Optimisation d'extraction des composés phénoliques et d'activités biologiques de tetrapleura tetraptera et aframomum citratum

This thesis explores the optimization of phenolic compounds extraction and the biological activities of two non woody forest products (Tetrapleura tetraptera and Aframomum citratum fruit extracts) spread in three agro-ecologic zones in Cameroon in a home food consumption context. The fruits are used for seasoning traditional recipes and in the traditional pharmacopeae. The general objective of this study was to contribute to a development of a therapeutic and preventive dietary supplement rich in dietary antioxidant to fight against oxidative stress on diabetic patents. As they are geographically harvested in many agro-ecologic areas, the various specific objectives were to investigate on their chemical and biological variabilities; on the impact of heat treatment (roasting) on their properties; to define the optimum conditions for total polyphenol recovery of a mix of the spices; and to administer a beverage obtained under optimum extraction conditions to diabetic rats in other to study their antidiabetic capabilities. The first trials results showed that for T. tetraptera, samples from the bimodal forest zone (BFZ) possess more sugars, calories, minerals and phenolic compounds. Gallic acid, chlorogenic acid, benzoic acid, 2-OH cinnamic acid, salycilic acid, flavone, gallocatechin, epigallocatechin gallate, naringin, phlorizin were among the predominant phenolic compounds identified in aqueous extract. Concerning A. citratum, samples from the BFZ contain more protein, fiber, phenolic and minerals (especially samples from the East region). A total of six dominant phenolic acids (Gallic, chlorogenic, protocatechuic, 2-OH cinnamic, caffeic, p-coumaric) and five flavonoids (epigallocatechin gallate, resveratrol, phlorizin, rutin, epicatechin, luteolin) were observed on the extracts. All the aqueous extracts biological activities (antioxidant, anti-inflammatory) of spices from the BFZ are dose dependent and more effective. Heat treatment significantly reduces fat, raw proteins and total sugars but improves raw fibre, phenolic contents and the biological activities of all the spices. For the total polyphenols recovery, the optimal conditions were: roasting temperature of 150°C, roasting time of 12.6 min, a brewing time of 11.9 min. After in vivo test on rats, the effect of the beverage alone is significantly the same as the conjoined administration of the beverage and the antidiabetic drug (Glibenclamide) reference and the administration the α-glucosidase inhibitor (Acarbose) after 4hrs when assessing the anti-hyperglycemic test on diabetic rats. The Glibenclamide effect is significantly improved by the beverage administration on hypoglycaemic assay and this synergy reduces diabetes complications on diabetic rats. As conclusion, the best areas to harvest are in the BFZ and the heat treatment applied has to be controlled. The beverage obtained with 95/5 Tetrapleura tetraptera/Aframomum citratum formulation possesses antoxidant, anti-nflammatory and hypoglycaemic activities. However there is a need for additional in vivo tests in order to confirm the different in vitro biological activities observed and to determine the human relevance of the beverage at the dose used

Optimisation of phenolic compounds and antioxidant activity extraction conditions of a roasted mix of Tetrapleura tetraptera (Schumach & Thonn.) and Aframomum citratum (C. Pereira) fruits using response surface methodology (RSM)

peer reviewedThe therapeutic abilities of Tetrapleura tetraptera and Aframomum citratum fruits used as spices are attributed to their bioactive molecules, including polyphenols. Sometimes used together and heated, they can undergo denaturation. The aim of the current study is to optimize the extraction of phenolic compounds and antioxidant potential of a roasted mix of Tetrapleura tetraptera and Aframomum citratum (95/5: w/w) fruits using RSM in a home food consumption context. The mix of spices was chosen according to the highest content of TPP and preliminary studies were performed to select the influencing variables. Roasting temperatures (130-170°C), roasting times (10-15 min) and brewing times (8-15 min) were investigated with a rotatable central composite design. Experimental results were fitted to the second-order polynomial model where multiple regressions and ANOVA were used to determine the coefficients of the model and the optimal conditions for the considered responses. The two spices are good sources of phenolic compounds, and they also show significant (p<0.05) dose-dependent radical scavenging activities (DPPH assay and inhibition of βcarotene discoloration) and reductive activities (FRAP assay and Phosphomolybdenum method). They significantly inhibit bovine serum albumin and 5-LOX denaturation. Brewing time and roasting time significantly (p<0.05) influence the responses and there is a strong (R2=0.93) correlation between the TPP and TAC of the beverage. The quadratic model fit well and the different factors used to test its accuracy and fitness were in satisfactory ranges. For TPP extraction (38.90 mgGAE/g dw) and TAC (50.75 mg TE/g dw) expression, the optimal conditions were reached at a roasting temperature of 150°C, roasting time of 12.62 min, brewing time of 11.91 min and a desirability of 0.95. The novel information on the optimisation of the process can be further used by scientists, consumers and herbalists for effective handling of fruits during the extraction process

Preheated (roasting) Aframomum citratum (C. Pereira) K. Schum and Tetrapleura tetraptera (Schumach & Thonn.) fruits beverage in vivo hypoglycaemic activity on streptozotocin-induced rats

Tetrapleura tetraptera and Aframomum citratum fruits are used as spices and in the traditional pharmacopeia in Cameroon. They are mostly combined and preheated for many purposes while cooking. The effects of roasting on the phenolic content of spices, phenolic profile of a beverage made with the mix of roasted spices and its hypoglycaemic activity on diabetes complications were investigated. Aqueous extract (infusion: 100°C; 1/5 g/ml) was prepared, and the total polyphenols and flavonoids contents before and after heat treatment were quantified. Four formulations of T. tetraptera/A. citratum (95/5; 90/10; 85/15; 80/20) were assessed and the in vitro glucose adsorption capacity of the extracts was studied to retain the most effective formulation (AEF). Phenolic and derivatives compounds of AEF were analysed using HPLC-DAD methodology. The AEF hypoglycaemic activity (250 mg/kg bw) and the various complications of hyperglycaemia after Streptozotocin induction (55 mg/kg) were examined on rats. Significant (p<0.05) improvements in phytochemical content were noticed for T. tetraptera and AEF extracts after heat treatment. Among the phenolic compounds identified, flavone, protocatechic, chlorogenic, p-Coumaric acids, and naringin showed the highest concentrations. Significantly, the effect of AEF is the same as the administration of AEF-Daonil (Glibenclamide) and Acarbose after 4h when assessing the anti-hyperglycaemic test. The influence of Daonil (the reference drug) is significantly improved by AEF, and this synergy has the best anti-hyperglycaemic, hypoglycaemic, hypotriglyceridaemic potential and boosts catalase, superoxide dismutase activities while reducing Malondialdehyde (liver, pancreas, haemolysates) and hydroperoxide (liver, plasma, and kidney) contents compared with the use of single AEF

Temperature dependent studies on nutritional, total polyphenols, flavonoids content and antioxidant activities of Aframomum citratum (C. Pereira) K.Schum and Tetrapleura tetraptera (Schumach & Thonn.) fruits

Description: Hard shelled fruits, Tetrapleura tetraptera and Aframomum citratum non-timber forest products are used as spices and for many medicinal recipes. Mostly used together, they undergo heat treatment before being milled when cooking "Mbongo Tchobi", a black spicy stew from central and coastal regions in Cameroon. Objectives: Evaluate the impact of roasting these spices on the physicochemical properties (dry matter, ash, raw protein, total sugar, raw fibre, pH, aw, total energy, total fat), phytochemical content (total polyphenol, total flavonoids) and the antioxidant activities (total antioxidant activity, FRAP, DPPH and lipid peroxidation inhibition assays) of their aqueous extracts in a home food consumption context. Methodology: Tetrapleura tetraptera and Aframomum citratum fruits from Ngola locality in YoKadouma (East region in Cameroon) locality were collected, sorted, cleaned and dried (72h, 45°C) in an oven. Cut into small pieces, a part was heated using roasting parameters deduced from preliminary tests (140°C/10min; 180°C/20min and 150°C/12min respectively for T. tetraptera, A. citratum and a formulation 95/5 of the two spices). The heated and unheated spices were ground and an infusion was prepared from boiling water in the proportion of 1/5 (g/ml) for both types of spices. Physicochemical and phytochemical characteristics (dry matter, total ash, fat, sugar, crude fibre and energy contents, pH, aw, total flavonoids and polyphenols) as well as the antioxidant activities of the aqueous extracts of the two spices and a mix of the two spices were evaluated before and after the heat treatment. Results: Heat treatment significantly (p˂0.05) reduces fat and total sugars contents but improves raw fibre contents for all spices. Phenolic content is more important for heated spices and percentage differences before and after heat treatment are between 8 and 23.20% for both spices. Extracts obtained with heated spices possess the best antioxidant potential. Strong significant positive correlations have been established between the phenolic compounds and the reductive antioxidant activities and negative correlations with the antiradical antioxidant activities as they are expressed as IC50 (mg/ml). Conclusion: In most of the features studied, the heated formulation (95/5) possesses the highest characteristics studied and the choice of heating these spices under the roasting parameters identified should be guided by the desire of improving the antioxidant potential because of the nutritional losses observed after heat treatment

Hypoglycaemic activity of preheated (roasting) Aframomum citratum (C. Pereira) K. Schum and Tetrapleura tetraptera (Schumach & Thonn.) fruits beverage on Streptozotocin-induced rats

peer reviewedTetrapleura tetraptera and Aframomum citratum fruits are used as spices and in the traditional pharmacopeia in Cameroon. They are mostly combined and preheated for many purposes while cooking. The effects of roasting on the phenolic content of spices, phenolic profile of a beverage made with the mix of roasted spices and its hypoglycaemic activity on diabetes complications were investigated. Aqueous extract (infusion: 100°C; 1/5 g/ml) was prepared, and the total polyphenols and flavonoids contents before and after heat treatment were quantified. Four formulations of T. tetraptera/A. citratum (95/5; 90/10; 85/15; 80/20) were assessed and the in vitro glucose adsorption capacity of the extracts was studied to retain the most effective formulation (AEF). Phenolic and derivatives compounds of AEF were analysed using HPLC-DAD methodology. The AEF hypoglycaemic activity (250 mg/kg bw) and the various complications of hyperglycaemia after Streptozotocin induction (55 mg/kg) were examined on rats. Significant (p<0.05) improvements in phytochemical content were noticed for T. tetraptera and AEF extracts after heat treatment. Among the phenolic compounds identified, flavone, protocatechic, chlorogenic, p-Coumaric acids, and naringin showed the highest concentrations. Significantly, the effect of AEF is the same as the administration of AEF-Glibenclamide (Glibenclamide) and Acarbose after 4h when assessing the anti-hyperglycaemic test. The influence of Glibenclamide (the reference drug) is significantly improved by AEF, and this synergy has the best anti-hyperglycaemic, hypoglycaemic, hypotriglyceridaemic potential and boosts catalase, superoxide dismutase activities while reducing Malondialdehyde (liver, pancreas, haemolysates) and hydroperoxide (liver, plasma, and kidney) contents compared with the use of single AEF

In vitro Biological activities of aqueous extracts of Tetrapleura tetraptera (Schumach&Thonn.) taub.andAframomumcitratum(C. Pereira) K.Schum from three Agroecologic zones in Cameroon: The polyphenol variabilities

The aim of this study is to study few phytochemical, nutritional and physicochemical constituents of twelve samples of Tetrapleura tetraptera (Schumach&Thonn.) taub.and nine of Aframomumcitratum(C. Pereira) K.Schum fruits collected in three Agro-ecologic zones in Cameroon: Bimodal forest zone (ZONE V), Unimodal forest zone (ZONE IV) and highlands zone (ZONE III). T. tetraptera fruits were spread over three Ago-ecological Zones (Zones V, IV, III) and A. citratum fruits were spread over two AEZ (Zones V, IV). Various analysis (dry matter, ash, total fat, crude proteins, total sugars, crude fibre contents; energy, water activity and pH; Fe, Ca, Mg and K contents; total polyphenols and flavonoids contents) using standard analytical, colorimetric, spectroscopy and spectrophotometric procedures were used. Phenolic compounds characterization was done on both spices aqueous extracts using HPLC. The results showed that concerning T. tetraptera samples, crude fibre content is significantly (p<0.05) high on samples from Zones IV and III while samples from Zone V possess more sugars, calories, minerals and phenolic compounds. About A. citratum, samples from Zone IV are the most sweet and the ones from Zone V contain more protein, fiber, phenolic and minerals (especially samples from the East region) contents.On T. tetraptera aqueous extracts, Gallic, chlorogenic, benzoic, 2-OH cinnamic, salycilic acids and flavone, gallocatechin, epigallocatechin gallate, naringin, phlorizin were among the predominant compounds identified. Localities from the littoral region (Nyanon, barebakem, NkwangsiII, MantemII) corresponding to Zone IV and III possess the smallest total polyphenols contents. However, the spices from Zone III have the lowest. About A. citratum, samples from Zone IV are the most sweet and the ones from Zone V contain more protein, fiber, phenolic and minerals (especially samples from the East region) contents. On aqueous extracts, a total of six dominant (in terms of quantity and frequency) phenolic compounds (Gallic, Chlorogenic, Protocatechuic, 2-OH Cinnamic, Caffeic, p-Coumaric acids) and five flavonoids (epigallocatechin gallate, resveratrol, phlorizin, rutin, epicatechin, luteolin) were observed on the extracts. Theobromine is present only in spices from the East region, while Kojic acid is present on spices from centre and Littoral regions. Samples from Zone IV (Lolodorf, Nyanon and Bonepoupa II) possess the smallest amounts of Total polyphenols. For both species, total phenolic acids content and total flavonoids content of aqueous extracts significantly (p<0,05) varied from one locality to another

Analysis of the Feeding Habits and Nutritional Status of Adolescents in Private Non-boarding Secondary Schools in Bamenda II Municipality, Cameroon

The study has assessed the feeding habits and nutritional status of adolescents in Bamenda II Municipality. Multi-stage sampling technique was used to select four private non boarding secondary schools in Bamenda II Municipality. Systematic sampling was used to select the respondents from form one to lower-sixth and consent forms were signed. Structured questionnaires were administered to 200 adolescents (11-19years). Dietary assessments were also carried out using food frequency questionnaires and 24hr dietary recall. The weight and height of students were taken to determine their body mass indices. The weights and heights of both sexes were taken and the readings were analyzed using standard deviation scores where &gt; median-2SD to + &lt; 1SD= Normal, Median&lt; - 2SD to &gt; - 3SD = moderate of under nutrition, &lt; Median – 3SD = severe under nutrition, + 1SD to &lt; + 3SD= overweight, and greater than + 3SD = obesity. Using BMI- for age boys/girls (Z- score) for assessing nutritional status of adolescents in this study, majority of them were within the normal range. Few were underweight, overweight and obese. For age group 11-14 years, 83.3 % were normal, 16.7% were obese, and 0% for underweight and overweight. For age group 15-17 years, 22.7 % were normal ,25.9 % were obese, 23.5% were under weight and&nbsp;&nbsp; 28.2% were overweight A significant difference (p&lt;0.05) was observed between males and females(15-17 years). For age group 18 and 19 years, 40% were normal ,0 % were obese,14.1 % were under weight and 32.9 % were overweight. A significant difference (X2 =8.0, d,f=3, p=0.040) was observed between males and females(18 and 19 years) .With respect to waist circumference, a percentage of the respondents fell within the normal range. for males and females. The respondents generally ate twice a day. Forty –one (41%) of the respondents said they consume tubers twice a week, 31.5% consume cereals and their products more than four times a week, 12.5% consume pulses, legumes and products twice a week, 32.5% consume animal products once a week, 36.5% consume eggs and dairy products twice a week and 25% consume fruits and vegetables twice a week . The 24hr dietary recall revealed that the diets were monotonous. Peer group influence affects their food choices, feeding habits and nutritional status

In vitro Biological activities of aqueous extracts of Tetrapleura tetraptera (Schumach & Thonn.) taub. and Aframomum citratum (C. Pereira) K.Schum from three Agroecologic zones in Cameroon

Study some phytochemical constituents and biological activities of twelve samples of Tetrapleura tetraptera (Schumach & Thonn.) taub. and nine of Aframomum citratum (C. Pereira) K.Schum fruits collected in three Agroecologic zones in Cameroon: Bimodal forest zone (ZONE V), Unimodal forest zone (ZONE IV) and highlands zone (ZONE III). Methods: Fresh fruits extracts were obtained by aqueous infusion (100°C/15min) and evaluated by spectrophotometric methods for total polyphenol (TPP), total flavonoids (TFLV) contents and antioxidant (DPPH, Total Antioxidant Capacity by the Phosphomolybdenum method or TAC, Iron reducing power or FRAP and inhibition of linoleic acid peroxidation or B.CAROT assays) and anti-inflammatory (Inhibitions of Protein denaturation and 5-LOX activity respectively INH.PROT and INH.5-LOX) properties. Principal Component Analysis providing a transparent view of information was performed. Results: T. tetraptera has the highest levels of TPP, TFLV and biological activities. For both species, fruits from ZONE V have the most important TPP, TFLV levels and biological activities. TPP and TFLV content of A. citratum and T. tetraptera fruits are positively and significantly (p<0.05) correlated. All extracts biological activities (0.25, 2.5, 25, 250 mg/mL) are dose-dependent and they have shown strong antioxidant and anti-inflammatory activities, but less than references (Ascorbic Acid, Diclofenac, Quercetin, and Butylated Hydroxytoluene). There is a positive correlation between TPP, TFLV and TAC, FRAP, B.CAROT assays and inverse correlations are observed with the IC50 (g/mL) of DPPH, INH.5-LOX and INH.PROT assays for both species. Conclusion: The fruits reveal their variabilities and those from ZONE V for both species are economically and healthcare challenging for herbalists, pharmaceutical firms, scientists and consumers. Indeed, most important extraction yield of bioactive compounds correlated with significant biological activities and the use of less material compare to an implementation in others AEZ with the same results are noted

Variabilities of Tetrapleura tetraptera (Schumach & Thonn.) taub. and Aframomum citratum (C. Pereira) K.Schum from three Agro-ecologic zones in Cameroon and effect of extraction methods on the phenolic compounds recovery

The fruits of Tetrapleura tetraptera and Aframomum citratum were identified among the most commonly used and available spices in Cameroonian cities. They are mainly collected in the bimodal forest (Zone V), unimodal forest (Zone IV) and the highlands (Zone III)2 zones. They are part of the traditional pharmacopeia in Central and West African countries. The aim of this study was to characterize fruit samples harvested on the three agroecological zones (AEZ) and to examine few traditional extraction methods for the phenolic compounds recovery in a domestic food consumption situation. Tetrapleura tetraptera fruits were harvested in twelve villages spread over three AEZ (Zones V, IV, III) and Aframomum citratum fruits were selected in nine villages spread over two AEZ (Zones V, IV). Various analysis (dry matter, ash,total fat, crude proteins, total sugars, crude fibre contents; energy, water activity and pH; Fe, Ca, Mg and K contents; total polyphenols and flavonoids contents) using standard analytical, colorimetric, spectroscopy and spectrophotometric procedures were used. For both extraction methods investigated (Maceration, infusion, decoction), an extraction ratio of 1/5 was used. Statistical analysis and Principal Component Analysis (PCA) were performed. The results showed that concerning Tetrapleura tetraptera samples, crude fibre content is significantly (p<0.05) high on samples from Zones IV and III while samples from Zone V possess more sugars, calories, minerals and phenolic compounds. About Aframomum citratum, samples from Zone IV are the most sweet and the ones from Zone V contain more protein, fibre, phenolic and minerals (especially samples from the East region) contents. For both species, decoction was the most efficiency extraction method. The result gives a graphic representation of the studied characteristics which can serve as a decision-making tool (for sampling) to guide the various stakeholders involved in the valuation and exploitation of these fruits