Aqueous Extracts Of Cotton Bracts Research Articles

Tannin inhibits cAMP pathways in bovine airway epithelium.

Tannin, isolated from aqueous extracts of cotton bracts, inhibits chloride secretion in airway epithelial cells. The effect of tannin on the epinephrine- and bradykinin-stimulated rise in intracellular free calcium and cyclic adenosine monophosphate (cAMP) was examined using bovine tracheal epithelial cells in suspension and culture. Basal intracellular calcium levels were 33 +/- 11 nM (mean +/- SEM, n = 54) and increased 13- to 15-fold after addition of epinephrine (10(-6) M) or bradykinin (2 x 10(-6) M). Tannin pretreatment blunted the subsequent response to epinephrine beginning at a tannin concentration of 10 micrograms/ml. Pretreatment with 100 micrograms/ml tannin completely inhibited the rise in intracellular free calcium in response to epinephrine but had no effect on the calcium response to bradykinin. In the absence of tannin, both bradykinin and epinephrine increased intracellular levels of cAMP. At a tannin concentration of 10 micrograms/ml, tannin inhibited the rise in intracellular cAMP in cells stimulated with either epinephrine or bradykinin but had no effect on bradykinin-stimulated prostaglandin E2 release. Tannin alone (10 micrograms/ml) increased prostaglandin E2 release. In other studies, tannin inhibited epinephrine binding to airway epithelial cells in a dose-dependent manner. R(o) decreased from 948 +/- 69 fmol/mg protein under control conditions (n = 4) to 587 +/- 131 fmol/mg protein in the presence of 25 micrograms/ml tannin (n = 3). Tannin had no effect upon the Kd for epinephrine binding (132 +/- 12 pM). Tannin had no effect on bradykinin binding to airway epithelial cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of tannins from different sources on airway epithelial and platelet function

The uniqueness of tannin isolated from aqueous extracts of cotton bracts (CBE) on the electrophysiological and ion transport properties of the canine tracheal epithelium and on 5-hydroxytryptamine (5-HT) release from platelets was investigated. The effect of CBE from Deltapine 41 cotton picked before (green, containing high-concentration, high-molecular-weight tannin) and after (brown, containing low-concentration, low-molecular-weight tannin) senescence and Darjeeling tea extracts and tannin isolated from Darjeeling tea were compared to the effects of Acala SJ-2 CBE and Acala SJ-2 tannin. Green Deltapine 41 CBE was similar to Acala SJ-2 CBE in decreasing short-circuit current (Isc) and net chloride secretion and in producing a dose-response release of 5-HT from platelets. Both Green and Brown Deltapine 41 CBE altered the paracellular pathway, but were less potent than Acala SJ-2 CBE. Brown Deltapine 41 CBE stimulated chloride transport in the airway epithelium and did not produce 5-HT release from human platelets. Darjeeling tea and tea tannin increased Isc and net chloride secretion and caused 5-HT release from platelets only at high concentrations. These studies demonstrate that all tannins are not alike; they suggest that molecular weight and concentration may be important for tannin activity and that the tannin in cotton bracts extract may be unique to cotton in its effect on the airway epithelium and on platelets.

Changes in the levels of bioactive components of cotton bracts accompanying senescence.

A series of bracts from Deltapine 41 variety cotton were harvested weekly from October 16 through November 25, 1982, and examined for changes in biologically active components accompanying senescence. Aqueous extracts of cotton bracts (CBE) were tested for their ability to cause 5-hydroxytryptamine (5-HT) release from human platelets and contraction of isolated canine tracheal smooth muscle (TSM). In addition, the amounts of soluble tannins (the platelet-activating factor found in CBE) and endotoxin were determined for each CBE. The amount of CBE decreased significantly from October 16 through November 25, whereas endotoxin levels rose dramatically from October 23 to November 6 and declined thereafter. The amount of soluble tannin and platelet 5-HT release both decreased from highs on October 23 to unmeasurable levels on November 25. Smooth muscle contraction was attributed to two primary factors contained in CBE. The major constrictor was a 5-HT receptor agonist and its levels remained stable from October 16 through October 30, but then decreased to unmeasurable levels by November 13. In contrast, CBE also contained lesser amounts of an acetylcholine receptor agonist whose levels paralleled the changes in endotoxin levels. We conclude that several important biochemical changes occur in cotton bracts during senescence and that these changes profoundly influence their biological activity in various assays.

Airway constrictor response to cotton bract extracts in the absence of endotoxin.

Crude and purified aqueous extracts of cotton bracts shown to cause airway constriction in naive subjects were assayed for endotoxin content. Pulmonary function measured by flow changes on partial expiratory flow volume curves was used to assess airway responses to the bract extracts after their inhalation by a panel of volunteers. These responses are similar to the acute responses experienced by cotton textile workers. Crude aqueous extracts from various bracts harvested before and after senescence of the cotton plant displayed endotoxin concentrations ranging widely from 0.086 to 50 micrograms/ml. No correlation was found between these differences in endotoxin content and the severity of the airway constrictor response. Purifying the bract extract by a series of procedures that included precipitation of polymeric material by addition of methanol and chromatography on an anion exchange column of DEAE-Sephacel resulted in the elimination of almost all the endotoxin. The partially purified extract contained less than 1 ng/ml of endotoxin. The panel of volunteers responded to this purified bract extract, however, with a decrease in pulmonary function which was more than 60% of that seen with the crude extract of bracts. It is concluded that aqueous extracts of cotton bract contain an agent(s) other than endotoxin that causes acute airway constriction in people.

Biologic Activity of Purified Cotton Bract Extracts in Man and Guinea Pig

Purified aqueous extracts of cotton bract induce acute airway constriction in healthy volunteers never before exposed to cotton bract. The response is similar to that of textile workers who inhale cotton dust. Approximately 60% of volunteers respond to bract extract with significant decreases in lung function, and these volunteers show an increased number of lymphocytes present in their lungs. Following inhalation of bract, the percent of polymorphonuclear leukocytes increases. Macrophages obtained by bronchoalveolar lavage from volunteers pre-challenged with bract extract release increased amounts of chemotactic factor and superoxide anion. Efforts to detect release of histamine and leukotrienes in volunteers following challenge with bract show no increase in urinary histamine and no significant release of leukotrienes in lung lavage fluid. Purified extracts exhibit chemotactic activity in vitro. They also contract guinea pig ileal longitudinal muscle in vitro. This preparation contains mast cells but no basophils, and the H-1 blocker, mepyramine blocks the contraction. Purified bract extracts contain no histamine or endotoxin but other contractors of smooth muscle may be present. The purified extract exhibits spectral, fluorescent, and radioimmune assay properties similar to a leukotriene B-like component. Cotton bract appears to have direct as well as cell-mediated activities.

Biologic activity of purified cotton bract extracts in man and guinea pig.

Purified aqueous extracts of cotton bract induce acute airway constriction in healthy volunteers never before exposed to cotton bract. The response is similar to that of textile workers who inhale cotton dust. Approximately 60% of volunteers respond to bract extract with significant decreases in lung function, and these volunteers show an increased number of lymphocytes present in their lungs. Following inhalation of bract, the percent of polymorphonuclear leukocytes increases. Macrophages obtained by bronchoalveolar lavage from volunteers pre-challenged with bract extract release increased amounts of chemotactic factor and superoxide anion. Efforts to detect release of histamine and leukotrienes in volunteers following challenge with bract show no increase in urinary histamine and no significant release of leukotrienes in lung lavage fluid. Purified extracts exhibit chemotactic activity in vitro. They also contract guinea pig ileal longitudinal muscle in vitro. This preparation contains mast cells but no basophils, and the H-1 blocker, mepyramine blocks the contraction. Purified bract extracts contain no histamine or endotoxin but other contractors of smooth muscle may be present. The purified extract exhibits spectral, fluorescent, and radioimmune assay properties similar to a leukotriene B-like component. Cotton bract appears to have direct as well as cell-mediated activities.

Quantitative Determination of Indole-3 Carboxyaldehyde in Aqueous Extracts of Cotton Bracts by HPLC

A reverse phase, high performance liquid chromatbgraphy procedure for the quantification of indole-3 carboxyaldehyde in aqueous extracts of cotton bract is described. The amount of indole-3 carboxyaldehyde that could be extracted by water was 14.3 and 14.1 ppm in frost-killed (brown) and air dried green cotton bract, respectively.

Characterisation of textile dust extracts: II. Bronchoconstriction in man.

Aqueous extracts of cotton bracts induce a concentration dependent decrease in flow rates on partial expiratory flow volume curves. It has been shown that the active substance(s) is stable to moderate heat and to acid or alkaline conditions. Results of dialysis and gel filtration suggest that the active component(s) has a molecular size of about 1000 daltons. The component(s) is not absorbed on to ion exchange resins but is readily removed from aqueous extract by activated charcoal. The bronchoconstrictor agent cannot be steam distilled or extracted by ether. It is readily soluble in water; a single extraction of bracts removes all biologically active material. It is proposed that healthy subjects, responsive to cotton bracts extract, can be used qualitatively to fractionate and quantitatively to assay the active substance(s) in this material.

Quantitative Determination of Scopoletin and Lacinilene C 7-Methyl Ether in Aqueous Extracts of Frost-Killed Cotton Leaf and Bract by HPLC

A high-performance liquid chromatography procedure for the separation and quan tification of scopoletin and lacinilene C 7-methyl ether in aqueous extracts of cotton bract and leaf was developed. A procedure involving an aqueous extraction followed by an ethanol extraction is described. The amounts of scopoletin present in frost- killed bract and leaf which could be extracted with water were 22.6 ppm and 21.6 ppm, respectively. The amounts of lacinilene C 7-methyl ether present in, and water extractable from, frost-killed cotton bract and leaf were 17.8 ppm and 17.6 ppm, respectively. Samples of cotton bract and leaf picked before a frost were also examined. The amounts of lacinilene C 7-methyl ether present in cotton bract and leaf appear to be dependent on the physiological state of the plant. The amount of scopoletin present in the samples picked before a frost could not be determined due to insufficient resolution in the vicinity of the scopoletin peak in the HPLC chromatograms.

Effects of aqueous extracts of cotton bract on isolated mast cells: a bioassay for byssinosis.

Mast cell degranulation, with its release of histamine and other bioreactive compounds, has been strongly implicated in the acute symptoms noted in mill workers following inspiration of cotton or flax textile dusts. This paper describes a method for the isolation and stimulation of these cells and methods for the quantitation of their degranulation.

Immune Mechanisms in Byssinosis

The pathogenesis of byssinosis has been attributed to several different immunopathologic mechanisms, including a type III (immune complex) pulmonary injury. To further examine this type III theory, sera (Monday preshift) from 59 cotton textile workers were examined by gel diffusion and counterimmunoelectrophoresis for precipitating antibodies to aqueous extracts of cotton bract, carpels, stems, leaves, immature cotton bract, carpels, stems, leaves, immature cotton lint, and cardroom cotton dust. Sera were also collected from 35 nonexposed normal volunteers and examined similarly. No true precipitating antibodies to these extracts could be detected in any of the control or worker serum samples. The aqueous extracts of cardroom cotton dust and cotton stems were found to contain naturally occurring components that precipitated (in agarose gel) beta-lipoprotein and gamma-globulins (mostly IgG) in a nonimmunologic manner. Sera from normal human controls and cotton textile workers all produced identical patterns of reaction with these two extracts. Treatment of these extracts with polyvinylpolypyrrolidone, a specific insoluble adsorbent for polyphenolic tannins, eliminated this pseudoimmune reaction. Although the role this pseudoimmune reaction may play in the pathogenesis of byssinosis is still unknown, it demonstrates the problems associated with laboratory-based investigations of the immunologic aspects of byssinosis.

Byssinosis: Airway constrictor response to cotton bracts

Inhalation of aqueous extracts of cotton bracts by healthy human volunteers induces reversible lung function changes and symptoms similar to those experienced by cotton textile workers with byssinosis. This airway constrictor response, maximal after 90–120 min, occurred in 95 out of 105 volunteers. This explains why byssinosis is highly prevalent under adverse conditions in cotton textile mills. The airway constrictor activity is retained in purified extracts of the cotton bracts which contain a small molecular (< 1,000 daltons), watersoluble, heat-stable compound.

Inhibition of luminol-dependent chemiluminescence of alveolar macrophages by possible etiological agents of byssinosis.

Aqueous extracts of cotton bracts inhibited luminol-dependent chemiluminescence of phagocytosing alveolar macrophages. The inhibitory compounds were partitioned into organic solvents. Chromotographic analysis indicated that these compounds were either lacinilene C or its 7-methyl ether and scopoletin. The fact that the inhibitory activity of these compounds was always less than that of the total extract suggests synergistic action. These compounds may function as etiological agents of byssinosis.