Phenolic Compounds from Water-Ethanol Extracts of Tetrapleura tetraptera Produced in Cameroon, as Potential Protectors against In Vivo CCl4-Induced Liver Injuries.

BACKGROUND: Liver diseases are a global health problem. Medicinal plants are being increasingly used to manage a wide variety of diseases including liver disorders. The aim of this study was to investigate the antioxidant properties and hepatoprotective activity of polyphenolic extract from the fruits of Tetrapleura tetraptera (T. tetraptera). RESULTS: The extract of T. tetraptera was administered at doses of 50 mg/kg and 100 mg/kg for 07 per os to rats before the induction of hepatotoxicity with of 2 ml/kg of 1:1 (v/v) carbon tetrachloride (CCl4) and olive oil through intraperitoneal route. The in vitro antioxidant and radical scavenging properties of T. tetraptera were conducted by the FRAP method, the phosphomolybdate method, and the inhibition potential of DPPH, ABTS, OH, and NO radicals. The extraction yield of T. tetraptera was 19.35%. This extract contains polyphenols (273.48 mg CAE/g DM), flavonoids (5.2549 mg SE/g DM), and flavonols (1.615 mg SE/g DM). This extract showed in vitro antioxidant activity, an inhibitor power of various free radicals, and radical scavenging potential dose-dependent. The fifty-percent inhibitory concentration of the extract (IC50) for the studied radical varied from 28.16 to 136 µg/L. In rats treated with the extract of T. tetraptera, in a dose-dependent manner, the levels of hepatotoxicity markers such as alanine aminotransferase (ALT), aspartate aminotransferase (AST), and alkaline phosphatase (ALP) significantly increased while the enzyme activities of superoxide dismutase (SOD), catalase (CAT), and the level of reduced glutathione (GHS) significantly increased compared to the control group. CONCLUSIONS: The extracts from the fruit of T. tetraptera demonstrate antioxidant activity and hepatoprotective effects.

In vitro organo-protective effect of bark extracts from Syzygium guineense var macrocarpum against ferric-nitrilotriacetate-induced stress in wistar rats homogenates.

BACKGROUND: Overconsumption of oxygen in mammalian cells often lead to the production of reactive oxygen species (ROS) resulting from different mechanisms. Escape of scavenging enzymes/components or nutritional failure are the most important origins. Plant-derived molecules may protect biological molecules either by quenching free radicals, delaying or preventing the ROS formation or by restoring antioxidant enzymes activities. The present study assessed the antioxidant, phenolic profile and protective effect of barks extracts of Syzyguim guineense var macrocarpum against ferric nitriloacetate-induced stress in the liver, heart kidney and brain tissues of wistar rat homogenates. METHODS: Three extracts (aqueous, ethanol and aqueous-ethanol) from the barks of S. guineense var macrocarpum were used in this study. The spectrophotometric standardized methods were used to determine the free radical scavenging and antioxidant potential of the extracts. The protective properties of these plant extracts were also investigated as well as the quantification of secondary metabolites content (total phenolic, flavonoids and flavonols content). The HPLC method helped for characterizing phenolic compounds present in these extracts. RESULTS AND DISCUSSION: All the extracts exhibited a free radical scavenging potential in a concentration dependent manner which varied from 15.18 ± 0.80 to 97.15 ± 0.71 % depending to the type of extract and the method used. The ethanol extract had the higher phenolic content (432.85 mg QE/g extract), including total flavonoids (961.66 mg QE/g extract) and flavonols content (25.12 mg QE/g extract) and higher total antioxidant capacity. Among the phenolic compounds present in the extracts, the HLPC profile revealed the presence of syringic acid and apigenin in all the extracts. The extracts demonstrated their protective effect mostly in liver and brain homogenates by delaying or preventing lipid peroxidation, restoring enzymatic activities and enhancing glutathione levels. CONCLUSION: The overall results demonstrated that the extracts exhibited significant antioxidant and protective effects in liver and brain liver homogenates.

Impact of daily supplementation of Spirulina platensis on the immune system of naïve HIV-1 patients in Cameroon: a 12-months single blind, randomized, multicenter trial.

BACKGROUND: Micronutrient deficiencies occur early in Human Immunodeficiency Virus (HIV) infections they have reverse effects on the nutritional status. The diet supplementation with a natural nutraceutical rich in proteins and micronutrient like Spirulina platensis, may be effective and efficient in delaying HIV disease progression by frequently reported improvement in immune response. METHODS: A prospective single-blind, randomized, multicenter study conducted on 320 HIV-1 ARV-naïve participants for 12 months. Participants received either S. platensis supplementation and standard care or standard care and local balanced diet without S. platenis. Selected hematological and biochemical as well as CD4 count cells, viral load copies were assessed at three separate times. RESULTS: Among the 169 ART-naïve participants enrolled in the study, the female was mostly represented (67.1%). The significant increase of CD4 count cells (596.32-614.92 cells count) and significant decrease of viral load levels (74.7 × 10(3)-30.87 × 10(3) copies/mL) of the patients who received a supplementation of S. platensis was found after 6 months of treatment. Haemoglobin level was also significantly higher in the same group while the fasting blood glucose concentration decreased after 12 months compared to control. CONCLUSION: A daily supplementation with S. platensis to diet combined with a reasonable balanced diet has significantly increased the CD4 cells and reduced the viral load after 6 months. Further studies are recommended among a large specific group of people infected by the HIV in order to investigate the mechanisms involved on the effect of S. platensis on immune system.

In vitro antioxidant properties, free radicals scavenging activities of extracts and polyphenol composition of a non-timber forest product used as spice: Monodora myristica.

BACKGROUND: Excessive production of free radicals causes direct damage to biological molecules such as DNA, proteins, lipids, carbohydrates leading to tumor development and progression. Natural antioxidant molecules from phytochemicals of plant origin may directly inhibit either their production or limit their propagation or destroy them to protect the system. In the present study, Monodora myristica a non-timber forest product consumed in Cameroon as spice was screened for its free radical scavenging properties, antioxidant and enzymes protective activities. Its phenolic compound profile was also realized by HPLC. RESULTS: This study demonstrated that M. myristica has scavenging properties against DPPH(•), OH(•), NO(•), and ABTS(•) radicals which vary in a dose depending manner. It also showed an antioxidant potential that was comparable with that of Butylated Hydroxytoluene (BHT) and vitamin C used as standard. The aqueous ethanol extract of M. myristica barks (AEH); showed a significantly higher content in polyphenolic compounds (21.44 ± 0.24 mg caffeic acid/g dried extract) and flavonoid (5.69 ± 0.07 quercetin equivalent mg/g of dried weight) as compared to the other studied extracts. The HPLC analysis of the barks and leaves revealed the presence of several polyphenols. The acids (3,4-OH-benzoic, caffeic, gallic, O- and P- coumaric, syringic, vanillic), alcohols (tyrosol and OH-tyrosol), theobromine, quercetin, rutin, catechine and apigenin were the identified and quantified polyphenols. All the tested extracts demonstrated a high protective potential on the superoxide dismutase (SOD), catalase and peroxidase activities. CONCLUSION: Finally, the different extracts from M. myristica and specifically the aqueous ethanol extract reveal several properties such as higher free radical scavenging properties, significant antioxidant capacities and protective potential effects on liver enzymes.

Effects of Spirulina platensis supplementation on lipid profile in HIV-infected antiretroviral naïve patients in Yaounde-Cameroon: a randomized trial study.

BACKGROUND: Cardiovascular diseases (CVD) and metabolic alterations are among the majors public health concern that have been reported in people living with HIV infections. Factors contributing to cardio metabolic syndrome in HIV include body fat distribution, dyslipidemia, insulin resistance, cardiovascular dysfunction and inflammation. The aim of the study was to determine the effect of Spirulina platensis (Cyanobacteriaceae) supplementation versus local diet on lipid profile in HIV-infected antiretroviral-naive patients. METHODS: A prospective single-blind, randomized, multicentre study was conducted from February 2010 to December 2012. A total of 320 HIV antiretroviral-naïve patients were screened and 169 were recruited in this study. Patients were randomized and received either Spirulina supplementation combined with local diet (n=82) or local diet only (n=87). Age, weight, body mass index (BMI), lipid profile, CD4 count, and local food intake variables were assessed on three separate occasions (three, six and twelve months). RESULTS: An average age of the patients was 35.6±9 years. The majority of participants were female 67.1%. Regarding the lipid profile, there is a significant increase in HDL-cholesterol and a significant decrease in total cholesterol, LDL-cholesterol and triglycerides in the group of patients who consumed Spirulina platensis. A change in the atherogenic index defined by the ratio CT/HDL-C substitutable by LDL-C/HDL-C and the TC/HDL decreased significantly from 10.83 at baseline to 2.22 after 12 months (p=0.21 and p<0.0001) in the patients taking Spirulina. CONCLUSIONS: Nutritional supplementation with Spirulina combined with a quantitative and qualitative balanced diet for at least six months can retard an exposition to lipid abnormalities in HIV-infected antiretroviral-naive patients. Further studies are recommended on a large group of people not infected with HIV and exposed to cardiovascular risk factors.

Fruits and barks extracts of Zanthozyllum heitzii a spice from Cameroon induce mitochondrial dependent apoptosis and Go/G1 phase arrest in human leukemia HL-60 cells.

BACKGROUND: Zanthoxylum heitzii is a spice used to prepare several dishes and to treat tumors, syphilis, malaria, cardiac palpitations, urogenital infections in the west region of Cameroon, but the antitumor mechanisms and chemical composition are not yet investigated. This study was aimed to determine the antiproliferative effects of four extracts from the fruits and barks of Zanthoxyllum heitzii (Rutaceae) on apoptosis in human promyelocytic cells, their mechanisms and the chemical composition. The 3-(4, 5-dimethylthiazole-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was used to determine the fifty percent inhibition (IC50) concentration of the cell lines after treatment. The effect on morphology was observed using a light or fluorescence microscopy. The rate of apoptosis and the cell cycle were measured using flow cytometry (FCM). The phytochemical analysis of the extract was carried with HPLC/MS methods. RESULTS: The phytochemical analysis of the extracts indicated the presence of four known polyphenols (Syringic acid, Juglon, Luteolin and Myricetin) in both fruits and barks of Z. heitzii but in different quantities. Syringic acid and Myricetin concentrations were between 17-21 fold higher in the fruits than the stem bark. Rhamnetin (393.35 µg/mL) and Oleuropein (63.10 µg/mL) were identified only in the stem barks of Z. heitzii. Among the four extracts tested for cytotoxicity properties, only the methanol extract of fruits and barks significantly inhibited cell proliferation of HL-60 cells with IC50 value of 20 µg/mL and 12 µg/mL respectively. HL-60 cells treated with Z. heitzii extracts significantly produced reactive oxygen species (ROS) with concurrent loss of mitochondrial membrane potential (MMP). Modifications in the DNA distribution and enhanced of G1/G0 phase cell cycle arrest were observed in a concentration dependent manner. CONCLUSIONS: Polyphenols from Z. heitzii plant exert inhibitory effect on HL-60 cells through the reactive oxygen species (ROS) generation, loss of mitochondrial membrane potential and cell cycle destabilization.

Antiproliferative activity and induction of apoptosis by Annona muricata (Annonaceae) extract on human cancer cells.

BACKGROUND: Annona muricata (A. muricata) is widely distributed in Asia, Africa and South America. Different parts of this plant are used to treat several diseases in Cameroon. The aim of this study is to determine the in vitro anti-proliferative effects and apoptotic events of A. muricata extracts on HL-60 cells as well as to quantify its phenols content. METHODS: The cell viability was measured by using 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay while the changes in morphology of HL-60 cells, membrane mitochondrial potential (MMP) and the cell cycle were used for assessment apoptosis induction. RESULTS: The results show that the concentration of phenols, flavonoids and flavonols in the extracts varied depending on the part of the plant. All the extracts tested inhibited the proliferation of HL-60 cells in a concentration dependent manner with IC50 varied from 6-49 µg/mL. The growth inhibition of the cells by extracts was associated with the disruption of MMP, reactive oxygen species (ROS) generation and the G0/G1 cell arrest. CONCLUSION: These findings suggest that the extracts from A. muricata have strong antiproliferation potential and can induce apoptosis through loss of MMP and G0/G1 phase cell arrest.

Protective effects of stem bark of Harungana madgascariensis on the red blood cell membrane.

BACKGROUND: Anemia is a condition that has multiple origins. One such origin is the destruction of red blood cells' (RBCs) membrane induced by free radicals. Treatment of anemia could therefore be enhanced by the use of free radicals' scavengers potentially found in some medicinal plants. In this study, the protective effect of Harungana madagascariensis on the RBCs' membrane physiology was investigated in vitro and in vivo. METHODS: In vitro hemolytic anemia was induced by incubation of fresh human RBCs with carbontetrachloride (CCl4) in Olive oil (Oo). Relaxation times of protons excited at 20 MHz (Carr-Purcell-Meiboom-Gill pulse sequence) in the absence or presence of paramagnetic Mn2+ ions (T2i for "extracellular" water and T2a for "intracellular" water, respectively) were determined at several temperatures (25-37°C) via Nuclear Magnetic Resonance (NMR) on a Bruker Minispec spectrometer. Water exchange times (Te) were consequently calculated using the Conlon-Outhred equation: 1/Te = (1/T2a) - (1/T2i). Morphological characteristics (mean cell volume, V, and cell surface area, A) were determined by photonic microscopy and the RBCs' diffusional water permeability (Pd) was calculated as Pd = (1/Te)*(Va/A), where Va is the aqueous volume in the RBC and is about 0.7 of the cell volume (V). The activation energy of the diffusional process (Ea) for the respective temperature range was estimated using the Arrhenius modified equation k = A(T/T0)n*e-Ea/RT. Inhibition of the water diffusion induced by incubation with para-chloro-mercuribenzoic acid (PCMB) at 25, 30 and 37°C was calculated as I(%) = [(Pd control - Pd sample)/Pd control]*100.To investigate the protective influence of the extract on the RBC membrane, inhibition of the water permeability was evaluated on membranes pre-incubated with the Harungana madagascariensis extract. Male rats were used in in vivo investigations. Malondialdehyde (MDA) and cholesterol in the RBC membrane were estimated by induction of lipid peroxidation while the antioxidant properties of catalase (CAT) and superoxide dismutase (SOD) on the membrane were evaluated in regard to their antioxidant properties on the membrane. RESULTS: T2a significantly decreased at each temperature. Te results were higher in both RBCs and RBCs + extract groups incubated with PCMB compared to non-incubated controls, but differences were not statistically significant. A high percentage (73.81 ± 7.22) of RBCs pre-incubated with the extract presented the regular biconcave shape. Inhibition by PCMB of the RBCs' membrane water permeability was increased at 30°C and decreased in the presence of extract (25°C and 37°C), while Ea decreased from 30.52 ± 1.3 KJ/mol to 25.49 ± 1.84 KJ/mol. Presence of the Harungana madagascariensis extract normalized the SOD and CAT activities as well as the MDA and membrane cholesterol concentrations altered by the CCl4-induced oxidative stress. CONCLUSION: Harungana madagascariensis could protect the RBCs' membrane through its antioxidative properties.

Induction of mitochondrial dependent apoptosis and cell cycle arrest in human promyelocytic leukemia HL-60 cells by an extract from Dorstenia psilurus: a spice from Cameroon.

BACKGROUND: The use of edible plants is an integral part of dietary behavior in the West region of Cameroon. Dorstenia psilurus (Moraceae) is widely used as spice and as medicinal plant for the treatment of several diseases in Cameroon. The aim of this study is to investigate the cytotoxic and apoptotic potential of methanol extract of D. psilurus in human promyelocytic leukemia (HL-60) cells and prostate cancer (PC-3) cells. METHODS: Cytotoxicity of D. psilurus extract was tested in HL-60 and PC-3 cells using 3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) reduction assay and flow cytometric methods RESULTS: The methanol extract of D. psilurus have significant in vitro cytotoxic activity in HL-60 cells and PC-3 cells with IC50 value of 12 ± 1.54 µg/ml and 18 ± 0.45 µg/ml respectively after 48 h. The mechanism of antiproliferative activity showed that after 24 h, D. psilurus extract induces apoptosis on HL-60 cells by the generation of reactive oxygen species (ROS) along with concurrent loss of mitochondrial membrane potential, modification in the DNA distribution and enhance of G2/M phase cell cycle. CONCLUSION: The extract induces apoptosis of HL-60 cells associated with ROS production, loss of mitochondrial membrane potential and apoptotic DNA fragmentation.

Antioxidant and Synergistic Antidiabetic Activities of a Three-Plant Preparation Used in Cameroon Folk Medicine.

Introduction. Several plant preparations like a mixture of aqueous extracts of Spilanthes africana; Portulaca oleracea; and Sida rhombifolia are currently utilized in Foumban (West Cameroon) to manage diabetes. The aim of this study is to investigate the antidiabetic property of the aqueous mixture of three plant extracts (1 : 1 : 1) on streptozotocin induced diabetes rats. Methods. Diabetes was induced to rats by intraperitoneal (i.p.) injection of streptozotocin (STZ) at a dose of 50 mg/kg b.w. The diabetic rats received different dosages of the mixture of extracts for 21 days and glibenclamide 6.5 mg/kg b.w. as positive control. Results. The results showed that the mixture of extracts significantly (p < 0.05) decreased the level of the glycaemia, the total cholesterol, triglyceride, and LDL-cholesterol as well as MDA, AST, ALT, and creatinine levels. It also increased significantly the concentration of HDL-cholesterol, glutathione, and TAOS. A great reduction of the atherogenic indexes CT/HDL and LDL/HDL of the treated groups was observed. Each extract and the mixture demonstrated significant scavenging property on DPPH and OH radicals and present a good antioxidant property. Conclusion. The mixture of plant extracts has hypoglycemic, antioxidant, and hypolipidemic properties and can be used for the management of diabetes mellitus.

In vitro antioxidant and anti-lipoperoxidative activities of bark extracts of Xylopia aethiopica against ion-mediated toxicity on liver homogenates.

Reactive oxygen species (ROS), products of normal cell metabolism may cause damage to biological macromolecules leading to severe health threats when they are present in high concentrations. Aromatic plants contain phytochemicals rich of antioxidants that prevent oxidant formation or scavenge oxidants produced under oxidative stress conditions. In the present study, we investigated the free radical scavenging effects, the antioxidant and ion toxicity preventive effect of Xylopia aethiopica (X. aethiopica), a plant of the family of Annonaceae used as spice in Cameroon. The scavenging properties of extracts of X. aethiopica were tested on 2, 2-diphenyl-1-picrylhydrazyl (DPPH), nitric oxide (NO), hydroxyl (OH), 2,2'-azinobis(3-ethylbenzthiazoline)-6-sulfonic acid (ABTS) radicals. The total antioxidant capacity was assayed by ferric reducing ability of plasma (FRAP), phosphomolybdenum antioxidant power (PAP), reduction assays. The protective potential was carried on superoxide dismutase (SOD), catalase and peroxidases. The results showed that both the ethanolic (BEE) and the hydroethanolic (BEH) extracts from the barks of X. aethiopica scavenged all the tested radicals. The sample BEH showed the highest total antioxidant capacity both in the FRAP and the PAP. This result was positively correlated to its higher phenolic content (30.74±0.44 CAE/g dried extract). The higher protective capacity of BEH on SOD, catalase and peroxidase activities was comparable to that of the vitamin C used as standard. In conclusion, X. aethiopica has a higher antioxidant and protective potential against ion-mediated oxidative damage and may be considered as a potential drug against metal-mediated toxicity.

Free radicals quenching potential, protective properties against oxidative mediated ion toxicity and HPLC phenolic profile of a Cameroonian spice: Piper guineensis.

Considerations on antioxidants derived from plants have continuously increased during this decade because of their beneficial effects on human health. In the present study we investigated the free radical scavenging properties of extracts from Piper guineense (P. guineense) and their inhibitory potentials against oxidative mediated ion toxicity. The free radical quenching properties of the extracts against [1,1-diphenyl-2-picrylhydrazyl (DPPH•), 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS•), hydroxyl radical (HO•), nitric oxide (NO•)] radical and their antioxidant potentials by FRAP and phosphomolybdenum were determined as well as their protective properties on liver enzymes. The phenolic profile was also investigated by HPLC. The results obtained, revealed that the extracts significantly inhibited the DPPH, NO, HO and ABTS radicals in a concentration depending manner. They also showed a significant ferrous ion chelating ability through FRAP and phosphomolybdenum antioxidant potential. Their polyphenol contents varied depending on the type of extracts and the solvent used. The hydroethanolic extracts (FFH) and the ethanolic extracts (FFE) of P. guineense leaves showed the higher level of phenolic compounds respectively of 21.62 ± 0.06 mg caffeic acid/g dried extract (CAE/g DE) and 19.01 ± 0.03 CAE/g DE. The HPLC phenolic compounds profile revealed a higher quantity of Eugenol, quercetin, rutin and catechin in the stem than in the leaves. The presence of these molecules could be responsible of the protective potentials of P. guineense extracts against lipid peroxidation and SOD, catalase and peroxidase. In conclusion, P. guineense extracts demonstrated significant antioxidant property and may be used as a prospective protector against metal related toxicity.

Afrostyrax lepidophyllus extracts exhibit in vitro free radical scavenging, antioxidant potential and protective properties against liver enzymes ion mediated oxidative damage.

BACKGROUND: Several studies described the phytochemical constituents of plants in relation with the free radical scavenging property and inhibition of lipid peroxidation. This study investigated the in vitro antioxidant property, and the protective effects of ethanolic and aqueous ethanol extract of the leaves and barks of Afrostyrax lepidophyllus (Huaceae) against ion mediated oxidative damages. METHODS: Four extracts (ethanol and aqueous-ethanol) from the leaves and barks of A. lepidophyllus were used in this study. The total phenols content, the antiradical and antioxidant properties were determined using standard colorimetric methods. RESULTS: The plant extracts had a significant scavenging potential on the 2,2-diphenyl-1-picrylhydrazyl (DPPH), hydroxyl (OH), nitrite oxide (NO) and 2,2-azinobis (3-ethylbenzthiazoline)-6-sulfonic acid (ABTS) radicals with the IC50 varied between 47 and 200 µg/mL depending on the part of plant and the type of extract. The ethanol extract of A. lepidophyllus bark (GEE) showed the highest polyphenolic (35.33 ± 0.29) and flavonoid (12.00 ± 0.14) content. All the tested extracts demonstrated a high protective potential with the increased of superoxide dismutase, catalase and peroxidase activities. CONCLUSION: Afrostyrax lepidophyllus extracts exhibited higher antioxidant potential and significant protective potential on liver enzymes.

Determinants of fructosamine levels in a multi-ethnic Sub-Saharan African population.

BACKGROUND AND PURPOSE: Fructosamine provides an estimate of diabetes control over a shorter period than HbA1c, and has been proposed as a suitable parameter to monitor glycemic control in low-income countries. The aim of this study was to investigate determinants of fructosamine levels in an urban non-diabetic population of Cameroon. METHODS: This was a cross-sectional study including 437 healthy adults with no known history of diabetes mellitus, aged 40 years and above, recruited from the ten administrative regions, representing major ethnic groups in the country. Plasma glucose and fructosamine were measured after an overnight fasting. Univariable and multivariable analyses were used to investigate the factors associated with fructosamine measurements. RESULTS: Fructosamine levels ranged from 68.2 to 940.8 µmol/l with a mean (standard deviation) of 294.4 (131.3) µmol/l. These levels varied significantly across regions and were higher in men than in women (p=0.001) and in those with screen-detected diabetes than in those with normoglycemia (p<0.0001). There was a negative correlation between fructosamine and body mass index (r=-0.15, p=0.009), and a positive correlation with fasting plasma glucose (FPG) (r=0.37, p<0.0001) and total bilirubinemia (r=0.21, p<0.0001). In multivariable model, sex, BMI, FPG, total bilirubine and screen-detected diabetes were no longer associated with fructosamine levels. CONCLUSION: Fructosamine was not independently associated with age, sex, ethnicity, and the glycemic status. Further studies need to be carried out to better elucidate all the factors determining the measurement of fructosamine in order to accurately interpret its values in diabetic populations.

Phenolic Content of Hypodaphnis Zenkeri and Its Antioxidant Effects against Fenton Reactions' Mediated Oxidative Injuries on Liver Homogenate.

Under oxidative stress conditions, endogenous antioxidant defenses are unable to completely inactivate the free radicals generated by an excessive production of reactive oxygen species (ROS). This state causes serious cell damage leading to a variety of human diseases. Natural antioxidants can protect cells against oxidative stress. Hypaodaphnis zenkeri (H. zenkiri) is a plant consumed as a spice in the Cameroonian diet, and its bark has been used in traditional medicine for the treatment of several diseases. The present study aims at investigating the antioxidant activity, which includes free radical scavenging and protective properties of an extract from H. Zenkiri against oxidative damage on a liver homogenate. The free radical assays determined the scavenging activities of 2,2-diphenyl-1-picrylhydrazyl (DPPH), hydroxyl (OH), nitrite oxide (NO) and 2,2-azinobis(3-ethylbenzthiazoline)-6-sulfonic acid (ABTS) radicals and the enzymes, whose protection was to be considered in the liver homogenate, including superoxide dismutase, catalase, and peroxidase. The antioxidative activities were studied using the ferric reducing antioxidant power (FRAP), reductive activity, and phosphomolybdenum antioxidant power (PAP) methods. In addition, the phenolic contents of the extracts were examined. The results showed that these extracts demonstrated significant scavenging properties and antioxidant activities, with the hydro-ethanolic extract of the bark of H. zenkeri (EEH) being the most potent. This extract had the highest total polyphenol (21.77 ± 0.05 mg caffeic acid (CAE)/g dried extract (DE)) and flavonoids (3.34 ± 0.13 mg quercetin (QE)/g dried extract) content. The same extract had significantly greater protective effects on enzyme activities compared to other extracts. The high performance liquied chromatography (HPLC) profile showed higher levels of caffeic acid, OH-tyrosol acid, and rutin in the leaves compared to the bark of H. zenkeri. In conclusion, the ethanolic and hydro-ethanolic extracts of the bark and leaves from H. zenkeri showed an antioxidant and protective potential against oxidative damage.

Syzyguim guineense Extracts Show Antioxidant Activities and Beneficial Activities on Oxidative Stress Induced by Ferric Chloride in the Liver Homogenate.

The aim of this study was to determine the in vitro antioxidant activity, free radical scavenging property and the beneficial effects of extracts of various parts of Syzygium guineense in reducing oxidative stress damage in the liver. The effects of extracts on free radicals were determined on radicals DPPH, ABTS, NO and OH followed by the antioxidant properties using Ferric Reducing Antioxidant Power assay (FRAP) and hosphomolybdenum (PPMB). The phytochemical screening of these extracts was performed by determination of the phenolic content. The oxidative damage inhibition in the liver was determined by measuring malondialdehyde (MDA) as well as the activity of the antioxidant enzymes superoxide dismutase (SOD), catalase (CAT) and peroxidase. Overall, the bark extract of the ethanol/water or methanol showed the highest radical scavenging activities against DPPH, ABTS and OH radicals compared to the other extracts. This extract also contained the highest phenolic content implying the potential contribution of phenolic compounds towards the antioxidant activities. However, the methanol extract of the root demonstrated the highest protective effects of SOD and CAT against ferric chloride while the hydro-ethanol extract of the leaves exhibited the highest inhibitory effects on lipid peroxidation. These findings suggest that antioxidant properties of S. guineense extracts could be attributed to phenolic compounds revealed by phytochemical studies. Thus, the present results indicate clearly that the extracts of S. guineense possess antioxidant properties and could serve as free radical inhibitors or scavengers, acting possibly as primary antioxidants. The antioxidant properties of the bark extract may thus sustain its various biological activities.

In vitro antioxidant properties, free radicals scavenging activities of extracts and polyphenol composition of a non-timber forest product used as spice: Monodora myristica

BACKGROUND: Excessive production of free radicals causes direct damage to biological molecules such as DNA, proteins, lipids, carbohydrates leading to tumor development and progression. Natural antioxidant molecules from phytochemicals of plant origin may directly inhibit either their production or limit their propagation or destroy them to protect the system. In the present study, Monodora myristica a non-timber forest product consumed in Cameroon as spice was screened for its free radical scavenging properties, antioxidant and enzymes protective activities. Its phenolic compound profile was also realized by HPLC. RESULTS: This study demonstrated that M. myristica has scavenging properties against DPPH',OH',NO', and ABTS'radicals which vary in a dose depending manner. It also showed an antioxidant potential that was comparable with that of Butylated Hydroxytoluene (BHT) and vitamin C used as standard. The aqueous ethanol extract of M. myristica barks (AEH); showed a significantly higher content in polyphenolic compounds (21.44 ± 0.24 mg caffeic acid/g dried extract) and flavonoid (5.69 ± 0.07 quercetin equivalent mg/g of dried weight) as compared to the other studied extracts. The HPLC analysis of the barks and leaves revealed the presence of several polyphenols. The acids (3,4-OH-benzoic, caffeic, gallic, O- and P- coumaric, syringic, vanillic), alcohols (tyrosol and OH-tyrosol), theobromine, quercetin, rutin, catechine and apigenin were the identified and quantified polyphenols. All the tested extracts demonstrated a high protective potential on the superoxide dismutase (SOD), catalase and peroxidase activities. CONCLUSION: Finally, the different extracts from M. myristica and specifically the aqueous ethanol extract reveal several properties such as higher free radical scavenging properties, significant antioxidant capacities and protective potential effects on liver enzymes.

Fruits and barks extracts of Zanthozyllum heitzii a spice from Cameroon induce mitochondrial dependent apoptosis and Go/G1 phase arrest in human leukemia HL-60 cells

BACKGROUND: Zanthoxylum heitzii is a spice used to prepare several dishes and to treat tumors, syphilis, malaria, cardiac palpitations, urogenital infections in the west region of Cameroon, but the antitumor mechanisms and chemical composition are not yet investigated. This study was aimed to determine the antiproliferative effects of four extracts from the fruits and barks of Zanthoxyllum heitzii (Rutaceae) on apoptosis in human promyelocytic cells, their mechanisms and the chemical composition. The 3-(4, 5-dimethylthiazole-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was used to determine the fifty percent inhibition (IC50) concentration of the cell lines after treatment. The effect on morphology was observed using a light or fluorescence microscopy. The rate of apoptosis and the cell cycle were measured using flow cytometry (FCM). The phytochemical analysis of the extract was carried with HPLC/MS methods. RESULTS: The phytochemical analysis of the extracts indicated the presence of four known polyphenols (Syringic acid, Juglon, Luteolin and Myricetin) in both fruits and barks of Z. heitzii but in different quantities. Syringic acid and Myricetin concentrations were between 17-21 fold higher in the fruits than the stem bark. Rhamnetin (393.35 µg/mL) and Oleuropein (63.10 µg/mL) were identified only in the stem barks of Z. heitzii. Among the four extracts tested for cytotoxicity properties, only the methanol extract of fruits and barks significantly inhibited cell proliferation of HL-60 cells with IC50 value of 20 µg/mL and 12 µg/mL respectively. HL-60 cells treated with Z. heitzii extracts significantly produced reactive oxygen species (ROS) with concurrent loss of mitochondrial membrane potential (MMP). Modifications in the DNA distribution and enhanced of G1/G0 phase cell cycle arrest were observed in a concentration dependent manner. CONCLUSIONS: Polyphenols from Z. heitzii plant exert inhibitory effect on HL-60 cells through the reactive oxygen species (ROS) generation, loss of mitochondrial membrane potential and cell cycle destabilization.