Download as PDF, PPTX
volatile oil 4 3.pdffffffffffffffffffff
- 1. PHYTOCHEMISTRY I VOLATILE OILS DR.YASMIN A. MAHGOUB, PhD. Lecturer Of Pharmacognosy Alexandria University
- 2. Chemistry of volatileoils Volatile oil constituents Terpenes Terpenoids Alcohols Aldehydes Esters Ketones Phenols Phenolic ethers Oxides Peroxides Aromatic compounds Nitrogen compounds Sulphur compounds Lactones
- 3.
- 4. Ketones 4 1- Monocyclic monoterpeneketones: Menthone Source: Peppermint oil. Uses: Used extensively in the manufacture of flavoring materials. Carvone Source: Oil of caraway. Uses: Used for flavoring of food products & beverages, in addition to mouth preparations, gargles and toothpastes.
- 5. Diosphenol Buchu camphor Has camphor-likeodor Source: Oil of Buchu. Uses: ✓ Leaves of buchu are used as herbal teas for treating kidney disorders as well as other problems of the urinary bladder (Diuretic). ✓ Diosphenol is an enolic compound (keto-enol transformation); soluble in dilute aqueous alkali and giving an intense green color with alcoholic FeCI3. Ketones 1- Monocyclic monoterpene ketones:
- 6. Camphor Source: Wood and leavesof the camphor tree. Uses: Locally camphor is rubefacient. Camphorated Opium tincture has antidiarrheal and analgesic properties. 6 2- Bicyclic monoterpene ketones: ✓ Most of the camphor of commerce is obtained synthetically from the α-pinene. ✓ Synthetic camphor is racemic, which contains CI-ions due to the method of preparation. ✓ Test for Cl-indicates its origin, natural or synthetic. Ketones
- 7. Determination of aldehydesand ketones ✓ A measured quantity of the oil is shaken with hot aq. solution of sodium bisulphite, a water-soluble additive compound is formed. ✓ The non-aldehyde portion of the oil separates as an oily layer, which can be measured using a cassia flask (by difference). 1. The bisulphite method:
- 8. Those volatileoils which contain aldehydes in very small amounts, or which contain other constituents that form water-soluble addition products with sodium bisulfite cannot be assayed accurately by these methods. In those cases, aldehydes and ketones are generally determined by the hydroxylamine method. 8 Determination of aldehydes and ketones
- 9. 2. The hydroxylaminehydrochloride method: This method based on reaction of the aldehydes and ketones with hydroxylamine HCl giving the oxime with liberation of HCI equivalent to the aldehyde or ketone content. The liberated HCl could be titrated against alkali. Determination of aldehydes and ketones
- 10. Chemistry of volatileoils Volatile oil constituents Terpenes Terpenoids Alcohols Aldehydes Esters Ketones Phenols Phenolic ethers Oxides Peroxides Aromatic compounds Nitrogen compounds Sulphur compounds Lactones
- 11. Phenols and phenolicethers to be studied Phenols Thymol Eugenol Phenolic ethers Anethole Myristicin Safrole Estragole Phenols • Gives with FeCl3 colored compounds • Weakly acidic. • React with alkali forming water soluble salts. OH Phenolic ethers • With HBr or HI → Phenol • Very stable, neutral compounds. • Not react with alkali. OR
- 12. Phenols Separation of phenols 12 Generalmethods of isolation: ✓ Phenols are sufficiently acidic, form water soluble salts (water soluble phenates) with aqueous fixed alkali solution. ✓ This property is used for separation of phenolic from non-phenolic constituents. Thus, the oil is shaken with aq. fixed alkali, the aqueous layer containing the phenolic content is separated from the oil.
- 13. 13 Thymol Source: Thyme oil. Uses: • Thymolpossesses disinfectant and antibacterial properties, it is used in mouth washes, gargles and other oral preparations. •It used as starting material for preparation of synthetic menthol. Phenols
- 14. 14 Eugenol Source: Oil of clove. Uses: ✓Eugenol is used as a good local antiseptic and analgesic (anesthetic). ✓ It is used in dentist offices to make zinc oxide eugenol paste for temporary fillings. ✓ Eugenol is used for the manufacture of vanillin. Phenols
- 15. ▪ In acassia flask, an accurately measured volume of the oil is shaken vigorously with a portion of aqueous caustic alkali. ▪ Further quantity of the alkali is then added to bring the un-dissolved oil into the graduated neck of the flask. ▪ When the liquid have separated and become clear, the volume of the oil insoluble in alkali is read. ▪ The volume of the phenol being determined by difference. Phenols Determination of phenol content
- 16. Phenolic ethers Anethole Source: Anise andfennel oils. Uses: ✓ Anethole is used widely for flavoring mouthwashes and gargles. ✓ Flavoring in foods and beverages. ✓ Anethole is a phytoestrogen. ✓ Anethole occurs as a white crystalline mass. Under the effect of light, heat or air, anethole losses its ability to crystalize and becomes a viscous yellow liquid. For this reason, anethole must be stored in well closed container away from light.
- 17. 17 Myristicin Source: Oil of Nutmeg. Myristicinis a psychoactive drug (that crosses the blood-brain barrier, where it affects brain function, resulting in alterations in mood, cognition, behavior and consciousness). Phenolic ethers
- 18. Safrole Source: Sassafras oil. Uses: Flavoring forbeverages and pharmaceutical preparations. ✓ It was banned by FDA after discovery of its carcinogenicity and hepatotoxicity in rats. ✓ Today, safrole is also banned for use in soap and perfumes by the International Fragrance Association. Phenolic ethers
- 19. Estragole Source: fennel oil. Uses: In perfumesand as a food additive ✓ Estragole is suspected to be carcinogenic and mutagenic for children, as indicated by a report of the European Union, Committee on Herbal Medicine Products. ✓ It is an isomer of anethole ,differ in the location of the double bond. Phenolic ethers
- 20. Oxides Cineole (Eucalyptol) Source: Oil ofEucalyptus. Uses: ✓ Cineole is used internally as an expectorant. ✓ Locally it is employed for its rubefacient effect. Determination or cineole: It is based on the formation of a solid, loose molecular complex of cineole and phosphoric acid (H3PO4) by the lowering of the freezing-point of the mixture, from which the cineole is regenerated by the addition of hot water. The volume of cineole liberated is measured in cassia flask.
- 21. Peroxides 21 Ascaridole Source: Chenopodium oil. Uses: Itis used as anthelmintic, particularly useful against hookworm and roundworm. Determination of ascaridole (Iodometrically) The method is based on the oxidizing action of the peroxide on acidified solution of KI and titration of the liberated iodine with sodium thiosulphate.
- 22. Chemistry of volatileoils Volatile oil constituents Terpenes Terpenoids Alcohols Aldehydes Esters Ketones Phenols Phenolic ethers Oxides Peroxides Aromatic compounds Phenyl propanoid Derivatives (C6-C3) Nitrogen compounds Sulphur compounds Lactones
- 23. How are thephenyl propanoid compounds synthesized inside the plant? 23 They are synthesized via the Shikimic acid pathway. The principal precursors for compounds (C6 - C3) are cinnamic acid and p- hydroxycinnamic acid. In some cases, the side chain may be C1 or C2 to give structure (C6 - C1) or (C6 - C2). Phenyl propanoid components of volatile oil
- 24. Chemistry of volatileoils Volatile oil constituents Terpenes Terpenoids Alcohols Aldehydes Esters Ketones Phenols Phenolic ethers Oxides Peroxides Aromatic compounds Nitrogen compounds Sulphur compounds Lactones
- 25. Nitrogen compounds Indole Skatole It iswidely used, but in traces, for the compounding of perfumes as a fixative.
- 26. Sulphides occur quitefrequently in plants, probably in the form of glycosides which are decomposed by the process of distillation. Allylisothiocyanate CH2=CH-CH2-N=C=S Source: It occurs in glycosidal combination as sinigrin in the seeds of black mustard. Uses: It is used externally in some pharmaceutical preparations e.g. plasters, as rubefacient. Sulphur compounds
- 27. Lactones 27 Bergaptene Source: Ammi majus fruits. Uses: Bergaptene is used for treatment of Leukoderma. (localized loss of pigmentation of the skin) It possesses photosensitizing effect. (Methoxy furanocoumarin)