Phytochemical screening, antioxidant, antiulcer and toxicity studies on Desmodium adscendens (Sw) DC Fabaceae leaf and stem

Purpose: To assess the phytochemical profile, toxicity, as well as the antioxidant, and antiulcer activities of the methanol extracts of Desmodium adscendens stem and leaf.Methods: Maceration procedure was employed in the preparation of the methanol extracts. Phytochemical characterization of the extracts was carried out according to standard methods. In vitro antioxidant activity was evaluated using 2, 2-diphenyl-1-picryhyldrazy (DPPH l) and ferric reducing antioxidant power assay (FRAP). Antiulcer activity was investigated using ethanol-induced ulcer model, while toxicity was assessed by observing the mice for mortality.Results: Phytochemical analysis indicate the presence of glycosides, alkaloids, tannins, flavonoids, and saponins in the stem and leaf. Methanol extracts of the plant exhibited antioxidant activity, with DPPH assay results showing median inhibitory concentration (IC50) of 87.59 (leaf), 108.87 (stem), 28.52 (alpha-tocopherol), and 5.05 μg/mL (ascorbic acid). The FRAP assay results for the stem and leaf extracts were 1483 and 1953 μM Fe2+/g dry plant, respectively, while for ascorbic acid it was 3463 μMFe2+/g. The extracts showed significant antiulcer activity, with 14.27 and 15.18 % ulceration inhibition for the leaf extract, and 12.31 and 13.36 % for the stem extract at administered doses of 100 and 200 mg/kg, respectively. Cimetidine and omeprazole (standards) showed ulceration inhibition of 5.53, and 8.26 % at 5.7 and 0.57 mg/kg doses, respectively.Conclusion: The methanol extracts of Desmodium adscendens stem and leaf offer significant protective activity against ethanol-induced gastric ulceration in rats, and the activity may be related to their antioxidant effect.Keywords: Antioxidant, Antiulcer, Toxicity, Desmodium adscenden

The In vitro biological activity of biosynthesized silver nanoparticles produced using mangifera indica stem bark extract and properties of Its pharmaceutical gel formulation

This study reports the production of silver nanoparticles using Mangifera indica stem bark (aqueous and methanol) extracts as capping agents and formulation of pharmaceutical gel loaded with the nanoparticles. The extracts were prepared using standard procedures and utilized in biosynthesizing silver nanoparticles. Biosynthesis was ascertained through colour changes, UV–Visible and FTIR spectroscopy. Antioxidant activity of the extracts and biosynthesized nanoparticles were examined by DPPH method. The antimicrobial evaluation was carried out on Pseudomonas aeruginosa and Staphylococcus aureus. Pharmaceutical gels were produced (F1–F5), and loaded with the nanoparticles. Nanoparticles exhibited maximum absorption under UV–visible spectroscopy between 315 and 320 nm. FTIR spectrum showed that alkene and ester functional groups were conferred on the silver nanoparticles by the extracts used. The nanoparticles demonstrated antimicrobial activity against the organisms, which was significantly higher (p < 0.05) than for extracts and reference drug. The antioxidant capacity was in a concentration-dependent manner but significantly lower (p < 0.05) than that of the reference drug. Formulated gels had acceptable organoleptic profiles, pH range of 6.8–7.1, high viscosity, and pseudoplastic flow patterns. The in vitro release profiles of the gels showed was gradual, with t90 higher than 2 h. The release seemed to be influenced by the viscosity of the gel systems. In addition, the release kinetics of the nanoparticle-loaded gel systems followed Higuchi model with r2 ranging from 0.9958 to 0.9980. Mangifera indica extracts were successfully used as bio-reducing agents in the synthesis of silver nanoparticles. The gel formulations had acceptable physical properties and release profiles

Hypoglycemic and antioxidative activities of ethanol seed extract of Hunteria umbellate (Hallier F.) on streptozotocininduced diabetic rats

Background: Diabetes, a global cause of mortality in developing countries is a chronic disorder affecting the metabolism of macromolecules and has been attributed to the defective production and action of insulin characterized by persistent hyperglycemic properties. This global disorder harms organs of the body such as the liver, kidney and spleen. Medicinal plants such as Hunteria umbellate have been shown to possess hypoglycemic, antioxidative and anti-diabetic properties owing to the high concentration of active phytochemical constituents like flavonoids and alkaloids. The present study seeks to evaluate the hypoglycemic activities of ethanolic seed extract of Hunteria umbellate on streptozotocin-induced diabetes rats. Methods: Thirty (30) female experimental rats were randomly divided into five groups with six rats per group and were administered streptozotocin (STZ) and Hunteria umbellate as follows. Group 1 served as control and was given only distilled water, group 2 rats were administered 60 mg/kg STZ; Group 3 was administered 60 mg/kg STZ and 100 mg/kg metformin; group 4 rats were administered 60 mg/kg STZ and 800 mg/kg Hunteria umbellate, group 5 rats 60 mg/kg STZ and 400 mg/kg Hunteria umbellate. The fasting blood glucose level of each rat was measured before sacrifice. Rats were then sacrificed 24 h after the last dose of treatment. Results: The results showed that Hunteria umbellate significantly reversed STZ-induced increase in fasting blood glucose and increase in body and organs weight of rats. Hunteria umbellate significantly reversed STZ-induced decrease in antioxidant enzyme in liver, kidney and spleen of rats. Hunteria umbellate significantly reversed STZinduced increase in oxidative stress markers in liver, kidney and spleen of rats

Emergence and spread of two SARS-CoV-2 variants of interest in Nigeria.

Identifying the dissemination patterns and impacts of a virus of economic or health importance during a pandemic is crucial, as it informs the public on policies for containment in order to reduce the spread of the virus. In this study, we integrated genomic and travel data to investigate the emergence and spread of the SARS-CoV-2 B.1.1.318 and B.1.525 (Eta) variants of interest in Nigeria and the wider Africa region. By integrating travel data and phylogeographic reconstructions, we find that these two variants that arose during the second wave in Nigeria emerged from within Africa, with the B.1.525 from Nigeria, and then spread to other parts of the world. Data from this study show how regional connectivity of Nigeria drove the spread of these variants of interest to surrounding countries and those connected by air-traffic. Our findings demonstrate the power of genomic analysis when combined with mobility and epidemiological data to identify the drivers of transmission, as bidirectional transmission within and between African nations are grossly underestimated as seen in our import risk index estimates

The evolving SARS-CoV-2 epidemic in Africa: Insights from rapidly expanding genomic surveillance.

Investment in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing in Africa over the past year has led to a major increase in the number of sequences that have been generated and used to track the pandemic on the continent, a number that now exceeds 100,000 genomes. Our results show an increase in the number of African countries that are able to sequence domestically and highlight that local sequencing enables faster turnaround times and more-regular routine surveillance. Despite limitations of low testing proportions, findings from this genomic surveillance study underscore the heterogeneous nature of the pandemic and illuminate the distinct dispersal dynamics of variants of concern-particularly Alpha, Beta, Delta, and Omicron-on the continent. Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve while the continent faces many emerging and reemerging infectious disease threats. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century

The evolving SARS-CoV-2 epidemic in Africa: Insights from rapidly expanding genomic surveillance

INTRODUCTION Investment in Africa over the past year with regard to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing has led to a massive increase in the number of sequences, which, to date, exceeds 100,000 sequences generated to track the pandemic on the continent. These sequences have profoundly affected how public health officials in Africa have navigated the COVID-19 pandemic. RATIONALE We demonstrate how the first 100,000 SARS-CoV-2 sequences from Africa have helped monitor the epidemic on the continent, how genomic surveillance expanded over the course of the pandemic, and how we adapted our sequencing methods to deal with an evolving virus. Finally, we also examine how viral lineages have spread across the continent in a phylogeographic framework to gain insights into the underlying temporal and spatial transmission dynamics for several variants of concern (VOCs). RESULTS Our results indicate that the number of countries in Africa that can sequence the virus within their own borders is growing and that this is coupled with a shorter turnaround time from the time of sampling to sequence submission. Ongoing evolution necessitated the continual updating of primer sets, and, as a result, eight primer sets were designed in tandem with viral evolution and used to ensure effective sequencing of the virus. The pandemic unfolded through multiple waves of infection that were each driven by distinct genetic lineages, with B.1-like ancestral strains associated with the first pandemic wave of infections in 2020. Successive waves on the continent were fueled by different VOCs, with Alpha and Beta cocirculating in distinct spatial patterns during the second wave and Delta and Omicron affecting the whole continent during the third and fourth waves, respectively. Phylogeographic reconstruction points toward distinct differences in viral importation and exportation patterns associated with the Alpha, Beta, Delta, and Omicron variants and subvariants, when considering both Africa versus the rest of the world and viral dissemination within the continent. Our epidemiological and phylogenetic inferences therefore underscore the heterogeneous nature of the pandemic on the continent and highlight key insights and challenges, for instance, recognizing the limitations of low testing proportions. We also highlight the early warning capacity that genomic surveillance in Africa has had for the rest of the world with the detection of new lineages and variants, the most recent being the characterization of various Omicron subvariants. CONCLUSION Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve. This is important not only to help combat SARS-CoV-2 on the continent but also because it can be used as a platform to help address the many emerging and reemerging infectious disease threats in Africa. In particular, capacity building for local sequencing within countries or within the continent should be prioritized because this is generally associated with shorter turnaround times, providing the most benefit to local public health authorities tasked with pandemic response and mitigation and allowing for the fastest reaction to localized outbreaks. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century

Antibacterial activity of extracts of Alchornea cordifolia (Schum and Thonn) Mull.Arg., Boerhavia diffusa (L) and Bridellia micranthaI (Hoscht) Baill. used in traditional medicine in Nigeria on Helicobacter pylori and four diarrhoeagenic bacterial pathoge

Extracts of leaves of Alchornea cordifolia, Boerhavia diffusa and Bridellia micrantha were investigated for antibacterial activity against Helicobacter pylori, Salmonella typhi, Salmonella enteritidis, Shigella flexneri and Enteroheamorrhagic Escherichia coli (EHEC). Results showed that the ethanolic extracts of the three plants and aqueous extracts inhibited the growth of all the organisms tested. However, the minimal inhibitory concentration (MIC) ranged between 15.6 and 31.25 mg/ml while the extracts were bacteriocidal at concentration ranging between 31.25 and 250 mg/ml. This indicates that leaf extracts of the three plants are of great potential in treating gastric ulcer and diarrhoea caused by theaforementioned bacteria

Design and sensitivity analysis of rock slope using Monte Carlo simulation

Abstract A probabilistic approach that is based on Monte Carlo simulation (MCS) was developed in this study to design and perform sensitivity analysis of rock slope. The probabilistic approach uses MCS to perform a series of single objective optimizations for design of rock slope and to perform sensitivity analysis of rock slope stability. The MCS-based approach was used to evaluate the failure probability of a rock slope system and to determine a safe maximum slope height for rock slope design. To achieve this, the performance of different rock properties and rock slope conditions were explicitly considered towards achieving the target reliability index of the rock slope. The approach can achieve multiple rock slope design specifications using different target reliability indexes from a single run of MCS. The proposed probabilistic approach was illustrated through an example of rock slope design to determine feasible designs under different rock slope conditions. Also, sensitivity studies were performed to explore the effects of uncertainties in tension crack depth and water depth in tension crack, and variability in rock unit weight. The results show that the effects of uncertainties and variability on rock slope stability can be significant and should be incorporated during design analysis. Incorporating such uncertainties and variability in rock slope design is achieved with relative ease using the proposed approach

Data-driven characterization of the correlation between uniaxial compressive strength and Youngs’ modulus of rock without regression models

Abstract The uniaxial compressive strength (UCS) and Youngs’ modulus (E) of rock are important parameters required during design and stability analysis of mining and geotechnical structures. There is correlation between UCS and E of rock, and the proper estimation of such correlation is important for reliable mining engineering analysis. However, limited quantity of UCS and E data pairs often available for most mining project sites makes it difficult to estimate reliable correlation between UCS and E. This study addresses the difficulty by developing Bayesian approach for characterizing the site-specific joint probability distribution of UCS and E that is data-driven, without the use of an empirical model. A major novelty of the proposed approach over previous studies is that it does not require selection or integration of a regression model as input to characterize the correlation between UCS and E. The likelihood function in the proposed approach is directly constructed from only limited UCS and E data pairs and their prior information as inputs. The Bayesian approach is incorporated into Markov Chain Monte Carlo (MCMC) simulation to generate samples pairs of UCS and E, which are then analysed for marginal statistics, marginal probability distribution, joint probability distribution and correlation. Real data of UCS and E obtained from uniaxial compression tests on migmatites at the Sanandaj-Sirjan zone in Iran is used to demonstrate the approach. The marginal statistics, distributions and correlation coefficient from the proposed approach is consistent with those of the measured data from the adopted site. This indicates that the approach is effective in characterizing the correlation between UCS and E, and can be used when there is need for such characterization at a site with limited data. Simulated data are also used in the approach and the results show that the quality and quantity of information available as inputs play an important role in the efficiency of the characterization by the approach. The hallmark of the proposed approach is that it is data-driven, and practitioners do not need to determine and select an appropriate site-specific regression model to evaluate the correlation between UCS and E of rock

A comparative study of geometric and geostatistical methods for qualitative reserve estimation of limestone deposit

Abstract Mining projects especially relating to limestone deposits require an accurate knowledge of tonnage and grade, for both short and long-term planning. This is often difficult to establish as detailed exploration operations, which are required to get the accurate description of the deposit, are costly and time consuming. Geologists and mining engineers usually make use of geometric and geostatistical methods, for estimating the tonnage and grade of ore reserves. However, explicit assessments into the differences between these methods have not been reported in literature. To bridge this research gap, a comparative study is carried out to compare the qualitative reserve of Oyo-Iwa limestone deposit located in Nigeria, using geometric and geostatistical methods. The geometric method computes the reserve of the limestone deposit as 74,536,820 ​t (mean calcite, CaO grade ​= ​52.15) and 99,674,793 ​t (mean calcite, CaO grade ​= ​52.32), for the Northern and Southern zones of the deposit, respectively. On the other hand, the geostatistical method calculates the reserve as 81,626,729.65 ​t (mean calcite, CaO grade ​= ​53.36) and 100,098,697.46 ​t (mean calcite, CaO grade ​= ​52.96), for the two zones, respectively. The small relative difference in tonnage estimation between the two methods (i.e., 9.51% and 0.43%), proves that the geometric method is effective for tonnage estimation. In contrast, the relative difference in grade estimation between the two methods (i.e., 2.32% and 1.26%) is not negligible, and could be crucial in maintaining the profitability of the project. The geostatistical method is, therefore, more suitable, reliable and preferable for grade estimation, since it involves the use of spatial modelling and cross-validated interpolation. In addition, the geostatistical method is used to produce quality maps and three-dimensional (3-D) perspective view of the limestone deposit. The quality maps and 3-D view of the limestone deposit reveal the variability of the limestone grade within the deposit, and it is useful for operational management of the limestone raw materials. The qualitative mapping of the limestone deposit is key to effective production scheduling and accurate projection of raw materials for cement production