Charles Fokunang

Synthesis of some p-toluenesulfonyl-hydrazinothiazoles and hydrazino-bis-thiazoles and their anticancer activity

A series of novel p-toluenesulfonyl-hydrazinothiazoles and hydrazino-bis-thiazoles derivatives (2a-f, 3a-f and 5-8) were synthesized by initial condensation of p-toluenesulfonylthiosemicarbazide 1 with a series of α-halogenocarbonyls in acetone or dimethylformamide (DMF)/acetone, mixture. All our synthesized compounds were submitted for further acylation reaction in the presence of acetic anhydride. The structures of newly synthesized derivatives 2a-f, 3a-f and 5-8 were confirmed by IR, (1)H-NMR, EIMS spectral data and elemental analysis. Compounds 2a, 2c, 2d, 2e and 3a showed significant anticancer activities (IC(50)<10 μM) on both prostate DU-145 and hepatocarcinoma Hep-G2 cancer cell lines.

Relationship between multiple drug resistance and biofilm formation in Staphylococcus aureus isolated from medical and non-medical personnel in Yaounde, Cameroon

Introduction Monitoring the prevalence of nasal carriage of multiple drug resistance (MDR) Staphylococcus aureus (SA) strains in hospital personnel is essential. These strains when transmitted from hospital personnel to patients with already weakened immune states or in-built medical devices, may limit the latters treatment options. This study aimed at assessing the potential exposure of patients to these MDR SA in a resource-limited hospital setting by assessing the prevalence and relationship between antimicrobial susceptibility and biofilm forming capacity of SA isolates from hospital personnel. Methods A total of 59 bacteria isolates phenotypically identified as Staphylococcus aureus obtained from medical (39) and non-medical personnel (20) in Yaounde were used in the study. Multiple drug resistance defined as resistance to four or more of twelve locally used antibiotics were determined by Kirby Bauer disc diffusion technique whereas quantification of biofilm production was by the microtitre plate method. Results Among the 59 SA isolates, the prevalence of MDR was 50.9%. Among medical personnel 48.7% had MDR as against 55.9% for non-medical personnel (p-value=0.648). The overall percentage of weak biofilm producers was 35.6%. Although the prevalence of weak biofilm formers was higher in isolates from non-medical personnel (40%) than medical personnel (33.3%) the difference was not statistically significant (p-value= 0.246). Slightly less than half (42.9%) of the weak biofilm producers were MDR. Conclusion Considering the high rates of MDR and that slightly less than half of biofilm formers were MDR, these trends need to be monitored regularly among hospital personnel in Yaounde.

In vivo anti-salmonella activity of aqueous extract of Euphorbia prostrata Aiton (Euphorbiaceae) and its toxicological evaluation

ABSTRACT Objective To investigate the in vivo anti-salmonella activity and the safety of aqueous extract of Euphorbia prostratra ( E. prostratra ), a plant commonly used in Cameroon by traditional healers. Methods A Salmonella typhimurium -infected rat model was used for the study. The physiological, biochemical and histopathological markers of possible side effects of this extract were studied using standard methods. Results The extract had a significant effect on the number of viable Salmonella typhimurium recovered from faeces, and could stop salmonellosis after 8 and 10 days of treatment for male and female rats, respectively, with non-toxic doses. However, the biochemical and histopathological analyses revealed that at relatively high doses (≥ 73.48 mg/kg for female and ≥ 122.71 mg/kg for male) the extract could induce liver damage, as illustrated by a rise of serum transaminases’ levels and significant inflammation of the parenchyma and portal vein. Side effects were also observed on the kidneys, as shown by both serum and urinary creatinine, and urinary proteins. Conclusions The overall results indicate that the aqueous extract of E. prostrata has the potential to provide an effective treatment for salmonellosis, including typhoid fever. However, it is necessary to extrapolate these results in large animals, in further studies.

Intestinal carriage of Extended Spectrum Beta-Lactamase producing E. coli in women with urinary tract infections, Cameroon

INTRODUCTION During the last decade, the prevalence of the intestinal carriage of extended spectrum beta-lactamases - producing Escherichia coli (ESBL-E. coli) has continued to increase worldwide in the community, especially in developing countries. Hence, we undertook a study to determine the ESBL-E. coli fecal carriage rate and the associated risk factors in Cameroonian women. METHODOLOGY A total of 86 women suspected of community-acquired urinary tract infections (UTI) were included in 10 health structures from May 2011 to April 2012. After filling a questionnaire, they provided a stool sample that was plated on selective media for ESBL producing bacteria. The identification of strains was obtained with mass spectrometry and the antibiotic susceptibility by disk diffusion in agar media. The ESBL type was determined by PCR. The relative abundance of ESBL-E. coli was measured for positive samples. Eventually, the presence of antibiotics in stool was assessed. RESULTS The carriage rate of ESBL-E. coli was 57/86 (66.3%). Phenotypic and molecular characterization showed that all ESBL-E. coli strains contained group 1 CTX-M enzymes. Multivariate analysis showed that ESBL-E. coli fecal carriage was associated with the presence of antibiotics in stools (p < 0.05). Although not significant, mean ESBL relative abundance tended to be higher in patients with antibiotic exposure. CONCLUSIONS Our results show that the carriage of ESBL-E. coli fecal carriage in women with UTI suspicion from the Cameroonian community is extremely high and associated with recent antibiotic intake.

Investigating zoonotic infection barriers to ape Plasmodium parasites using faecal DNA analysis

African apes are endemically infected with numerous Plasmodium spp. including close relatives of human Plasmodium falciparum, Plasmodium vivax, Plasmodium ovale, and Plasmodium malariae. Although these ape parasites are not believed to pose a zoonotic threat, their ability to colonise humans has not been fully explored. In particular, it remains unknown whether ape parasites are able to initiate exo-erythrocytic replication in human hepatocytes following the bite of an infective mosquito. Since animal studies have shown that liver stage infection can result in the excretion of parasite nucleic acids into the bile, we screened faecal samples from 504 rural Cameroonians for Plasmodium DNA. Using pan-Laverania as well as P. malariae- and P. vivax-specific primer sets, we amplified human P. falciparum (n = 14), P. malariae (n = 1), and P. ovale wallikeri (n = 1) mitochondrial sequences from faecal DNA of 15 individuals. However, despite using an intensified PCR screening approach we failed to detect ape Laverania, ape P. vivax or ape P. malariae parasites in these same subjects. One faecal sample from a hunter-gatherer contained a sequence closely related to the porcupine parasite Plasmodium atheruri. Since this same faecal sample also contained porcupine mitochondrial DNA, but a matching blood sample was Plasmodium-negative, it is likely that this hunter-gatherer consumed Plasmodium-infected bushmeat. Faecal Plasmodium detection was not secondary to intestinal bleeding and/or infection with gastrointestinal parasites, but indicative of blood parasitaemia. Quantitative PCR identified 26-fold more parasite DNA in the blood of faecal Plasmodium-positive than faecal Plasmodium-negative individuals (P = 0.01). However, among blood-positive individuals only 10% - 20% had detectable Plasmodium sequences in their stool. Thus, faecal screening of rural Cameroonians failed to uncover abortive ape Plasmodium infections, but detected infection with human parasites, albeit with reduced sensitivity compared with blood analysis.

Evaluation of the Antidiabetic Properties of Hydro-Alcoholic Extract and Its Fractions from Physalis peruviana L. Leaves on Streptozotocin-Induced Diabetic Wistar Rats

The purpose of this study was to investigate the antidiabetic activity of extracts from leaves of Physalis peruviana L. used in the Eastern part of the Democratic Republic of the Congo used against diabetes. Different fractions with hexane, ethyl acetate and residue were obtained from the hydroalcoholic extract of Physalis peruviana leaves. The antidiabetic evaluation of hydroalcoholic and its fractions was evaluated in diabetic rats by a single administration of streptozotocin (50 mg/kg body weight) intravenously. The Reference group received glibenclamide (6.5 mg/kg body weight) and each test group received 100 mg/kg of body weight. Those groups were compared with a control group which received only a Tween 20 solution (1 ml per 100 g body weight). Serum biochemical profiles were evaluated by some blood markers including serum glucose, serum alanine transaminase (ALT), serum aspartate transaminase (AST) serum creatinine, total protein, triglyceride, total cholesterol, HDL-cholesterol and LDL-cholesterol. Antidiabetic profile evaluation showed no significant variation (P < 0.05) in blood glucose between groups after 28 days of treatment. There was no significant difference in the biochemical markers change including creatinine, ALT, AST, total protein, triglycerides, total cholesterol, HDL-cholesterol and LDL-cholesterol. The hydroalcoholic extract from the leaves of Physalis peruviana L. and its fractions showed antidiabetic activity suggesting future detailed studies for new chemical entities lead drug discovery.