PHYTOCHEMICAL

1. What is phytochemical?
                 Phytochemicals are chemical compounds that occur naturally in plants (phyto means "plant" in Greek). Some are responsible for color and other organoleptic properties, such as the deep purple of blueberries and the smell of garlic. The term is generally used to refer to those chemicals that may have biological significance, for example carotenoids orflavonoids, but are not established as essential nutrients.
2. What is Phytochemical Screening?
              Phytochemical screening is a process of tracing plant constituents. For example you want to found out if a certain plant contains alkaloids (a plant constituent) then, you will be performing a phytochemical screening procedures for alkaloids (in this case mayer's and Wagner's test). There are general plant constituents that can be performed with a standard test. And these are screenig for:  Alkaloids  Saponin glycosides  Cardenolides and Bufadionolides  Flavonoids  Tannins and Polyphenolic compounds  Anthraquinones  Cyanogenic glycosides  Carbohydrates  Fixed oils, Fats, and Volatile oils.-Marian m. elevera.
3. What are the different reagents used in Phytochemical Screening?

4.What are the indicators of the presence of each phytochemical?
SteroidsLibermann – Burchard Reaction: 2 ml extract was mixed with chloroform. To this 1-2 ml acetic anhydride and 2 drops concentrated sulphuric acid were added from the side of test tube. First red, then blue and finally green colour appears.
Lignin-
With alcoholic solution of phloroglucinol and concentrated hydrochloric acid appearance of                  red colour shows the presence of lignin.
Glycosides- Alcoholic extract when made alkaline, shows blue or greenfluorescence.

Terpenoids -    Noller’s test: The substance was warmed with tin and thionyl chloride. Pink                                               coloration indicates the presence of triterpenoids.
Proteins- Appearance of red colour shows the presence of proteins and free amino acids.
Biuret test: Equal volume of 5% solution of sodium hydroxide and 1% copper sulphate were added. Appearance of pink or purple colour indicates the presence of proteins and free amino acids.
Carbohydrates - Appearance of reddish orange precipitate shows the presence of carbohydrates.
Gums and mucilages-About 10ml of various extracts were added separately to 25ml of absolute alcohol with constant stirring and filtered. The precipitate was dried in air and examined for its swelling properties and for the presence of carbohydrates.
Phytoserol- Appearance of bluish green colour shows the presence of phytosterol.
Oils and Fats- Appearance of oil stain on the paper indicates the presence of fixed oil.
Tannins and Phenols- Dilute ferric chloride solution (5%) - violet colour
1% solution of gelatin with 10%NaCl - white precipitate
10% lead acetate solution - white precipitate
Flavanoids-With aqueous solution of sodium hydroxide blue to violet colour (Anthrocyanins), yellow colour (Flavones), yellow to orange (Flavonones).
With concentrated sulphuric acid yellowish orange colour (Anthrocyanins), orange to crimson colour (Flavonones).
Shinoda’s test – the extracts were dissolved in alcohol, to that a piece of magnesium and followed by concentrated hydrochloric acid was added drop wise and heated. Appearance of magenta colour shows the presence of flavonoids.

BACTERIA

What comes into your mind when you heard the the word "bacteria"? When we heard bacteria, the frirst thing that we think is all about dirts and diseases. But what is the true meaning of BACTERIA? The word bacteria is a plural form of bacterium comes from Greek word "bakteria" which means "little stick". Bacteria are microscopic living organisms, usually one-celled that can be found everywhere. They can be dangerous, such as when they cause infections. They can also beneficial to our life, because of their usefulness that can help our daily life. They can be Independent (free living organisms) or Parasites (depend on other organisms for life). They can reproduce by fission.

Bacteria can be classified using GRAM STAIN TEST, who developed by Hans Christian Gram in the 1800s. It is a method for classifying different types of bacteria using a chemical stain and viewing through a microscope. Most bacteria are classified into 2 groups. The Gram-positive and Gram-negative. We classified the bacteria as Gram-positive if it has thick layer of peptidoglycans that can stained purple by the crystal violet dye. so that the bacteria apper purple or blue. While the Gram-negative has thin layer of peptidoglycans, so they cannot retain the crystal viole dye and thus they appear red or pink due to the retention of the counter stain.

Gram-positive bacteria can also cause different diseases. Some of these diseases are Anthrax, Rheumatic fever, Diphtheria, Botulism, Septic sone throat, Boils, Tetanus, Gas gangrene, and Toxic shock syndrome.
Gram-negative can cause many types of infections and are spread to humans in a variety of ways. Several species, including Escherichia coli, are commoncausesof food–borne disease. Vibrio cholerae—thebacteria responsible for cholera—is a waterborne pathogen.Gram-negativebacteria can also cause respiratory infections, such as certain typesof pneumonia,and sexually transmitted diseases, including gonorrhea. Yersinia pestis, theGram-negative bacterium responsible for plague, is transmitted to people through the biteof an infected insect or handling an infected animal.