สารบัญ

Thai name น้ำมันเทียนตาตั๊กแตน (NAM MAN THIAN TA TAKKATAEN)

Category Carminative.

Definition Dill Oil is obtained by distillation from the dried ripe fruits of Anethum graveolens L. (Family Apiaceae).  It contains not less than 43.0 per cent w/w and not more than 63.0 per cent w/w of carvone (C₁₀H₁₄O).

Origin of plant  Dill Oil-yielding plant is native to North Africa, Republic of Chad, Iran, Arabian Peninsula, eastern Mediterranean, and western Asia.

Constituents Dill Oil contains predominantly carvone, limonene, and dill apiole. It also contains fatty acids, mainly oleaic acid, linoleic acid, and capric acid. Other major constituents found are phenolic acids, e.g., caffeic, p-coumaric, vanillic acids, etc.

Description Colourless or pale yellow liquid which becomes yellowish brown on storage; odour, characteristic of the crushed fruit.

Solubility test  Soluble, at 20, in 1 volume of ethanol (90 per cent) and in 10 volumes of ethanol (80 per cent).

Packaging and storage Dill Oil shall be kept in well-filled, well-closed containers, protected from light, and stored at a temperature not exceeding 25.  It darkens in colour on storage.

Weight per milliliter 0.895 to 0.910 g (Appendix 4.9).

Optical rotation +70 to +80, at 20 (Appendix 4.8).

Refractive index 1.481 to 1.492, at 20 (Appendix 4.7).

Assay  To about 1.5 g of Dill Oil, accurately weighed, in a glass-stoppered tube approximately 25 mm in diameter and 150 mm long add 10 ml of hydroxylamine in ethanol (90 per cent) TS. Titrate with 1 M potassium hydroxide in ethanol (90 per cent) VS until the red colour changes to yellow.  Place the tube in a water-bath at 75 to 80 and, at 5-minute intervals, neutralize with 1 M potassium hydroxide in ethanol (90 per cent) VS; after 40 minutes complete the titration to the full yellow colour of the indicator.  This procedure gives an approximate value for the carvone content of the oil.

      Repeat this procedure, using as the colour standard for the end-point of the titration the titrated liquid of the first determination with the addition of 0.5 ml of 1 M potassium hydroxide in ethanol (90 per cent) VS.  Calculate the content of carvone from the second determination. Each ml of 1 M potassium hydroxide in ethanol (90 per cent) VS is equivalent 151.4 mg of carvone (C₁₀H₁₄O).