Isolation and Characterization of SARS-CoV-2 in Kenya

The discovery of Severe Acute Respiratory Syndrome-Coronavirus-2 (SARS-CoV-2) in Wuhan, Hubei province, China, in December 2019 raised global health warnings. Quickly, in 2020, the virus crossed borders and infected individuals across the world, evolving into the COVID-19 pandemic. Notably, early signs of the virus’s existence were observed in various countries before the initial outbreak in Wuhan. As of 12th of April, the respiratory disease had infected over 762 million people worldwide, with over 6.8 million deaths recorded. This has led scientists to focus their efforts on understanding the virus to develop effective means to diagnose, treat, prevent, and control this pandemic. One of the areas of focus is the isolation of this virus, which plays a crucial role in understanding the viral dynamics in the laboratory. In this study, we report the isolation and detection of locally circulating SARS-CoV-2 in Kenya. The isolates were cultured on Vero Cercopithecus cell line (CCL-81) cells, RNA extraction was conducted from the supernatants, and reverse transcriptase-polymerase chain reaction (RT-PCR). Genome sequencing was done to profile the strains phylogenetically and identify novel and previously reported mutations. Vero CCL-81 cells were able to support the growth of SARS-CoV-2 in vitro, and mutations were detected from the two isolates sequenced (001 and 002). Genome sequencing revealed the circulation of two isolates that share a close relationship with the Benin isolate with the D614G common mutation identified along the S protein. These virus isolates will be expanded and made available to the Kenya Ministry of Health and other research institutions to advance SARS-CoV-2 research in Kenya and the region.

Pancreaticβ-cell dysfunction in type 2 diabetes:Implications of inflammation and oxidative stress

Insulin resistance and pancreaticβ-cell dysfunction are major pathological mechanisms implicated in the development and progression of type 2 diabetes(T2D).Beyond the detrimental effects of insulin resistance,inflammation and oxidative stress have emerged as critical features of T2D that defineβ-cell dysfunction.Predominant markers of inflammation such as C-reactive protein,tumor necrosis factor alpha,and interleukin-1βare consistently associated withβ-cell failure in preclinical models and in people with T2D.Similarly,important markers of oxidative stress,such as increased reactive oxygen species and depleted intracellular antioxidants,are consistent with pancreaticβ-cell damage in conditions of T2D.Such effects illustrate a pathological relationship between an abnormal inflammatory response and generation of oxidative stress during the progression of T2D.The current review explores preclinical and clinical research on the pathological implications of inflammation and oxidative stress during the development ofβ-cell dysfunction in T2D.Moreover,important molecular mechanisms and relevant biomarkers involved in this process are discussed to divulge a pathological link between inflammation and oxidative stress duringβ-cell failure in T2D.Underpinning the clinical relevance of the review,a systematic analysis of evidence from randomized controlled trials is covered,on the potential therapeutic effects of some commonly used antidiabetic agents in modulating inflammatory makers to improveβ-cell function.

In Silico Evaluation of Potential Ligands of Cancer Cells for Surfactin from Bacillus spp.

Cancer is one of the most prevalent diseases worldwide,which causes significant morbidity and mortality.Designing and developing a potential anti-cancer drug is an active field of research worldwide.Microorganisms have been considered a potential source of anti-cancer drugs.One such microbe-derived compound is surfactin,which shows potential anti-cancer activities.In this study,we evaluated the binding potential of surfactin with several cancer cell ligands via an in-silico approach.Hence,molecular docking studies were performed to test the binding potential of surfactin against four targets.The analyses revealed that surfactin from Bacillus sp.can bind with the targeted ligands(coenzyme A,D-leucine,glycerol,and(R)-3-hydroxytetradecanal)with significant affinity.Surfactin showed the highest binding affinity(-7.7 kcal mol-1)to coenzyme A among the targeted ligands.These results may be useful for developing anti-cancer drugs.Nevertheless,further experimental studies are needed to investigate the ligand binding capacity and anti-cancer potential of such surfactin-like molecules.

Genetic diversity and occult hepatitis B infection in Africa: A comprehensive review

BACKGROUND Occult hepatitis B infection(OBI)is a globally prevalent infection,with its frequency being influenced by the prevalence of hepatitis B virus(HBV)infection in a particular geographic region,including Africa.OBI can be transmitted th-rough blood transfusions and organ transplants and has been linked to the development of hepatocellular carcinoma(HCC).The associated HBV genotype influences the infection.AIM To highlight the genetic diversity and prevalence of OBI in Africa.METHODS This systematic review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines and involved a comprehensive search on PubMed,Google Scholar,Science Direct,and African Journals Online for published studies on the prevalence and genetic diversity of OBI in Africa.RESULTS The synthesis included 83 articles,revealing that the prevalence of OBI varied between countries and population groups,with the highest prevalence being 90.9%in patients with hepatitis C virus infection and 38%in blood donors,indicating an increased risk of HBV transmission through blood transfusions.Cases of OBI reactivation have been reported following chemotherapy.Genotype D is the predominant,followed by genotypes A and E.CONCLUSION This review highlights the prevalence of OBI in Africa,which varies across countries and population groups.The study also demonstrates that genotype D is the most prevalent.

A comparative review of HLA associations with hepatitis Band C viral infections across global populations

Hepatitis B （HBV） and hepatitis C （HCV） viral infection or co-infection leads to risk of development of chronic infection, cirrhosis and hepatocellular carcinoma （HCC）. Immigration and globalization have added to the challenges of public health concerns regarding chronic HBV and HCV infections worldwide. The aim of this study is to review existing global literature across ethnic populations on HBV and HCV related human leukocyte antigen （HLA） associations in relation to susceptibility, viral persistence and treatment. Extensive literature search was conducted to explore the HLA associations in HBV and HCV infections reported across global populations over the past decade to understand the knowledge status, weaknesses and strengths of this information in different ethnic populations. HLA DR13 is consistently associated with HBV clearance globally. HLADRB1＊11/＊12 alleles and DQB1＊0301 are associated with HBV persistence but with HCV clearance worldwide. Consistent association of DRB1＊03 and ＊07 is observed with HCV susceptibility and non-responsiveness to HBV vaccination across the population. HLA DR13 is protective for vertical HBV and HCV transmission in Chinese and Italian neonates, but different alleles are associated with their susceptibility in these populations. HLA class I molecule interactions with Killer cell immunoglobulin like receptors （KIR） of natural killer （NK） cells modulate HCV infection outcome via regulating immune regulatory cells and molecules. HLA associations with HBV vaccination, interferon therapy in HBV and HCV, and with extra hepatic manifestations of viral hepatitis are also discussed. Systematic studies in compliance with global regulatory standards are required to identify the HLA specific viral epitope, stage specific T cell populations interacting with different HLA alleles during disease progression and viral clearance of chronic HBV or HCV infections among different ethnic populations. These studies would facilitate stage specific therapeutic strategies for clearance of HBV and HCV infections or co-infections across global populations and aid in identification of HBV-HCV combined vaccine. HLA associations of chronic HBV or HCV development with confounding host factors including alcohol, drug abuse, insulin resistance, age and gender are lacking and warrant detailed investigation across global populations.

Characterization of hepatitis B virus X gene quasispecies complexity in mono-infection and hepatitis delta virus superinfection

Hepatitis delta virus(HDV) seems to strongly suppress hepatitis B virus(HBV)replication, although little is known about the mechanism of this interaction. Both these viruses show a dynamic distribution of mutants, resulting in viral quasispecies. Next-generation sequencing is a viable approach for analyzing the composition of these mutant spectra. As the regulatory hepatitis B X protein(HBx) is essential for HBV replication, determination of HBV X gene(HBX)quasispecies complexity in HBV/HDV infection compared to HBV monoinfection may provide information on the interactions between these two viruses.AIM To compare HBV quasispecies complexity in the HBX 5' region between chronic hepatitis delta(CHD) and chronic HBV mono-infected patients.METHODS Twenty-four untreated patients were included: 7/24(29.2%) with HBeAgnegative chronic HBV infection(CI, previously termed inactive carriers), 8/24(33.3%) with HBeAg-negative chronic hepatitis B(CHB) and 9/24(37.5%) with CHD. A serum sample from each patient was first tested for HBV DNA levels.The HBX 5' region [nucleotides(nt) 1255-1611] was then PCR-amplified for subsequent next-generation sequencing(MiSeq, Illumina, United States). HBV quasispecies complexity in the region analyzed was evaluated using incidencebased indices(number of haplotypes and number of mutations), abundancebased indices(Hill numbers of order 1 and 2), and functional indices(mutation frequency and nucleotide diversity). We also evaluated the pattern of nucleotide changes to investigate which of them could be the cause of the quasispecies complexity.RESULTS CHB patients showed higher median HBV-DNA levels [5.4 logIU/mL,interquartile range(IQR) 3.5-7.9] than CHD(3.4 logIU/mL, IQR 3-7.6)(P = n.s.)or CI(3.2 logIU/mL, IQR 2.3-3.5)(P < 0.01) patients. The incidence and abundance indices indicated that HBV quasispecies complexity was significantly greater in CI than CHB. A similar trend was observed in CHD patients, although only Hill numbers of order 2 showed statistically significant differences(CHB2.81, IQR 1.11-4.57 vs CHD 8.87, 6.56-11.18, P = 0.038). There were no significant differences in the functional indices, but CI and CHD patients also showed a trend towards greater complexity than CHB. No differences were found for any HBV quasispecies complexity indices between CHD and CI patients. G-to-A and C-to-T nucleotide changes, characteristic of APOBEC3 G, were higher in CHD and CI than in CHB in genotype A haplotypes, but not in genotype D. The proportion of nt G-to-A vs A-to-G changes and C-to-T vs T-to-C changes in genotype A and D haplotypes in CHD patients showed no significant differences. In CHB and CI the results of these comparisons were dependent on HBV genotype.CONCLUSION The lower-replication CHD and CI groups show a trend to higher quasispecies complexity than the higher-replication CHB group. The mechanisms associated with this greater complexity require elucidation.

Analysis of hepatitis B virus preS1 variability and prevalence of the rs2296651 polymorphism in a Spanish population

AIM To determine the variability/conservation of the domain of hepatitis B virus(HBV) pre S1 region that interacts with sodium-taurocholate cotransporting polypeptide(hereafter, NTCP-interacting domain) and the prevalence of the rs2296651 polymorphism(S267 F, NTCP variant) in a Spanish population. METHODS Serum samples from 246 individuals were included and divided into 3 groups: patients with chronic HBV infection(CHB)(n = 41, 73% Caucasians), patients with resolved HBV infection(n = 100, 100% Caucasians) and an HBV-uninfected control group(n = 105, 100% Caucasians). Variability/conservation of the amino acid(aa) sequences of the NTCPinteracting domain,(aa 2-48 in viral genotype D) and a highly conserved pre S1 domain associated with virion morphogenesis(aa 92-103 in viral genotype D) were analyzed by next-generation sequencing and compared in 18 CHB patients with viremia > 4 log IU/mL. The rs2296651 polymorphism was determined in all individuals in all 3 groups using an in-house real-time PCR melting curve analysis.RESULTS The HBV pre S1 NTCP-interacting domain showed a high degree of conservation among the examined viral genomes especially between aa 9 and 21(in the genotype D consensus sequence). As compared with the virion morphogenesis domain, the NTCPinteracting domain had a smaller proportion of HBV genotype-unrelated changes comprising > 1% of the quasispecies(25.5% vs 31.8%), but a larger proportion of genotype-associated viral polymorphisms(34% vs 27.3%), according to consensus sequences from Gen Bank patterns of HBV genotypes A to H. Variation/conservation in both domains depended on viral genotype, with genotype C being the most highly conserved and genotype E the most variable(limited finding, only 2 genotype E included). Of note, proline residues were highly conserved in both domains, and serine residues showed changes only to threonine or tyrosine in the virion morphogenesis domain. The rs2296651 polymorphism was not detected in any participant.CONCLUSION In our CHB population, the NTCP-interacting domain was highly conserved, particularly the proline residues and essential amino acids related with the NTCP interaction, and the prevalence of rs2296651 was low/null.

Investigation of benzylisoquinoline alkaloid biosynthetic pathway and its transcriptional regulation in lotus

Lotus predominantly accumulates benzylisoquinoline alkaloids(BIAs),but their biosynthesis and regulation remain unclear.Here,we investigated structural and regulatory genes involved in BIA accumulation in lotus.Two clustered CYP80 genes were identified to be responsible for the biosynthesis of bis-BIAs and aporphine-type BIAs,respectively,and their tissue-specific expression causes divergence in alkaloid component between leaf and embryo.In contrast with the common(S)-reticuline precursor for most BIAs,aporphine alkaloids in lotus leaf may result from the(S)-N-methylcoclaurine precursor.Structural diversity of BIA alkaloids in the leaf is attributed to enzymatic modifications,including intramolecular C–C phenol coupling on ring A and methylation and demethylation at certain positions.Additionally,most BIA biosynthetic pathway genes show higher levels of expression in the leaf of high-BIA cultivar compared with low-BIA cultivar,suggesting transcriptional regulation of BIA accumulation in lotus.Five transcription factors,including three MYBs,one ethylene-responsive factor,and one basic helix–loop–helix(bHLH),were identified to be candidate regulators of BIA biosynthesis in lotus.Our study reveals a BIA biosynthetic pathway and its transcriptional regulation in lotus,which will enable a deeper understanding of BIA biosynthesis in plants.

Intracellular Delivery of mRNA in Adherent and Suspension Cells by Vapor Nanobubble Photoporation

Efficient and safe cell engineering by transfection of nucleic acids remains one of the long-standing hurdles for fundamental biomedical research and many new therapeutic applications,such as CAR T cell-based therapies.mRNA has recently gained increasing attention as a more safe and versatile alternative tool over viral-or DNA transposon-based approaches for the generation of adoptive T cells.However,limitations associated with existing nonviral mRNA delivery approaches hamper progress on genetic engineering of these hard-to-transfect immune cells.In this study,we demonstrate that gold nanoparticle-mediated vapor nanobubble(VNB)photoporation is a promising upcoming physical transfection method capable of delivering mRNA in both adherent and suspension cells.Initial transfection experiments on HeLa cells showed the importance of transfection buffer and cargo concentration,while the technology was furthermore shown to be effective for mRNA delivery in Jurkat T cells with transfection efficiencies up to 45%.Importantly,compared to electroporation,which is the reference technology for nonviral transfection of T cells,a fivefold increase in the number of transfected viable Jurkat T cells was observed.Altogether,our results point toward the use of VNB photoporation as a more gentle and efficient technology for intracellular mRNA delivery in adherent and suspension cells,with promising potential for the future engineering of cells in therapeutic and fundamental research applications.

Phytochemical analysis and anti-oxidant activities of Albuca bracteata Jacq.and Albuca setosa Jacq bulb extracts used for the management of diabetes in the Eastern Cape,South Africa

Objective:The bulb of Albuca bracteata Jacq.,and Albuca setosa commonly used in Eastern Cape Province of South Africa for the treatment of several types of disease conditions including diabetes,was investigated for their phytochemical contents and antioxidant activities.Methods:The antioxidant activity was determined by evaluating the effect of various solvent extracts(acetone,methanol,ethanol and water) on 2,2 – diphenyl-2-picrylhydrazyl(DPPH) scavenging activity,2,20– azino-bis(3-ethylbenzthiazoline-6-sulfonic acid diammonium salt(ABTS),ferric reducing power,hydrogen peroxide and nitric oxide scavenging activity while the various extracts were also analysed for phytochemical their contents.Results:The results obtained indicate that polyphenols,proanthocyanidins,saponins and alkaloids are present in higher concentrations.The composition of phenols(117 mg/g),flavonols(26.28 mg/g),proanthocyanidins(84.85 mg/g) and flavonoids(5.36 mg/g) were significantly higher in the acetone extract while saponin and alkaloids contents were higher in the aqueous extract.Antioxidant studies of the extracts for nitric oxide,hydrogen peroxide,ABTS and DPPH showed high antioxidant potential in a concentration-dependent manner that was not significantly different from Vitamin C,BHT and Rutin used as standard references.The methanol extract showed higher ferric reducing potential compared to the aqueous extract but was significantly different from Vitamin C,BHT and Rutin.Conclusion:This implies that the bulb of Albuca bracteata may serve as a natural source of antioxidants,which together with the numerous phytochemicals present,could account for its folkloric use as a medicinal plant.

Antioxidant, antibacterial and phytochemical properties of two medicinal plants against the wound infecting bacteria

Objective: To investigate the antioxidant, antibacterial and phytochemical properties of ethanol extracts of Brachylaena elliptica and Brachylaena ilicifolia against wound infecting bacteria normally found in diabetic patients.Methods: The in vitro antioxidant activity of the two plants extracts were investigated spectrophotometrically using 1,1-diphenyl-2-picrylhydrazyl, nitric oxide, azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) diammonium salt, hydrogen peroxide(H_2O_2) and ferric reducing power. The antibacterial assay and minimum inhibitory concentration(MIC) was determined using the agar dilution method against five bacteria strains using amoxycillin and ciprofloxacin as positive control. The phytochemical analyses(tannins,total phenol, flavonoids, flavonols, proanthocyanidin, alkaloids and saponins) were assessed using standard methods.Results: The ethanol extract of both plants exhibited strong antioxidant activities in some cases when compared to the standards(vitamin C and BHT). The antibacterial activity of both plants showed an appreciable broad spectrum activity against these wound pathogens with MIC value ranges between 0.3 mg/m L and 5 mg/m L. Tannins,phenols, flavanols, proanthocyanidins and alkaloids content of B. ilicifolia were significantly higher than those in B. elliptica. However, there were no significant differences in the flavanoid content of both plants extracts.Conclusions: These results indicated that the ethanol leaf extracts of these plants have antioxidant and antibacterial activity against the tested bacteria possibly due to the presence of bioactive compounds and therefore could be used as alternative therapy against wound infection caused by these bacteria in diabetic patients.

Corrosion and mechanical properties of a novel biomedical WN43magnesium alloy prepared by spark plasma sintering

Alloying of Mg with rare-earth(RE)elements proved to be beneficial for their in-vitro and in-vivo performance.In this work,a novel WN43(Mg-4 wt%Y-3 wt%Nd)alloy with a well-defined composition was prepared,where,unlike in the commercial WE43 alloy,the possibly harmful RE mischmetal was substituted by less toxic Nd.A modern spark plasma sintering(SPS)technique was used to effectively produce WN43 samples from atomized powders.Sintering temperatures of 400℃-550℃ and holding times of 3 or 10 min were used and wellcompacted final materials were successfully prepared.It was shown that a superior combination of corrosion and mechanical properties was attained in the samples sintered at 500℃ and 550℃,while the effect of sintering time was rather negligible.The performance of this material was exceptional within the group of Mg alloys prepared by powder metallurgy and comparable with conventionally prepared alloys.Moreover,it was shown that a great variety of mechanical and corrosion characteristics can be obtained by altering the SPS parameters so as to fulfill case-specific requirements typical of biomedical materials.Consequently,the novel WN43 alloy prepared by SPS seems to be a particularly suitable material for biomedical use.

In vitro antioxidant capacity and free radical scavenging evaluation of standardized extract of Costus afer leaf

Absolute methanol extract leaf of Costus afer was comprehensively investigated for free radical scavenging activities and antioxidant activities using battery of testing:1,1-diphenyl-2-picrylhydrazyl(DPPH)scavenging,hydroxyl radical scavenging,hydrogen peroxide radical scavenging,2,2-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid)(ABTS)scavenging,nitric oxide inhibition,anti-lipid peroxidation,ferrous chelating potential,reducing power potential,total antioxidant capacity,cupric reducing antioxidant capacity CUPRAC and ferric reducing antioxidant power(FRAP).The content of phenol,flavonoid,cupric,anthocyanin were also investigated.The results suggest that the antioxidant potentials of the extract may be responsible for its medicinal potentials.Cell viability assay revealed that up to12g/ml of the extract is safe for Chang liver cell and no sign of toxicity was observed after the extract treatment of 2000 mg/kg in albino rats.

Safety Properties and Probiotic Potential of Bacillus subtilis KATMIRA1933 and Bacillus amyloliquefaciens B-1895

This study reports on the safety and putative probiotic properties of Bacillus amyloliquefaciens B-1895 and Bacillus subtilis KATMIRA1933. According to the bacterial reverse mutation (Ames) test, cell-free supernatants of B. amyloliquefaciens B-1895 and B. subtilis KATMIRA1933 were not mutagenic. The two strains co-aggregated with Escherichia coli and Pseudomonas aeruginosa, and cell-free supernatants inhibited the growth of Streptococcus intermedius and Porphyromonas gingivalis. Endospores of B. amyloliquefaciens B-1895 and B. subtilis KATMIRA1933 were tolerant to 0.3% (w/v) bile salts and survived incubation for 4 h in MRS broth at pH 2.0 to 3.0. The ability of the two strains to produce antimicrobial compounds potentiates their application in health care formulations, personal care products, food and animal feed.

Cross-sectional evaluation of circulating hepatitis B virus RNA and DNA: Different quasispecies?

BACKGROUND Different forms of pregenomic and other hepatitis B virus(HBV)RNA have been detected in patients’sera.These circulating HBV-RNAs may be useful for monitoring covalently closed circular DNA activity,and predicting hepatitis B eantigen seroconversion or viral rebound after nucleos(t)ide analog cessation.Data on serum HBV-RNA quasispecies,however,is scarce.It is therefore important to develop methodologies to thoroughly analyze this quasispecies,ensuring the elimination of any residual HBV-DNA.Studying circulating HBV-RNA quasispecies may facilitate achieving functional cure of HBV infection.AIM To establish a next-generation sequencing(NGS)methodology for analyzing serum HBV-RNA and comparing it with DNA quasispecies.METHODS Thirteen untreated chronic hepatitis B patients,showing different HBV-genotypes and degrees of severity of liver disease were enrolled in the study and a serum sample with HBV-DNA>5 Log10 IU/mL and HBV-RNA>4 Log10 copies/mL was taken from each patient.HBV-RNA was treated with DNAse I to remove any residual DNA,and the region between nucleotides(nt)1255-1611 was amplified using a 3-nested polymerase chain reaction protocol,and analyzed with NGS.Variability/conservation and complexity was compared between HBV-DNA and RNA quasispecies.RESULTS No HBV-DNA contamination was detected in cDNA samples from HBV-RNA quasispecies.HBV quasispecies complexity showed heterogeneous behavior among patients.The Rare Haplotype Load at 1%was greater in DNA than in RNA quasispecies,with no statistically significant differences(P=0.1641).Regarding conservation,information content was equal in RNA and DNA quasispecies in most nt positions[218/357(61.06%)].In 102 of the remaining 139(73.38%),HBV-RNA showed slightly higher variability.Sliding window analysis identified 4 hyper-conserved sequence fragments in each quasispecies,3 of them coincided between the 2 quasispecies:nts 1258-1286,1545-1573 and 1575-1604.The 2 hyper-variable sequence fragments also coincided:nts 1311-1344 and 1461-1485.Sequences between nts 1519-1543 and 1559-1587 were only hyper-conserved in HBV-DNA and RNA,respectively.CONCLUSION Our methodology allowed analyzing HBV-RNA quasispecies complexity and conservation without interference from HBV-DNA.Thanks to this,we have been able to compare both quasispecies in the present study.

Assessment of Heavy Metals and Microbial Pollution of Lettuce (<i>Lactuca sativa</i>) Cultivated in Two Sites (Paspanga and Tanghin) of Ouagadougou, Burkina Faso

Environmental pollution can have detrimental effects on crop yield and its consumers. The current study was designed to investigate the potential human health risks associated with the consumption of lettuce crop contaminated with toxic heavy metals and microbiological status. Irrigated water, soil and lettuce were analyzed by AAS technics for heavy metals including Cd, Cr, Cu, Mn, Ni, Pb and Zn. Transfer factor (TF), daily intake of metals (DIM) and health risk index (HRI) were also calculated. Microbial analysis was carried out for the presence foodborne pathogens. The results showed that the heavy metals contents were higher in the soil than wastewater and the vegetables. Heavy metals ranged (mg·Kg-1) for Cd (1.27 to 2.93), Cr (7.28 to 7.38), Cu (0.91 to 1.70), Mn (0.29 to 6.60), Ni (1.74 to 2.16), Pb (1.32 to 1.69), Zn (3.08 to 3.79);and were higher than the WHO maximum limit permissible (ML) in vegetables. HRI TF values designated an enhanced bio-contamination. Microbial numeration revealed the presence of spoiler and pathogenic microorganisms. The lettuce tested was not safe for human use, especially for direct consumption by human beings.

The Essential Oil of <i>Eucalyptus grandis</i>W. Hill ex Maiden Inhibits Microbial Growth by Inducing Membrane Damage

Eucalyptus grandis is a medicinal plant which has been indicated by Zulu traditional healer in the treatment of respiratory tract infections, bronchial infections, asthma and cough. The investigation of the essential oil of this plant could help to verify the rationale behind the use of the plant as a cure for these illnesses. Essential oil was hydro-distilled from the fresh leaves and characterised for the chemical constituents and bioactivity. The main constituents of the oil of the E. grandis are α-Pinene (29.69%), p-Cymene (19.89%), 1,8-cineole (12.80%), α-Terpineol (6.48%), Borneol (3.48%) and D-Limonene (3.14%). The essential oil of E. grandis showed high scavenging of DPPH and ABTS radicals, and was actively against 13 of the 16 organisms tested with the MIC ranging from 0.625 mg - 5.0 mg/ml;the MBC value ranged from 2.5 mg - 10 mg/ml. The essential oil also inhibited the growth of 7 of the 8 antibiotic resistant bacteria tested, with MIC ranging from 5 mg/ml - 10 mg/ml. The DNA extracted from the affected microorganisms did not show any damage however, there was an increase of released cytosolic LDH activity. We conclude that the antibacterial activity of the essential oil was exhibited through cell membrane damage rather than the damage of the DNA. It is apparent that the bioactivity of the essential oil of E. grandis plays an important role in the plants’ use in folk medicine for the treatment of respiratory tract illnesses.

Tamarind seed coat extract restores reactive oxygen species through attenuation of glutathione level and antioxidant enzyme expression in human skin fibroblasts in response to oxidative stress

Objective:To investigate the role and mechanism of tamarind seed coat extract(TSCE) on normal human skin fibroblast CCD-l064Sk cells under normal and oxidative stress conditions induced by hydrogen peroxide(H_2O_2).Methods:Tamarind seed coats were extracted with boiling water and then partitioned with ethyl acetate before the cell analysis.Effect of TSCE on intracellular reactive oxygen species(ROS),glutathione(GSH) level,antioxidant enzymes such as superoxide dismulase(SOU),glutathione peroxidase(CPx) and catalase activity including antioxidant protein expression was investigated.Results:TSCE significantly attenuated intracellular ROS in the absence and presence of H_1O_2by increasing GSH level In the absence of H_2O_2,TSCE significantly enhanced SOD and catalase activity but did not affected on CPx.Meanwhile,TSCE significantly increased the protein expression of SOD and CPx in H_2O_2-treated cells.Conclusions:TSCE exhibited antioxidant activities by scavenging ROS.attenuating GSll level that could protect human skin fibroblast cells from oxidative stress.Our results highlight the antioxidant mechanism of tamarind seed coat through an antioxidant enzyme system,the exlracl potentially benefits for health food and cosmeceutical application of tamarind seed coat.

In vitro assessment of the synergism between extracts of Cocos nucifera husk and some standard antibiotics

Objective: To evaluate the interactions between the crude extracts of Cocos nucifera(C.nucifera) and six front line antibiotics(ampicillin sodium salt, penicillin G sodium,amoxicillin, chloramphenicol, ciprofloxacin and tetracycline hydrochloride), against some bacterial pathogens linked with human infection.Methods: The pulverized husk of C.nucifera was dissolved in 95% n-hexane and extracted using Soxhlet extraction method and sterile distilled water(aqueous).The antibacterial susceptibility of the crude extracts of C.nucifera was tested against environmental and clinical strains(6) obtained from the South African Bureau of Standards(SABS), Vibrio(6) and Listeria pathogens(6).The agar-well diffusion method was used for screening the extracts for their antibacterial activity.The minimum inhibitory concentration and minimum bactericidal concentration of the extracts were determined.Time-kill assay was used to evaluate bactericidal and/or bacteriostatic activity.The synergistic effect of the crude extracts and antibiotics was assessed and evaluated by adopting the checkerboard methods.Results: With the time-kill assay, the highest bactericidal activity was observed on Vibrio fluvialis EL041 with a-5.6 ± 0.2 log_(10)CFU/mL decrease in cell density as a result of the combination of the extracts and chloramphenicol at two-fold minimum inhibitory concentrations.Synergisms using the time-kill assay constituted about 72%, while indifference constituted about 28%.The checkerboard method revealed synergistic interaction in 67% of the combinations, and indifference in 33%.There was no specificity in the observed synergy to a particular class of antibiotics.Conclusions: This investigation suggests the crude extracts of C.nucifera to be a potential broad spectrum antimicrobial compound.Therefore, further study is needed to isolate the pure compounds from these crude extracts.

Effect of cationic microemulsion on hemolysis and immune cell uptake

Squalene-based oil-in-water nanoemulsions, constituents in influenza vaccines, have been approved in Europe as human licensed adjuvants (1)With similar constituents but easier manufacturing procedure and greater physical stability [2],microemulsion was of interest. To improve cellular uptake,positive surface charge of nanosystems has been reported(3)In the present study, cationic microemulsions were prepared, characterized and evaluated in immune cell.