Anna M. Clarke

Volatile Compounds in Honey: A Review on Their Involvement in Aroma, Botanical Origin Determination and Potential Biomedical Activities

Volatile organic compounds (VOCs) in honey are obtained from diverse biosynthetic pathways and extracted by using various methods associated with varying degrees of selectivity and effectiveness. These compounds are grouped into chemical categories such as aldehyde, ketone, acid, alcohol, hydrocarbon, norisoprenoids, terpenes and benzene compounds and their derivatives, furan and pyran derivatives. They represent a fingerprint of a specific honey and therefore could be used to differentiate between monofloral honeys from different floral sources, thus providing valuable information concerning the honey’s botanical and geographical origin. However, only plant derived compounds and their metabolites (terpenes, norisoprenoids and benzene compounds and their derivatives) must be employed to discriminate among floral origins of honey. Notwithstanding, many authors have reported different floral markers for honey of the same floral origin, consequently sensory analysis, in conjunction with analysis of VOCs could help to clear this ambiguity. Furthermore, VOCs influence honey’s aroma described as sweet, citrus, floral, almond, rancid, etc. Clearly, the contribution of a volatile compound to honey aroma is determined by its odor activity value. Elucidation of the aroma compounds along with floral origins of a particular honey can help to standardize its quality and avoid fraudulent labeling of the product. Although only present in low concentrations, VOCS could contribute to biomedical activities of honey, especially the antioxidant effect due to their natural radical scavenging potential.

Marked susceptibility of South African Helicobacter pylori strains to ciprofloxacin and amoxicillin: Clinical implications

OBJECTIVES Helicobacter pylori-associated infection is common in South Africa, as in other developing countries. Antibiotic resistance is recognised as a major cause of treatment failure. We studied the susceptibility and resistance patterns of H. pylori to guide empiric treatment and prevent the emergence of resistance. METHODS Two hundred H. pylori strains obtained from gastric biopsies of patients presenting with gastric-related morbidities attending Livingstone Hospital, Port Elizabeth, were evaluated for their susceptibility to seven antibiotics - metronidazole, clarithromycin, tetracycline, amoxicillin, gentamicin, ciprofloxacin and erythromycin. H. pylori was isolated following standard microbiology procedures, and susceptibility determined using the Kirby-Bauer disc diffusion and agar dilution methods. Comparisons of antimicrobial resistance rates with sex of the patients were determined using the chi-square test; a p-value of <0.05 was considered significant. RESULTS Marked susceptibility was observed for ciprofloxacin (100%) and amoxicillin (97.5%), and good activity for clarithromycin (80%) and gentamicin (72.5%). However, marked resistance (95.5%) was observed for metronidazole. The minimal inhibitory concentration (MIC) ranged from 0.0625 microg/ml to 8 microg/ml. The lowest MIC, with a range of 0.0625 - 1 microg/ml, was recorded for ciprofloxacin, while the highest (5 - 8 microg/ml) was noted for gentamicin. CONCLUSION Multidrug resistance was commonly encountered - a finding of clinical significance that calls for continuous surveillance of antibiograms to guide empiric treatment. We advocate the inclusion of ciprofloxacin in the treatment regimen of H. pylori infection in our study environment.

Selected South African Honeys and Their Extracts Possess In Vitro Anti-Helicobacter pylori Activity

BACKGROUND AND AIMS Eradication of Helicobacter pylori by triple therapy often results in a failure rate of 10-20%; thus, there is a need to seek alternative treatments. The aim of this study was to screen selected South African honeys for their anti-H. pylori activity, to extract the antimicrobial components using organic solvents and to determine the minimum inhibitory concentrations (MICs) of the extracts. METHODS Three locally produced honeys from different regions in South Africa were screened for anti-H. pylori activity at four different concentrations using the agar well diffusion technique. Subsequently, Pure honey was extracted using n-hexane, diethyl ether, chloroform and ethyl acetate; extracts were also examined for anti-H. pylori activity by agar well diffusion method. The MICs of the three most active extracts were determined both by visual inspection and spectrophotometric analysis at 620 nm using the broth microdilution method. The results were analyzed by one-way ANOVA at 95% significance level. RESULTS All honeys demonstrated anti-H. pylori activity and were most active at 75% v/v. The positive control (clarithromycin) recorded a zone diameter of 18.0 ± 7.4 mm not significantly different (p >0.05) from honeys at 75% v/v and solvent extracts. Chloroform extract recorded the lowest MIC(95) values that ranged from 0.156-5% v/v confirming this extract to be the most active. CONCLUSION All honeys demonstrated anti-H. pylori activity at concentrations ≥10%, as did the solvent extracts. Therefore, these honeys and solvent extracts possess potential compounds with therapeutic activity that could be further exploited as lead molecules in the treatment of H. pylori infections.

An African perspective on Helicobacter pylori: prevalence of human infection, drug resistance, and alternative approaches to treatment

Abstract Helicobacter pylori is a Gram-negative, micro-aerophilic, motile, curved rod that inhabits the gastric mucosa of the human stomach. It chronically infects thousands of millions of people world-wide, and is one of the most genetically diverse of bacterial species. Infection with the bacterium leads to chronic gastritis, peptic ulceration, gastric cancers and gastric mucosa-associated lymphoid-tissue (MALT) lymphoma. The prevalence of infection appears to be partly determined by geographical and socio–demographic factors, being higher in Africa than elsewhere. Current treatment, based on potent combinations that each consist of a proton-pump inhibitor and two antibiotics, is successful in 80%–90% of patients. Some undesirable side-effects, poor patient compliance and drug resistance are, however, associated with significant levels of treatment failure and with contra-indications for some patients. Antibiotic resistance in H. pylori is a growing global concern that merits the urgent attention of public-health authorities. Numerous pieces of clinical evidence have revealed that eradication of the organism from a patient results in improvement of gastritis and drastically decreases the frequency of relapse of gastric and duodenal ulcers. Natural products, including medicinal plants and honey, may offer useful alternatives in the treatment of H. pylori-related infections.

Helicobacter pylori Antigenemia in an Asymptomatic Population of Eastern Cape Province, South Africa: Public Health Implications

Helicobacter pylori is a major cause of such upper gastrointestinal diseases as gastritis, peptic ulcer, and gastric cancer. The risk of infection is increased in those living in the developing world, which has been ascribed to precarious hygiene standards, crowded households, and deficient sanitation common in this part of the world. Fecal samples were collected from 356 apparently healthy subjects, consisting of 168 males and 188 females aged from 3 months to > or = 60 years (Mean = 31 years). A standardized questionnaire describing demographic characteristic including age, sex, household hygiene, socioeconomic status, and so on was applied. A sandwich-type enzyme immunoassay amplification technology (Amplified IDEIA Hp StAR, Oxoid, UK) was used to analyze the fecal samples for the detection of H. pylori antigens using monoclonal antibodies specific for H. pylori antigens. Fishers exact test was used to assess the univariate association between H. pylori infection and the possible risk factors. Odds ratio (OR) and the corresponding 95% confidence interval (CI) were calculated to measure the strength of association using EPI INFO 3.41 package. P values of < .05 were required for significance. H. pylori antigen was detected in 309 of the 356 subjects giving an overall prevalence of 86.8%. Prevalence increased with age from 75.9% in children < 12 years age to 100% in young adults aged 25-47 years and subjects aged > or = 60 years (P < .05). H. pylori prevalence was higher in females than in males. Of 188 females who participated in the study, H. pylori antigen was detected in 172 (91.5%) versus 144 (85.7%) 168 males (P > .05). Interestingly, H. pylori antigen was detected more often (100%) in the high socioeconomic group than in those of low socioeconomic group (85.9%) (P > .05). The results of this study have revealed a high prevalence of H. pylori antigens in fecal samples of asymptomatic individuals in the Nkonkobe municipality, an indication of active infection. Socioeconomic status, contaminated water, and poor sanitation may play a role in H. pylori transmission in this population. This finding is of public health and epidemiologic significance.

Helicobacter pylori prevalence in dyspeptic patients in the Eastern Cape province - race and disease status

Objectives. We examined Helicobacter pylori infection in patients with gastric-related morbidities at Livingstone Hospital, Port Elizabeth, to determine the prevalence and risk factors for infection according to race, endoscopic diagnosis, age and sex. Methods. Gastric biopsies were collected from 254 consecutive patients and H. pylori isolated on Columbia agar base supplemented with 7% sheeps blood and Skirrows supplement containing trimethoprim (2.5 mg), vancomycin (5 mg) and cefsulodin (2.5 mg). Amphotericin (2.5 mg) was added to the medium. Recovered isolates were identified following standard microbiology and biochemical techniques. Presumptive isolates were further confirmed by polymerase chain reaction (PCR) targeting the glmM gene. Fishers exact test was used to assess the univariate association between H. pylori infection and the possible risk factors. Odds ratios (ORs) and corresponding 95% confidence intervals (CIs) were calculated to measure the strength of association, using EPI INFO 3.41 software. P-values <0.05 were required for significance. Results. The overall prevalence of H. pylori was 66.1% (168/254). Of the 168 positive subjects, H. pylori prevalence was highest in patients with non-ulcer dyspepsia (NUD) (32.7%; 55/168), and lowest (0%; 0/168) in those with atypical oesophageal reflux disease and gastroduodenitis, respectively. The prevalence of infection was highest among coloureds (68.4%; 89/130) and lowest in whites (59.5%; 25/ 42). Prevalence increased with age. Conclusion. The prevalence of H. pylori is high in dyspeptic patients in Eastern Cape Province. Gender, antibiotic treatment and alcohol consumption may be risk factors for infection. These findings are of clinical and epidemiological significance.

Crude Ethanolic Extracts of Garcinia kola Seeds Heckel (Guttiferae) Prolong the Lag Phase of Helicobacter pylori: Inhibitory and Bactericidal Potential

Problems associated with current treatment regimens have generated a considerable interest in alternative approaches for the eradication of Helicobacter pylori infections using phytochemical compounds. In an attempt to identify potential sources of such compounds, the antimicrobial activity of five solvent extracts of Garcinia kola seeds were investigated against 30 clinical strains of H. pylori and a standard control strain, NCTC 11638, using standard microbiological techniques. Metronidazole and amoxicillin were included in these experiments as positive control antibiotics. All the extracts tested exhibited anti-H. pylori activity with zone diameters of inhibition between 0 and 25 mm. The ethanol extract demonstrated considerable anti-H. pylori activity with a percentage susceptibility of 53.3% and minimum inhibitory concentration for 50% susceptibility (MIC₅₀) values ranging from 0.63 to 5.0 mg/mL. Ranges of MIC₅₀ values for amoxicillin and metronidazole were 0.01-0.63 mg/mL and 0.04-5.0 mg/mL, respectively. The inhibitory activity of the ethanol extract was similar to that of metronidazole (P > .05) as opposed to amoxicillin (P < .05). The extract caused a 12-hour extension of the lag phase of H. pylori at 1.25 mg/mL. The same observations were recorded when this concentration was doubled and quadrupled alongside a killing rate of 80.1% and 93.7%, respectively, after 24 hours and of 100% after 30 hours. These results demonstrate that the ethanol extract of G. kola may contain therapeutically useful compounds against H. pylori.

Detection of Phytoconstituents in Column Fractions of n-Hexane Extract of Goldcrest Honey Exhibiting Anti-Helicobacter pylori Activity

BACKGROUND AND AIMS Alternative therapy for Helicobacter pylori eradication from natural products is gaining much attention. This study sought to isolate and characterize the fraction responsible for the antibacterial activity in Goldcrest (GC) n-hexane extract. METHODS Thin-layer chromatography (TLC) of the extract was carried out on Silica gel plates to determine the presence of chemical compounds, which were separated and partially purified by column chromatography. The obtained fractions GCCL, GCF2, GCF3 and GCF4 were tested for anti-H. pylori activity using the broth microdilution method. Volatile compounds in the active fractions were identified by gas chromatography-mass spectrometry (GC-MS) analysis. MINITAB was used for statistical analysis at 95% confidence interval. RESULTS The best antibacterial activity was exhibited by GCF3 (5 mg/mL), which was composed of many compounds with known antimicrobial and antioxidant properties. A total of 16 volatile compounds were identified from fractions GCF2, GCF3 and GCF4 into the following families; alcohol, ketone, aliphatic acid, benzene compound, hydrocarbon, furan and pyran derivatives. CONCLUSIONS The demonstration of antibacterial activity by the column fractions of GC n-hexane extract may provide new lead molecules that could serve as selective agents for H. pylori chemotherapy and control.

Helicobacter pylori infection and transmission in Africa: Household hygiene and water sources are plausible factors exacerbating spread

Helicobacter pylori (H. pylori) is a microaerophilic motile curve rod that inhabits the gastric mucosa of the human stomach. The organism chronically infects billions of people worldwide and is one of the most genetically diverse of bacterial species. Infection with the bacterium which leads to chronic gastritis, peptic ulceration, gastric cancers and gastric malt lymphoma has been reported to follow a pattern linked to geographic and socio-demographic factors. Studies have documented a higher prevalence in Africa than elsewhere although the pathological outcomes do not correlate with infection. H. pylori transmission pathways are still vague, but the risks of transmission include precarious hygiene standards, over-crowding and contaminated environment and water sources amongst others. The possible routes of transmission include oral-oral, faecal-oral and person- to -person, either with or without transitional transmission steps during episodes of diarrhoea or gastro-oral contact in the event of vomiting. Use of contaminated water including municipal tap water has also been suspected to have a high impact in the transmission of the organism. To generate the data presented in this paper, we conducted an internet based search on relevant literature pertaining to H. pylori epidemiology in general and Africa in particular. Sites such as Pubmed, AJOL, Scopus and Goggle scholar were mainly used. This paper therefore attempts to appraise the role of household hygiene and water sources in the transmission of this organism in the developing world context.

Environmental and demographic risk factors associated with the prevalence of Cryptosporidium infection in the Alice rural settlements of the Eastern Cape Province of South Africa: a pilot study

Abstract We undertook this study to identify the risk factors and prevalence of Cryptosporidium spp. in HIV-positive and HIV-negative diarrhea patients in the Alice rural settlement in the Eastern Cape Province of South Africa. A total of 180 stool specimens (35 HIV-positive diarrhea, 125 HIV-negative diarrhea patients, and 20 apparently healthy subjects) were screened for cryptosporidiosis using an ELISA-based approach. Sociodemographic information, water supply, and animal contact were recorded for diarrhea-positive patients. The data were analyzed using Pearson’s χ2-test and Fisher’s exact test. Cryptosporidium antigen was detected in 122 of 180 specimens (overall prevalence=67.8%). In HIV-positive diarrhea patients, the age groups 31–43 years (mean age 36.5 years) and 70–82 years (mean age 75.8 years) had a higher prevalence (100%) of the antigen than age groups 18–30 years (mean age 23.2 years) and 83–95 years (mean age 88.8 years) (50.0%). In HIV-negative diarrhea patients, the prevalence was highest (87.5%) at ages 18–30 years (mean age 23.2 years) and lowest (35.7%) at ages 83–95 years (mean age 88.8 years). Cryptosporidium antigenemia was slightly higher in females (78.2%, mean age 46.7 years) than in males (71.1%, mean age 42.6 years), but the difference was not significant (p>0.05). No apparently healthy control subject was infected with Cryptosporidium. HIV-negative patients had a significantly higher prevalence of antigen than HIV-positive patients, with farm animals considered a possible risk factor. In HIV-positive diarrhea patients, the prevalence peak was detected in more low income patients (85.7%) than in high income patients (32%). The high infection rate of specific groups was associated with exposure to a contaminated water supply. The results indicate that Cryptosporidium infection is highly prevalent in adult fecal specimens from the Nkonkobe Municipality, an indication of active infection that is likely to emerge as a major human pathogen in this locality owing to socioeconomic changes that favor transmission.