PHARMACOLOGY

 GLYCOSIDES ::

These are complex plant principles of organic nature They have different subnames (e.g. glucoside galactoside etc) according to the sugar they contain when they are made to combine with a non sugar component they are known as aglycones or genins Their molecules have C,O,H and some glycosides also contain sulphur and nitrogen 

Glycosides are generally water soluble colourless compounds some of them being optically active 

Glycosides of medicinal importance are digoxin digitoxin and gitoxin from the cardiotonic digitals rhein of the anthracene group from rhubarb and aloin from aloes both being purgatives 

OILS ::

The term oil is applied to a large number of liquids which are insoluble in water and highly viscous oils are of two kinds 

(a) Volatile oils ::

volatile oils are liquids that impart an aroma to a plant and are volatilzed by heat they evaporate and leave no greasy stain Because of their pleasant odour and taste they are frequently used as flavouring agents Examples are peppermint spearmint and clove oil oil of wintergreen ad almost pure methyl salicylate used locally for relief of muscle and joint pains 

(b) Fixed oils ::

Fixed oils are the glycerides of oleic palmitic and stearic acids Fixed oils of vegetable origin include olive oil castor oil croton oil and peamit oil fixed oils of animal origin are cod liver oil shark liver oil lard and butter fixed oils do not exert marked pharmacological activity Olive oil and cotton seed oil are used as food of high calorific value Fats are fixed oils which remain solid at ordinary temperature 

    waxes are composed of fatty acids combined with monohydric alcohol They are more firm with a higher melting point and are mostly used as ointment bases The term lipids includes fixed oils fats and waxes minerals oils are mixture of hydrocarbons of the methane and related aliphatic series obtained from petroleum by fractional distillation They are produced in various consistencies hard paraffin soft paraffin and liquid paraffin The first two are used as ointment bases and liquid paraffin is used as a laxative