Indian Journal of Pharmacology, Vol. 39, No. 2, March-April, 2007, pp. 119-120
Mast cell stabilization property of Coleus aromaticus leaf extract in rat peritoneal mast cells
Kumar A, Elango K, Markanday S, Undhad CV, Kotadiya AV, Savaliya BM, Vyas DN, Datta D
TIFAC CORE in Herbal Drugs, JSS College of Pharmacy, Ootacamund - 643 001
Code Number: ph07029
Coleus aromaticus Benth ., (Lamiaceae), syn. Coleus amboinicus (Lour.) Spreng. or Plectranthus ambonicus Lour, is commonly known as Indian / country borage. It is a large succulent herb with aromatic leaves, found abundantly in India. The leaves of this plant are traditionally used for the treatment of severe bronchitis, asthma, diarrhea, epilepsy, renal and vesicle calculi and fever.  C. aromaticus has been reported to exhibit antilithiotic,  chemopreventive,  antiepileptic  and antioxidant  properties. The present study was undertaken to evaluate the mast cell stabilization property of the leaf extract in rat mesentery.
The aerial part of C. aromaticus consisting of the leaves were obtained from M/S. Arya Vaidya Sala, Kottakal and authenticated by the Department of Pharmacognosy of this institute. The leaves were washed properly and cut into small pieces before being subjected to cold maceration for seven days. The solvents used for aqueous and hydroalcoholic extraction were distilled water and 50% v/v ethanol in distilled water respectively. After seven days, the aqueous and hydroalcoholic macerates were filtered through muslin cloth and concentrated using a rotary evaporator. The concentrated extracts were freeze-dried to provide dry aqueous (1.2% w/w) and hydroalcoholic (0.9% w/w) extracts. Approval was obtained from IAEC before conducting the studies.
Three to four overnight-fasted male Wistar rats (200-250 g) were sacrificed with an overdose of anesthetic ether. The abdomen was cut open to expose the intestine. Pieces of mesentery with connecting lobes of fat and blood vessels were rapidly dissected out and small pieces of the mesentery were cut and placed in beakers for 30 ± 1 min. These beakers contained Ringer Locke (in mM: NaCl 154, KCl 5.6, CaCl 2 2.2, NaHCO 3 6.0 and dextrose 5.5) solution with different concentrations of C. aromaticus extracts. Later, the tissues were exposed to Compound 48/80 (C 48/80 at 0.8 µg/ml to promote mast cell degranulation)  and the tissues were incubated further for 30 ± 1 min. The pieces of mesentery were then removed and placed on clean slides. Excess fatty layers and adhering small intestine tissues were carefully removed. The trimmed tissue was dipped in 4% formaldehyde solution containing 0.1% toludine blue for 20-30 min and the tissue was then washed in acetone and then xylene (2 changes each) for 5 ± 1 min each wash.
The stained mesentery pieces were viewed through a digital light microscope (M/S. Motic, Korea) at 100x magnification and 100 mast cells were counted. The number of intact and fragmented or disrupted mast cells was noted. A mast cell was considered disrupted if four or five granules were found around the mast cells. The percentages of fragmented or disrupted mast cells as well as of the intact mast cells were tabulated 7 . Six pieces of mesentery were used for each concentration of the test substance (leaf extract). Values were expressed as mean ± SE. The values were statistically analyzed using One-Way Analysis of Variance (ANOVA) followed by Tunkey's multiple comparison test. P values < 0.5 were considered to be statistically significant. The analysis was carried out using GraphPad Prism software V.4.
C 48/80, a known mast cell degranulating agent, produced a significant ( P < 0.001) reduction in intact rat mesenteric mast cells, 14.7 ± 2.2, when compared to the mesentery exposed to the vehicle, Ringer Locke`s solution, alone, 81.5 ± 3.4. Concentrations of 10 and 100 µg/ml of both the aqueous and hydroalcoholic extracts of C. aromaticus produced dose-dependent and significant ( P < 0.001) increases in the numbers of intact mast cells when compared to C 48/80-treated tissues [Figure - 1]. Based on these results, it could be suggested that Coleus aromaticus stabilizes mast cells in the rat mesenteric tissue. As mast cells play a major role in Type I hypersensitivity-mediated diseases like allergic asthma and rhinitis,  studies are under way to evaluate the efficacy of Coleus aromaticus due to its mast stabilization property in these animal allergic models.
Copyright 2007 - Indian Journal of Pharmacology
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