Plant secondary metabolites
description
Transcript of Plant secondary metabolites
PLANT SECONDARY METABOLITES
Dr. Muayad S. Shawkat
University of Baghdad
College of Science
Department of Biotechnology
*These compounds are played many important rules in plant life such as involved in defense against herbivores and pathogens, regulation of symbiosis, control of seed germination, and chemical inhibition of competing plant species (allelopathy), and therefore are an integral part of the interactions of species in plant and animal communities and theadaptation of plants to their environment.
*Plant secondary metabolites are a diverse group of molecules that are involved in the adaptation of plants to their environment but are not part of the primary biochemical pathways of cell growth and reproduction.
* The mechanisms by which these substances have beneficial effects on health may also be related to their toxic effects, and the difference between toxicity and beneficial effects may be dose- and structure-dependent.The term “plant extract" determines the part/parts of a plant used for preparing medicine (for example: leaves, flowers, seeds, roots, barks, stem....etc). Studies on the use of plant extracts for controlling disease have shown the importance of natural chemicals (phytochemicals) as possible sources of non-phytotoxic and easily biodegradable, alternative fungicides and antibiotics
* In addition, plant secondary metabolites are also associated with improved nutritive value and may have beneficial effects on animal health.
* Growing interest in the potential health-promoting effects of plant secondary metabolites in human foods has prompted research on their potential to prevent or treat cancer, circulatory disease, and viral infection.
o Extraction: as the term is used pharmaceutically, involves the separation of medicinally active portions of plant or animal tissues from various parts of plants by using selective solvents in standard extraction procedures. Selection of the solvent depends on the polarity of solvent and solubility of the desired components of the material.
Preparing the plant Material: Plants were dried before extraction. freeing of plant under study from
contamination From other plants from disease
General methods Extraction:
choosing of the precise method of extraction depend on texture and water content of the plant material.
1. Maceration the whole or coarsely powdered crude drug is placed in a container with the solvent and allowed to stand at room temperature for a period of at least 3 days with frequent agitation until the soluble matter has dissolved.
2. Hot Continuous Extraction (Soxhlet)
In this method, the finely ground crude drug is placed in a porous bag or “thimble” made of strong filter paper, which is placed in chamber E of the Soxhlet apparatus. The extracting solvent in flask A is heated, and its vapors condense in condenser D. The condensed extractant drips into the thimble containing the crude drug, and extracts it by contact. When the level of liquid in chamber E rises to the top of siphon tube C, the liquid contents of chamber E siphon into flask A.
CO2
Primary carbon metabolism
Photosynthesis
Phosphoenol pyruvate
Pentose phosphate pathway
Erythrose-4-phosphate
pyruvate
Acetyl Co-ATCA Cycle
Aliphatic amino acid
Shikimic acid Mevalonic acid Pathway
Terpenes
Malonic acid Pathway
Phenolic compounds
Aromatic amino
acids
Nitrogen containing compound
s
A/ TerpenoidsB/ Nitrogen containing secondary metabolitesC/ Phenolic compounds
MAIN GROUPS OF PLANT SECONDARY METABOLITES
ISOPRENE C5 is the basic unit of the terpenoidsProduction in Plants: * Flowers
* Leaves * Fruit
Biological Role(volatile and non volatile): -Flavour, fragrance, scent -Antibiotics -Hormones -Membrane lipids -Insect attractants -Insect antifeedants
THE TERPENOIDS
C5-hemiterpenes -e.g. isopreneC10-monoterpenes -e.g. limoneneC15-sesquiterpene -e.g. abscisic acid (ABA)C20-diterpene -e.g. gibberellinC30-triterpne -e.g. brassinosteroidsC40-tetraterpenes -e.g. carotenoids> carbons -polyterpenes-e.g. ubiquinones, rubber
TERPENOIDS --IMPORTANT MOLECULES !
Nitrogen containing compounds! Alkaloids (pseudo-, True-, proto-) Extremly heterogenous group alkali like have important pharmacological properties further classified in to many groups- Pyridine alkaloids , e.g. nicotine- pyrrolidine alkaloids , e.g. stachydrine- piperidine alkaloids , e.g. coniine- tropane alkaloids , e.g. atropine- quinoline alkaloids , e.g. quinine- Isoquinoline alkaloids , e.g. berberine- Quinolizidine alkaloids , e.g. lupinine- Indol alkaloids , e.g. resrpine- Imidazol alkaloids , e.g. pilocarpine
Phenylalkylamines: e.g. Ephedrine
Pyridine and piperidine e.g. lobeline, nicotine
Tropane e.g. Atropine.
CH2 CH CH3
NH2
N NH
NCH3 OH
Quinoline e.g.quinine and quinidine
Isoquinoline e.g. papaverine
Phenantheren e.g. Morphine
N
N
Indole e.g.ergometrine
Imidazole e.g. pilocarpine
Purine e.g. caffeine
NH
N
N
N
N N
N
H
Purine
1
2
34
56 7
8
9
Steroidal e.g. Solanum and Veratrum
alkaloids
Terpenoide.g. Taxol
Cyanogenic glycosides
widely distributed in plantsvolatile poisons e.g. Lotustraline
Glucosinolates contain nitrogen and sulpher volatile toxins strong deterrent
Cyanogenic Glycosides
Non-Protein amino acids
found in plants of the family leguminosae
e.g. Canavanine resemble in structure with arginine
there are not incorporated in to protiens
Phenolics
• Plants produce a variety of compounds that contain one or more phenol groups - called phenolics
• Thousands of phenolics occur in plants
Phenolics
• Large group of diverse compounds• Many serve as defense compounds against
herbivores and pathogens• Some function in support – primary cmpd• Some attract pollinators• Some absorb UV light• Some reduce growth of competitors
Tannins
• They are high molecular weight phenolic compounds
• They are widely distributed in plants.• capable of precipitation of animal proteins
Classification of Tannins:
True Tannins(High molecular weight compounds)
Hydrolysable Tannins(Pyrogallol)
Condensed Tannins(Catechol)
PseudotanninsLow molecular weight compounds
e.g. Gallic acid, Flavan-3,4-diol
Not hydrolysable ,no sugar in mol.
Uses of Tannins:
• 1) Antioxidant.• 2) Antidiarrheal.• 3) Antidote for heavy metals poisoning.• 4)Treatment of burns, ulcers, inflammations• 4) Astringent to stop bleeding (hemorrhage)• 5)Treatment of Hemorrhoids.• 6) Tanning industry.
Lignin a complex phenolic
• Primary metabolite - secondary cell wall component occurs in all vascular plants
• Structural function• Also protective because deters herbivores
due to its toughness• Blocks growth of many pathogens because
only small group of fungi can degrade
Flavinoids
• One of the largest classes of phenolics• Carbon skeleton has 15 carbons with two
benzene rings connected by a 3-C bridge
-C3-
Anthocyanins
• Colored flavinoids - red, pink, blue, purple pigments
• Attract animal pollinators and seed dispersers
Anthocyanin
- cyanidine cyanidine 3-glucoside cyanidine 3-rutinoside
- peonidine peonidine 3-glucoside peonidine derivative
B
Flavones and Flavonols
• Also flower pigments• Absorb UV not visible light - not visible to
human eye but visible to many insects - maybe be attractants, nectar guides
• Also present in leaves where they protect against UV-B damage
• Appeared to be involved in legume roots in attracting N-fixing bacteria
Some applications of Important plants and their compounds in
biotechnology
Green Tea (Camellia sinensis)
Polyphenols from leaves
anti-cancer inhibiting tumor initiation and cell proliferation
anti-oxidant
Wine Grape (Vitis vinifera) Contains over 50 different
flavonoid phenolics including resveratrol and catechins
Reduces heart disease by inhibiting platelet aggregation, lowering LDL (low density lipoproteins) and acting as antioxidants
Ginger (Zingiber officinale)
from the rhizome Over 12 compounds
with anti-oxidant activities greater than vitamin E
anti-tumor anti-emetic (inhibits
vomiting)
Garli c (Allium sativum)Onion (Allium cepa) Organo-sulfur
compounds from leaves
Anti-carcinogenic and anti-microbial
Anti-atherosclerosis and anti-hypertensive
Toxic in high amounts
Soybeans (Glycine max) Contains phytoestrogens like isoflavones Reduces health risks associated with menopause:
osteoporosis and heart disease in women Reduces prostrate, colon and breast cancer
Thank You