Pharmacognosy is the study of medicines from natural sources. The American Society of Pharmacognosy defines pharmacognosy as "the study of the physical, chemical, biochemical and biological properties of drugs, drug substances or potential drugs or drug substances of natural origin as well as the search for new drugs from natural sources".
The word "Pharmacognosy" derives from the Greek words pharmakon (drug), and gnosis or knowledge. The term was used for the first time by the Austrian physician Schmidt in 1811. Originally - during the 19th century and the beginning of the 20th century - pharmacognosy was used to define the branch of medicine or of commodity sciences ("Warenkunde" in German), which dealt with drugs in their crude, or unprepared, form.
A "crude drug" means a dried unprepared natural material of plant, animal or mineral origin, which is used for medicine. The term drug derives from the Lower Saxon/Dutch "Droog", which means "dried" as in dried herbs (and has little to do with the modern pharmaceutical meaning of the term). The term "Pharmakognosie" and it discipline developed in German speaking areas of Europe - where it is a synonym of "Drogenkunde" ("science of the crude drugs").
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 is widely used in the field of Chinese medicine especially in the field of herbal medicine.
Techniques commonly using in the field of phytochemistry are extraction, Isolation and structural elucidation (MS,1Dand 2D NMR) of natural products, as well as various chromatography techniques (MPLC, HPLC, LC-MS). Phytochemical technique mainly applies to the quality control of Chinese 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.