Phytotherapy PG 906 Fall Semestre 2024-2025 Lecture 1 PDF

Phytotherapy PG 906 Fall Semestre2024-2025 Shaza Hussiny Aly, PhD Lecturer of Pharmacognosy Faculty of Pharmacy Badr University in Cairo 2024 Lecture 1 29-9-2024  Introduction...

Phytotherapy PG 906 Fall Semestre2024-2025 Shaza Hussiny Aly, PhD Lecturer of Pharmacognosy Faculty of Pharmacy Badr University in Cairo 2024 Lecture 1 29-9-2024  Introduction https://upl oa d. wi k imed ia. or g/ wi ki ped ia /commons /t humb/ 3/ 30 /V i en na Di oscor ides P la nt.j pg / 22 0p x-Vi e nnaD ios cori de sP l ant. jpg History The healing properties of plants were discovered by chance. The observation that animals favored certain plants when they were injured or ill may have helped to guide primitive man in the search of cures for his ailments. Knowledge of the medicinal value of these plants was initially passed on De Materia Medica verbally then records on the use of medicinal plants were preserved in writing The Ebers Papyrus (about 1550 BC) presents a large number of crude drugs that are still of great importance (castor seed, gum arabic, aloe, etc.). The Greek Dioscorides rigorously collected information about 600 plants and remedies and collected them in his Materia Medica, a term used to define the knowledge of drugs for many hundreds of years. Ebers Papyrus Gorge Ebers 1837 -1898  Linnaeus made an important contribution to the development of plant science through the introduction of the new system for naming and classifying plants. In any case, since 1980 there has been a gradual increasing appearance of herbal medicines and their galenical Discorides preparations from medical practice and pharmacy shelves. Linnaeus  Avicenna ‫انيس نبا‬Ibn Sīnā, (980–1037) ✓ He made fundamental contributions to medicine and the European reawakening. ✓ About 100 treatises, the best known is The Canon of Medicine, ‫بطالىف نوناقال‬which was a standard medical text in Western Europe for seven centuries. ✓ One of the most important citations from Avicenna concerning psychological and organ diseases was: “The best and effective remedy for the treatment of patients should be through the improvement of the power of the human body in order to increase its immune system, which is based on the beauty of the surroundings and letting him listen to the best music and allow his best friends to be with him.” 12 Definitions Medicinal plants: Contain chemicals with pharmacological activity in humans and/or animals. Herbal medicine" or “Botanical medicine“ or Herbal remedy: The use of plants or plant substances as medicinal agents. It includes four branches: phytopharmacy, phytochemistry, phytopharmacology and phytotherapy. 13  Phytopharmacy: It deals with the preparation of natural drugs either in natural form (medicinal teas) , or in pharmaceutical preparations (tinctures and extracts ). Phytochemistry: It deals with the study of chemical constituents of the plants such as alkaloids , glycosides , essential oils. It explains their distribution, isolation, chemical reactions and biosynthesis.  Phytophamacology: It concerns with testing of natural drugs which have multiple effects on animals and humans. Phytotherapy describes the efficacy and limitation of herbal medicines in the treatment of human diseases: it covers everything, from herbal medicines with powerful actions to those with "very gentle" action. It is the bridge between herbal folklore (i.e. traditional) and allopathic (conventional) medicine.  The "crude drugs", called "simples" in the Middle Ages: represent the dried or fresh herbs or the starting material from which chemically pure compounds can be isolated. Crude drugs Phytopharmaceutical" is a term used for those medicinal preparations made by extracting botanical products with appropriate solvents to yield extracts, tinctures, or the like. Nutraceuticals  Phytomedicine or Herbal medicine: use plants or their crude products for the treatment of diseases. It may include also animal, fungi or bacteria. Conventional medicine : It is a type of medicine in which medical doctors and other healthcare professionals (such as nurses, pharmacists, and therapists) treat symptoms and diseases using drugs (Pure chemicals), radiation, or surgery. The drugs of plant, animal, synthetic, semi-synthetic, organic or inorganic nature.  Difference between herbal and conventional medicine Conventional medicine Herbal medicine Contains one active principle Contains several active in high concentration principle in low concentration Simple with single indication. Complex for several different uses.  The Complexity of Herbal Medicines The quality of a herbal medicine is believed to be directly related to its active principles, "secondary plant constituents”. However, herbal medicines contain other substances, often neglected and poorly understood, which render the ingredients "active".  They are generally inactive substances (cellulose, lignin, etc.) but also substances of minimal pharmacological interest, such as the bitter or aromatic substances that stimulate the gastric and intestinal secretions thus making the dissolution, and consequently the absorption of the active principle possible or more complete. The tannins and saponins, very common in the vegetable kingdom, may facilitate intestinal absorption of active plant principles. There is also the possibility of interactions between plant constituents.  Classification of herbal drugs according to POTENCY A) Highly potent herbs Toxic (Aconite and Nux vomica) They contain useful but toxic constituents as cardiac glycosides containing herbs such as Digitalis, Strophanthus and Squill. They should be prescribed by Specialist. B)Intermediately potent Solanaceous herbs C) Gentle or mild herbs Highly safe and constitute the majority of herbal medicine. They are safe , non-toxic and suitable for self-treatment.  The safety of Herbal Medicines Herbs are plants, they are often perceived as “ natural” and therefore safe. However, many different side effects to herbs have been reported including ▪ Side effects from biologically active constituents from herbs. ▪ Side effects caused by contaminants, ▪ Side effects caused by herb–drug interactions.  The situation is complicated in several ways: ✓ The sources of herbal material are diverse; ✓ The active (and toxic) components vary as a result of climate, soil quality, genetic factors ✓Exposure to chemicals; quality control is lacking so that problems such as contaminations with heavy metals or microorganisms and adulteration with botanicals and/or chemicals may arise during preparation, storage or shipping  Undesirable effects of herbal medicines (Side effects and/ or Toxic reactions) No drug can be effective and simultaneously free of side effects. The idea that herbal drugs are safe and free from side effects is false. 1- Mislabelling Proper identification of the plant and labelling with common name and Latin name prevent this. 2- Intentional addition of Un-natural toxic substances Chemical analysis of some Chinese herbal remedies used for arthritis proved that they contain some synthetic anti-inflammatory drugs such as Indomethacin and phenyl butazone. Thus toxic manifestations produced through the use of such products are due to synthetic additives. 3- Natural toxic contaminants Plant material used for herbal medicines may be contaminated with micro- organisms or their by-products that can lead to serious adverse effects. 4- Normal toxic substances Herbal drugs containing pyrrolizidine alkaloids have been used since long times, but the first case reported about their hepatotoxicity appeared few years ago. Rauwolfia preparations that are used in the management of hypertension were found to promote breast cancer.  Standardization of Herbal Medicines The use of herbal preparations inadequately standardized involves a considerable risk of distortion and produces a false negative overall result.  Standardization would seem to be a step forward, but this makes little sense when: ▪ Most herbal medicines have yet to yield identity of their pharmacological active principle(s). ▪ Attempts at standardization are confounded by the complex composition of herbs. ▪ Active principles (antagonists as well agonists) may coexist. The desired effect may require concerned action of some or all components of the particular herb. ▪ The problem is to determine the active component upon which standardization will be based. 27  Standardization of Herbal Medicines The standardization, in the case of a herbal drug, is not simply an analytical evaluation, e.g. the identification and assay of active principles or of a marker. It means the body of information and controls that are necessary to guarantee the constancy of composition, and consequently the constancy of activity, of an herbal medicine".  Chromatographic techniques (TLC, G C , HPLC,LC-MS…etc) yield good results and are considered the most suitable. , it is better to define a fingerprint of the herbal medicine. However, in the absence of a specific chromatographic method, other methods have to be used: spectrophotometry, colorimetry, gravimetric determinations