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Articles by Jules-Roger Kuiate
Total Records ( 6 ) for Jules-Roger Kuiate
  Donatien Gatsing , Christiane F.N. Nkeugouapi , Bridget F. Nji-Nkah , Jules-Roger Kuiate and Felicite M. Tchouanguep
  The antibacterial activity, bioavailability and acute toxicity of the leaf extracts of Alchornea cordifolia were evaluated. The phytochemical screening was also done. Results of the in vitro antibacterial tests showed that all but the hexane extract exhibited antibacterial activities against P. aeruginosa (MIC = 2.5 mg mL-1), E. coli (MIC = 3.75 mg mL-1), S. aureus (MIC = 5 mg mL-1) and K. pneumoniae (MIC = 10 mg mL-1). Results of the serum antimicrobial activity test against P. aeruginosa showed that with animals administered the extract, serum antimicrobial activity was observed as from 3 h 45 min for the doses 2.84 and 5.68 g kg-1, independently of the sex of animals. The peaks of serum activity (maximum activity, Amax) were obtained at 6 and 4 h (Tmax) with the doses 2.84 and 5.68 g kg-1, respectively. The area under the curve (AUC) was greater with the dose 2.84 g kg-1 than with the dose 5.68 g kg-1. Flavonoids, triterpenes, saponins, anthocyanins, steroids, polyphenols and tannins were found in the leaves of this plant. Results of the acute toxicity study of the aqueous leaf extract of A. cordifolia with mice showed that the LD50 was >32 g kg-1. The data obtained in this study suggest that the leaves of A. cordifolia contain antibacterial principle(s) which are biologically available and which may not be toxic. However, at doses ≥4 g kg-1, this extract may have a depressant or sedative effect on the central nervous system, may reduce the pain perception and may induce loss of body weight.
  Gerald N. Teke , Paul K. Lunga , Hippolyte K. Wabo , Jules-Roger Kuiate and Jean P. Dzoyem
  The stem bark of E. abyssinica is used in traditional medicine for the treatment of diarrhoea in west region of Cameroon. To substantiate this folkloric claim, the methanol extract, fractions and isolated compounds from E. abyssinica stem bark were investigated for their antidiarrhoeal activities in Wistar albino rats. The methanol extract of E. abyssinica stem bark was pre-dissolved in a mixture of methanol and water and partitioned into n-hexane, ethyl acetate and n-butanol fractions. The ethyl acetate portion was fractionated by column chromatography and the structures of isolated compounds elucidated by spectroscopic analyses in conjunction with literature data. Antidiarrhoeal activity was investigated in terms of purging index, consistency of faeces and intestinal transit in castor oil induced diarrhoea, and faecal Shigella load, faecal frequency, variation in bodyweight and blood chemistry in Shigella-induced diarrhoea model in Wistar rats. Two known compounds [(5S,6R,8aR)-5-(carboxymethyl)-3,4,4a,5,6,7,8,8a-octahydro-5,6,8atrimethylnaphthalenecarboxylic acid (1), methyl 3,4,5-trihydroxybenzoate (2) were isolated. The methanol extract, fractions and isolated compounds showed antidiarrhoeal activities evidenced by the reduction in % respondent to diarrhoea, a delay in the period for diarrhoea induction, reduction in purging index and wateriness of faeces. Compounds 1 and 2 inhibited diarrhoeal droppings by 81.01 and 87.34%, respectively. Compared to the methanol extract, fractionation increased the shigellocidal activity with ethyl acetate fraction most active. The experimental findings show that the methanol extract, fractions and isolated compounds from E. abyssinica stem bark possess significant antidiarrhoeal activities justifying the traditional use of this plant in diarrhoeal treatment and may be developed as phytomedicine.
  Raymond S. Mouokeu , Rosalie A.N. Ngono , Christopher Tume , Monique O. Kamtchueng , Guy S.S. Njateng , Dzoyem Jean Paul , Jean De Dieu Tamokou and Jules-Roger Kuiate
  Medicinal plants are rich sources of secondary metabolites which are claimed to possess immunomodulatory properties, justifying why the present study was designed to investigate the immunomodulatory potential of Crassocephalum bauchiense leaves extracts. Leaves were macerated successively in hexane, ethyl acetate and methanol. The ethyl acetate extract was further fractionated into six fractions (F1 to F6) using flash chromatography. The activities of the extract and its fractions were investigated on macrophage NO production model while their proliferative effects were evaluated on macrophages and peripheral blood lymphocytes by the thiazolyl blue (MTT) test. Extract and fractions significantly inhibited NO production by peritoneal macrophages. However, they enhanced macrophage and lymphocyte proliferation in vitro at lower concentrations (<64 or <128 μg mL-1). Fraction F2 significantly increased Delayed-type herpersensitivity reaction (DTH) in mice. This activity was potentiated when the fraction was co-administered with cyclophosphamide. The fraction did not show any activity on antibody production. The total leucocytes count (mainly lymphocytes) was higher in the extract-treated groups when compared to the controls. Fraction F2 significantly suppressed myelosuppression induced by cyclophosphamide as from 25 mg kg-1 of body weight (bw). Oral administration of the fraction caused lethal signs of toxicity from 16 mg kg-1 bw. The LD50 was estimated at 22 mg kg-1 bw. These results indicate that C. bauchiense ethyl acetate extract and its fraction F2 have relatively interesting immunostimulatory effects on lymphocytes. In associated with its kwon antimicrobial properties, one can conclude that this plant species is a candidate for anti-infective phytomedicine preparation.
  Paul K. Lunga , Joseph M.M. Nkodo , Jean D. Tamokou , Jules-Roger Kuiate , Donatien Gatsing and Joseph Tchoumboue
  Background and Objective: Paullinia pinnata is an African woody vine whose leaf decoction has been used in Cameroon for the treatment of bacterial infections like typhoid fever, syphilis, gonorrhea, diarrhoea and symptoms such as stomach-ache and waist pain. The present study was designed to evaluate the adverse side effects resulting from the use of P. pinnata methanol leaf extract in the treatment of Salmonella typhimurium-induced typhoid in Wistar rats. Methodology: After the establishment of infection by oral administration of a S. typhimurium suspension, animals were treated by the daily administration of P. pinnata methanol leaf extract at various doses (55.75, 111.50, 223 and 446 mg kg-1 b.wt.). The effect of the extract on body weight evolution was monitored daily. Results: Also, the effect of the extract on relative organ weight, biochemical parameters as well as liver histology was assessed. Irrespective of sex, typhoid fever induced an abnormal increase in the relative weight of most vital organs of toxicological importance. However, extract treatment normalized the excessive increase in relative organ weights; while inducing a significant (p<0.05) body weight gain in a dose-dependent manner. The level of liver enzymes (ALT and AST) were significantly (p<0.05) reduced after the treatment of the animals with P. pinnata leaf extract. The histopathological analysis of the liver revealed that extract treatment greatly reduced the degree of liver affections in a dose-dependent manner. However, at high doses (dose ≥223 mg kg-1 b.wt.) the extract was capable of stimulating hepatic necrosis. Conclusion: The overall results of this study indicate that the methanolic extract of P. pinnata leaves has hepatoprotective effects especially in males. It has adverse side effects at high doses and even at low doses in female rats and thus, should be used with caution in male and should probably be eliminated from the treatment of female subjects.
  Jean-de-Dieu Tamokou , Joseph Tsemeugne , Emmanuel Sopbue Fondjo , Prodipta Sarkar , Jules-Roger Kuiate , Arnaud Ngongang Djintchui , Beibam Luc Sondengam and Prasanta Kumar Bag
  Objective: The emergence of resistance to the major classes of antibacterial drugs is recognized as a serious health concern. Chemotherapy of cervical cancer, a devastating cancer with increasing worldwide incidence and mortality rates is largely ineffective. The discovery and development of effective antibacterial/anticancer agents is urgently needed. The present study reports on the evaluation of antibacterial and anticancer properties of some azo compounds containing thiophene backbone. Methodology: The antibacterial activity of the synthesized compounds was assessed by performing Minimum Inhibitory Concentration (MIC), Minimum Bactericidal Concentration (MBC) and the time-kill kinetic study, while the cytotoxic activity was determined by the 3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay using HeLa (cancer cell lines) and Vero (normal) cells. Results: All of the compounds tested here showed significant antibacterial activity against the strains of Gram-positive bacteria, Staphylococcus aureus and Gram-negative multi-drug resistance bacteria, Vibrio cholerae (causative agent of cholera) and Shigella flexneri (causative agent of shigellosis), as well as the significant cytotoxic activity (LC50, 1.03-106.73 μg mL–1) against HeLa cells. Among these, compounds 3, 6 and 7 showed the most antibacterial (MIC, 8-64 μg mL–1) and cytotoxic (LC50, 1.03-2.37 μg mL–1) activities with selectivity index values ranged from 71.19-144.80, which were much higher than that of the reference drug, paclitaxol. The presence of the nitro functional group in compounds 3 and 6 could explain their good antibacterial and cytotoxic activities. Conclusion: These results indicate that the synthesized compounds have both antibacterial and anticancer properties with no toxicity to normal cells.
  Yamssi Cedric , Vincent Khan Payne , Noumedem Anangmo Christelle Nadia , Norbert Kodjio , Etung Kollins , Leonelle Megwi , Jules-Roger Kuiate and Mpoame Mbida
  Background and Objective: Coccidiosis remains one of the most important infectious cause of digestive disorders in rabbits. The aim of this study was to evaluate in vitro anticoccidial and antioxidant activities of Psidium guajava (P. guajava) extracts. Materials and Methods: Sporulation inhibition bioassay was used to evaluate the activity of Psidium guajava extracts on sporulation of Eimeria flavescens, Eimeria stiedae, Eimeria intestinalis and Eimeria magna oocysts and sporozoites. The set up was examined after 24 and 48 h for the oocysticidal activities and after 12 and 24 h for anti-sporozoidal activities. The antioxidant activity was determined by measuring FRAP (ferric reducing-antioxidant power), 1,1-Diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging and nitric oxide (NO) radical scavenging. The cytotoxicity of the most active extract was determined against animal cell lines fibroblast L929, HEPG2 and HeLa cells using MTT assay. The impact of the toxicity was established by analyzing the selectivity index (SI) values. Data obtained were analyzed using one-way analysis of variance (ANOVA) and were determined by Waller-Duncan test using SPSS. Results: The highest efficacy of tested plant extracts was recorded after 24 h, which varied according to different concentrations of the tested extracts. The highest efficacy was 88.67±2.52% at the concentration of 30 mg mL–1 of the methanolic extract against E. intestinalis. Most extracts including the aqueous extract exhibited good anti-sporozoidal activities against E. flavescens, E. stiedae, E. intestinalis and E. magna sporozoites at 1000 μg mL–1. The highest viability inhibitory percentage was 97.00±1.73% at a concentration of 1000 μg mL–1 of P. guajava methanolic extract against E. intestinalis sporozoites. These results also showed that methanolic and ethyl acetate extract, possessed strong antioxidant activities (IC50<20 μg mL–1). The methanolic extract of P. guajava exhibited CC50 of >30 μg mL–1 against selected cell lines, suggesting that the compounds were not toxic. Phytochemical screening of the most active extract showed presence of alkaloids, flavonoids, saponins and phenols. Conclusion: These results provide confirmation to the usage of Psidium guajava against
coccidiosis by Agricultural farmers in Cameroon.
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