Year : 1979 | Volume
: 27 | Issue : 4 | Page : 56--58
Effect of nutmeg on prostaglandin biosynthesis of eye tissues
Veena Misra, WG Unger, RN Mishra
District Hospital, Agra, India
B-1, District Hospital Campus, Agra
|How to cite this article:|
Misra V, Unger W G, Mishra R N. Effect of nutmeg on prostaglandin biosynthesis of eye tissues.Indian J Ophthalmol 1979;27:56-58
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Misra V, Unger W G, Mishra R N. Effect of nutmeg on prostaglandin biosynthesis of eye tissues. Indian J Ophthalmol [serial online] 1979 [cited 2020 Jun 3 ];27:56-58
Available from: http://www.ijo.in/text.asp?1979/27/4/56/32576
Prostaglandins (Pgs) have long been associated with the response of the rabbit eye to chemical or mechanical irritation resulting in prolonged miosis, vasodilatation, increased capillary permeability and sustained rise in intra ocular presence Pgs are formed chiefly by the tissues of iris and ciliary body. Pgs, has been isolated from sheep iris and Prostaglandin F 2 and E 2 have been identified in cat and rabbit iris. Indomethacin by acting as a Pg synthatase inhibitor prevented the Pg like activity in aqueous humour and considerably reduced the increased intra ocular presence produced by Pgs and be of value as ocular anti-inflammatory agents.
Recently, nutmeg, the dried kernels of the seeds of myristica fragrans, have been shown to act as an inhibitor of Pg biosynthesis in isolated colonic mucosa'. Not much work has been done to study its inhibitory effect on Pg biosynthesis in various tissues of body. The present study deals with fractioning nutmeg and to explore the Pg inhibitory effect of nutmeg and its various fractions on eye tissues. The study was conducted in the department of physiology, institute of ophthamology, London.
Materials and Methods
Investigation was chiefly carried out in two parts. In the first part, rats weighing 80 to 100 Gms. Were divided in three main groups of 10 rats each. Group I of the normal rats which served as control were kept strictly on laboratory diet for 10 days. Rats of the second group (Group II) received ground nutmeg 40 mg. twice daily and those of Group III received indomethacin 10 mg. daily subcutaneously in the morning. After 10 days, all rats were sacrificed and prostaglandins was bioassayed on eyes of rats. All the eye structures except lens were used for estimating prostaglandins. The second part of the investigation chiefly consisted of:
1. Chemical extraction of active constituents of nutmeg.
2. Fractionation of the above extract in six different fractions and estimating the Pg inhibitory effect of each fraction.
3. Refractionation in silicic acid column of the particular fraction having maximum inhibitory effect on Pg biosynthesis.
For chemical extraction, 25 gms. of powdered nutmeg was extracted five times at room temperature with a mixture of chloroform and ethanol (2:1), 50 ml. each time. The above obtained extracts were mixed and dried together in a thin film evaporator at room temperature. This procedure ensured a complete extraction of active components of nutmeg.
Six different fractions were obtained from the above extract by treating it subsequently with petroleum, Ether, benzene, chloroform, acetone, methanol and water 100 ml each separately and labelled as Fr. I, II, III, IV, V&VI.
Fraction I, having maximum inhibitory effect on Pg biosynthesis was further subfractioned in silicic acid column. Seven subfractions were obtained by treating with different percentage combination of petroleum. ether, benzene, chloroform and methanol. Subfractions were labelled as S. Fr. A,B,C,D,E,F & G. Weight and physical properties of each fraction and subfraction were observed.
For extraction of prostaglandins, rats belonging to the first part of the experiment and also the normal rats on which Pg inhibitory effect of various fractions and subfractions to be measured were stunned to death. Both eyes were taken out quickly.
Pgs were assayed against PgE 2 on rat's stomach strip suspended in organ bath.
First set of experiment suggsted that rats of gp. ii & iii which were given nutmeg orally and indomethacin subcutaneously respectively showed marked inhibition of Pg biosynthesis, compared to controlled group (gp. i). It was observed that petroleum ether fraction (fr. i), which is yellowish white solid at room temperature, insoluble in water but soluble in fat solvent had maximum Pg inhibitory activity of which subfraction obtained by further fractionation of Fr. I in silicic acid column with benzene and chloroform mixture had maximum Pg inhibitory effect.
Prostaglandins like in other tissues of body have also been isolated from sheep iris, besides this, large amount of Pgs like material is present in various inflammatory conditions of eye resulting from chemical or mechanical irritation of eyes.
Nutmeg, which consist of dried kernels of the seeds of mystica fragrance (Myristicacae) contains not less than 5% v/w of volatile oils. It also contains 35% of solid fat, the chief fatty acid constituents are myristic acid (60%), palmatic, oleic linolic and lauric acid.
Bennet et al showed that nutmeg is a potent inhibitor of prostaglandin synthesis in human isolated colonic mucosa and a non selective depressant of the responses of the rat stomach muscle to it. Mishra et al showed that nutmeg and also its fractions can inhibit the Pg biosynthesis in kidney tissue of rats both in vivo and vitro (under publication). Here also our results suggest that it has definite inhibitory effect on prostaglandin biosynthesis on eye tissue of rats when given orally or when its different fractions and subfractions were treated with eye in vitro.
Clinically nutmeg have been tried by Fawell et al in conditions of diarrhoea associated with medullary carcinoma of thyroid when lung metastasis are present. Large amount of Pg like material are present in blood and tumour tissue. The diarrhoea responded to nutmeg and it was suggested that it may act by interfering with the synthesis or action of prostaglandins. In eyes also, it has been shown that prostaglandins are associated with various inflammatory conditions (iritis, iridocyclitis) and clinical symptoms or mechanical irritation of eyes. The beneficial and curative effect of nutmeg in above mentioned conditions merits further support by clinical and experimental study.
Recently, nutmeg has been shown to act as potent inhibitor of prostaglandin biosynthesis. The present study deals with fractioning nutmeg and to explore the inhibitory effect of nutmeg and its various fractions on prostaglandin biosynthesis(l). It was observed that when nutmeg was fed orally to rats it showed marked inhibition of prostaglandin biosynthesis. (2) The petroleum ether fraction (Fr. I) of nutmeg had maximum prostaglandin inhibitory effect.
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