Pharmacognosy

Deema Nasser Hijjawi

Description

This book discusses the pharmacology and medicinal plants, Pharmacognosy define as: An applied science that deals with the biologic؟ biochemical, and economic features of natural drugs and their constituent, It is؟ study of drugs that original in the plant and animal kingdoms.

Sujets

• PHARMACOLOGY
• Médecine

Informations

• Publié par: Academic for Publishing & Distribution Co.
• Date de parution: 01 janvier 2009
• Nombre de lectures: 9
• EAN13: 9796500016627
• Langue: English
• Poids de l'ouvrage: 1 Mo

Extrait

PHARMACOGNOSY

Dr. Deema Nasser Hijjawi Arabic College ﺔﻴﻘﻴﺒﻄﺘﻟا ءﺎﻘﻠﺒﻟا ﺔﻌﻣﺎﺟ ﺔﻄﺧ ﻖـﻓو بﺎـﺘﻜﻟا

ﻊﻳزﻮﺘﻟاو ﴩﻨﻠﻟ نﻮﻴمدﺎﻛﻷا

 Introduction The term Pharmacognosy was introduced by seydler (medical student) this name is formed from two Greek words pharmakon, drug and gnosis knowledge... Pharmacognosy define as:

An applied science that deals with the biologic, biochemical, and economic features of natural drugs and their constituents.

It is a study of drugs that original in the plant and animal

kingdoms.

Examples:

- Digitalis leaf

- Rauwolfia root

 Isolated

 Glycoside

 Purified

 Alkaloid

Drug constituents can be from: 1.Natural substances. 2.Synthetic substances.

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Digitoxin

Rserpin

Which here identical chemical structure and therapeutic properties... 3.Semisynthetic substances. Not entirely a synthetic process but a chemical modification of a natural product. Crude drug: They are vegetable or animal drugs that consist of natural substances. They have undergone only the processes of collection and drying Preparation of drugs for the commercial market.

1. Collection:

Can occur from cultivated plants or from wild plants.

In the first one our crude drug will be free from

impurities: The proper time of harvesting or collecting is important because the nature and quantity of constituents active principles vary greatly in some

species according to the season. Collect the proper part of plant which contain our active principles.

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Collection can be by hand or cal using mechanical devices. In some drugs where the skillful selection of plan part is important factor like in Digitalis hand collection replace the mechanical one. 2. Drying: By drying a plant material, we remove the moisture to ensure good keeping qualities and to prevent molding, the action of enzymes, action of bacteria. Proper and successful drying involves tow main principles: -Control of temperature (temp). -Regulation of the air flow. -The plant material can be dried either by the sun or by the use of artificial heat… 3. Garbling: It is the final step in the preparation of a crude drug.

It consists of the removal of extraneous matter, such as other parts of plant, dirt, and added adulterants. This step is done during collection, and should be carried out after the drug is dried and before it is packaged.

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4. Packaging, storage and preservation. It is imp, to choose the type of packaging that provide

ample protection to the drug and gives economy of space… Drugs that arelikely to deteriorate from absorbed moisture (digitalis) are packed in moisture-proof cans. Proper storage and preservation are important factors in maintaining a high degree of quality of the

drug... Excessive moisture not only increases the weight of the drug thus reducing the percentages of the active principles, but also favors enzymatic activity and facilitate fungal growth…

Light adversely affects drugs that are highly colored, rendering them unattractive and possibly causing undesirable changes in their active principles. Because high temperatures accelerate all chemical reactions including those involved in delerioration, drugs must always be stored at low temperature the ideal temperature is just above freezing, but since this is impractical in most cases, the warehouse or other

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storage place should be as cool as possible certain drugs, such as the biologics, must be stored at a temperature

between 2º and 8ºc. Therefore, the warehouse should be:

Cool, dark, and well ventilated with dry air. The protection of drug against attacks by insects is an important factor in maintaining safety of the drug.

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 Photosynthesis

An organism acquires their nutrition by one of two major modes:

1. Autotrophic: not totally self- sufficient . However, they are self-feeders. Produce their organic molecules from Co 2 other and inorganic raw materials obtained from environment. 2. Heterotrophs: Unable to make their own food they live on compounds produced by other organisms. They are other-feeding. Plants are autotrophs: The only nutrients they required are Co 2  carbon dioxide from air H 2 o, water and minerals from soil. Plants use light as a source of energy to synthesize organic

substances. We can call them photoautotrophs. Chloroplasts are the site of photosynthesis in plant. All green parts of plants including green stems have chloroplasts.

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The color of the leaf is from chlorophyll green pigment located within the chloroplasts. Co 2 enters the leafs and O 2 exits by way of microscopic pores called Stomata. In plant me have 3 kinds of pigments: chlorophyll a, b, and carotenoids.

Only chlorophyll a can participate directly in the light reactions, which convert solar energy to chemical energy other two pigments can absorb light and

transfer the energy to chlorophyll a. A plant chlorophyll a molecule a long with the other two accessory pigment molecules are locales in the

chloroplast .

 Chlorophyll a has : a) Head called porphyrin ring.  This part is the light absorbing part With Mg atom at the center.

b) Hydrocarbon tail Gire stability to the structure inside the chloroplasts membrane. What exactly happens when chlorophyll absorb light (photons)?  Electrons  é After absorption of a photon chlorophyll molecule

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