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Dive into the research topics where Gabriel A. Agbor is active.

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Featured researches published by Gabriel A. Agbor.


Lipids in Health and Disease | 2006

The use of a Cissus quadrangularis formulation in the management of weight loss and metabolic syndrome

Julius E. Oben; Dieudonne Kuate; Gabriel A. Agbor; Claudia E. N. Momo; Xavio Talla

AimOnce considered a problem of developed countries, obesity and obesity-related complications (such as metabolic syndrome) are rapidly spreading around the globe. The purpose of the present study was to investigate the use of a Cissus quadrangularis formulation in the management of metabolic syndrome, particularly weight loss and central obesity.MethodsThe study was a randomized, double-blind, placebo-controlled design involving 123 overweight and obese persons (47.2% male; 52.8% female; ages 19–50). The 92 obese (BMI >30) participants were randomized into three groups; placebo, formulation/no diet, and formulation/diet (2100–2200 calories/day). The 31 overweight participants (BMI = 25–29) formed a fourth (no diet) treatment group. All participants received two daily doses of the formulation or placebo and remained on a normal or calorie-controlled diet for 8 weeks.ResultsAt the end of the trial period, statistically significant net reductions in weight and central obesity, as well as in fasting blood glucose, total cholesterol, LDL-cholesterol, triglycerides, and C-reactive protein were observed in participants who received the formulation, regardless of diet.ConclusionCissus quadrangularis formulation appears to be useful in the management of weight loss and metabolic syndrome.


Lipids in Health and Disease | 2007

The effect of Cissus quadrangularis (CQR-300) and a Cissus formulation (CORE) on obesity and obesity-induced oxidative stress

Julius E. Oben; Damaris Mandob Enyegue; Gilles I. D. Fomekong; Yves B Soukontoua; Gabriel A. Agbor

AimObesity is generally linked to complications in lipid metabolism and oxidative stress. The aim of this study was to compare the effect of a proprietary extract of Cissus quadrangularis (CQR-300) to that of a proprietary formulation containing CQR-300 (CORE) on weight, blood lipids, and oxidative stress in overweight and obese people.MethodsThe first part of the study investigated the in vitro antioxidant properties of CQR-300 and CORE using 3 different methods, while the second part of the study was a double-blind placebo controlled design, involving initially 168 overweight and obese persons (38.7% males; 61.3% females; ages 19–54), of whom 153 completed the study. All participants received two daily doses of CQR-300, CORE, or placebo and were encouraged to maintain their normal levels of physical activity. Anthropometric measurements and blood sampling were done at the beginning and end of the study period.ResultsCQR-300 as well as CORE exhibited antioxidant properties in vitro. They also acted as in vivo antioxidants, bringing about significant (p < 0.001) reductions in plasma TBARS and carbonyls. Both CQR-300 and CORE also brought about significant reductions in weight, body fat, total cholesterol, LDL-cholesterol, triglycerides, and fasting blood glucose levels over the respective study periods. These changes were accompanied by a significant increase in HDL-cholesterol levels, plasma 5-HT, and creatinine.ConclusionCQR-300 (300 mg daily) and CORE (1028 mg daily) brought about significant reductions in weight and blood glucose levels, while decreasing serum lipids thus improving cardiovascular risk factors. The increase in plasma 5-HT and creatinine for both groups hypothesizes a mechanism of controlling appetite and promoting the increase of lean muscle mass by Cissus quadrangularis, thereby supporting the clinical data for weight loss and improving cardiovascular health.


Lipids in Health and Disease | 2008

The use of a Cissus quadrangularis/Irvingia gabonensis combination in the management of weight loss: a double-blind placebo-controlled study

Julius E. Oben; Judith Laure Ngondi; Claudia E. N. Momo; Gabriel A. Agbor; Caroline S Makamto Sobgui

AimTo evaluate the effects of two formulations, Cissus quadrangularis-only and a Cissus quadrangularis/Irvingia gabonensis combination, on weight loss in overweight and obese human subjects.MethodsThe study was a 10 week randomized, double-blind, placebo-controlled design involving 72 obese or overweight participants (45.8% male; 54.2% female; ages 21–44; mean age = 29.3). The participants were randomly divided into three equal (n = 24) groups: placebo, Cissus quadrangularis-only, and Cissus quadrangularis/Irvingia gabonensis combination. Capsules containing the placebo or active formulations were administered twice daily before meals; no major dietary changes nor exercises were suggested during the study. A total of six anthropomorphic and serological measurements (body weight, body fat, waist size; total plasma cholesterol, LDL cholesterol, fasting blood glucose level) were taken at baseline and at 4, 8 and 10 weeks.ResultsCompared to the placebo group, the two active groups showed a statistically significant difference on all six variables by week 10. The magnitude of the differences was noticeable by week 4 and continued to increase over the trial period.ConclusionAlthough the Cissus quadrangularis- only group showed significant reductions on all variables compared to the placebo group, the Cissus quadrangularis/Irvingia gabonensis combination resulted in even larger reductions. This apparently synergistic formulation should prove helpful in the management of obesity and its related complications.


Journal of Herbal Pharmacotherapy | 2008

In vitro antioxidant activity of three Piper species.

Gabriel A. Agbor; Joe A. Vinson; Julius E. Oben; Jeanne Ngogang

Reactive oxygen species are known to play a role in numerous pathological conditions, and antioxidants from plant sources have been of great help in modulating this effect. This study assesses the methanolic exttacts of the leaves of three Piper species (Piper guineense Schum and Thonn, Piper nigrum L. and Piper umbellatum L.) (Piper-aceae) for their polyphenolic concentration and free radical scavenging activity. The Folin-Ciocalteu method was used to assess the polyphenolic concenttation while the reducing power, l,l-diphenyl-2-picrylhydrazyl (DPPH), Superoxide radical, hydroxyl radical, nitric oxide scavenging and metal chelating activities were employed in studying the radical scavenging activity of the extracts. All three spices exhibited a marked polyphenolic concentration and dose dependent free radical scavenging activity. The free polyphenolic concentration of the three spices was in the order P. umbellatum(15.9 ± 1.9 mg/g) > P. guineense(12.6 ± 0.3 mg/g) > P. nigrum(9.8 ± 0.8). The three Piper extracts exhibited a 79.8-89.9% scavenging effect on DPPH, an 85.1-97.9% scavenging effect on nitric oxide at a dose level of 10 mg/ml and a 47.1-51.6% scavenging effect on Superoxide radical at a dose level of 8 mg/ml extraction. Piper extracts also exhibited a 57-76.1% scavenging effect on hydroxyl radical at 5 mg/ml, a 0.4-0.6 reducing power and an 88.3-93.9% metal chelating activity at a dose level of 8 mg/ml of extract. Thus, these Piper species can play a role in the modulation of free radical induced disorders.


Chinese Journal of Natural Medicines | 2010

Antioxidant Effect of Herbs and Spices on Copper Mediated Oxidation of Lower and Very Low Density Lipoprotein

Gabriel A. Agbor; Joe A. Vinson; Julius E. Oben; Jeanne Ngogang

Abstract Aim The present study investigates the antioxidant effect of two extracts (hydrolyzed and non-hydrolyzed) of five herbs and eight spices in the prevention of LDL + VLDL oxidation promoted by cupric ion. Methods The polyphenolic concentrations of these extracts were measured using Folin-Ciocalteu reagent. The antioxidant quality was analyzed by the determination of lag-time, concentration of polyphenol that will inhibit 50% of oxidation of LDL + VLDL (IC 50 ) and phenol antioxidant index (PAOXI). Results The hydrolyzed extracts had significant higher polyphenol concentration, longer lag-time, lower IC 50 and higher PAOXI than the non-hydrolyzed extracts ( P Conclusion The reaction rate and concentration of conjugated diene formed suggested that all the extracts had similar reaction mechanism in the prevention of copper mediated LDL + VLDL oxidation.


International journal of food science | 2014

Folin-Ciocalteau Reagent for Polyphenolic Assay

Gabriel A. Agbor; Joe A. Vinson; Patrick E. Donnelly

Summary of Manual Dual Reagent Procedure [2] Up to100 µL of properly diluted sample in an organic water-mis-cible solvent with at least 6 mL of water + 0.5 mL of F-C reagent (Sigma); wait between 1 - 8 min, add 1.5 mL of Na 2 CO 3 ; mix and bring to 10 mL total volume with water; then measure absorbance The volume can be scaled down to conserve reagents. Abstract The chemistry of the Folin-Ciocalteu is described and two Folin assays (single and dual reagent) are described for the assay of phenols and polyphenols with respect to experimental detail and critically evaluated for pure compounds and for mixtures (plant extracts). The single rea-gent method was found to be more precise and sensitive. The problem of interferences in the Folin assay was evaluated for both methods. Interferences for the dual reagent methodology can be eliminated by a solid phase removal of phenols using a commercial resin (Oasys HLB) or polyvinylpyrrolidone resin (Polyclar AT). A new basic/acid hydrolysis combed with the Polyclar AT was used to measure the total phenols in a sample as previous methods measured only the phenolic groups not bound as ether or ester groups. A semi-automated method, microplate reader, is described as to the experimental procedure and applicability. Miscellaneous uses of the Folin assay including flow injection,urine analysis and a mixed standard are briefly described.


Food Chemistry | 2012

Piper species protect cardiac, hepatic and renal antioxidant status of atherogenic diet fed hamsters

Gabriel A. Agbor; Luli Akinfiresoye; Julianne Sortino; Robert L. Johnson; Joe A. Vinson

Pre-clinical and clinical studies points to the use of antioxidants as an effective measure to reduce the progression of oxidative stress related disorders. The present study evaluate the effect of three Piper species (Piper guineense, Piper nigrum and Piper umbellatum) for the protection of cardiac, hepatic and renal antioxidant status of atherogenic diet fed hamsters. Hamsters were classified into eight groups: a normal control, atherogenic control and six other experimental groups (fed atherogenic diet supplemented with different doses of P. nigrum, P. guineense and P. umbellatum (1 and 0.25 g/kg) for 12 weeks. At the end of the feeding period the heart, liver and kidney from each group were analyzed for lipid profile and antioxidant enzymes activities. Atherogenic diet induced a significant (P<0.001) increase in the lipid profile across the board and equally significantly altered the antioxidant enzyme activities. Supplementation with Piper species significantly inhibited the alteration effect of atherogenic diet on the lipid profile and antioxidant enzymes activities. The Piper extracts may possess an antioxidant protective role against atherogenic diet induced oxidative stress in cardiac, hepatic and renal tissues.


BioMed Research International | 2014

In Vitro Antiplasmodial Activities and Synergistic Combinations of Differential Solvent Extracts of the Polyherbal Product, Nefang

Protus Arrey Tarkang; Kathrin Diehl Franzoi; Sukjun Lee; Eunyoung Lee; Diego Vivarelli; Lucio H. Freitas-Junior; Michel Liuzzi; Tsabang Nolé; Lawrence Ayong; Gabriel A. Agbor; Faith A. Okalebo; Anastasia N. Guantai

Nefang, a polyherbal product composed of Mangifera indica (bark and leaf), Psidium guajava, Carica papaya, Cymbopogon citratus, Citrus sinensis, and Ocimum gratissimum (leaves), is a potential therapy against P. falciparum malaria. In vitro antiplasmodial activities of its constituent solvent extracts were analyzed on CQ-sensitive (3D7) and multidrug resistant (Dd2) P. falciparum strains. The interactions involving the differential solvent extracts were further analyzed using a variable potency ratio drug combination approach. Effective concentration 50 (EC50) values were determined by nonlinear regression curve-fitting of the dose-response data and used in calculating the fractional inhibitory concentration 50 (FIC50) and combination indices (CI) for each pair. The derived EC50 values (3D7/Dd2, μg/mL) are Nefang-96.96/55.08, MiB-65.33/34.58, MiL-82.56/40.04, Pg-47.02/25.79, Cp-1188/317.5, Cc-723.3/141, Cs-184.4/105.1, and Og-778.5/118.9. Synergism was obtained with MiB/Pg (CI = 0.351), MiL/Pg (0.358), MiB/Cs (0.366), MiL/Cs (0.482), Pg/Cs (0.483), and Cs/Og (0.414) when analyzed at equipotency ratios. Cytotoxicity testing of Nefang and the solvent extracts on two human cell lines (Hep G2 and U2OS) revealed no significant toxicity relative to their antiplasmodial activities (SI > 20). Taken together, our data confirm the antimalarial activities of Nefang and its constituent plant extracts and identified extract pairs with promising synergistic interactions for exploitation towards a rational phytotherapeutic and evidence-based antimalarial drug discovery.


African Journal of Laboratory Medicine | 2016

Whole blood pathogen reduction technology and blood safety in sub-Saharan Africa: A systematic review with regional discussion

Asa'ah Nkohkwo; Gabriel A. Agbor; Emmanuel Acha Asongalem; Claude Tagny; Tazoacha Asonganyi

Background Despite vast improvements in transfusion services in sub-Saharan Africa over the last decade, there remain serious concerns on the safety and adequacy of the blood supply across the region. Objective This review paper ascertains the role of pathogen reduction technology (PRT) in improving blood safety and supply adequacy in the region. Method The state of blood safety in sub-Saharan Africa was reviewed. Meetings, seminars and correspondence were undertaken with key clinicians, scientists and professional bodies in the region, including the World Health Organization’s Regional Office for Africa, to examine the suitability of PRT for improving the safety of whole blood transfusion, a prevalent transfusion format in the region. Results Existing literature suggests that combining PRT with current blood safety measures (such as serology) would improve the safety and adequacy of the blood supply for transfusions in sub-Saharan Africa. This was echoed by the findings of the stakeholder meetings. Conclusion Following a detailed appraisal of two leading PRT systems, the Mirasol® PRT System and the Cerus S-303 System, we suggest that companies conduct comprehensive toxicological evaluation of the agents used for PRT and publish this in the scientific literature. We also recommend that the safety and efficacy of these technologies should be established in a randomised clinical trial conducted in sub-Saharan Africa.


Pharmaceutical Biology | 2014

Evaluation of the antidiarrheal and antioxidant properties of Justicia hypocrateriformis

Gabriel A. Agbor; Frida Longo; Estelle A. Makong; Protus Arrey Tarkang

Abstract Content: Justicia hypocrateriformis Vahl (Acanthaceae) is used as an herbal remedy for diarrhea in Cameroon folk medicine. Objective: This study evaluates the antidiarrheal and antioxidant properties of the aqueous extract of J. hypocrateriformis (JH). Materials and methods: Preliminary phytochemical screening and an acute toxicity testing of the extract were carried out. The antidiarrheal activity of JH extract (100, 250, and 500 mg/kg) was assessed at curative and preventive levels in castor oil-induced diarrhea in mice. The antioxidant activity was measured by ferric reducing antioxidant power (FRAP), total phenolic content, and radical scavenging activity. Results: A high lethal dose (LD50) of 14.35 g/kg obtained in acute toxicity implies the extract is not toxic. Phytochemical screening revealed the presence of phenols, tannins, flavonoids, saponins, anthraquinones, and anthocyanins. JH showed a significant protection against castor oil-induced diarrhea as evidenced by a decrease in the number of defecation and wet stool. JH (100–500 mg/kg, p.o.) produced a non-significant dose-dependent decrease in castor oil-induced intestinal transit in the preventive study. In the curative and in healthy mice study, the decrease was only significant at 500 mg/kg. JH possessed a radical scavenging activity with an IC50 of 9.93 mg/ml compared to 4.90 mg/ml for catechin. JH FRAP of 2703.77 ± 0 mg/g (catechin equiv) and phenolic concentration of 14 169.99 ± 612.39 mg/g (catechin equiv) were also obtained. Conclusion: Justicia hypocrateriformis extract possesses antidiarrheal activity supported by its antioxidant potential and phytochemical constituents.

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Julius E. Oben

University of Yaoundé I

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Jeanne Ngogang

University of Yaoundé I

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Frida Longo

University of Yaoundé I

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