for 'falling sickness' (epilepsy) and congestive heart failure, substance derived from living plants used in modern medicine to treat heart conditions
• Valerian


  Roots have been a popular cure-all, now known to be effective as a sedative, may explain why it was held in high esteem
• Lemon Balm


  Member of mint family, uplifting fragrance, said to 'make a merry heart', leaves used in herbal teas, essential oils in aromatherapy
• Rosemary


  Helps preserve and enhance mental abilities, used to 'comforteth the memory' and avoid 'dulnesse of the minde', being investigated for effects on Alzheimer's
• Peony


  Used as a treatment for epilepsy, roots or seedpods 'hung about the neck' to prevent or diminish seizures, recommended for children
• Dandelion


  Don't pick dandelions because they make you wet the bed, a diuretic, roots, foliage and flowers are edible, herbal treatments for variety of conditions, particularly of the kidneys and liver
• Sage


  Aiding digestion, relieving cramps, reducing diarrhoea, drying up phlegm, fighting colds, acting as a salve for cuts and burns, killing bacteria and reducing inflammation and swelling, scientific name 'Salvia officinalis' means 'to be saved' and 'officially approved for medicinal use'
• Sage has potential cognitive-enhancing and protective effects
• Aloe Vera


  Leaves contain a gel used on skin in cancer, some treatments damage skin, extract from outer lining of leaves aloe latex used to treat constipation, licensed in Germany but not recommended in USA
• Echinacea


  Herb from North America, liquid extract from leaves, roots or whole plant used to prevent or cure common cold and as antiseptic for wounds, commonly used as complementary medicine for cancer in USA to help immune system
• Green Tea


  From unfermented leaves of Camellia sinensis, used as people consider it boosts immune system, gives energy, detoxifies body
• St John's Wort


  Herbal remedy used for mild to moderate depression, made from flowers/buds, active ingredients hypericin and hyperforin may change activity of neurotransmitters
• Turmeric


  Spice from Asia, active substance is curcumin (diferuloyl methane), used as people think it kills cancer cells and lowers cancer levels in countries that eat a lot, lab studies show it can kill cells and prevent others from growing
• Main classes of plant-derived medicines

  • Steroids
  • Alkaloids
• Steroids - Chemistry


  Plant derived
• Alkaloids - Chemistry


  Organic compound, with N, usually in ring structure, physiologically active on vertebrate nervous systems, diverse class of compounds
• Alkaloids - Effects


  Antihypertensive, Cancer chemotherapy, Neurotoxin
• Chaulmoogra Oil


  First effective treatment for leprosy, a bacterial disease affecting sensitive individuals, acts by being an antagonist of biotin synthesis required for bacterial growth, now replaced with antibiotics
• Malaria- Cinchona


  Caused by protozoans, quinine inhibits parasite's ability to digest haemoglobin and formation of haemozoin which causes symptoms
• Cinchona officinalis


  About 40 species native to Andean area of South America, bark used to treat malaria, Cromwell's death in 1658 was from malaria
• Salix - Aspirin


  Hippocrates used willow bark to treat pain, Bayer Co. chemist synthesized and named aspirin in 1897, aspirin inhibits cyclo-oxygenase enzyme that catalyzes prostaglandin generation, acts as anti-inflammatory and inhibits secondary tumours
• Papaver - Alkaloids


  Pain killers - Morphine, Heroin, Codeine
• Dioscorea


  Wild Yam, convenient source for steroidal saponins which can be converted into synthetic hormones (progestin) for use in contraceptives

  Diosgenin --> Dehydropregenolone acetate --> Progesterone
• Catharanthus roseus


  Effective drugs vs. lymphomas (Hodgkin's disease)
• Paclitaxel (Taxol)


  Approved in UK for various cancers, first discovered in 1966 in screening of herbal remedies for anticancer drugs
• Camptothecin(CPT)


  Cytotoxic quinoline alkaloid which inhibits topoisomerase I, resulting in DNA damage and cell death, first discovered in 1966 in Camptotheca acuminata (Happy tree) used in traditional Chinese medicine, synthetic derivatives developed with good results, two analogues approved for cancer chemotherapy: Topotecan & Irinotecan