Antioxidant Activities and Tyrosinase Inhibition Effects of Phaleria Macrocarpa Extracts

Background

The ethyl acetate and chloroform extracts of stems, leaves and fruits of Phaleria macrocarpa were screened for their antioxidant capacity and tyrosinase inhibition properties.

Material and Method

The total phenolic content (TPC), 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging and ferric-ion reducing power (FRAP) were used to evaluate their antioxidant capacity. Tyrosinase inhibition effect was measured using mushroom tyrosinase inhibition assay.

Result

Ethyl acetate extract of P. macrocarpa''s stem exhibited highest total phenolic content, DPPH free radical scavenging and ferric reducing power. Meanwhile, chloroform extracts of leaves and fruits demonstrated potent anti-tyrosinase activities as compared to a well-known tyrosinase inhibitor, kojic acid.

Conclusion

Since chloroform extracts of leaves and fruits have low antioxidant capacities, the tyrosinase inhibition effect observed are antioxidant independent. This study suggests direct tyrosinase inhibition by chloroform extracts of Phaleria macrocarpa.     

Total Anti-Oxidant Capacity,Flavonoid, Phenolic Acid and Polyphenol Content in Ten Selected Species of Zingiberaceae Rhizomes

Background

Natural products such as herbs, fruits, spices, beverages, vegetables are becoming more popular among scientific community and consumers because of their potential to arrest the effect of free radicals in human system. This study determined the total antioxidant capacity of ten selected species of Zingiberaceae (Ginger) used as spices and for medicinal purposes in Southeast Asia.

Materials and Methods

Methanol was used as the extraction solvent, 2,2 - diphenyl-1-picrylhydrazil (DPPH) for free radical scavenging activity and ferric reducing antioxidant power (FRAP) assays. Phenolic compounds were measured using Total flavonoid, Phenolic acid and Polyphenols content assay to evaluate the quality of the antioxidant capacity of the rhizomes and vitamin C as positive control.

Results

The results obtained revealed that Curcuma longa and Zingiber officinale had the highest free radical scavenging capacity of 270.07mg/TE/g DW and 266.95mg/TE/g DW and FRAP assay, Curcuma longa and Zingiber officinale also gave the highest ferric reducing power of 231.73mg/TE/g DW and 176.26mg/TE/g DW respectively. For Phenolic compounds, Curcuma longa and Curcuma xanthorrhiza gave the highest values of flavonoid (741.36mg/NGN/g DW and 220.53mg/NGN/g DW), phenolic acid (42.71mg/GAE/g DW and 22.03mg/GAE/g DW) and polyphenols (39.38mg/GAE/g DW and 38.01mg/GAE/g DW) respectively. Significant and positive linear correlations were found between Total antioxidant capacity and Phenolic compounds (R = 0.65 – 0.96).

Conclusion

This study provides evidence that extracts of Zingiberaceae (Ginger) rhizomes are a potential source of natural antioxidants and could serve as basis for future drugs and food supplements     

Anti-Inflammatory and Antioxidant Activities of Methanol Extracts and Alkaloid Fractions of Four Mexican Medicinal Plants of Solanaceae

Background

Methanol extracts and alkaloid fractions of different parts of four plant species belonging to Solanaceae family and used in Mexican traditional medicine were investigated for their total phenolic contents, anti-inflammatory and antioxidant properties.

Materials and Methods

The total phenolic compounds of each extract was determined according to the Folin-Ciocalteu method, while the in vitro radical scavenging activities of the extracts were assessed using the DPPH and ABTS radicals. The in vivo anti-inflammatory activity was determined using the TPA-induced mouse ear edema model.

Results

The methanol extracts contained the highest concentrations of phenolic compounds and also exhibited the best reducing power on the DPPH and ABTS radicals, in a concentration-dependent fashion. However, the anti-inflammatory activity did not follow the same trend, as some alkaloid fractions that showed low radical reducing power exhibited the strongest anti-inflammatory activity.

Conclusion

The methanol extract obtained from the flowers of Nicotiana glauca presented the best overall performance with the largest amount of phenolic compounds (111 µg garlic acid equivalents/g of extract), the best antioxidant activity (94.80% inhibition of DPPH and 97.57% of ABTS) and the highest anti-inflammatory activity (81.93% inhibition of the inflammation).     

Bioactivity-Guided Isolation of Anticancer Agents from Bauhinia Kockiana Korth

Background

Flowers of Bauhinia kockiana were investigated for their anticancer properties.

Methods

Gallic acid (1), and methyl gallate (2), were isolated via bioassay-directed isolation, and they exhibited anticancer properties towards several cancer cell lines, examined using MTT cell viability assay. Pyrogallol (3) was examined against the same cancer cell lines to deduce the bioactive functional group of the phenolic compounds.

Results

The results showed that the phenolic compounds could exhibit moderate to weak cytotoxicity towards certain cell lines (GI₅₀ 30 – 86 µM), but were inactive towards DU145 prostate cancer cell (GI₅₀ > 100 µM).

Conclusion

It was observed that pyrogallol moiety was one of the essential functional structures of the phenolic compounds in exhibiting anticancer activity. Also, the carboxyl group of compound 1 was also important in anticancer activity. Examination of the PC-3 cells treated with compound 1 using fluorescence microscopy showed that PC-3 cells were killed by apoptosis.     

Antioxidant and Antibacterial Activities of Flavonoid Glycosides from Ficus Exasperata Vahl-Holl (Moraceae) Leaves

Background

Ficus exasperata Vahl-Holl (Moraceae) leaves are used for infectious and inflammatory conditions in many West African Countries. However, there is need for more phytochemical studies to justify the ethnomedicinal uses of the plant.

Material and Methods

The crude 50% aqueous ethanolic extract of the leaves was partitioned successively between water and; n-hexane, ethyl acetate and n-butanol. The fractions were subjected to antimicrobial activity using agar diffusion test. n-Butanol fraction, which showed both antimicrobial and radical scavenging activities was subjected to repeated chromatographic fractionation on both silica and Sephadex LH-20 columns. Each stage of the purification was monitored by thin layer chromatographic diphenylpicryl hydrazyl autographic assay. Three compounds were isolated. The structures of the compounds were elucidated using spectroscopic methods, shift reagent studies, acid hydrolysis, and by comparison with literature data.

Results

The compounds were identified as apigenin C-8 glucoside (1), isoquercitrin-6-O-4-hydroxybenzoate (2) and quercetin-3-O-β-rhamnoside (3). The solvent fractions and isolated compounds were found to inhibit the growth of Gram +ve organisms only.

Conclusion

These flavonoid glycosides are being reported in this plant species for the first time. Their weak in vitro antimicrobial activity suggest the flavonoids may be acting as pro-drug. The radical scavenging activity of the compounds may justify some of the ethnomedicinal uses of the plant as free radicals are implicated in the aetiology of many inflammatory diseases.     

Antioxidant Activity In Vitro and Hepatoprotective Effect of Phlomis Maximowiczii In Vivo

Background

A number of medicinal plants and there compounds played a major role in the treatment of hepatic disorders. They were widely used for the treatment of these disorders, and oxidant stress injury was one of the liver injury mechanisms. The present study evaluated the antioxidant activity and the hepatoprotective effect of each extracts of Phlomis maximowiczii.

Materials and Methods

The antioxidant activity was assayed by the methods of ABTS, FRAP and DPPH in vitro. Hepatoprotective effect of P. maximowiczii extracts was examined using carbon tetrachloride-induced acute liver injury in mice.

Results

P. maximowiczii n-butanol (PMBU) extract, ABTS (IC₅₀=18.96 µg/mL), DPPH (IC₅₀=25.15 µg/mL), and FRAP (RACT₅₀=2775.6±144.18 µmol/g), showed higher scavenging capacity than that of P. maximowiczii ethyl acetate (PMEA). The n-butanol extract could significantly reduce the level of GPT, GOT and MDA (P<0.05, P<0.001 and P<0.001, respectively) and increase the level of SOD (P<0.001), respectively.

Conclusion

The antioxidant activity of n-butanol extract in vitro was related with the level of MDA and SOD in vivo, and hepatoprotective effect of n-butanol extract also had relationship with its antioxidant activity in vivo.     

The Antimicrobial Activity of Liquidambar Orientalis Mill. Against Food Pathogens and Antioxidant Capacity of Leaf Extracts

Background

Medicinal plants are an important source of substances which are claimed to induce antimicrobial, antimutagenic and antioxidant effects. Many plants have been used due to their antimicrobial treatments. Antimicrobial and antioxidant activities of L. orientalis have not been reported to the present day. The aim of this work was to investigate of the antimicrobial and antioxidant potentials of different extracts from L. orientalis.

Materials and Methods

The extracts were screened for antimicrobial activity against different food pathogens. These bacteria include 4 Gram positive and 3 Gram negative bacteria and one fungi. The leaf extracts of plant were tested by disc diffusion assay. The MIC was evaluated on plant extracts as antimicrobial activity. In addition to, the plant extracts were tested against the stable DPPH (2,2-diphenyl-1-picryl-hydrazylhydrate) free-radical.

Results

The acetone, ethanol and methanol extracts of L. orientalis showed maximum inhibition zone of 12 mm against Yersinia enterocolitica, Listeria monocytogenes and Staphylococcus aureus. In addition to, the methanol extract displayed a strong antioxidant activity (trolox equivalent = 2.23 mM).

Conclusion

L. orientalis extracts have antimicrobial, and antioxidant potential. Our results support the use of this plant in traditional medicine and suggest that some of the plant extracts possess compounds with good antibacterial properties that can be used as antibacterial agents in the search for new drugs.     

Evaluation of the Antioxidant Activity of Root Extract of Pepper Fruit (Dennetia Tripetala), and It's Potential for the Inhibition of Lipid Peroxidation

Background

The antioxidant properties of ethanolic root extract of pepper fruit (Donnetia tripetala), and its effect on lipid peroxidation of some fresh beef tissues during frozen storage were investigated.

Materials and Methods

The antioxidant parameters were assessed using standard methods, while malondialdehyde levels of different fresh beef tissue sections treated with the extract prior to freezing, were estimated in a colorimetric reaction with thiobarbituric acid.

Results

The H₂O₂-scavenging ability of the extract was similar to that of ascorbic acid, with a maximum scavenging power of 55.61 ±4.98%, and an IC₅₀ value of 86µg/ml. The extract exhibited a concentration-dependent ferric ion-reducing power, although this was significantly lower relative to that of the ascorbic acid (p < 0.05). The total phenolic content was 212.5 ± 0.002 mg/g, while the nitric oxide-scavenging ability was 64.33 ± 0.2% after 150 min. The capacity of the extract to inhibit lipid peroxidation in frozen heart muscle slices was significantly higher than that of vitamin C (p < 0 .05), but comparable to vitamins C and E in frozen testes and kidney slices.

Conclusion

These results suggest that the root extract of D. tripetala is rich in antioxidants which can be applied to meat preservation during refrigerated storage.     

A New Bioactive Thiophenolic Glycoside from the Leaf of Massularia Acuminata (G. Don Bullock) Ex Hoyle (Rubiaceae)

Background

Massularia acuminata is a small tree or shrub of tropical rainforest. The leaves are used in Nigerian ethno-medicine for the treatment of microbial infections and pharmacological report suggested the leaf extract as possessing antioxidant activity. This study was therefore carried out to determine the most antioxidant and antimicrobial active fraction(s) of Massularia acuminata leaf and the constituent(s) responsible for the activities.

Matherials and Methods

The leaf of Massularia acuminata was investigated for in vitro antioxidant and antimicrobial activities, using a 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay and agar dilution method respectively.

Results

The ethyl acetate fraction demonstrated the best activities among the partitioned fractions tested. Bioassay guided purification of the most active ethyl acetate fraction led to isolation of a new thiophenolic glycoside, characterized as 4-(3′,3′-dihydroxy-1-mercaptopropyl)phenyl glycosylpyranoside.

Conclusion

The isolated compound from the leaf of Massularia acuminata demonstrated antioxidant and antimicrobial activities and may be responsible for the activities of leaf extract and its ethyl acetate fraction, hence this may justify its ethnomedicinal use.     

Investigation of Antioxidant Potentials of Solvent Extracts From Different Anatomical Parts of Asphodeline Anatolica E. Tuzlaci: An Endemic Plant to Turkey

Background

The genus Asphodeline (Liliaceae) is represented in Turkey by 20 taxa, which are traditionally used for medicinal purposes in Anatolia.

Materials and Methods

In this study, we tested the phytochemical content and antioxidant effect of different solvent extracts obtained from different anatomical parts of Asphodeline anatolica. The different extracts of each plant parts were tested for antioxidant activity using different chemical assays. The total antioxidant components were also calculated.

Results

Generally, acetone extracts produced the seed and root exhibited significantly higher antioxidant activity with high antioxidant components. Total phenolic content of extracts were significantly correlated with antioxidant potentials (except for, metal chelating activity).

Conclusion

On the basis of the results obtained, A. anatolica extracts should be regarded as a valuable source of natural antioxidants for food and therapeutic applications.     

Evaluation of Antioxidant and Antimicrobial Potential of Two Endangered Plant Species Atropa Belladonna and Matricaria Chamomilla

Background

Plants are the natural source of antioxidants as well as antimicrobial compounds that has great potentials in pharmaceutical industry. In the present study, two medicinal plants Atropa belladonna and Matricaria chamomilla were collected from Northern areas of Pakistan.

Materials and Methods

The extracts of the collected plants were obtained by microwave assisted extraction (MAE) with changing parameters, power level and time; methanol and ethanol were solvents used during extraction. The extracts of plants were tested against different bacterial strains.

Results

It was observed that ethanolic extracts of Atropa belladonna has more significant antimicrobial activity against S.aureus than E.coli. In parallel, methanolic extract of Matricaria chamomilla showed greater significant antibacterial activity against S.aureus when compared with E.coli. In comparison, ethanolic extracts of Matricaria chamomilla has shown more significant results against S. aureus than E.coli (p≤0.05). Both plants had no antibacterial activity against S.typhi. The free radical scavenging activity observed by DPPH assay, indicate that both plants have antioxidant activity at all levels of concentrations in solvent tested during the present work. However, methanolic extracts had greater antioxidant activity when compared with ethanolic extracts.

Conclusion

Present study is thus helpful in highlighting present potentials for antioxidant and antimicrobial properties in the selected plants.     

Carboxylic acid derivatives of histone deacetylase inhibitors induce full length SMN2 transcripts: a promising target for spinal muscular atrophy therapeutics

Introduction

Proximal spinal muscular atrophy (SMA) is a common autosomal recessively inherited neuromuscular disorder. It is caused by homozygous absence of the survival motor neuron 1 (SMN1) gene. SMN2, which modulates the severity of the disease, represents a major target for therapy. The aim of this study was to investigate whether SMN2 expression can be increased by caffeic acid, chlorogenic acid and curcumin, which are designed by modifications of the carboxylic acid class of histone deacetylase (HDAC) inhibitors.

Material and methods

Using quantitative real-time PCR, we analysed the levels of full-length SMN2 and Δ7SMN2 mRNA. We performed LDH cytotoxicity assay to analyse whether SMN2 activating concentrations of caffeic acid, chlorogenic acid and curcumin were cytotoxic to fibroblasts.

Results

We found that caffeic acid and curcumin were more efficient than chlorogenic acid and increased full-length SMN2 mRNA levels 1.5 and 1.7-fold, respectively. Δ7SMN2 mRNA levels were measured to investigate alternative splicing of exon 7. We also found that cytotoxicity was not observed at SMN2 activating concentrations.

Conclusions

Our data suggest that carboxylic acid derivatives including phenolic structure and symmetry could be a good candidate for SMA treatment.     

Baboons as potential reservoirs of zoonotic gastrointestinal parasite infections at Yankari National Park,Nigeria

Background

Zoonoses pose a risk to public health.

Objective

To carry out the investigation of the prevalence of gastrointestinal parasites of baboons, Papio anubis, frequenting the Wikki base Camp in Yankari National Park, Nigeria

Method

Formol-ether concentration technique was used to isolate parasite eggs and cysts from faecal samples.

Results

Parasites recovered were Ascaris lumbricoides, Ancylostoma duodenale, Strongyloides stercoralis, Fasciola sp, Schistosoma mansoni, Hymenolepis nana, and Trichostrongylus sp, and cysts of protozoan parasites Entomoeba histolytica, E. coli, and Iodamoeba butschii.

Conclusion

Most of the parasites identified are known to have high pathologic involvement in humans, implicating the baboons as potential source and reservoirs for human zoonotic parasitic infections although further molecular work would be necessary to ascertain if these gastrointestinal parasites are the same strains that infect humans     

Antioxidant Activity and Inhibitory Effect of Some Commonly Used Medicinal Plants Against Lipid Per-Oxidation in Mice Brain

Background

The present study compares the protective properties of aqueous extracts of six medicinal plants, Phyllanthus emblica, Terminalia chebula (black and yellow), Terminalia arjuna, Balsamodendron Mukul and Alium sativum against lipid per-oxidation in mice brain.

Methods

The antioxidant activities were analyzed by lipid per-oxidation assay, 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical assay, total antioxidant activity and metal chelation.

Results

The extracts (fruits and bark) showed inhibition against thiobarbituric acid reactive species (TBARS) induced by pro-oxidant (10 µM FeSO4) in mice brain. Moreover, the free radical scavenging activities of the extracts was evaluated by the scavenging of DPPH radical (IC₅₀, 23.23±1.2 µg/ml (Phyllanthus emblica), 20.24±0.9 µg/ml (Terminalia chebula yellow) and 17.33±1.1 µg/ml (Terminalia chebula black), 19.44±0.45 µg/ml (Terminalia arjuna), 56.59±2.1 µg/ml (Balsamodendron Mukul) and < 200 µg/ml (Alium sativum).

Conclusion

The higher antioxidant and inhibitory effect of Terminalia chebula black in this study could be attributed to its significantly higher phenolic content, Fe(II) chelating ability, reducing ability and free radical scavenging activity. Therefore oxidative stress in brain could be potentially prevented by the intake of these plants.     

Acute toxicity effects of the methanolic extract of Fagara zanthoxyloides (Lam.) root-bark

Background

Fagara zanthoxyloides is a well known medicinal plant in Uganda. It is used extensively in malaria and other infections. However nothing is known about its toxicity.

Objective

The objective of the study was to evaluate the acute toxicity of the methanolic extract of the root-bark of F. zanthoxyloides, in mice.

Methods

Methanolic extract of the root-bark of the plant was administered orally to mice at various dose levels to determine the acute toxic effects and the median lethal dose (LD₅₀) in mice.

Results

The LD50 of the methanolic extract was found to be 5.0 g/Kg body weight within 95 % confidence limits. The mice showed signs of cerebral irritation before dying. Histopathological examinations of the viscera showed congestion and focal necrosis of the liver and renal tubules.

Conclusion

It was concluded that the extract of F. zanthoxyloides is safe, however the cerebral mechanism that lead to the death of the mice need to be investigated further.     

Antidiabetic and haematinic effects of Parquetina nigrescens on alloxan induced type-1 diabetes and normocytic normochromic anaemia in Wistar rats

Background

The plant, Parquetina nigrescens is used in folklore medicine to treat diabetes mellitus and its complications in several parts of West Africa.

Objective

To determine the effect of Parquetina nigrescens extract on fasting blood glucose in alloxan-induced diabetic rats.

Methods

The blood glucose levels, complete blood count, erythrocyte indices and osmotic fragility, body and organ weights were evaluated.

Results

Diabetic rats treated with the extract showed significant (P<0.01) reduction of the blood glucose to levels comparable to that of the non-diabetic control and those treated with chlorpropamide (standard drug). Similarly, there was significant (P<0.01) reduction in the complete blood count in the diabetic rats.

Discussion

The anaemia, leucopenia and thrombocytopenia associated with the diabetes were corrected in the animals treated with the extract and chlorpropamide. The extract also reduced the erythrocyte osmotic fragility, body and organ weights. Parquetina nigrescens demonstrated antidiabetic property by reducing the elevated blood glucose in alloxan treated rats which is comparable to animals that received the standard drug.

Conclusion

Paraquetina nigrescens stabilized the erythrocyte membrane, decreased the body weight probably by lowering lipogenesis. However, the mechanism underlying the antidiabetic and haematinic properties of Parquetina nigrescens remains to be elucidated.     

Evaluation of persistent antimicrobial effects of an antimicrobial formulation

Context:

Community-acquired methicillin-resistant Staphylococcus aureus (MRSA) is becoming more prevalent in healthy athletic populations. Various preventive measures have been proposed, but few researchers have evaluated the protective effects of a prophylactic application of a commercially available product.

Objective:

To compare the persistent antimicrobial properties of a commercially available antimicrobial product containing 4% chlorhexidine gluconate (Hibiclens) with those of a mild, nonmedicated soap (Dr. Bronner''s Magic Soap).

Design:

Cross-sectional study.

Setting:

Microbiology laboratory, contract research organization.

Patients or Other Participants:

Twenty healthy human volunteers.

Intervention(s):

The test and control products were randomly assigned and applied to both forearms of each participant. Each forearm was washed for 2 minutes with the test or control product, rinsed, and dried. At, 1, 2, and 4 hours after application, each forearm was exposed to MRSA for approximately 30 minutes.

Main Outcome Measure(s):

Differences in numbers of MRSA recovered from each forearm, test and control, at each postapplication time point were compared.

Results:

Fewer MRSA (P < .0001) were recovered from the forearms treated with the test product (4% chlorhexidine gluconate) than from the forearms treated with the control product (nonmedicated soap).

Conclusions:

The 4% chlorhexidine gluconate product demonstrated persistent bactericidal activity versus MRSA for up to 4 hours after application.     

Characterization of plasma membrane bound inorganic pyrophosphatase from Leishmania donovani promastigotes and amastigotes

Background

Currently, a major problem in the management of visceral leishmaniasis or kala-azar, especially in the Indian subcontinent, is the growing unresponsiveness to conventional antimonial therapy. Membrane bound pyrophophatase (PPases) do not exist in plasma membrane from mammals. Thus, H⁺-PPases from Leishmania plasma membrane might be potential target in rational chemotherapy of the disease caused by Leishmania parasites.

Objective

To characterize the activities of inorganic pyrophophatase (PPase) in the plasma membrane of Leishmania donovani promastigote and amastigote.

Methods

Culture method of promastigote and amastigote were developed. We assayed PPase activity in isolated plasma membrane of L. donovani.

Results

We characterized K⁺-PPase present in the plasma membrane of Leishmania donovani and investigated its possible role in the survival of promastigote and amastigote. PPase activity was stimulated by K⁺ ions and sodium orthovanadate, inhibited by pyrophosphate analogs imidodiphosphate and alendronate, KF, DCCD, thiol reagent parachloromercuribenzenesulfonate (PCMBS), N-ethylmaliemide (NEM), phenylarsineoxide, ABC superfamily transport modulator verapamil and was also by F₁F_o-ATPase inhibitor quercetin.

Conclusion

We conclude that there are significant differences within promastigote, amastigote and mammalian host in cytosolic pH homeostasis to merit the inclusion of PPase transporter as putative targets for rational drug design.     

Staphylococcus aureus carriage among GPs in the Netherlands

Background

The extent to which GPs serve as a reservoir for antibiotic-resistant Staphylococcus aureus is unknown and not well studied.

Aim

To determine the prevalence of nasal S. aureus carriage among GPs in the Netherlands, as well as the antimicrobial resistance and the genotypes of isolated S. aureus.

Design of study

Observational, point-prevalence, and cross-sectional study.

Setting

GPs attending the annual conference of the Dutch College of General Practitioners in 2006.

Method

Nasal swabs were randomly taken from 395 GPs and analysed for the presence of S. aureus. Antimicrobial susceptibility was determined by a microbroth dilution method and the genotypes by spa typing, which was associated with multilocus sequence typing.

Results

Of the GPs, 129/395 (33%; 95% confidence interval [CI] = 28 to 37%) were carriers of S. aureus. No meticillin-resistant S. aureus (MRSA) was found. Resistance was observed to penicillin (71%; 95% CI = 63 to 79%), fusidic acid (7%; 95% CI = 3 to 13%), and clarithromycin (6%; 95% CI = 3 to 12%). In 72% of the isolates, an MRSA-related genotype of S. aureus was found.

Conclusion

The low antibiotic resistance found among S. aureus of GPs suggests that GPs are not a reservoir of antibiotic-resistant S. aureus strains. The relatively high resistance to fusidic acid, which has not previously been described in the Netherlands and is mostly because of antibiotic use, suggests that patients infect GPs and not the other way round. GPs may be at risk for nasal carriage of S. aureus with an MRSA-related genotype.     

Lack of Association of the APOE ε4 Allele with the Risk of Obstructive Sleep Apnea: Meta-Analysis and Meta-Regression

Study Objectives:

Reports on the association of polymorphisms in the gene encoding apolipoprotein E (APOE)—a vital macromolecule in cholesterol metabolism—with obstructive sleep apnea (OSA) have provided conflicting results. Our objective was to meta-analytically synthesize the existing evidence for the association of the APOE ε4 allele with the risk of OSA.

Design:

Random effects meta-analysis and meta-regression

Setting:

Genetic epidemiological studies reporting the association of APOE ε4 allele with OSA susceptibility.

Patients or Participants:

Synthesis of APOE ε4 allele data from 6,508 subjects including 1,901 cases of OSA and 4,607 controls.

Interventions:

None

Measurements and Results:

Eight studies were included in the random effects meta-analysis; the summary effect size measured as odds ratio (OR) for association of the APOE ε4 allele with the risk of OSA was found to be 1.13 (95% confidence interval 0.86–1.47). There was a statistically significant heterogeneity (I² = 72%, P = 0.001) across study results that was not explained by the mean age, proportion of males, or the proportion possessing the APOE ε4 allele or when grouped based on the geographic location of the study.

Conclusions:

The hypothesis that the APOE ε4 allele may be causally associated with OSA cannot be supported on the basis of published literature.

Citation:

Thakre TP; Mamtani MR; Kulkarni H. Lack of association of the APOE ε4 allele with the risk of obstructive sleep apnea: meta-analysis and meta-regression. SLEEP 2009;32(11):1507-1511.