Exploring redox imbalance and inflammation for asthma therapy

BACKGROUND

Asthma is a prolonged inflammatory disorder of the airways, that affects an estimated 300 million people worldwide. Asthma is triggered by numerous endogenous and exogenous stimuli with symptoms like wheezing, cough, short of breath, chest tightening, airway obstruction, and hyperreactivity observed in patients.

OBJECTIVE

The review seeks to identify targets of redox imbalance and inflammation that could be explored to create effective treatments for asthma.

METHODS

The methodology involved a search and review of literature relating to asthma pathogenesis, redox homeostasis, and inflammation.

RESULTS

 Eosinophils and neutrophils are involved in asthma pathogenesis. These inflammatory cells generate high levels of endogenous oxidants such as hydrogen peroxide and superoxide, which could result in redox imbalance in the airways of asthmatics. Redox imbalance occurs when the antioxidant systems becomes overwhelmed resulting in oxidative stress. Oxidative stress and inflammation have been linked with asthma inflammation and severity. Reactive oxygen species (ROS)/reactive nitrogen species (RNS) cause lung inflammation by activating nuclear factor kappa-B (NF-κB), mitogen-activated protein kinase (MAPK), activator protein-1, as well as additional transcription factors. These factors stimulate cytokine production which ultimately activates inflammatory cells in the bronchi, causing lung cellular injury and destruction. ROS/RNS is also produced by these inflammatory cells to eradicate invading bacteria. Antioxidant treatments for asthma have not yet been fully explored.

CONCLUSION

Redox and inflammatory processes are viable targets that could be explored to create better therapy for asthma.

Antidiarrhoeal Activity of Musa paradisiaca Sap in Wistar Rats

The folkloric claim of Musa paradisiaca sap in the management of diarrhoea is yet to be substantiated or refuted with scientific data. Therefore, the aim of the current study was to screen the sap of M. paradisiaca for both its secondary metabolites and antidiarrhoeal activity at 0.25, 0.50, and 1.00 mL in rats. Secondary metabolites were screened using standard methods while the antidiarrhoeal activity was done by adopting the castor oil-induced diarrhoeal, castor oil-induced enteropooling, and gastrointestinal motility models. The sap contained flavonoids, phenolics, saponins, alkaloids, tannins, and steroids while cardiac glycosides, anthraquinones, triterpenes, cardenolides, and dienolides were not detected. In the castor oil-induced diarrhoeal model, the sap significantly (P < 0.05) prolonged the onset time of diarrhoea, decreased the number, fresh weight, and water content of feaces, and increased the inhibition of defecations. Na(+)-K(+)-ATPase activity in the small intestine increased significantly whereas nitric oxide content decreased. The decreases in the masses and volumes of intestinal fluid by the sap were accompanied by increase in inhibition of intestinal fluid content in the enteropooling model. The sap decreased the charcoal meal transit in the gastrointestinal motility model. In all the models, the 1.00 mL of the sap produced changes that compared well with the reference drugs. Overall, the antidiarrhoeal activity of Musa paradisiaca sap attributed to the presence of alkaloids, phenolics, flavonoids, and/or saponins which may involve, among others, enhancing fluid and electrolyte absorption through de novo synthesis of the sodium potassium ATPase and/or reduced nitric oxide levels.

Antiglycation, antioxidant and toxicological potential of polyphenol extracts of alligator pepper, ginger and nutmeg from Nigeria

OBJECTIVE

To evaluate the antioxidant and antiglycation potential of polyphenols from three spices; alligator pepper, ginger and nutmeg.

METHODS

Polyphenol extracts of these spices were subjected to brine-shrimp lethality assay, phytotoxicity test, DPPH and superoxide anion radical scavenging as well as BSA-glucose antiglycation assay.

RESULTS

Results obtained showed that polyphenol extract of ginger has the highest antioxidant potential with IC50 0.075 and 0.070 mg/mL for DPPH and superoxide anion radical scavenging assay while alligator pepper displayed highest antiglycation activity with IC50 0.125 mg/mL. However, nutmeg extract exhibited weakest cytotoxic and phytotoxic potential with LD50 4359.70 and 1490 µg/mL respectively.

CONCLUSIONS

It can be concluded that the polyphenol extracts of alligator pepper, ginger and nutmeg displayed good antioxidant as well as antiglycation potential and are safe for consumption.

Effect of aqueous extract of Cochlospermum planchonii rhizome on some kidney and liver functional indicies of albino rats

Aqueous extract of Cochlospermum planchonii Hook. Ef. x Planch rhizome was investigated for its toxic effects in albino rats using some liver and kidney functional indices as 'markers'. Thirty six albino rats weighing 200.08 ± 10.21 were randomly assinged into six groups (A-F) of six animals each. Animals in groups A-E were orally administered on daily basis with 1 ml of the extract corresponding to 50 mg/kg body weight of the extract for 1, 3, 5, 10 and 15 days while those in the control group received orally 1 ml of distilled water. Rats in all the groups were sacrificed 24 hours after the completion of their respective doses. The extract significantly (P<0.05) decreased alkaline phosphatase (ALP) activities in the liver leading to 80.95% loss by the end of the experimental period. While there was no consistent pattern in the kidney ALP activity and serum bilirubin level, the serum enzyme compared well (P>0.05) with the control value. There was no effect (P>0.05) on the acid phosphatase activity of the tissues and serum of the animals. The extract also reduced the urea, albumin and creatinine content in the serum of the animals. The alterations in the biochemical parameters by the aqueous extract of Cochlospermum planchoni may have consequential effects on the normal functioning of the liver and kidney of the animals. Therefore, the 50 mg/kg body weight of the aqueous extract of Cochlospermum planchoni rhizome may not be completley safe as an oral remedy.

Antioxidant and drug detoxification potential of aqueous extract of Annona senegalensis leaves in carbon tetrachloride-induced hepatocellular damage

CONTEXT

 Despite the myriad uses of Annona senegalensis Pers. (Annonaceae) leaves in folklore medicine of Nigeria, the basis is yet to be substantiated by scientific investigations.

OBJECTIVES

 To investigate the antioxidant (in vitro and in vivo) and drug detoxification potential of aqueous extract of A. senegalensis leaves in CCl₄-induced hepatocellular damage.

MATERIALS AND METHODS

 In vitro antioxidant activity of the aqueous extract of A. senegalensis leaves was evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH), H₂O₂, superoxide ion, 2,2'-azinobis-(3-ethylbenzthiazoline-6-sulfonate) (ABTS) and ferric ion models while in vivo antioxidant and drug detoxification activities of the extract at 100, 200, and 400 mg/kg body weight were done by assaying the levels of enzymic and non-enzymic indices in CCl₄-induced hepatocellular damage.

RESULTS

 The extract at 1 mg/mL scavenged DPPH, H₂O₂, superoxide ion, and ABTS radicals, whereas ferric ion was significantly (P <0.05) reduced. The levels of alkaline and acid phosphatases, alanine and aspartate aminotransferases, superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, glucose-6-phosphate dehydrogenase, reduced glutathione, vitamins C and E, glutathione S-transferase, nicotinamide adenine dinucleotide (reduced):Quinone oxidoreductase, uridyl diphosphoglucuronyl transferase, malondialdehyde, and lipid hydroperoxide that decreased in CCl₄ treated animals were significantly attenuated by the extract in a manner similar to the animals treated with the reference drug.

DISCUSSION AND CONCLUSION

 The ability of the aqueous extract of A. senegalensis leaves to scavenge free radicals in vitro and reversal of CCl₄-induced hepatocellular damage in rats suggest antioxidant and drug detoxification activities. Overall, this study has justified the rationale behind some of the medicinal uses of the plant in folklore medicine of Nigeria.

Biochemical changes in the kidney and liver of rats following administration of ethanolic extract of Psidium guajava leaves

Furtherance to a previous report on the anti-trypanosomal properties of Psidium guajava aqueous leaf extract in rats experimentally infected with Trypanosoma brucei brucei, we have evaluated the effects of the daily intraperitoneal administration of P. guajava leaf extract to rats on the activities of alkaline phosphatase (ALP), aspartate aminotransferase (AST), alanine aminotransferase (ALT) and acid phosphatase (ACP) in the kidney, liver and serum. The results obtained revealed that the administration of the extract produced significant increase in the serum activities of AST, ALT, ALP and ACP when compared with the control (p < 0.05). Also AST, ALT and ALP and ACP activities in the tissues of animals administered the extract revealed inconsistent changes (p < 0.05) relative to control. The increase in the serum activity of ALP may be an indicator that there was a likely compromise to the integrity of the plasma membrane as a result of the ethanolic extract administration. This could have caused leakages of the other enzymes investigated, which may explain the corresponding increases in the serum activities of AST, ALT and ACP observed.

Aqueous extract of Securidaca longepedunculata root induce redox imbalance in male rat liver and kidney

The effect of aqueous extract of Securidaca longepedunculata root on redox homeostasis in male rat liver and kidney was investigated. Rats were grouped into four: A, B, C and D, where A (the control) received orally 1 mL of distilled water; B, C and D (test groups) received orally 200, 400 and 800 mg/kg body weight of the extract, respectively, for 28 days. Extract administration significantly reduced (p < .05) alkaline phosphatase activity in the liver and kidney with corresponding increases in the serum. Acid phosphatase activity increased significantly (p < .05) in the liver and kidney, while there was no significant change (p > .05) in the serum acid phosphatase activity. There was also significant decrease (p < .05) in the activities of superoxide dismutase, catalase, glutathione peroxidase and glutathione reductase in the liver and kidney. Liver and kidney levels of GSH, vitamins C and E were also significantly reduced (p < .05). Serum malonidialdehyde and lipid hydroperoxide increased significantly (p < .05) in all the extract-treated groups. The available data from this study revealed that aqueous extract of S. longepedunculata root exerted its toxicity in the animals by depleting the antioxidant systems. This may consequently expose the cells and cellular macromolecules to oxidative damage by reactive oxygen species generated either from the metabolism of the extract or other in vivo means.

Toxicological implications of aqueous extract of Bambusa vulgaris leaves in pregnant Dutch rabbits

Aqueous extract of Bambusa vulgaris L. leaves at 250 and 500 mg/kg body weight was investigated for toxic effects in pregnant rabbits. Apparently healthy, female rabbits (Dutch) weighing between 1.62 and 1.70 kg as previously used in our abortifacient study were paired overnight with male rabbits in ratio 2:1 and those that became pregnant were completely randomized into three groups (A-C). Group A (the control), received orally 1.85 mL/kg body weight (3 mL) of distilled water thrice daily on days 1-9 of pregnancy while groups B and C were treated orally with the same volume corresponding to 250 and 500 mg/kg body weight of the extract. Clinical signs of toxicity were not observed in all the animals during the study. The extract did not significantly alter (p > .05) the serum follicle stimulating hormone and total protein content of the pregnant rabbits throughout the exposure period whereas, the concentrations of luteinizing hormone, progesterone, albumin, globulin, urea and calcium decreased in the serum of the rabbits. At 250 mg/kg body weight, the extract increased kidney alkaline phosphatase (ALP) activity whereas at 500 mg/kg body weight of the extract, the ALP level was similar to the control group. Liver ALP at all doses, as well as the activity of gamma glutamyl transferase (GGT) at 500 mg/kg body weight was reduced. This reduction was accompanied by an increase in serum ALP and GGT at these doses. At 250 mg/kg, the extract increased kidney GGT. Conversely, at 500 mg/ kg, kidney GGT activity decreased. Liver and serum GGT were not altered by the 250 mg/kg. The extract also increased the serum levels of creatinine, uric acid, sodium, potassium and bicarbonate ions as well as total and conjugated bilirubin. In the hepatocytes of extract-treated animals, there was no evidence of necrosis, inflammation, fibrosis and degenerative changes in the central vein and radiating hepatic cords, while the glomerulus and the tubules of the nephrons also remained intact. The alterations in biochemical parameters by the aqueous extract of B. vulgaris leaves suggests adverse effect on the synthetic, secretory, reabsorptive and excretory functions of liver and kidney of the animals. Therefore, the absence of histopathological lesions in the hepatocytes and nephrons implies that histopathological changes are not a sensitive assay for the assessment of tissue damage by the extract.

Mode of cellular toxicity of aqueous extract of Fadogia agrestis (Schweinf. Ex Hiern) stem in male rat liver and kidney

The mode of cellular toxicity of aqueous extract of Fadogia agrestis stem in male rats was investigated. Rats were grouped into four: A, B, C and D where A (the control) received orally 1 mL of distilled water; B, C and D (test groups) received orally 18, 50 and 100 mg/kg body weight of the extract, respectively, for 28 days. Infrared spectroscopy indicated the presence of hydroxyl (OH) and primary amine (CONH). Clinical toxicity symptoms such as respiratory distress, epistasis, salivation, hypo- and hyperactivity were not observed at any period of the experiment. No mortality was also recorded. Extract administration significantly reduced (p < .05) the activities of alkaline phosphatase, lactate dehydrogenase and gamma glutamyl transferase in the liver and kidney with corresponding increases in the serum. Serum malondialdehyde also increased significantly in all the extract-treated groups. The liver and kidney body weight ratios of the extract-treated animals compared well (P > .05) with their controls throughout the experimental period. The extract did not cause any swelling, atrophy or hypertrophy of the organs. The other evidence in this study suggests disruption of the ordered lipid bilayer of the plasma membranes of the hepatocytes and nephrons. This might have resulted from peroxidation of the polyunsaturated fatty acids on the membranes of the hepatocytes and nephrons made possible by the functional groups or the product of metabolism of the extract. This may be responsible for the compromise of the integrity of the plasma membranes of the hepatocytes and nephrons.

Aphrodisiac potentials of the aqueous extract of Fadogia agrestis (Schweinf. Ex Hiern) stem in male albino rats

AIM

To evaluate the phytochemical constituents and the aphrodisiac potential of the aqueous extract of Fadogia agrestis (Rubiaceae) stem in male albino rats.

METHODS

The aqueous stem extract of the plant was screened for phytochemical constituents. Male rats were orally dosed with 18 mg/kg, 50 mg/kg and 100 mg/kg body weight, respectively, of the extract at 24 h intervals and their sexual behavior parameters and serum testosterone concentration were evaluated at days 1, 3 and 5.

RESULTS

Phytochemical screening revealed the presence of alkaloids and saponins while anthraquinones and flavonoids are weakly present. All the doses resulted in significant increase in mount frequency, intromission frequency and significantly prolonged the ejaculatory latency (P 0.05) and reduced mount and intromission latency (P 0.05). There was also a significant increase in serum testosterone concentrations in all the groups in a manner suggestive of dose-dependence (P 0.05).

CONCLUSION

The aqueous extract of Fadogia agrestis stem increased the blood testosterone concentrations and this may be the mechanism responsible for its aphrodisiac effects and various masculine behaviors. It may be used to modify impaired sexual functions in animals, especially those arising from hypotestosteronemia.

Effect of chronic consumption of metabisulphite on the integrity of the rat kidney cellular system

The effect of chronic consumption of metabisulphite, a food preservative, on the integrity of the rat kidney cellular system was investigated. The levels of activities of some 'marker' enzymes were measured both before and after administration of between 1 and 15 doses of the chemical compound. Feeding of metabisulphite (5 mg/kg body wt.) to rats resulted in loss of alkaline phosphatase activities from the kidney beginning after the first dose. This was accompanied by a reduction of lactate dehydrogenase activity which was noticed as a secondary reaction, taking place after five daily doses. This was accompanied by an increase in alkaline phosphatase and a decrease in lactate dehydrogenase activities in the serum. An increased urinary excretion of protein and alkaline phosphatase activity was also obtained. Other enzymes assayed (acid phosphatase and glutamate dehydrogenase activities) were not significantly affected in the tissues and urine. All these results indicated that there is cellular damage to rat kidney as a result of chronic consumption of metabisulphite. They also indicate that the damage was primarily on the plasma membrane. The proximity of the soluble portion of the cytoplasm to the plasma membrane also makes it a secondary site of injury in the kidney cell.

Effect of repeated administration of berenil on urinary enzyme excretion with corresponding tissue pattern in rats

The effect of repeated administration of berenil, a trypanocide, on urinary excretion of some enzyme activities in rat and their corresponding levels in the kidney and serum was investigated. Daily administration of this drug to rats resulted in increased urinary volume, excretion of protein, alkaline phosphatase and lactate dehydrogenase activities. However, the level of acid phosphatase activity was not significantly increased while muramidase activity disappeared completely during the period of drug administration. In the kidney tissue, there was a significant loss of lactate dehydrogenase activity immediately after the first dose and this trend continued until the end of drug administration. In the same tissue, there was an increase in alkaline phosphatase activity while the lysosomal enzymes were not significantly affected. In the serum, except for the increase in alkaline phosphatase activity, all other enzymes were not significantly affected. All these results indicate that there is cellular damage to rat kidney as a result of repeated berenil administration, and that the plasma membrane and the soluble portion of the cytoplasm are the primary site of injury to the cells. They also suggest that urinary enzyme excretion could be useful in determining the site of cellular damage by chemical agents in kidneys.

Studies on correlations between chloroquine-induced tissue damage and serum enzyme changes in the rat

The administration of chloroquine to rats resulted in a significant elevation of serum enzymes and a corresponding decrease of these enzymes in the tissues. The changes in serum and kidney enzymes were most marked, thus indicating a primary renal dysfunction.

Rat kidney lysosomal membrane damage induced by suramin in vitro and in vivo

The effect of suramin, an acid naphthylamine, on rat kidney lysosomal membrane integrity was studied. Lysosomal particles were incubated with suramin (0.1-0.4 mM) and light scattering behaviour of the mixtures were subsequently measured. There was a significant decrease (P less than 0.005) in the amount of light absorbed in the presence of suramin compared to lysosomal particle suspension alone. This was accompanied by release of acid phosphatase, a lysosomal 'marker' enzyme, into the suspending medium. These effects were reduced in the presence of acetylsalicylic acid, a known lysosomal membrane stabilizer. Administration of suramin to rats resulted in loss of kidney acid phosphatase and lysozyme activities from the tissue. These results indicate labilization of rat kidney lysosomal membrane by suramin molecules both in vitro and in vivo.

Alkaline phosphatase activities following repeated suramin administration in some rat tissues in relation to their functions

The effect of repeated administration of suramin, a trypanocide and filariacide, on the level of alkaline phosphatase activity in some rat tissues and organs was investigated. Daily administration of this drug to rats resulted in a very significant increase in enzyme activity in the kidney and small intestine immediately after the first dose. Activity observed in the liver was not affected until after the third dose when the level was increased. In the heart and the large intestine, administration of the drug did not affect the enzyme activity levels throughout the duration of drug administration. These results suggest that repeated suramin administration may result in very large increases in alkaline phosphatase activity in the tissues and organs which are involved in active transport mechanisms.

Labilising effect of suramin on rat kidney lysosomes in vivo

The effect of administration of suramin on the urinary levels of some lysosomal enzymes in rats was investigated. The urinary levels of acid phosphatase and lysozyme were significantly elevated 24 h after drug administration. The high levels were sustained for 9 days after drug administration was terminated. These actions were indicative of labilization of kidney lysosomal membrane by the drug molecules, the membrane being repaired and integrity restored some days following termination of drug administration.

Effect of chloroquine on the stability of rat kidney lysosomes in vivo and in vitro

1. Chronic administration of chloroquine to rats results in increased urinary excretion of lysosomal acid phosphatase, muramidase and cathepsin D. 2. Various concentrations of chloroquine caused lysosomal membrane swelling as shown by decrease of light absorbance in lysosomal suspensions. 3. Incubating lysosomal suspensions in the presence of chloroquine resulted in a marked lysosomal acid phosphatase release. 4. Addition of acetylsalicylic acid, a lysosomal membrane stabilizer, into a lysosomal suspension containing chloroquine, reduced the degree of lysosomal membrane swelling and acid phosphatase release. 5. The results suggest a labilizing effect of chloroquine on rat kidney lysosomes.