Antisickling Activity Research Articles

The antisickling agent, 5-hydroxymethyl-2-furfural: Other potential pharmacological applications.

For the last two decades, the aromatic aldehyde 5-hydroxymethyl-furfural (5-HMF) has been the subject of several investigations for its pharmacologic potential. In 2004, the Safo group reported that 5-HMF has potent antisickling activity by targeting and ameliorating the primary pathophysiology of hypoxia-induced sickling of erythrocytes (red blood cells [RBC]). Following the encouraging outcome of the preclinical and phase I/II clinical studies of 5-HMF for the treatment of sickle cell disease (SCD), there have been multiple studies suggesting 5-HMF has several other biological or pharmacologic activities, including anti-allergic, antioxidant, anti-hypoxic, anti-ischemic, cognitive improvement, anti-tyrosinase, anti-proliferation, cytoprotective, and anti-inflammatory activities. The wide range of its effects makes 5-HMF a potential candidate for treating a variety of diseases including cognitive disorders, gout, allergic disorders, anemia, hypoxia, cancers, ischemia, hemorrhagic shock, liver fibrosis, and oxidative injury. Several of these therapeutic claims are currently under investigation and, while promising, vary in terms of the strength of their evidence. This review presents the research regarding the therapeutic potential of 5-HMF in addition to its sources, physicochemical properties, safety, absorption, distribution, metabolism, and excretion (ADME) profiles.

Antisickling, hemolytic activities and toxicological evaluation of three plants species from the Nigerien Pharmacopoeia: Annona senegalensis Linné. Boscia senegalensis (Pers) Lam. and Ampelocissus afr

The aim of this study consits to evaluate the antisickling and antihemolytic activities and to determine the subacute toxicity of three plants Annona senegalensis L.; Boscia senegalensis (Pers) Lam.; and Ampelocissus africana (Lour) Merr.. The plant material contains leaves and bark of Annona senegalensis roots, leaves and bark root of Boscia senegalensis and the roots of Ampelocissus africana. A single method (80% ethanol maceration) is used to extract the five samples. The antisickleemic and antihemolytic effects are established with sickle cells disease (SCD) in the presence of sodium metabisulfite. Subacute toxicity is tested on Wistar strain rats. All samples showed an antisickling effect but leaves of Annona senegalensis (LAS) showed the highest percentage of antisickling activity (89.55%) at 50mg/ml. The anti-hemolytic effect was demonstrated in all samples by inhibition of hemolysis in the presence of a hemolysant. The toxicity results showed that the aqueous extracts of Annona senegalensis leaves and Boscia senegalensis root bark have non-toxic effects to wistar strain rats. However, some manifestations including fatigue, stretching and slight dyspenea were observed at doses of 150mg/mL and 300mg/mL. This work can contribute as a starting point towards the development of an improved traditional medicine (ITM) method which can help to treat the sickle cell disease. Keywords: Annona senegalensis L., Boscia senegalensis (pers) Lam and Ampelocissus Africana (Lour) Merr. Antisickness activity, Toxicity.

A Comparative Evaluation of the Antisickling, Elemental and Proximate Analysis of the Leaves of Three Khaya species Found in Nigeria

Sickle cell disease (SCD) is traditionally treated in Nigeria by the Traditional Medical Practitioners (TMPs) with medicinal plants and other plant products. One of the herbs commonly used singly or in combination with other plant materials is Khaya, which is widely distributed in Africa, with three species existing in Nigeria. These are Khaya senegalensis A. Juss (KS), Khaya grandifoliola (WELW) CDC (KG) and Khaya ivorensis A. Chev. (KI). In this study we evaluated the anti-sickling activities of the leaf extracts of the three Khaya species leaves with a view to authenticating the ethnomedicinal claims, and assess the proximate as well as the elemental constituents that may contribute to the properties. Dried leaves of the Khaya species were extracted by cold maceration and Soxhlet methods using water, ethanol and petroleum spirit as extractives. Filtered extracts were concentrated in vacuo at 40oC and dried in a lyophilizer. Inhibitory and reversal models were employed to evaluate their anti-sickling effects on Hb SS red blood cells following standard procedures. Proximate and elemental analysis were determined using the simple analytical procedure as described by the Association of Official Analytical Chemistry (AOAC) of 1987, 13th Edition Washington DC P1094 and Dry Ashing method of AOAC 2006 respectfully. Anti-sickling results showed that the Soxhlet ethanol extracts of the Khaya species demonstrated significant (p≤0.05) ability to reverse and inhibit the sickling of red blood cells in-vitro with KI having the highest inhibitory and reversal of 60.04+1.77% and 74.97+2.23% respectively at 4 mg/ml concentration. The proximate analysis revealed the richness of the Khaya leaves in minerals, proteins and carbohydrates. Khaya leaves contained calcium, magnesium, sodium, phosphorus, and other essential elements within the limits of dietary requirement. Khaya species could therefore be recommended for further development into herbal remedy in the management of sickle cell disease.

LC-MS/MS Analysis of crude Flavonoid Compounds from <i>Justicia secunda</i> from Democratic Republic of the Congo and evaluation of their antisickling Activity

<i>Justicia secunda</i> Vahl (Acanthaceae) is a tropical herbaceous plant traditionally used by indigenous peoples of the Democratic Republic of the Congo (DRC) to treat symptoms associated with sickle cell disease (SCD), a genetic condition with life-threatening complications. Given the lack of side-effect-free drugs, alternative herbal therapies that can reduce or reverse red blood cell sickling may serve as safe and effective treatments. The primary objective of this study is to conduct a phytochemical screening of crude flavonoids extracted from <i>J. secunda</i> using LC-ESI/MS/MS. <i>J. secunda</i> extracts were evaluated for their phytoconstituents and anti-sickling properties. The anti-sickling properties were assessed through reverse sickling estimation, polymerization and oxidation inhibition, and osmotic fragility assays. Fractionation of the methanol extract and chemical profiling were performed by flash chromatography and high-performance thin-layer chromatography analysis respectively. Characterization and identification of the crude flavonoids were done using chromatography and spectroscopy methods. Chemical screening of crude flavonoids revealed the presence of 12 flavonoid O-glycosides based on one flavonol (methoxy-kaempferol) and two flavones (luteolin and apigenin). The crude flavonoid extracts demonstrated maximum reversal of sickled red blood cells (91.9 ± 0.8%), significant inhibition of hemoglobin polymerization (77.8 ± 7.6%) and hemoglobin S auto-oxidation (96.3 ± 0.2), and provided maximum protection of red blood cells against hyperhemolysis. The results validate the traditional use of <i>J. secunda</i> and identify potential compounds for the development of novel anti-sickling agents.

A Systematic Review of Medicinal Plants and Their Compounds Validated as Agents for the Management of Sickle Cell Disease

Some plants used in traditional medicine to manage sickle cell disease have been validated pharmacologically to ascertain their anti-sickling properties. However, there is no global systematic review of the evidence in support of their use for sickle cell management. This research aimed to conduct a systematic review of the pharmacological evidence to highlight species, genera, and some phytochemicals which could be primed for novel anti-sickling medications. The Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) guidelines were used. Articles in English, published from 2000 to 2022 were included in the analysis. The literature search covered 411 publications of which 82 were found to be eligible. More than half (53.65%) of the articles were published from 2016 to 2022. Anti-sickling research from Africa accounted for 86.58% of the publications, with more than half coming from Nigeria, 12.20% from Asia and only 1.22% from Europe. The Fabaceae, Euphorbiaceae, and Annonaceae were the top three plant families whereas Zanthoxylum and Terminalia were the most reported genera. Carica papaya and Terminalia catappa were the most reported species. Sickling reversal ( n = 33/82) and hemoglobin polymerization studies ( n = 29/82) were the most reported assays. Benzoic acid derivatives, butyl stearate, ellagic acid derivatives, and some pentacyclic triterpenoids were the only plant derived compounds validated for anti-sickling activities. A total of 117 plant species with anti-sickling activities were documented. Studies on secondary metabolites with anti-sickling properties to serve as scaffolds for novel drug development for sickle cell management were limited.

Evaluation of Antisickling Activity and Antibacterial Potential of Methanolic Root Extract of Ximenia americana Linn. (Olacacaea)

Aims: This research work was done in order to evaluate invitro antisickling activity, and antibacterial potentials of the methanolic root extract of Ximenia americana, Linn. Olacaceae. Study Design: It is an experimental research work. Place and Duration of Study: Department of Microbiology and Biotechnology, National Institute of Pharmaceutical Research and Development (NIPRD), Idu, Abuja, Nigeria. The study was carried out between December, 2019 to June, 2020. Methodology: Evaluation of the antisickling activity of the methanolic root extract of Ximenia americana was carried out in two-fold; viz. the ability of the plant extract to inhibit or prevent sickling (antisickling effect) of erythrocytes from blood samples obtained from sickle cell disease (SCD) volunteers on one hand, and the ability of the extract to reversed pre-sickled erythrocytes using standard protocols. The antibacterial assay was done using microtiter broth dilution method to determine the minimum inhibitory concentration (MIC) on some selected encapsulated bacterial (E. coli, Salmonella typhi, Staphylococcus aureus, Pseudomonas mirabilis, Pseudomonas aeruginosa, Bacillus subtilis, and Klebsiella pneumonia) that have been reported to caused complications in SCD. Results: The methanolic root extract of Ximenia americana showed a concentration dependent antisickling activity across concentration gradient. The percent sickling inhibition was dose-dependent (0.05 mg = 60 %, 0.5 mg = 62 %, 1 mg = 88 %, 2 mg = 87 %, and 4 mg = 90 %), this result was statistically significant (p < 0.05 vs control) when compared to the untreated group (25 %). Similarly, the result of the sickle red cell reversal by the test extract demonstrated a percent dose-dependent reversibility (0.05 mg = 36 %, 0.5 mg = 40 %, 1 mg = 48 %, 2 mg = 58 %, and 4 mg = 63 %), a result that was significantly (p < 0.5 vs control) compared to the control (19 %). The antimicrobial assay result showed that, the sensitivity of the selected microorganisms to the plant extract was concentration dependent. Staphylococcus aureus and Bacillus subtilis showed better sensitivity to the extract with higher zones of inhibition (8 mm and 7 mm) at 80 mg/mL concentration. Conclusion: Methanolic root extract of Ximenia americana L demonstrated a significant dose-dependence antisickling and sickle cell reversal activities, with p < 0.05 vs control. Also, the extract showed sensitivity against some selected bacteria isolates as a result possess antibacterial activity against susceptible microorganism.

Cyclic Peptides as Aggregation Inhibitors for Sickle Cell Disease.

Sickle cell disease is a missense genetic disorder characterized by the aggregation of deoxy-HbS into helical fibers that distort erythrocytes into a sickle-like shape. Herein, we investigate, through molecular dynamics, the effect of nine 5-mer cyclic peptides (CPs), tailor-designed to block key lateral contacts of the fibers. Our results show that the CPs bind orthogonally to the main HbS pocket involved in the latter contacts, with some revealing exceedingly long residence times. These CPs display moderate to high specificity, exhibiting molecular recognition events even at a HbS/CP (1:1) ratio. A much lower HbS-CP binding free energy, longer residence times, and higher specificity are also found relative to a previously reported CP with modest in vitro antisickling activity. These results indicate that some of these CPs have the potential to reduce the concentration of aggregation-competent deoxy-HbS, precluding or delaying the formation of lateral contact at the homogeneous nucleation stage.

Optimization of Lentiviral ß-Globin Vectors in a Forward Orientation to Enhance Therapeutic Effectiveness for Sickle Cell Disease

Sickle cell disease (SCD) is a monogenic hemoglobin (Hgb) disorder characterized by a single pointmutation in the β-globin gene which causes Hgb polymerization under low oxygen tension and sickling of red blood cells (RBCs) which in turn drives severe systemic injury. Gene addition technologies like hematopoietic stem cell (HSC) targeted lentiviral (LV) gene therapy are among the most promising curative strategies for SCD. To expand this approach, improvements in LV titer, transduction efficiency, along with suppression of native sickle-globin, are preferred to generate successful therapeutic outcomes. One such improvement targets LV orientation: the relationship between the DNA encoding the β-globin gene in the LV and the promoter driving healthy β-globin gene expression. We created a forward-oriented β-globin-expression vector with an improved titer that results in more efficient transduction of human CD34+ cells in vitro, in human reconstituting CD34+ cells in xenografted mice, and in rhesus reconstituting CD34+ cells(Uchida N. et al., 2019). We report here on further optimization of LVs that in addition to forward orientation, also express shRNA that decreases native β-globin and sickle-globin, which could enhance the assembly of corrected Hgb tetramers. Seven unique constructs which varied in anti-β-globin shRNA sequences, packaging elements, and regulatory elements, were transduced into MEL-BB88 cells and expanded for 2 weeks. gDNA was collected for vector copy number (VCN) analysis, and treated with 10 µM hemin to induce Hgb expression. Five days after hemin-induction, cells were harvested for benzidine staining and immunoblot analysis to validate globin expression. Sca-1+ HSC/progenitor (HSPC) BM cells were isolated from Towne's humanized SCD donor mice prior to stimulation for 48 h with cytokines, then transduced at an MOI of 24 twice, 24 h apart. To assess the in vivo engraftment potential of the transduced HSPCs, 2.5x10^6 cells were transplanted into lethally irradiated CD45.1 recipient mice. Peripheral blood (PB) was sampled at 2-week intervals for PBMC chimerism and lineage engraftment, Hgb electrophoresis, Lorrca OxygenScan and OsmoScan assays, and PB VCN. Whole BM from engrafted recipients was collected at 30 weeks and used for secondary transplantation assays which were again analyzed over 24 weeks for PB engraftment, VCN, and donor Hgb expression. LVs were produced at varying titers and all successfully transduced MEL-BB88 cells with VCNs between 1 and 5 that were maintained following hemin induction. Interestingly, variations in RRE elements dramatically affected human globin expression in vitro. Furthermore, the transplanted mice engrafted fully with HSPCs transduced with multiple vectors. Notably, mice transplanted with HSPCs transduced with vector CX0066p (LCR-Enhancer-P-HBB-shmiR-3g1.223 + 3g2.30a-R1) maintained a VCN of 0.2-0.4 in PB for the 30-week duration of the primary transplant. Cellulose acetate gels of RBCs from PB showed ~40% HbA in a background of HbS. The P50 right-shifted towards normal, RBC counts increased, WBC counts decreased, and OxygenScan parameters were all corrected towards controls and away from those values obtained from mice transplanted with mock transduced HSPCs. EI max and EI min increased while pO2@95% decreased. Lastly, the RBC sickling was corrected in an in vitro sickling assay. In conclusion, based on LV titer, MEL cell expression, transduction efficiency, engraftment of modified cells, in vivo globin expression, anti-sickling activity, and oxygen transport, these constructs provide outstanding Hgb expression and phenotype correction. Consequently, these candidates serve as a solid foundation for future human gene therapy products in the treatment of SCD.

Targeted modification of furan-2-carboxaldehydes into Michael acceptor analogs yielded long-acting hemoglobin modulators with dual antisickling activities.

Sickle cell disease (SCD) is the most common genetic disorder, affecting millions of people worldwide. Aromatic aldehydes, which increase the oxygen affinity of human hemoglobin to prevent polymerization of sickle hemoglobin and inhibit red blood cell (RBC) sickling, have been the subject of keen interest for the development of effective treatment against SCD. However, the aldehyde functional group metabolic instability has severly hampered their development, except for voxelotor, which was approved in 2019 for SCD treatment. To improve the metabolic stability of aromatic aldehydes, we designed and synthesized novel molecules by incorporating Michael acceptor reactive centers into the previously clinically studied aromatic aldehyde, 5-hydroxymethylfurfural (5-HMF). Eight such derivatives, referred to as MMA compounds were synthesized and studied for their functional and biological activities. Unlike 5-HMF, which forms Schiff-base interaction with αVal1 nitrogen of hemoglobin, the MMA compounds covalently interacted with βCys93, as evidenced by reverse-phase HPLC and disulfide exchange reaction, explaining their RBC sickling inhibitory activities, which at 2 mM and 5 mM, range from 0% to 21% and 9% to 64%, respectively. Additionally, the MMA compounds showed a second mechanism of sickling inhibition (12%-41% and 13%-62% at 2 mM and 5 mM, respectively) by directly destabilizing the sickle hemoglobin polymer. In vitro studies demonstrated sustained pharmacologic activities of the compounds compared to 5-HMF. These findings hold promise for advancing SCD therapeutics.

ANTIOXIDANT AND ANTI-SICKLING ACTIVITY OF EXTRACTS FROM THE STEM AND ROOTS BARKS OF STRYCHNOS INNOCUA (DEL.)

Objective: In Togo Strychnos innocua represents a plant traditionally used to cure sickle cell disease. This study aims to carry out a phytochemical study and evaluate the antioxidant and anti-sickling activity of Strychnos innocua root and stem barks to support its use. Methods: Hydroethanolic and ethanolic extracts of each plant organ were obtained by maceration. Polyphenol content was determined using the Folin-Ciocalteu’s reagent and the flavonoid content using Aluminium trichloride (AlCl3) method. The anti-sickling activity of hydroethanolic extracts of root and stem barks was tested on SS blood samples from sickle cell patients using the Emmel test. Antioxidant activity was assessed by DPPH and FRAP methods on both the hydroethanolic and ethanolic extracts. Results: Results indicate that the highest levels of polyphenols were measured in the hydroethanolic extract of the root barks (59.32±1.77 mg GAE/g) and the ethanol extract of the stem barks (98.27±2.44 mg GAE/g). The hydroethanolic extract of the root barks and the ethanolic extract of the stem barks showed high levels of flavonoids. Extracts from both organs significantly reduced falciformation (p<0.001) at a rate of 22% (root) and 35% (stem) compared with the control (94%). In addition, root and stem extracts showed slight antioxidant activity. Conclusion: Results justify the traditional use of Strychnos innocua roots in treating sickle cell anaemia.

In-vitro Antisickling Activity of Pergularia daemia, Canna indica and Petiveria alliacea Plants used in the Treatment of Sickle Cell Anaemia in Edo State, Nigeria

Sickle cell disease is a genetic blood disorder that affects the shape and transportation of the red blood cells (RBCs) in blood vessels, leading to various clinical complications. Available medicines for treating the disease are insufficiently effective, toxic or expensive. Therefore, there has been a pressing need for effective and inexpensive therapeutic agents from indigenous medicinal plants. Petiveria alliacea, Canna indica and Pergularia daemia, respectively were evaluated for their cationic constituents as a measure for their antisickling activity in sickle cell anaemia disorder. The three medicinal plants were extracted separately with methanol solvent using maceration method for 72 hours. The extracts were concentrated using a rotary evaporator (Model RE, 200, USA). Phytochemical screenings were conducted using standard method, while other portions of the extract were subjected to dry ash digestion for determination of mineral elements by emission flame photometry (EFP) and atomic absorption spectrophotometry (AAS). Evaluation of the antisickling activity of the extracts was done using the sodium metabisulphite (SMBS) test. Eugenol, terpenoids and alkaloids were present in the three plant extracts, while K+ values recorded for Petiveria alliacea, Canna indica and Pergularia daemia were 54.30 mg kg–1, 180.10 mg kg–1 and 28.30 mg kg–1, respectively. Other mineral elements detected in the three plants were Cu2+, Zn2+, Fe2+ and Mg2+. The leaves extract of Canna indica and Pergularia daemia at high dose of 300 µg/mL caused significant reductions of sickle red blood cells from 15% to 6% and 15% to 1%, respectively at 90 minutes of the antisickling test. The research confirmed that extracts of both Canna indica and Pergularia daemia used in this study have significant antisickling properties in invitro studies than Petiveria alliacea.
 Keywords: Antisickling activity, Petiveria alliacea, Canna indica, Pergularia daemia, sickle cell, phytochemicals, minerals

Antisickling Studies of the Aqueous Leaf Extract of Detarium microcarpum (Tallow Tree)

Detarium microcarpum (DM) is shrub that grows wildly in Nigeria. Few studies have been conducted on the leaf extract. The plant forms part of some recipes used in the treatment of sickle cell disease. This study aims to determine the phytochemical composition and antisickling property of various concentrations of Detarium microcarpum aqueous leaf extract. Quantitative and qualitative phytochemical screenings were conducted using established protocols while the antisickling prevention and reversal studies were evaluated using Emmel’s test. There was no significant difference between the antisickling prevention (p>0.05) and reversal (p>0.05) property of the aqueous extract compared to positive control (p-hydroxybenzoic acid). Phytochemical screening revealed high abundance of flavonoids and very little presence of terpenoids among the classes of phytochemicals screened. There was also no significant variation in the antisickling activity of the various doses (0.1 mg/ml, 1 mg/ml and 10 mg/ml) of the extract tested. The LD50 conducted showed that it is completely safe in mice. The findings from this study suggest that Detarium microcarpum aqueous extract at various concentrations possesses both sickling prevention and reversal effect which may be exploited for the management of sickle cell disease.

Evaluation of 2D and 3D Erythroid Differentiation Protocols Using Sickle Cell Disease and Healthy Donor Induced Pluripotent Stem Cells.

Sickle cell disease (SCD) is a highly prevalent genetic disease caused by a point mutation in the HBB gene, which can lead to chronic hemolytic anemia and vaso-occlusive events. Patient-derived induced pluripotent stem cells (iPSCs) hold promise for the development of novel predictive methods for screening drugs with anti-sickling activity. In this study, we evaluated and compared the efficiency of 2D and 3D erythroid differentiation protocols using a healthy control and SCD-iPSCs. iPSCs were subjected to hematopoietic progenitor cell (HSPC) induction, erythroid progenitor cell induction, and terminal erythroid maturation. Differentiation efficiency was confirmed by flow cytometry analysis, colony-forming unit (CFU) assay, morphological analyses, and qPCR-based gene expression analyses of HBB and HBG2. Both 2D and 3D differentiation protocols led to the induction of CD34+/CD43+ HSPCs. The 3D protocol showed good efficiency (>50%) and high productivity (45-fold) for HSPC induction and increased the frequency of BFU-E, CFU-E, CFU-GM, and CFU-GEMM colonies. We also produced CD71+/CD235a+ cells (>65%) with a 630-fold cell expansion relative to that at the beginning of the 3D protocol. After erythroid maturation, we observed 95% CD235a+/DRAQ5- enucleated cells, orthochromatic erythroblasts, and increased expression of fetal HBG2 compared to adult HBB. A robust 3D protocol for erythroid differentiation was identified using SCD-iPSCs and comparative analyses; however, the maturation step remains challenging and requires further development.

Comparative antisickling and antioxidant activities of Pseudobombax ellipticum cultivars in relation to their metabolite profiling using LC/MS.

Pseudobombax ellipticum is native to South America and is cultivated worldwide mostly for its medicinal benefits. The plant is used traditionally in respiratory disorders such as dry cough, in the treatment of fever and stomach pain, and as an antimicrobial and analgesic. The antisickling and antioxidant effects of the flowers of P. ellipticum (Kunth) Dugand (red) and P. ellipticum cultivar alba (white) were compared using an in vitro assay in 2% sodium metabisulfite sickling induction model, DPPH, and metal chelation assays. Both red and white flowers exhibited antioxidant and antisickling activities. In DPPH assay, lower IC50 (34.89 ± 0.98 and 53.28 ± 1.14 μg mL-1) in red and white flowers respectively were detected relative to Trolox as a positive control (56.82 ± 0.87 μg mL-1). Comparable metal chelation activity (81.4 and 77.8 μM EDTA equivalent/mg) was detected in red and white flowers of both cultivars respectively. The average readings of the "reversal of sickling test "revealed a decrease in sickling percent from 49% to 15% in red flowers and to 18% in white flowers. Also, polymerization inhibition rate was increased from 0.34 to 1 and to 0.92 in red and white flowers respectively. Total phenolics, flavonoids and anthocyanins were quantified in red and white flowers as (163.9, 43.13 mg gallic acid equivalent/g extract), (71.92, 34.5 mg rutin equivalent/g extract) and (127.0, 85.9 mg pelargonidine-3-mono glucoside equivalent/kg extract), respectively. Liquid chromatography mass spectrometry (LC-MS) analysis was further employed for detection and identification of anthocyanins in flower extracts. Eight new anthocyanins were identified for the first time in genus Pseudobombax. These results reveal the potential role for both red and white flower extracts as possible antisickling agents in sickle cell anemia management.

Phytochemical investigation and antisickling properties of a Poly-herbal formula on the HBSS Red Blood Cells

The aim of this study was to evaluate the sickle-formation inhibition of a recipe of three plants: Zanthoxylum leprieurii, Xylopia aethiopica and Harungara madagascariensis. The 70% hydroethanolic extract (EZHm) and the decoctate (DZHm) were used to determine the chemical groups by colorimetric and precipitation reactions. These extracts were also used to evaluate the antisickling properties by Emmel's method, following the protocol described by Image. The biological tests revealed that the total extracts have concentration-dependent and time-dependent anti-sickle cell activity. These extracts act by reducing the polymers of sickle cells. After 120 min the inhibition percentages were 87.35% DZHm, 87.28% EZHm and 85.07% phenylalanine in the presence of 10 mg/mL of the test substances. Plant extracts show a strong antisickling activity which would be due to its phytochemical constituents such as primary (aromatic amino acid) and secondary (alkaloids, phenolic compounds, saponosides, sterols, polyterpenes) metabolites found in these extracts. These extracts, even if they are crude, constitute a hope for the discovery of many antisickling active principles. This natural poly-herbal formula product could improve the quality of life of people with sickle cell disease.

Mineral Element Contents and Antisickling Activity of Cyttaranthus congolensis and Hypoxis angustifolia Traditionally Used to Treat Sickle Cell Disease in Kwilu Province, Democratic Republic of the Congo

The objective of the present study was to determine the composition in mineral elements, the antisickling activity and the osmotic brittleness test, of the twenty three extracts of two plants Cyttaranthus congolensis, Hypoxis angustifolia used in the management of sickle cell disease by the traditional healers in Kwilu province. Mineral composition analyses of these two plants were performed using X-ray fluorescence spectrometric method. Twenty three( 23) mineral elements were identified in each of these two plants among others: Potassium (K), Phosphorus (P), Calcium (Ca), Sodium (Na), Magnesium (Mg), Sulfur (S), Chlorine (Cl) and trace elements such as: Aluminum (Al), Silicon (Si), Vanadium (V), Chromium (Cr), Manganese (Mn), Iron (Fe), Nickel (Ni), Copper (Cu), Zinc (Zn), Selenium (Se), Bromine (Br), Molybdenum (Mo), Tin (Sn), Iodine (I), Barium (Ba) and Lead (Pb). Mineral elements related to sickle cell disease are: Iron (Fe), Zinc (Zn), Selenium (Se), Copper (Cu), Calcium (Ca), Magnesium (Mg) and Manganese (Mn). Of all these elements, Potassium and Calcium are in higher content while Lead, Tin, Bromine, Copper and Nickel are in trace amounts. The antisickling activity of Cyttaranthus congolensis and Hypoxis angustifolia extracts, was tested using the Emmel test. The results obtained showed a significant in vitro antisickling activity for both plants. The osmotic fragility test used to confirm the Emmel test showed that the hemolysis rate decreased with increasing NaCl concentration. In the presence of anthocyanins, the antihemolytic activity at different NaCl concentrations was higher than the control. This indicates the action of the extracts of these plants on the osmotic fragility of red blood cell membrane.

Can Crude Oil Exploration Influence the Phytochemicals and Bioactivity of Medicinal Plants? A Case of Nigerian Vernonia amygdalina and Ocimum gratissimum

The Nigerian Niger-Delta crude oil exploration often results in spills that affect indigenous medicinal plant biodiversity, likely changing the phytochemical profile of surviving species, their bioactivity or toxicity. In crude oil-rich Kokori and crude oil-free Abraka, classic examples of indigenous plants occupying the medicine-food interface include Vernonia amygdalina (VAL) and Ocimum gratissimum leaves (OGL). These plants are frequently utilised during pregnancy and in anaemia. To date, no scientific investigation has been reported on the potential changes to the phytochemical or bioactivity of the study plants. To discuss the similarities and dissimilarities in antisickling bioactivity and phytochemicals in VAL and OGL collected from Kokori (VAL-KK and OGL-KK) and Abraka (VAL-AB and OGL-AB), in silico, in vitro and comparative UPLC-QTOF-MS analysis was performed. Nine unique compounds were identified in OGL-KK, which have never been reported in the literature, while differences in antisickling potentials were observed in VAL-KK, OGL-KK and, VAL-AB, OGL-AB. Our findings show that VAL-AB and OGL-AB are richer and more diverse in phytochemicals and displayed a slightly higher antisickling activity than VAL-KK and OGL-KK. Ligand-based pharmacophore modelling was performed to understand the potential compounds better; this study may provide a basis for explaining the effect of crude oil spills on secondary metabolites and a reference for further research.

Design, Synthesis, and Investigation of Novel Nitric Oxide (NO)-Releasing Aromatic Aldehydes as Drug Candidates for the Treatment of Sickle Cell Disease.

Sickle cell disease (SCD) is caused by a single-point mutation, and the ensuing deoxygenation-induced polymerization of sickle hemoglobin (HbS), and reduction in bioavailability of vascular nitric oxide (NO), contribute to the pathogenesis of the disease. In a proof-of-concept study, we successfully incorporated nitrate ester groups onto two previously studied potent antisickling aromatic aldehydes, TD7 and VZHE039, to form TD7-NO and VZHE039-NO hybrids, respectively. These compounds are stable in buffer but demonstrated the expected release of NO in whole blood in vitro and in mice. The more promising VZHE039-NO retained the functional and antisickling activities of the parent VZHE039 molecule. Moreover, VZHE039-NO, unlike VZHE039, significantly attenuated RBC adhesion to laminin, suggesting this compound has potential in vivo RBC anti-adhesion properties relevant to vaso-occlusive events. Crystallographic studies show that, as with VZHE039, VZHE039-NO also binds to liganded Hb to make similar protein interactions. The knowledge gained during these investigations provides a unique opportunity to generate a superior candidate drug in SCD with enhanced benefits.

Ethnopharmacological Study of the Medicinal Plants Used in the Treatment of Sickle Cell Anemia in the West Region of Cameroon.

Background Sickle cell anemia (SCA) or sickle cell disease (SCD) is a genetic disease associated with increased morbidity and mortality in Africa and other developing nations. Therefore, modern and traditional remedies are being introduced for use in the treatment and management of this disease. This is because safe, effective, and inexpensive therapeutic agents are urgently needed for the treatment of this disease in Africa and other developing nations. Objective The purpose of this study is to identify medicinal plant species commonly used by traditional healers in the treatment of sickle cell patients across some localities in the west region of Cameroon. Material and Methods. The ethnopharmacological survey was carried out in several districts within some localities of the western region of Cameroon. The survey was based on a semistructured questionnaire that was administered to 17 traditional healers and 62 sickle cell patients. It took place between November 2018 and March 2019. Personal information of participants and plant therapy data were gathered. Plants were identified at the National Herbarium of Cameroon. Literature review determined pharmacological effects and phytochemical compounds of the identified plants. Data were generally analysed using Epi Info 7 software for Windows. Results Twelve medicinal plant species belonging to 10 families are being used in the treatment of sickle cell anemia across the study sites. Euphorbiaceae is the dominant family with three plant species. Bark (39.3%) and seeds (35.7%) are the most used plant parts, which get administered through maceration, decoction, and chewing in water. According to the literature review, the identified plants have pharmacological effects and phytochemical compounds (especially polyphenols and alkaloids) that signify the presence of antioxidant compounds, which may possess an antisickling activity. There is therefore a need to conduct another study to scientifically validate (in vitro) antisickling properties of these plants. Conclusion This study has revealed promising medicinal plants that are currently applied in the traditional treatment of sickle cell anemia. Although still inconclusive, the association of pharmacological effects and phytochemical compounds with these medicinal plants justifies their use in traditional pharmacopoeia.

Isolation and Characterisation of Quercitrin as a Potent Anti-Sickle Cell Anaemia Agent from Alchornea cordifolia.

Alchornea cordifolia Müll. Arg. (commonly known as Christmas Bush) has been used traditionally in Africa to treat sickle cell anaemia (a recessive disease, arising from the S haemoglobin (Hb) allele), but the active compounds are yet to be identified. Herein, we describe the use of sequential fractionation coupled with in vitro anti-sickling assays to purify the active component. Sickling was induced in HbSS genotype blood samples using sodium metabisulphite (Na2S2O5) or through incubation in 100% N2. Methanol extracts of A. cordifolia leaves and its sub-fractions showed >70% suppression of HbSS erythrocyte sickling. The purified compound demonstrated a 87.2 ± 2.39% significant anti-sickling activity and 93.1 ± 2.69% erythrocyte sickling-inhibition at 0.4 mg/mL. Nuclear magnetic resonance (NMR) spectra and high-resolution mass spectroscopy identified it as quercitrin (quercetin 3-rhamnoside). Purified quercitrin also inhibited the polymerisation of isolated HbS and stabilized sickle erythrocytes membranes. Metabolomic comparisons of blood samples using flow-infusion electrospray-high resolution mass spectrometry indicated that quercitrin could convert HbSS erythrocyte metabolomes to be like HbAA. Sickling was associated with changes in antioxidants, anaerobic bioenergy, and arachidonic acid metabolism, all of which were reversed by quercitrin. The findings described could inform efforts directed to the development of an anti-sickling drug or quality control assessments of A. cordifolia preparations.