|This article does not cite any references or sources. (November 2006)|
Phytochemistry is in the strict sense of the word the study of phytochemicals. These are chemicals derived from plants. In a narrower sense the terms are often used to describe the large number of secondary metabolic compounds found in plants. Many of these are known to provide protection against insect attacks and plant diseases. They also exhibit a number of protective functions for human consumers.
Phytochemistry can be considered sub-fields of Botany or Chemistry. Activities can be led in botanical gardens or in the wild with the aid of Ethnobotany. The applications of the discipline can be for Pharmacognosy, or the discovery of new drugs, or as an aid for plant physiology studies.
Techniques commonly used in the field of phytochemistry are extraction, isolation and structural elucidation (MS,1D and 2D NMR) of natural products, as well as various chromatography techniques (MPLC, HPLC, LC-MS).
Constituent elements 
The list of simple elements of which plants are primarily constructed—carbon, oxygen, hydrogen, calcium, phosphorus, etc.—is not different from similar lists for animals, fungi, or even bacteria. The fundamental atomic components of plants are the same as for all life; only the details of the way in which they are assembled differs.
The following tables list element nutrients essential to plants. Uses within plants are generalized.
|Element||Form of uptake||Notes|
|Nitrogen||NO3– NH4+||Nucleic acids, proteins, hormones, etc.|
|Oxygen||O2 H2O||Various organic compounds|
|Carbon||CO2||Various organic compounds|
|Hydrogen||H2O||Various organic compounds|
|Potassium||K+||Cofactor in protein synthesis, water balance, etc.|
|Calcium||Ca2+||Membrane synthesis and stabilization|
|Magnesium||Mg2+||Element essential for chlorophyll|
|Phosphorus||H2PO4–||Nucleic acids, phospholipids, ATP|
|Sulfur||SO42–||Constituent of proteins and coenzymes|
|Element||Form of uptake||Notes|
|Chlorine||Cl-||Aids in root growth|
|Boron||H BO3||Affects reproduction|
|Manganese||Mn2+||Activity of some enzymes|
|Zinc||Zn2+||Involved in the synthesis of enzymes and chlorophyll|
|Copper||Cu+||Enzymes for lignin synthesis|
|Molybdenum||MoO42-||Nitrogen fixation, reduction of nitrates|
|Nickel||Ni2+||Enzymatic cofactor in the metabolism of nitrogen compounds|
Eastern medicine 
Phytochemical technique mainly applies to the quality control of Chinese medicine, Ayurvedic medicine(Indian traditional medicine) or herbal medicine of various chemical components, such as saponins, alkaloids, volatile oils, flavonoids and anthraquinones. In the development of rapid and reproducible analytical techniques, the combination of HPLC with different detectors, such as diode array detector (DAD), refractive index detector (RID), evaporative light scattering detector (ELSD) and mass spectrometric detector (MSD), has been widely developed.
In most cases, biologically active compounds in Chinese medicine, Ayurvedic Medicine(Indian Herbal Medicine) or herbal medicine have not been determined. Therefore, it is important to use the phytochemical methods to screen and analyze bioactive components, not only for the quality control of crude drugs, but also for the elucidation of their therapeutic mechanisms. Modern pharmacological studies indicate that binding to receptors or ion channels on cell membranes is the first step of some drug actions. A new method in phytochemistry called biochromatography has been developed. This method combines human red cell membrane extraction and high performance liquid chromatography to screen potential active components in Chinese medicine.