LAB2

• Phytochemicals


  Bioactive compounds found in plants
• Phytochemicals


  • Play a crucial role in protecting human health
  • There are over 4,000 cataloged phytochemicals
  • Classified based on physical, protective, and chemical characteristics
  • Contribute to the plant's color, aroma, and flavor
• Phytochemicals


  • Non-starch polysaccharides
  • Terpenoids
  • Alkaloids
  • Phenolics
  • Polyphenolic compounds
  • Flavonoids
  • Carotenoids
  • Tocopherols
  • Ascorbic acids
  • Secondary metabolites
• Plant chemicals (secondary metabolites)


  • Not essential for basic survival functions
  • Play crucial roles in protecting the plant from environmental stressors like pollution, UV exposure, and pathogens
• Non-starch polysaccharides


  • Have antibacterial and antifungal properties
• Terpenoids, Alkaloids, and Phenolics


  • Act as inhibitors of microorganisms
  • Reduce the risk of fungal infections
• Polyphenolic compounds, flavonoids, carotenoids, tocopherols, and ascorbic acid


  • Function as antioxidants by quenching oxygen free radicals and inhibiting lipid peroxidation
• Carotenoids, polyphenols, curcumin, and flavonoids


  • Have anticancer properties by inhibiting tumor growth and metastasis
• Reductive acids, tocopherols, phenols, and other compounds


  • Act as detoxifying agents by inhibiting procarcinogen activation and tumorigenesis
• Alkaloids, terpenoids, and biogenic amines


  • Serve as neuropharmacological agents, antioxidants, and cancer chemopreventive agents
• Xanthoproteic Test


  1. Tests for presence of aromatic amino acids (proteins containing aromatic rings)

  2. Indication of positive results: Formation of yellow color upon the addition of concentrated nitric acid

  3. Principle: Nitration of aromatic rings in amino acids or proteins by concentrated nitric acid leads to the formation of yellow-colored nitro compounds, indicating the presence of aromatic amino acids or proteins
• Wagner's Test


  1. Tests for presence of alkaloids

  2. Indication of positive results: Formation of a brownish-red precipitate

  3. Principle: Wagner's reagent (iodine in potassium iodide) reacts with alkaloids to form insoluble iodine-alkaloid complexes, leading to the formation of the precipitate
• Concentrated Sulfuric Acid Test

  1. Tests for presence of flavonoids

  2. Indication of positive results: Formation of various color changes (typically ranging from yellow to orange to red) depending on the specific flavonoid present

  3. Principle: Flavonoids contain phenolic structures that can undergo dehydration and oxidation reactions when treated with concentrated sulfuric acid, leading to the formation of various colored compounds
• Gelatin Test


  1. Tests for presence of tannins

  2. Indication of positive results: Formation of a white precipitate

  3. Principle: Tannins can form insoluble complexes with proteins such as gelatin, resulting in the formation of a precipitate
• Sodium Hydroxide Test


  1. Tests for presence of flavonoids

  2. Indication of positive results: Yellow coloration

  3. Principle: Flavonoids react with sodium hydroxide to produce yellow coloration due to the presence of conjugated double bonds in their structure
• Salkowski Test


  1. Tests for presence of terpenoids or steroids

  2. Indication of positive results: Development of a reddish-brown coloration

  3. Principle: The reaction involves the formation of a complex between the terpenoids/steroids and sulfuric acid, leading to the development of the characteristic color
• Keller-Killiani Test


  1. Tests for presence of glycosides, particularly cardiac glycosides

  2. Indication of positive results: Formation of red color

  3. Principle: The reagent (glacial acetic acid and concentrated sulfuric acid) reacts with cardiac glycosides to produce a red color due to the presence of sugar moieties in the glycoside molecule
• Frothing Test


  1. Tests for presence of saponins

  2. Indication of positive results: Formation of froth upon shaking

  3. Principle: Saponins can form stable foam when shaken vigorously due to their amphiphilic nature, which can allow them to interact with water and trap air bubbles