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Anti-sickling effect of MX-1520, a prodrug of vanillin: An in vivo study using rodents
British Journal of Haematology
Abstract
Vanillin, a food additive, covalently binds with sickle haemoglobin (Hb S), inhibits cell sickling and shifts the oxygen equilibrium curve towards the left. These effects would potentially benefit patients with sickle cell disease (SCD). However, vanillin has no therapeutic effect if given orally because orally administered vanillin is rapidly decomposed in the upper digestive tract. To overcome this problem, a vanillin prodrug, MX-1520, which is biotransformed to vanillin in vivo, was synthesized. Studies using transgenic sickle mice, which nearly exclusively develop pulmonary sequestration upon exposure to hypoxia, showed that oral administration of MX-1520 prior to hypoxia exposure significantly reduced the percentage of sickled cells in the blood. The survival time under severe hypoxic conditions was prolonged from 6.6 +/- 0.8 min in untreated animals to 28.8 +/- 12 min (P < 0.05) and 31 +/- 7.5 min (P < 0.05) for doses of 137.5 and 275 mg/kg respectively. Intraperitoneal injection of MX-1520 to bypass possible degradation in the digestive tract showed that doses as low as 7 mg/kg prolonged the survival time and reduced the percentage of sickled cells during hypoxia exposure. These results demonstrate the potential for MX-1520 to be a new and safe anti-sickling agent for patients with SCD.
... Vanillin, 5-HMF and TD-7 lack this hydroxyl protection. In an effort to solve the problem of aldehyde metabolism, Zhang, et al. prepared a prodrug of vanillin (MX-1520) (Figure 1), where the aldehyde functional group was protected by L-cysteine ethyl ester group (thiazolidine group), which gradually decomposes over a period of time to release the parent active vanillin [34]. MX-1520 resulted in a much better oral bioavailability compared to vanillin. ...
... Synthesis of 1-(2-(3-((6-(hydroxymethyl)pyridin-2-yl)methoxy)-5 methoxyphenyl) thiazolidin-4-yl)propan-1-one, (Pro-7). TD-7 prodrug, Pro-7 was synthesized following the published procedure for synthesizing the thiazolidine prodrug of vanillin, MX-1520 [34]. To a suspension of 2-((6-(hydroxymethyl)pyridin-2-yl)methoxy)-5-methoxybenzaldehyde (TD-7) (0.706 mmol) in ethanol was added a solution of L-cysteine (1.76 mmol) dissolved in ethanol containing ethylenediamine, EDA (1.76 mmol). ...
... Based on the findings of the thiazolidine prodrug of vanillin [34], we decided to employ a similar strategy of protecting the active aldehyde group of TD-7 from undue metabolism by coupling the aldehyde group with L-cysteine ethyl ester group to from thiazolidine prodrug of TD-7. This approach is expected to improve TD-7 oral bioavailability. ...
The synthetic allosteric effector of hemoglobin, TD-7 has been investigated as a potential therapeutic agent for the treatment of sickle cell disease. The pharmacologic activity of TD-7 is due to formation of a Schiff-base interaction between its aldehyde group and the two N-terminal αVal1 amines of hemoglobin, effectively inhibiting sickling of red blood cells. However, TD-7 faces a challenge in terms of poor oral bioavailability due to rapid in-vivo oxidative metabolism of its aldehyde functional group. To address this shortcoming, researches have explored the use of a L-cysteine ethyl ester group to cap the aldehyde group to form a thiazolidine aromatic aldehyde prodrug complex, resulting in the improvement of the metabolic stability of this class of compounds. This report details the synthesis of a thiazolidine prodrug of TD-7, referred to as Pro-7, along with a comprehensive investigation of Pro-7 functional and biological properties. In an in-vitro Hb modification and Hb oxygen affinity studies using normal whole blood, as well as erythrocyte sickling inhibition using sickle whole blood, Pro-7 exhibited a gradual onset but progressive increase in all activities. Additionally, in-vivo pharmacokinetic studies conducted with Sprague Dawley rats demonstrated that Pro-7 can undergo hydrolysis to release TD-7. However, the blood concentration of TD-7 did not reach the desired therapeutic level. These findings suggest that the incorporation of the L-cysteine ethyl ester group to TD-7 represents a promising strategy to enhance the metabolic stability of aromatic aldehydes that could lead to the development of a more effective drug for the treatment of sickle cell disease.
... It is a benzaldehyde with methoxy and hydroxy functional groups at positions 3 and 4 respectively. Its reported medicinal properties include neuroprotection, anticancer activity, antidiabetic activity, antimutagenic activity, and anti-sickling activity [20,[22][23][24][25][26][27]. ...
... Reproductive Toxicology 102 (2021)[24][25][26][27][28][29][30][31][32][33][34] ...
Testicular dysfunctions leading to male infertility has been reported in type 2 diabetes (T2D), with glucose dysmetabolism, cholinergic and purinergic dysfunction being major contributors. In the present study, the effect of vanillin on glucose metabolism, purinergic and cholinergic dysfunctions were investigated in testicular tissues of T2D rats. Male Sprague-Dawley rats were divided into 6 groups containing 5 rats each. T2D was induced in rats by administering 10% fructose ad libitum for 14 days and injecting intraperitoneally with 40 mg/kg streptozotocin thereafter. T2D rats were orally administered vanillin at 150 and 300 mg/kg bodyweight (bw). Diabetic control (DC) consisted of untreated diabetic rats, while normal control (NC) consisted of normal rats and they were administered distilled water only. Metformin was used as the standard antidiabetic drug. After 5 weeks treatment, the rats were sacrificed, and the testes harvested. Induction of T2D led to significant depleted testicular levels of glutathione, glycogen content, superoxide dismutase and catalase activities, with concomitant elevated levels of nitric oxide, malondialdehyde, acetylcholinesterase, glucose-6-phosphatase, fructose-1,6-biphophastase, glycogen phosphorylase, amylase and lipase activities. These activities and levels were significantly reversed to near normal in rats treated with both doses of vanillin and compared favorably with metformin. These results when taken together, suggest the therapeutic effect of vanillin against hyperglycemia-mediated metabolic dysfunctions in testes of T2D rats. This is depicted by the ability of the phenolic to attenuate oxidative imbalance, purinergic and cholinergic dysfunctions, while suppressing glucose dysmetabolism.
... In this case, the synthetic prodrug of vanillin (MX-150) was designed to release vanillin after ingestion and absorption into the body. 21 After oral administration of equimolar amounts of vanillin (100 mg/kg) or the prodrug (186 mg/kg), the C max of vanillin and prodrug-derived vanillin were 2.45 and 9.51 μg/mL, respectively, and the area under the curve from zero to last time point (AUC last ) values were 17.4 and 565.8, respectively. The bioavailability of vanillin delivered by this prodrug was approximately 30-fold greater than vanillin given alone. ...
... However, in light of the apparent rapid breakdown of vanillin in the GI tract and the need for administration of larger doses, its potential oral efficacy for general treatment of SCD was considered problematic. 21 Subsequently, strategies to encapsulate and derivatize vanillin so as to improve bioavailability have been investigated. Such products along with a number of other potential therapeutic agents are being evaluated to replace hydroxyurea for treatment of SCD patients because of the poor response rate, poor tolerance, and undesirable side effects of hydroxyurea. ...
The vanilla bean, obtained from Vanilla planifolia and Vanilla tahitensis, members of the Orchidaceae family, is the source of vanilla extract, one of the most desired and widely used food flavorings worldwide. Besides uses of vanilla in foods, perfumes, and pharmaceuticals, it has complementary medicinal applications including alleviation of fever, spasms, and gastrointestinal irritations, to name a few. However, support from the scientific literature for human health benefits of vanilla and its chemical constituents vanillin and vanillic acid is limited and preliminary. This narrative review provides a summary of findings from human and animal studies addressing potential health benefits of the extract of this bean and select extract components.
... La vanilline est oxydée dans la partie supérieure du tractus digestif en acide vanillique éliminé par voie urinaire. Pour garantir les qualités de la vanilline plusieurs méthodes sont utilisées afin d'éviter cette oxydation, on retiendra notamment celle consistant à ingérer une prodrogue qui sera alors biotransformée en vanilline évitant l'oxydation de cette dernière (Zhang et al., 2004). Ainsi par voie orale les DL50 varient de 1400mg/kg chez le cobaye à 4200mg/kg chez le rat de lignée Sprague Dawley. ...
... Cette prodrogue est biotransformée à l'intérieur de l'organisme en vanilline (Zhang et al., 2004). ...
La vanille, liane appartenant à la famille des Orchidaceae, est une épice connue et grandement utilisée. La préparation des fruits, de leur culture à leur séchage, demande beaucoup d'attention afin d'éviter les contaminations, d'obtenir de bon rendement et surtout de bonne qualité. Nos ancêtres utilisaient la vanille notamment comme digestif, aphrodisiaque, désinfectant. Des études pharmacologiques ont montré que la vanille, notamment grâce à son composant aromatique majeur, la vanilline, présentait effectivement certaines qualités comme antibactérien, antioxydant, antimitotique, et un certain pouvoir apaisant. Cette action apaisante constitue notamment pour les bébés prématurés une solution naturelle et saine à un problème de taille : l'apnée du sommeil. Cette épice était utilisée depuis les Aztèques comme aromatisant du chocolat, l'aidant ainsi à être plus digeste. Cette utilisation perdure de nos jours : elle est utilisée comme aromatisant des médicaments, des compléments alimentaires mais aussi et surtout dans l'alimentation. Comme arôme, nous observons aussi l'utilisation d'une substance synthétique dérivée, l'éthylvanilline, plus stable et moins onéreuse que l'extrait de vanille ou la vanilline naturelle. Cette molécule ne présenterait apparemment pas les mêmes propriétés pharmacologiques que la vanilline. Depuis 1960, une molécule, dérivée de la vanilline, le cyclovalone est commercialisée. Les avancées majeures en thérapeutique semblent encore à venir, avec notamment une étude en cours d'un dérivé de la vanilline, mieux assimilable dans l'organisme que celle-ci, pouvant permettre de lutter contre la drépanocytose.
... A drug that prolongs the delay time prior to polymerization might be of therapeutic value in SCD, because a longer delay time decreases the probability of SS cell sickling. Reported antisickling/antidrepanocytary agents in this group include a formulated phytomedicine, Niprisan (Nix-0699), a chemical compound 5hydroxymethyl-2-furfural [5HMF], and MX-1520 (a prodrug of a food additive, Vanillin) which modify intracellular sickled hemoglobin and inhibit sickling of red blood cells [10][11][12][13]. ...
... The antisickling effects of MX-1520, a prodrug of vanillin, have been analyzed using rodents in vivo. This prodrug was produced because vanillin rapidly decomposed in the upper digestive tract and so was ineffective when taken orally in its original form [11]. A naturally occurring aromatic aldehyde, 5-hydroxymethyl-2-furfural (5HMF), was found to modify intracellular sickled hemoglobin and to inhibit sickling of red blood cells. ...
Sickle cell anemia is a genetically inherited disease in which the "SS" individual possesses an abnormal beta globin gene. A single base substitution in the gene encoding the human -globin subunit results in replacement of 6 glutamic acid by valine, leading to the devastating clinical manifestations of sickle cell disease. This substitution causes drastic reduction in the solubility of sickle cell hemoglobin (HbS) when deoxygenated. Under these conditions, the HbS molecules polymerize to form long crystalline intracellular mass of fibers which are responsible for the deformation of the biconcave disc shaped erythrocyte into a sickle shape. First-line clinical management of sickle cell anemia include, use of hydroxyurea, folic acid, amino acids supplementation, penicillinprophylaxis, and antimalarial prophylaxis to manage the condition and blood transfusions to stabilize the patient's hemoglobin level. These are quite expensive and have attendant risk factors. However, a bright ray of hope involving research into antisickling properties of medicinal plants has been rewarding. This alternative therapy using phytomedicines has proven to not only reduce crisis but also reverse sickling (). The immense benefits of phytomedicines and nutraceuticals used in the management of sickle cell anemia are discussed in this paper.
http://www.hindawi.com/journals/tswj/2013/269659/
... Anti-sickling impact for vanillin has been tested in vitro in mice and scientific studies (Zhang, 2004). There is an increase in hypoxic situation and reduction in percentage of sickle cells. ...
From the secretly organized chocolate-flavoring condiment of the Aztec emperor, Montezuma, to the ice cream-flavoring aspect of today, Vanilla has excursion centuries been an essential object withinside the spice alternate of the world. Originally Mexican, approximately 90% of the world's 1,000 annual metric heaps of vanilla "beans" come from Madagascar, almost 50% of that are ate up withinside the United States. It can also additionally marvel you to analyse that Vanilla bean pods come from an orchid (which already sounds expensive). In fact, the vanilla orchid (Vanilla planifolia) is the best orchid that produces a suitable for eating fruit, the biggest own circle of relatives of flowering plant life withinside the world. It's a tropical orchid, and there is extra than one hundred fifty types of Vanilla, alevin though best types, Bourbon and Tahitian are used commercially. Vanilla is possibly the world's maximum famous flavor, however much less than 1% of it comes from a completely herbal source, the Vanilla Orchid. To make certain pollination and the pleasant Vanilla bean flavor, every flower on each Orchid is Hand Pollinated. The farmers circulate speedy thru snaking vines, looking for the pale, waxy plant life that bloom simply one morning every year. They use thin, pointed sticks to boost the sensitive membrane that separates the male and woman components of the flower. With thumb and forefinger, they push the segments into every different to make certain pollination. Vanilla grows withinside the 20-diploma band both facet of the Equator and is local to the Americas. The vanilla you already know pleasant, Vanilla planifolia (additionally referred to as fragrans), historically grew wild at the Atlantic Gulf facet of Mexico from Tampico round to the northeast tip of South America, and from Colima, Mexico to Ecuador at the Pacific facet. It additionally grew at some stage in the Caribbean.
... It is majorly found in the vanilla bean and seed pods of Vanillus planifolia belonging to the Orchidaceae family (Ciriminna et al. 2019, Arya et al. 2021. Vanillin has been reported for its antioxidant (Tai et al. 2011), anticancer (Lirdprapamongkol et al. 2009), anti-sickling (Zhang et al. 2004), neuroprotective (Dhanalakshmi et al. 2015), cardioprotective (Sirangelo et al. 2020), and antidiabetic (Lu et al. 2019) activities. The protective effect of vanillin in streptozotocin (STZ) induced diabetes in 2 days old male pups have been reported (Lu et al. 2019). ...
Objective: This study investigated the antidiabetic effect of vanillin using in vitro, in silico, and in vivo experimental models.
Methodology: Type 2 diabetes (T2D) was induced in male Sprague-Dawley (SD) rats using fructose–streptozotocin (STZ) , then orally administered low (150 mg/kg bodyweight) or high (300 mg/kg bodyweight) dose of vanillin for 5 weeks intervention period.
Results: Vanillin suppressed the levels of blood glucose, serum cholesterol, triglyceride, low-density lipoprotein cholesterol (LDL-c), alanine transaminase (ALT), aspartate transaminase (AST), creatinine, urea, uric acid, when elevated serum insulin, HDL-cholesterol, and concomitantly improved pancreatic b-cell function, glucose tolerance, and pancreatic morphology. It also elevated both serum and pancreatic tissue GSH level, SOD and catalase activities, and hepatic glycogen level, while depleting malondialdehyde level, a-amylase, lipase, acetylcholinesterase, ATPase, ENTPDase and 5'-nucleotidase,
glucose-6-phosphatase, fructose-1,6-bisphosphatase, and glycogen phosphorylase activities.
Conclusions: The results indicate the potent antidiabetic effect of vanillin against T2D and its associated complications.
... With an understanding of the metabolic instability of vanillin, a prodrug of vanillin, thiazovanillin (MX1520) ( Figure 5B), in which L-cysteine protected the aldehyde group by forming a thiazolidine complex, was synthesized and studied [118]. Although MX1520 showed improved oral pharmacokinetic properties compared to vanillin, it was not studied in the clinic presumably due to its weak potency. ...
Introduction
Sickle cell disease (SCD) is a debilitating inherited disorder that affects millions worldwide. Four novel SCD therapeutics have been approved, including the hemoglobin (Hb) modulator voxelotor.
Areas Covered
This review provides an overview of discovery efforts towards modulating Hb allosteric behavior as a treatment for SCD, with a focus on aromatic aldehydes that increase Hb oxygen affinity to prevent the primary pathophysiology of hypoxia-induce erythrocyte sickling.
Expert Opinion
The quest to develop small molecules, especially aromatic aldehydes, to modulate Hb allosteric properties for SCD began in the 1970s; however, early promise was dogged by concerns that stalled support for research efforts. Persistent efforts eventually culminated in the discovery of the anti-sickling agent 5-HMF in the 2000s, and reinvigorated interest that led to the discovery of vanillin analogs, including voxelotor, the first FDA approved Hb modulator for the treatment of SCD. With burgeoning interest in the field of Hb modulation, there is a growing landscape of intellectual property, including drug candidates at various stages of preclinical and clinical investigations. Hb modulators could provide not only the best chance for a highly effective oral therapy for SCD, especially in the under-developed world, but also a way to treat a variety of other human conditions.
... Chemo-preventive effects of VA in carcinogenic rats in causing moratorium of metastatic invasion of tumor cell lines through the activation NF-KB was demonstrated (Akagi et al., 1995;Cheng et al., 2008). Additionally, it was used in the treatment of sickle cell anemia (Zhang et al., 2004). Antimutagenic activities against chromosomal mutations in human cells were exhibited by natural VA and cinnamaldehyde (CA). ...
A series of 4-hydroxy-3-methoxy benzaldehyde (vanillin) derivatives (3a–3r) was designed for the principle of Schiff base condensation with several individual sulfanilamide analogues. The inhibitory potencies of the designed compounds were evaluated through molecular docking simulation studies against the targets, breast cancer-topo isomerase-IIa and estrogen receptor-a; and the top scoring poses with higher binding energy were selected to assess the mode of binding and stability of each complex through molecular dynamics simulations. Compounds that remained stable in the active sites
of the both target receptors through a number of strong H-bonds and hydrophobic contacts were selected. Based on the computational results, these selected compounds, 3b, 3e and 3f were synthesized and were followed up for structural elucidation attempts, by FT/ATR, 1H NMR and 13C NMR.
From the experimental in vitro studies on 3b, 3e and 3f, the following remarkable activities against
breast cancer cell line were done; IC50 values of 3b, 3e and 3f were noted, 6.7, 4.3 and 11 ng/mL,
respectively. These newly synthesized compounds may be used as novel inhibitors of nuclear receptors
with potential therapeutic applications in control of cancer.
... Chemo-preventive effects of VA in carcinogenic rats in causing moratorium of metastatic invasion of tumor cell lines through the activation NF-KB was demonstrated (Akagi et al., 1995;Cheng et al., 2008). Additionally, it was used in the treatment of sickle cell anemia (Zhang et al., 2004). Antimutagenic activities against chromosomal mutations in human cells were exhibited by natural VA and cinnamaldehyde (CA). ...
... Chemo-preventive effects of VA in carcinogenic rats in causing moratorium of metastatic invasion of tumor cell lines through the activation NF-KB was demonstrated (Akagi et al., 1995;Cheng et al., 2008). Additionally, it was used in the treatment of sickle cell anemia (Zhang et al., 2004). Antimutagenic activities against chromosomal mutations in human cells were exhibited by natural VA and cinnamaldehyde (CA). ...
A series of 4-hydroxy-3-methoxy benzaldehyde (vanillin) derivatives (3a–3r) was designed for the principle of Schiff base condensation with several individual sulfanilamide analogues. The inhibitory potencies of the designed compounds were evaluated through molecular docking simulation studies against the targets, breast cancer-topo isomerase-IIα and estrogen receptor-α; and the top scoring poses with higher binding energy were selected to assess the mode of binding and stability of each complex through molecular dynamics simulations. Compounds that remained stable in the active sites of the both target receptors through a number of strong H-bonds and hydrophobic contacts were selected. Based on the computational results, these selected compounds, 3b, 3e and 3f were synthesized and were followed up for structural elucidation attempts, by FT/ATR, ¹H NMR and ¹³C NMR. From the experimental in vitro studies on 3b, 3e and 3f, the following remarkable activities against breast cancer cell line were done; IC50 values of 3b, 3e and 3f were noted, 6.7, 4.3 and 11 ng/mL, respectively. These newly synthesized compounds may be used as novel inhibitors of nuclear receptors with potential therapeutic applications in control of cancer.
Communicated by Ramaswamy H. Sarma
... In the survival study, while all the untreated mice died within the first 15 min under hypoxia (5% O 2 ), 50% of the S-NACH-treated mice survived at 30 min, which was 1 h after S-NACH administration (Figure 6), a typical duration tested for survival (33,40,41). Because S-NACH exhibited maximal effectiveness at 2 h, mice under hypoxia were observed for an additional 1 h, during which 37.5% of S-NACH-treated animals survived. ...
Sickle cell disease (SCD) is an autosomal recessive genetic disease caused by a single point mutation, resulting in abnormal sickle hemoglobin (HbS). During hypoxia or dehydration, HbS polymerizes to form insoluble aggregates and induces sickling of red blood cells (RBCs). RBC sickling increases adhesiveness of RBCs to alter the rheological properties of the blood and triggers inflammatory responses, leading to hemolysis and vaso-occlusive crisis sequelae. Unfractionated heparin (UFH) and low-molecular weight heparins (LMWH) have been suggested as treatments to relieve coagulation complications in SCD. However, they are associated with bleeding complications after repeated dosing. An alternative sulfated nonanticoagulant heparin derivative (S-NACH) was previously reported to have none to low systemic anticoagulant activity and no bleeding side effects, and it interfered with P-selectindependent binding of sickle cells to endothelial cells, with concomitant decrease in the levels of adhesion biomarkers in SCD mice. S-NACH has been further engineered and structurally enhanced to bind with and modify HbS to directly inhibit sickling, thus employing a multimodal approach. Here, we show that S-NACH can (i) directly engage in Schiff-base reactions with HbS to decrease RBC sickling under both normoxia and hypoxia in vitro, ii) prolong the survival of SCD mice under hypoxia, and (iii) regulate the altered steady state levels of pro- and antiinflammatory cytokines. Thus, our proof of concept in vitro and in vivo preclinical studies demonstrate that the multimodal S-NACH is a highly promising candidate for development into an improved and optimized alternative to LMWHs for the treatment of patients with SCD.
... As vanillin is rapidly degraded in the upper gastrointestinal tract of oral administration, a prodrug of vanillin, namely, MX-1520, was explored in transgenic sickle mice that can develop pulmonary sequestrations under hypoxic condition. Treatment of MX-1520 significantly reduced the percentage of sickle cell in blood as well as prolonged the survival time after oral as well as intraperitoneal administration in severe hypoxic condition (Zhang et al. 2004). It is reported that INN-312 and INN-298, pyridyl derivatives of vanillin, increased antisickling activity by 90-fold as compared to vanillin. ...
Sickle cell anemia (SCA) is an inherited disorder in the β-globin chain of hemoglobin that affects millions of people around the world, especially children. This disease prevalently occurs in some Mediterranean and Saharan Africa. For the treatment of SCA patients, a wide range of drugs have been explored by targeting antisickling activity, γ-globulin induction, antiplatelet effect, etc., but hardly a few drugs have shown potential to combat with this complex disease phenomenon. In spite of unprecedented advances in modern system of medicine, people in the disease-prone area have been taking traditional medicinal plants or plant-derived products to increase the life span of patients. Moreover, numerous clinical trials have been going on for the use of natural products under the purview of symptomatic management of SCA. This chapter is focused on the effect of natural products in pure form or characterized phytoconstituents on particularly inhibition of hemoglobin polymerization. This summarized information will be beneficial for further exploration of new therapeutics in the treatment arena of SCA.
... As vanillin is rapidly degraded in the upper gastrointestinal tract of oral administration, a prodrug of vanillin, namely, MX-1520, was explored in transgenic sickle mice that can develop pulmonary sequestrations under hypoxic condition. Treatment of MX-1520 significantly reduced the percentage of sickle cell in blood as well as prolonged the survival time after oral as well as intraperitoneal administration in severe hypoxic condition (Zhang et al. 2004). It is reported that INN-312 and INN-298, pyridyl derivatives of vanillin, increased antisickling activity by 90-fold as compared to vanillin. ...
... Some agents with anti-sickling or sickling reversal properties that belong to this category are; a prepared phytomedicine also known as Niprisan(Nix-0699), a chemical compound 5-hydroxymethyl-2-furfural (5HMF), and MX-1520 (a precursor of Vanillin). These compounds alter the shape of sickle haemoglobin (HbS), thus preventing the formation of crescent-shaped red blood cells (Wambebe et al. 2001;Iyamu et al. 2003;Zhang et al. 2004;Abdulmalik et al. 2005). However, some of the medications employed in the treatment of the disease are expensive and may not be affordable for most rural people having this disease especially in Africa. ...
... Some agents with anti-sickling or sickling reversal properties that belong to this category are; a prepared phytomedicine also known as Niprisan(Nix-0699), a chemical compound 5-hydroxymethyl-2-furfural (5HMF), and MX-1520 (a precursor of Vanillin). These compounds alter the shape of sickle haemoglobin (HbS), thus preventing the formation of crescent-shaped red blood cells (Wambebe et al. 2001;Iyamu et al. 2003;Zhang et al. 2004;Abdulmalik et al. 2005). However, some of the medications employed in the treatment of the disease are expensive and may not be affordable for most rural people having this disease especially in Africa. ...
Sickle cell disease is a group of diseases inherited through the gene and it affects the haemoglobin in the red blood cell. This study investigated the methanol seed extract of Buchholzia coriacea for possible in vitro anti-sickling effects and also determined the effect of Mucuna pruriens seed extract on the solubility and oxygen-binding rate of sickle cell haemoglobin. Sickle cell blood was collected from sickle cell disease patients with subsequent addition of 2% sodium metabisulphite to cause more sickling. Varying concentrations of the seed extracts (50%, 25%, 12.5% and 6.25%) were added to the pre-treated blood for these in vitro assays. The results showed that the extract of Buchholzia coriacea significantly (P < 0.05) inhibited sickling at all concentrations with the highest percentage inhibition of 73.3 ± 5.8, reversed sickled erythrocytes at all concentrations with the highest percentage reversal of 83.3 ± 5.8 and significantly (P < 0.05) inhibited polymerisation at all concentrations used in comparison to the parallel control. The extract of Mucuna pruriens seed significantly (P < 0.05) increased the solubility of sickle haemoglobin at 50%, 25%, 12.5% and 6.25% concentrations, increased Fe 2+/ Fe 3+ ratio from 1.7 (control) to 12.2 (50% concentration) and reduced osmotic fragility (at 12.5% and 6.25% concentrations) when compared with parallel control. The results indicate the feasibility of the seed extracts as promising agents in the management of sickle cell disease.
... Vanillin forms a covalent bond with the sickle hemoglobin and inhibits the sickling of cells. Since vanillin degrades upon oral administration, a prodrug MX-1520 was developed by the researchers that enhanced the bioavailability of vanillin (about 30 times higher) [14]. ...
Chemically, ‘vanillin’ belongs to the class of benzaldehydes, its structural formula being 4-hydroxy-3-methoxybenzaldehyde. It is one of the key constituents of vanilla pods, primarily from the species of Vanilla planifolia. However, since it is uneconomical to grow vanilla on a large scale, it is prepared synthetically to meet the diverse demands of growing food and pharmaceutical industries. Recently, vanillin has warranted the attention of the scientific community because of its versatility and utility. From the medicine cabinet to your savory platter, its ubiquitous presence is what makes one wonder, “is
this the next-gen supermolecule we had been waiting for?”
... Another constituent of Peru Balsam, 3,4-dimethoxycinnamaldehyde (#5), was also tested in the same study but showed no effect. Vanillin (#7) may improve psoriatic skin inflammation (Cheng et al. 2017), inflammatory bowel disease (Wu et al. 2009) via oral delivery and promises to combat oxidative brain injury (Makni et al. 2012) as well as sickle cell disease (Zhang et al. 2004) and relax coronary and basilar arteries (Raffai et al. 2015) when injected. Nerolidol (#9) has been shown to protect kidneys from injury in mice when administered interperitoneally (Zhang et al. 2017). ...
Peru Balsam, a resinous substance derived from Myroxylon balsamum var. pereirae, has historically been used as a topical ointment for various skin conditions such as scabies, poorly healing wounds, eczema, and haemorrhoids. The ingredients responsible for these properties are not fully elucidated. We investigated the chemical composition of two Peru Balsam samples, one historical and one modern, using gas chromatography/mass spectrometry to identify the active ingredients responsible for its pharmaceutical properties. Both Peru Balsam specimens investigated had similar compositions, showing the stability of the substance. Components identified are effective against scabies, exhibit antimicrobial activity and aid skin penetration. These properties are consistent with historical uses of Peru Balsam. Several ingredients are also known allergens. This study, combining chemical information with scientific literature related to pharmaceutical properties of natural substances, represents a breakthrough in the elucidation of active ingredients in Peru Balsam.
... To overcome such drawback, a vanillin pro-drug was designed to have a thiazolidine protection of the aldehyde group to bypass the gastrointestinal metabolism. Such compound showed significant improved oral pharmacokinetics and pharmacodynamics, yet, it still suffered from some degradation in the digestive tract [71]. 5-Hydroxymethyl-2-furfural (5-HMF, a vanillin isoster) was reported to have a remarkable antisickling activity. ...
Background
Sickle cell disease (SCD) is a chronic hemolytic disease caused by an altered hemoglobin molecule (HbS) and was first termed as a molecular disease. Glutamic acid in the normal hemoglobin molecule (HbA), was replaced by valine in HbS at the sixth position of both β-chains. This alteration was proved to be due to a single point mutation GTG instead of GAG in the genetic code. Since the discovery of sickle cell disease in 1910, great efforts have been done to study this disease on a molecular level. These efforts aimed to identify the disease etiology, pathophysiology, and finally to discover efficient treatment. Despite the tremendous work of many research groups all over the world, the only approved drug up to this moment, for the treatment of SCD is the hydroxyurea.
Main text
In this review, the antisickling pharmaco-therapeutics will be classified into two major groups: hemoglobin site directed modifiers and ex-hemoglobin effectors. The first class will be discussed in details, here in, focusing on the most important figures in the way of the rational drug design for SCD treatment aiming to help scientists solve the mystery of this problem and to get clear vision toward possible required therapy for SCD.
Conclusion
Despite the large number of the antisickling candidates that have been reached clinical studies yet, none of them has been introduced to the market. This may be due to the fact that hemoglobin is a large molecule with different target sites, which requires highly potent therapeutic agent. With this potency, these drugs should be safe, with acceptable oral pharmacokinetic and pharmacodynamic properties. Such ideal drug candidate needs more efforts to be developed.
... Vanillin, for example, is a chemical compound that confers the smell and flavor of vanilla, is used as a sleep prevention agent and an aphrodisiac (Bythrow, 2005). Functional uses of vanillin indicate that it exhibits chemopreventive effects in multiorgan carcinogenesis models in rats (Akagi et al., 1995) and prevents the invasion and migration of cancer cells (Cheng et al., 2008); it can also be used to treat sickle cell anemia (Zhang et al., 2004). Besides, vanillin has been shown to inhibit lipopolysaccharide-stimulated NF-KB activation and cyclooxygenase-2 gene expression in murine macrophages (Murakami et al., 2007). ...
... Also, newly discovered functional uses of vanillin indicate that the latter exhibits chemopreventive effects on multiorgan carcinogenesis models in rats (Akagi et al., 1995) and prevents the invasion and migration of cancer cells (Cheng et al., 2008). It can also be used to treat sickle cell anemia (Zhang et al., 2004). Besides, vanillin has been reported to inhibit cyclooxygenase-2 gene expression in macrophages (Murakami et al., 2007). ...
Context:
Vanillin is known to possess important antioxidant activity.
Objective:
The current study was conducted to establish the therapeutic efficiency of vanillin against potassium bromate (KBrO3)-induced depression-like behavior and oxidative stress in mice.
Material and methods:
Mice were exposed during 15 days either to potassium bromate (KBrO3), KBrO3+ vanillin or to only vanillin.
Results:
Our results revealed a significant modification in the fatty acid composition of the KBrO3-treated mice. In addition, KBrO3 induced a significant reduction in enzymatic activities and gene expressions, Na(+) -K(+ ) and Mg(2+)-ATPases, acetylcholinesterase and butylcholinesterase activities. The gene expression of tumor necrosis factor-α, interleukin-1β, interleukin-6 and COX2, significantly increased in the cerebrum of KBrO3-treated group. Histopathological observations were consistent with these effects. Co-treatment with vanillin significantly attenuated KBrO3-induced oxidative stress and inflammation.
Conclusion:
This work suggests that vanillin mitigates KBrO3-induced depression, and that this neuroprotective effect proceeds through anti-oxidant and anti-inflammatory activities.
... This prodrug was prescribed for rats before creating a hypoxic condition. Zhang et al. used extract on rats, before induction of hypoxic condition (22). In this study, we also used the aqueous extract of the C. fistula, before hypoxic condition, this time on human cells, in vitro. ...
Background: Sickle cell anemia is an autosomal recessive genetic blood disorder caused by a replacement of an amino acid in the hemoglobin structure, followed by disturbance in its electrical charge. In this disorder, the solubility of hemoglobin is reduced, in hypoxic condition, and formation of crystals occurs, leading to sickling the shape of red blood cells (RBC). The Cassia Fistula (C. fistula) (Flous Plant), as a flowering plant in the fabaceae family, is used as a traditional medicine in the treatment of sickle cell anemia. Objectives: The aim of this study was to evaluate the impact of aqueous extract of C. fistula (the ripped fruit) on red cells in sickle cell anemia. Materials and Methods: The aqueous extract of C. fistula fruit was obtained by vacuum distillation method, using different dilutions of 1:2, 1:4, 1:8, 1:16, 1:50, 1:100, 1:200. The RBC from individuals presenting the hemoglobin S (HbS) trait were washed and treated with different dilutions. After 24 hours incubation, they were evaluated by sickling test (sodium metabisulfite test). The Wilcoxon signed ranks test was used for data analysis. Results: Sickle cells were observed among 20% of subjects with the dilution of 1:50 and 70% of subjects with the dilution of 1:100. Mean percentage of sickle red cells with dilutions of 1:50, 1:100 and 1:200 were 3.75%, 25.75% and 43.0%, respectively. Conclusions: It is suggested that C. fistula may protect RBC against sickling, in hypoxic conditions, in individuals with HbS gene defect.
... The most popular approach to prevent or reverse sickling in vitro and in vivo is to employ compounds or techniques which directly affect the hemoglobin (Hb) molecule. Reported antisickling / antidrepanocytary agents in this group include a formulated phytomedicine – Niprisan (Nix- 0699), a chemical compound 5-hydroxylmethyl -2- furfural (5HMF) and MX-1520 (a prodrug of a food additive, vanillin) which modify intracellular sickled hemoglobin and inhibit sickling of red blood cells (Abdulmalik et al., 2005; Zhang et al., 2004; Iyamu et al., 2003; Wambebe, 2001). It is acknowledged world-wide that traditional medicine can be explored and exploited to be used along-side synthetic pharmaceutical products for enhanced health management. ...
Carica papaya dried leaves have been indicated in sickle cell anemia management by local indigenous folk and in recent scientific research. In this research, dried C. papaya leaves were extracted using the soxhlet extraction method with 5 different solvents to give five different fractions namely hexane, chloroform, ethyl acetate, butanol and water. This research examined the crude extract and the various leaf extract fractions of C. papaya L. (Caricaceae) for possible in vitro antisickling activities on Hb ss red blood cells obtained from non-crisis state sickle cell patients involving the use of positive (p-hydroxybenzoic acid 5 µ µ µ µg /ml) and negative (normal saline) controls for the antisickling experiments. Pretreatment of SS cell suspensions with C. papaya leaf extract and fractions all inhibited formation of sickle cells under severe hypoxia at varying degrees, with only 0 -5% sickle cells in the crude extract at 60 min compared with untreated SS cell suspensions which had over 80% sickle cells. Analysis of two different concentrations of C. papaya crude extract (10 and 5 mg/ml) showed the 10 mg/ml extract as the concentration with highest antisickling effect. Butanol extract showed the highest antisickling activity at 10 mg/ml concentration, while the ethyl acetate extract had the highest antisickling activity at 5 mg/ml concentration. These results further indicate the possibility of C. papaya leaf extract as potential phytotherapy for sickle cell anemia.
... Estratégias de modificação molecular usando a latenciação têm sido realizadas a fim de alterar as propriedades farmacocinéticas da vanilina para melhorar a absorção oral. 58 Aldeídos heterocíclicos como furfural (16), 5-metil-furfural, 5-etil-furfural e 5-hidroximetil-furfural (17) são moléculas que aumentam a afinidade da Hb pelo oxigênio, inibindo a polimerização (Figura 5). O 5-hidroximetil-furfural (17) apresenta baixa toxicidade e é cerca de 3,5 vezes mais potente que a vanilina (15) em inibir a polimerização. ...
Sickle Cell Disease (SCD) is a disease characterized by a punctual mutation (GTG - GAG) in the sixth codon of the gamma globin gene leading to a substitution of glutamic acid by a valine in the β chain of hemoglobin. Despite the huge progress on the molecular knowledge of the disease in recent years, few therapeutic resources were developed. Currently, the treatment is mainly done with the anticancer agent hydroxyurea. This review summarizes current knowledge about possible targets and new approaches to the discovery new compounds to treat the symptoms of SCD.
... A decade later, a study with the prodrug of vanillin, where the aldehyde group was protected by L-cysteine to form a thiazolidine complex (thiazo-vanillin; Fig. 3) was shown to have significantly improved oral pharmacokinetic and pharmacodynamic properties when compared to the corresponding free aldehyde vanillin, suggesting a viable strategy to improve oral bioavailability, as well as the efficacy of similar antisickling aldehydes. 91 In a collaborative effort between Don Abraham, Martin Safo, Osheiza Abdulmalik, and Toshio Asakura, 5-HMF (Fig. 3) was shown to have remarkable antisickling activity. 42,63 A single oral dose of 100 mg/kg of 5-HMF was sufficient to protect transgenic sickle mice from death from acute pulmonary sequestration of sickle cells after a hypoxic challenge, 63 while chronic administration of up to 375 mg/kg/day of 5-HMF for two years was nontoxic to rats or mice. ...
The pathophysiology of sickle cell disease involves the polymerization of sickle hemoglobin in its T state, which develops under low oxygen saturation. One therapeutic strategy is to develop pharmacologic agents to stabilize the R state of hemoglobin, which has higher oxygen affinity and is expected to have slower kinetics of polymerization, potentially delaying the sickling of red cells during circulation. This strategy has stimulated the investigation of aromatic aldehydes, aspirin derivatives, thiols, and isothiocyanates that can stabilize the R state of hemoglobin in vitro. One representative aromatic aldehyde agent, 5-hydoxymethyl-2-furfural, protects sickle cell mice from the effects of hypoxia.
... Its isomer p-vanillin (vanillin) is also thought to react with αHis103 to promote the oxy conformation, with possible other interactions at key sites of polymer contact (βHis116 and βHis117). In vivo, although vanillin itself is poorly absorbed, a pro-drug MX-1520 was shown to protect sickle rats against hypoxia [31]. ...
Aromatic aldehydes like o-vanillin were designed to reduce the complications of sickle cell disease (SCD) by interaction with HbS, to reduce polymerisation and RBC sickling. Present results show that o-vanillin also directly affects RBC membrane permeability. Both the K+–Cl− cotransporter (KCC) and the Ca2 +-activated K+ channel (or Gardos channel) were inhibited with IC50 of about 0.3 and 1 mM, respectively, with activities almost completely abolished by 5 mM. Similar effects were observed in RBCs treated with the thiol reacting reagent N-ethylmaleimide or with the Ca2 + ionophore A23187, to circumvent any action via HbS polymerisation. The deoxygenation-induced cation conductance (sometimes termed Psickle) was partially inhibited, whilst deoxygenation-induced exposure of phosphatidylserine was completely abrogated. Na+/K+ pump activity was also reduced. Notwithstanding, o-vanillin stimulated K+ efflux through an unidentified pathway and resulted in reduction in cell volume (as measured by wet weight − dry weight). These actions are relevant to understanding how aromatic aldehydes may affect RBC membrane permeability per se as well as HbS polymerisation and thereby inform design of compounds most efficacious in ameliorating the complications of SCD.
... An advantage of the short half-life of vanillin is that urinary VA excretion is less likely to be sustained from one meal to the next, possibly resulting in falsely elevated VA concentrations without prior vanillin intake. However, for protocols requiring a biomarker with longer half-life, a prodrug of vanillin has been described, 11 which may also prove useful as a tool for measuring dietary compliance. It is not clear from these data why VA excretion was so low for HbSS 4. Possibilities include changed metabolism of vanillin due to acute illness, liver and/or kidney disease. ...
Background & aims
Current self-report methods to monitor dietary intake are often unreliable. As part of a dietary intervention study, we investigated whether adding a common food flavor (vanillin) to test diets and measuring the major metabolic end product vanillic acid in urine, could provide assessment of compliance with dietary supplements.
Methods
After baseline urine was collected 10 subjects (6 control and 4 study patients) consumed 1.3 g of vanillin in a liquid test meal as the last food at bedtime and collected the first morning urine. Next a kinetic excretion study was performed in which 6 controls consumed a vanillin spiked drink with continued urine sampling at 30-min intervals for 5 h. Vanillic acid concentrations were measured by reverse phase high-performance liquid chromatography.
Results
The test diet was consumed just before bedtime; the first morning void vanillic acid concentration gave a reliable indication of compliance (3 males 0.224±0.041 and 3 females 0.290±0.099 mg/ml; mean±SD). Thirty-minute sampling of vanillic acid excretion for 6 controls was maximal 1 h after the test diet, returning to baseline after 4 h.
Conclusion
Vanillin is a useful, inexpensive and non-toxic biochemical marker for confirming compliance with experimental diets.
... The curative properties of vanillin have also been showcased against sickle cell diseaseas an effective inhibitor of red blood cell sickling. Zhang et al. (2004) provided details on the vanillin prodrug MX-1520, which was synthesized to treat red blood cell sickling with vanillin, in vivo. ...
Orchidaceae, the largest and most diverse family of flowering plants is widespread, with a broad range of ethnobotanical applications. Southern Africa is home to approximately 494 terrestrial and epiphytic orchid species, of which, 49 are used in African traditional medicine to treat cough and diarrheal symptoms, madness, promote conception, relieve pain, induce nausea, and expel intestinal worms and for many cultural practices. The biological activity and chemical composition of South African medicinal orchid species are yet to be explored fully. In this review we highlight the potential for pharmacological research on South African medicinal orchid species based on their traditional medicinal uses.
... blood cells. Reported antisickling agents in this group include Niprisan, MX-1520 and 5HMF (Iyamu et al., 2003; Chaojie Zhang et al., 2004; Abdulmalik et al., 2005), which modify intracellular sickle hemoglobin and inhibit sickling of red blood cells. Attempts to find alternative, cheaper and less toxic therapies for SCD management, led to the discovery of antisickling properties of Cajanus cajan seeds (Ekeke and Shode, 1985) and Zanthoxyllum macrophylla (formerly Fagara) roots used locally by traditional healers in Nigeria (Sofowora et al., 1975; Elekwa et al., 2005). ...
Sickle cell disease (SCD) results from a mutation in the hemoglobin inside the red blood cells, where a glutamic acid at position 6 is replaced by a valine. Many phytomedicines have been identified as potential antisickling agents, stemming from reported usage as ethnomedicines by the local folk. This research examined methanolic leaf extracts of Carica papaya L. (Caricaceae) for possible in vitro antisickling and membrane-stabilizing activities involving the use of positive (p-hydroxybenzoic acid 5 μ μ μ μg/ml) and negative (normal saline) controls for the antisickling experiments and osmotic fragility test on Hb ss red blood cells obtained from non-crisis state sickle cell patients. Fragiliograms indicated that the plant extract reduced hemolysis and protected erythrocyte membrane integrity under osmotic stress conditions. Pretreatment of SS cell suspensions with C. papaya leaf extract inhibited formation of sickle cells under severe hypoxia, with only 0 - 5% sickle cells at 40 min compared with untreated SS cell suspensions which had over 60% sickle cells. These results indicate the feasibility of C. papaya as an attractive potential candidate for SCD therapy.
... The pro-drug, MX-1520, has been investigated in rodents and shown to be bioavailable after oral administration in rats and still to retain its efficacy. [14,15] 5HMF was found to be rapidly absorbed into the bloodstream, binding and modifying HbS molecules at levels as high as 90 % without being destroyed in the gastrointestinal tract. [13] ...
We describe an electrochemistry-based technique to control and monitor the polymerisation of sickle-cell haemoglobin (HbS). The polymerisation was monitored as a change in turbidity during the depletion of oxygen in a small volume custom-built thin-layer electrochemical cell. The cell allowed the investigation of HbS polymerisation as a function of HbS concentration, temperature and solution pH. We confirm that the oxygen was efficiently depleted using finite-element modelling to accurately recreate the electrochemical thin-layer cell. Understanding the nucleation and growth of HbS polymerisation will provide a better understanding of the pathophysiology of sickle-cell disease in vivo, and thus help improve therapeutic strategies for this common and frequently disabling disorder.
... It exhibits chemopreventive effects on multiorgan carcinogenesis models in rats 17 and suppresses the invasion and migration of cancer cells [18][19][20] and could be used to treat sickle cell anemia. 21 Recently, vanillin has been shown to inhibit lipopolysaccharide-stimulated nuclear factor kappa B (NF-kB) activation and cyclooxygenase 2 gene expression in murine macrophages. 22 In addition, according to Sasaki et al., 23 vanillin is reported to be effective in reducing substance-induced mutations. ...
In this study, the protective effects of vanillin were evaluated against carbon tetrachloride (CCl(4))-induced kidney damages in Wistar albino rats. CCl(4) (1 ml/kg, intraperitoneally [i.p.]) caused a significant induction of renal disorder, oxidative damage and DNA fragmentation as evidenced by increased plasma creatinine, urea and uric acid levels, increased lipid peroxidation (malondialdehyde [MDA]) and protein carbonyl. Furthermore, glutathione levels, catalase, superoxide dismutase, glutathione transferase and glutathione peroxidase activities were significantly decreased. A smear without ladder formation on agarose gel was also shown, indicating random DNA degradation. Pretreatment of rats with vanillin (150 mg/kg/day, i.p.), for 3 consecutive days before CCl(4) injection, protected kidney against the increase of MDA and degradation of membrane proteins compared to CCl(4)-treated rats and exhibited marked prevention against CCl(4)-induced nephropathology, oxidative stress and DNA damage. Kidney histological sections showed glomerular hypertrophy and tubular dilatation in CCl(4)-treated rats, however, in vanillin pretreated rats, these histopathological changes were less important and present a similar structure to that of control rats. These data indicated the protective role of vanillin against CCl(4)-induced nephrotoxicity and suggested its significant contribution of these beneficial effects.
... Vanillin (Fig. 1), a compound widely used in foods, beverages, cosmetics and drugs, has been reported to have such multiple functions as antimutagenic, [12][13][14][15][16][17][18] antiangiogenetic, 19) anti-colitis, 20) anti-sickling, 21) and antianalgesic effects. 22,23) However, the results of studies on the antioxidative activity of vanillin have not been consistent. ...
The antioxidative properties of vanillic acid esters were systematically evaluated by multiple assays to compare with the well-known antioxidants, vanillic acid and Trolox. We first performed assays with the model radicals, DPPH, galvinoxyl and ABTS cation (ABTS(•+)) types. Methyl vanillate, ethyl vanillate and butyl vanillate showed stronger activity than Trolox in the ABTS(•+)-scavenging assay, but showed no activity in the DPPH radical- and galvinoxyl radical-scavenging assays. In contrast, vanillic acid could quench the three radicals. We then evaluated their antioxidative activities by an ORAC assay and an oxidative hemolysis inhibition assay (OxHLIA), using physiologically relevant peroxyl radicals. Vanillic acid esters and vanillic acid exerted much stronger activity than Trolox in the ORAC assay and OxHLIA. The antioxidative activity by OxHLIA was strongly correlated to the lipophilicity of vanillic acid and its esters. These results indicate that the protective effect of vanillic acid esters against free radical-induced biomembrane damage increased with increasing lipophilicity.
The Chemistry inside Spices & Herbs: Research and Development brings comprehensive information about the chemistry of spices and herbs with a focus on recent research in this field. Experts in phytochemistry have contributed reviews with the aim to give the reader deep knowledge about phytochemical constituents in herbal plants and their benefits. The contents include reviews on the biochemistry and biotechnology of spices and herbs, herbal medicines, biologically active compounds and their role in therapeutics among other topics. Chapters which highlight natural drugs and their role in different diseases and special plants of clinical significance are also included. Volume 3 covers several topics: the treatment of Polycystic Ovary Syndrome (PCOS), managing rheumatoid arthritis and related inflammatory conditions, orchid-derived natural flavoring and therapeutic agent Vanillin, Silymarin's utility in treating hepatic diseases, phytochemistry and pharmacological activities of Hygrophila spinosa, pharmacological and chemical aspects of Tulsi, Combretum caffrum as a potential anticancer molecule, and the roles of herbs in treating diabetes. This book is an ideal resource for scholars (in life sciences, phytomedicine and natural product chemistry) and general readers who want to understand the importance of herbs, spices and traditional medicine in pharmaceutical R&D and clinical research.
Introduction
In sickle cell disease (SCD), a single amino acid substitution at β6 of the haemoglobin (Hb) chain replaces glutamate with valine, forming HbS instead of the normal adult HbA. Loss of a negative charge, and the conformational change in deoxygenated HbS molecules, enables formation of HbS polymers. These not only distort red cell morphology but also have other profound effects so that this simple aetiology belies a complex pathogenesis with multiple complications. Although SCD represents a common severe inherited disorder with life-long consequences, approved treatments remain inadequate. Hydroxyurea is currently the most effective, with a handful of newer treatments, but there remains a real need for novel, efficacious therapies.
Areas covered
This review summarises important early events in pathogenesis to highlight key targets for novel treatments.
Expert opinion
A thorough understanding of early events in pathogenesis closely associated with the presence of HbS is the logical starting point for identification of new targets rather than concentrating on more downstream effects. We discuss ways of reducing HbS levels, reducing the impact of HbS polymers, and of membrane events perturbing cell function, and suggest using the unique permeability of sickle cells to target drugs specifically into those more severely compromised.
One of the most substantially used flavors in the food, beverage, perfume, and pharmaceutical industries, vanillin is in demand worldwide. Indonesia, Madagascar, and China are the leading producers of natural vanillin. It is thought to be first isolated from vanilla beans in the 1850s by evaporating vanilla extract and recrystallizing the resulting solids. The paper industry made synthetic vanillin largely more available in the 1930s from the sulfite pulping process for preparing wood pulp. Vanillin's popularity is largely due to its similar taste and aroma to natural vanilla. Today, almost all vanillin is produced synthetically; however, there are many efforts to utilize biosynthetic processes for vanillin production due to the high costs and small quantities of vanilla beans.
Hydroxyurea (HU) is the key drug to treat Sickle cell anemia (SCA). However, its treatment is associated with the liability of myelosuppression. The present study aimed to investigate the potential of epicatechin as supplementation therapy for the symptomatic management of SCA under HU therapy. A panel of experiments were performed at first to observe epicatechin's effect on sickling and hemolytic behaviour using SCA patient's blood (ex vivo). Thereafter, the effect of HU in the presence or absence of epicatechin was investigated on cytokine inhibition in rat splenocytes (ex vivo) as well as alterations in hematological parameters and kidney function tests in rats (in vivo). Then, any effect of epicatechin on pharmacokinetic modulation of HU in rats was elucidated along with the underlying mechanism using a battery of in vitro and in vivo models. Epicatechin exhibited potent action on anti-sickling, polymerization inhibition, and erythrocyte membrane stability. It did not show any inherent hemolytic activity and reduced TNF-α level during concomitant administration with HU. Based on hematological changes in rats, epicatechin treatment aided to the beneficial effect of HU and prevented the treatment-linked disadvantageous effects of HU like neutropenia. The plasma exposure of HU was significantly augmented in rats upon simultaneous oral administration of epicatechin with HU. Down-regulation of Oatp1b2 and catalase possibly contributed to this pharmacokinetic interaction. Epicatechin is found to be a promising candidate and should further be explored at a reduced dose level of HU towards offsetting the dose-dependent myelosuppressive effect of HU under the frame of supplementation therapy in SCA.
Vanillin (4-hydroxy-3-methoxybenzaldehyde) is a known natural aromatic flavoring agent and the major component of vanilla extracted from cured vanilla pods. Vanillin has several applications in foods, beverages, pharmaceuticals, perfumes and cosmetics. The Food and Drug Administration (FDA) and Flavor and Extract Manufacturers Association (FEMA) have recommended vanillin as safe and pose minimum detrimental consequences. Additionally, several studies have reported the pharmacological activities of vanillin including anticancer, antidiabetic, antioxidant, antisickling, antimicrobial, anti-inflammatory, aphrodisiac, cardio-protective, diuretic, amongst others. In spite of these interesting reports, the general perception of vanillin has been restricted to its role as a food additive. Therefore, we reviewed the pharmacological activities of vanillin to demonstrate its therapeutic potentials, especially as a component of functional foods. We further highlighted the biosynthesis, toxicity, bioavailability and other applications of the compound. Our review revealed that vanillin holds promising potentials in the prevention and cure of diverse human (metabolic and non-metabolic) diseases and is relatively bioavailable in the systemic circulation that could warrant a clinical trial.
Inflammationandfibrosisaretwopathologicalfeaturesofchronickidneydisease (CKD).Renalfibrosisisconsideredtobeoneofthemostimportantconditions,asit maybetheresultofexcessiveextracellularmatrixproteinproductionanddeposition, orprolongedexposuretonephrotoxicsubstancesordrugs.Unfortunately,nosuitabletherapiesormedicationsarecurrentlyavailabletopreventrenalfibrosis.We conductedthisstudyfortheevaluationoftheprotectivepotentialofvanillinby reversingTAA(250mg/kgTAAfor6weeks)inducedrenalinjuryinrats.Theconcentrationsoftheproteinstumournecrosisfactoralpha(TNFα),interleukin-6(IL-6), extracellularsignalregulatedkinase1/2(Erk1/2),andtransforminggrowthfactor beta-1(TGF-β1)inkidneytissueswereassessedusingELISA.KidneyInjury Molecule-1(KIM-1)andmothersagainstdecapentaplegichomologue2,3(SMAD 2,3)expressionswereevaluatedusingrealtimePCR.Wealsoestimatedtheexpressionofα-smoothmuscleactin(α-SMA)usingimmunohistochemistry.Treatmentwith vanillin(100mg/kg)significantlyamelioratedkidneyInjuryandimprovedthekidney function.Vanillintreatmentalsosignificantlydecreasedthemalondialdehyde(MDA) content,andelevatedglutathioneperoxidase(GPx)andcatalase(CAT)activitiesin kidneytissues.Vanillinalsoreducedα-SMArenalexpressionandTNFα,IL-6,TGF-β1, andErk1/2renallevels.Vanillinsignificantlydecreasedtheexpressionofthegenes encodingKIM-1andSMAD2,3andamelioratedhistologicalabnormalitiesinkidney architecture.Ourmoleculardockingfindingsshowedthatvanillinhasagoodbinding modeinsideTGF-βtypeIreceptors(ALK5)bidingsite.
Vanillin is a phenolic aldehyde that is responsible for the production of vanillin aroma. Apart from being an excellent flavoring agent, vanillin also has a wide range of applications in nonfood industries as a polishing agent, deodorant, fruit ripening agent, etc., which have paved way for increasing the market demand of vanillin. Primarily, vanillin is produced from pods of plant Vanilla planifolia , but the production rate was much low, which could not meet the world's demand. Thus, an alternative sources and methods for improving vanillin production are required. Plants aside, vanillin is also produced by various microbes as a secondary metabolite, and this knowledge has led to the development of alternate strategies such as chemical, synthetic, and biotechnological production of vanillin. Sustainable production of vanillin through biotechnological approaches by exploiting the metabolic pathways of microbes has gained renewed attention. This review summarizes the development of vanillin production from natural methods to modern biotechnological strategies. We have highlighted the new trends employed in production process using various microbes as cell factories and the use of agrowaste in vanillin production. Further, the clinical significance of vanillin as antimicrobial, antioxidant, anticarcinogenic, antimutagenic agents, etc., and the applications of vanillin in various industries like pharma, food, and cosmetics are discussed in detail.
There is a dichotomy between the increasing utility of aldehydes as tool molecules that bind to "undruggable" protein sites and the designation of the aldehyde functional group as structural alert by the medicinal chemistry community. Herein we compile information about pharmacologically active aldehydes that are being used in humans. We summarize the learnings from these data, discuss advantages and challenges associated with aldehydes, and derive strategies for the successful development of aldehydes within drugs discovery programs.
The asymmetric unit of Schiff base of the title molecule, C18H15NO2, was synthesized from naphthalen-2-ylamine and 2‑hydroxyl-3‑methoxy-benzaldehyde. The two phenyl rings (naphthyl and salicylaldehyde) and the azomethine group are practically co-planar, the dihedral angle between the benzenaldehyde moiety and amino phenyl plane is 14.36(9)°. An interamolecular O2−H1A•••N2 hydrogen bond generates the S(6) ring motif. The double bond distance (N2−C11; 1.281(2)Å) and the bond angle (C2−N2−C11;122.86(15)°) of the title Schiff base agreed with similar azomethines derivatives. Title crystal structure is mainly stabilized by the C − H•••O and π•••π interactions. The rings are parallelly displaced in which that π−stacking interaction is an offset or slipped stacking. The ring normal and the vector between the ring centroids form an angle of about 15.63° up to centroid-centroid distance of 3.9982(11)Å. The intermolecular interactions were quantified using PIXEL and Hirshfeld surface analysis. The quantum chemical calculations were performed to understand their electronic properties and to elucidate the chemical reactivity.
Sickle cell disease (SCD) is the most common severe inherited disorder affecting millions of people. The condition arises from the presence of the abnormal hemoglobin S (HbS) in patients' red blood cells (RBCs). Deoxygenated HbS can polymerize and the multiple complications of SCD all follow from this. There is no effective therapy although hydroxyurea is given to more severely affected patients. One possible treatment rationale is the use of drugs that interact directly with HbS, increasing its oxygen affinity to reduce polymerization and lessen vascular problems in blood vessels with moderately low oxygen tension. The most successful reagents with this mechanism of action have been aromatic aldehydes. A number of them reduce sickling but, to date, none has proved clinically useful. Heterocyclic aldehyde 5-hydroxymethyl-2-furfural (5-HMF or AES-103) was identified around a decade ago. 5-HMF is certainly effective on sickle RBCs in vitro. This compound reduces sickling and mortality in transgenic sickle mice and has progressed to phase II clinical trials in humans. Nevertheless, there are potential caveats which argue against it becoming clinically useful. Further data from trials are keenly awaited while newer compounds with similar actions continue to be discovered. The best will target RBCs specifically, hence reducing possible side effects.
Nicosan (formerly called Niprisan) is a multiple herbal drug that has been approved in Nigeria for the treatment of sickle cell disease. This phytomedicinal-based drug was developed by traditional healers in Nigeria and has recently been the subject of in vitro studies and clinical trials. Nicosan is an extract mixture of four plants, Piper guineenses, Pterocarpus osun, Eugenia caryophyllum, and Sorghum bicolor, which grow wild or are cultivated in West Africa. In this chapter, we will discuss the development history of this herbal drug and its chemical properties.
We previously found that blood samples collected from steady-state patients with sickle cell disease (SCD) without exposure to air contain a new type of reversibly sickled cells (RSCs) with blunt edges at a level of as high as 78%. Since partial oxygenation of once-deoxygenated sickled cells with pointy edges to near venous oxygen pressure generates similar sickled cells with blunt edges in vitro, we named them as partially oxygenated sickled cells (POSCs). On the other hand, partial deoxygenation of once-oxygenated SS cells to venous oxygen pressure generates partially deoxygenated sickled cells (PDSCs) with pointy edges. In this study, we obtained blood samples from 6 steady-state patients with SCD under venous oxygen pressure without exposure to air, subjected them to various oxygenation/deoxygenation/reoxygenation cycles, and studied their filterability through a membrane filter with pore diameter of 3 μm, which is the theoretical minimum diameter of a capillary. Our results indicated that discocytes, POSCs with blunt edges, and irreversibly sickled cells could deform and pass through the filter, while PDSCs with pointy edges were rigid and could not. The filterability of SS cells seems to be related to the length and amount of deoxy-hemoglobin S fibers in the cells.
Vanilla planifolia originated from Mesoamerica – Mexico and Guatemala. The Totonac Indians of Papantla in north-central Vera Cruz, were the earliest to cultivate vanilla and the oldest use of vanilla use related to the pre-Columbian Maya of southeasten Mexico (Lubinsky et al. 2008). It has been cultivated and escaped or persisted in many areas of the tropics and the south Pacific. Today, the most important exporters are Madagascar and Réunion (formerly called Bourbon), even before México. In Asia, Indonesia is the most successful producer.
The development of new anti-cancer treatments with greater efficacy and fewer side effects remains a significant challenge of modern scientific and medical research. Curcumin, a natural polyphenol found in the dietary spice turmeric, has been demonstrated to inhibit cancer cell survival and proliferation, and to induce apoptosis without promoting the development of side effects. However, due to its sparing solubility and low bioavailability, curcumin has not yet been clinically used to treat cancer. This review describes the main physicochemical properties of curcumin, including its chemical structure, stability, and degradation products as a function of pH and temperature. It also describes the proposed mechanisms by which curcumin exhibits anti-cancer activity. Finally, we review the various approaches that have been studied to enhance the solubility and bioavailability of curcumin, including the preparation of co-crystals, and the development of delivery systems based on liposomes, micelles, exosomes, nanoparticles and dendrimers.
Vanilla is a tropical orchid belonging to the family Orchidaceae and it is mainly used in food, perfumery, and pharmaceutical preparations. The quality of the bean depends on the volatile constituent's, viz., the vanillin content, the species of the vine used, and the processing conditions adopted. Hence, proper pollination during flowering and curing by exercising utmost care are the important aspects of vanilla cultivation. There are different methods of curing, and each one is unique and named after the places of its origin like Mexican process and Bourbon process. Recently, Central Food Technological Research Institute, Mysore has developed know-how of improved curing process, where the green vanilla beans are cured immediately after harvest and this process takes only 32 days, which otherwise requires minimum of 150-180 days as reported in traditional curing methods. Vanillin is the most essential component of the 200 and odd such compounds present in vanilla beans. Vanillin as such has not shown any antioxidant properties, it is along with other compounds has got nutraceutical properties and therefore its wide usage. The medicinal future of vanilla may definitely lie in further research on basic science and clinical studies on the constituents and their mechanism of action.
Vanilla has been coveted over the ages for culinary and medicinal reasons alike. Vanilla’s high status in the culinary world comes from a long history of flavoring sweet, sensual desserts such as ice cream, sugar cookies, puff pastries, and butter creams. While vanilla’s history is steeped in culinary traditions, its lesser know uses as an aphrodisiac and a medical botanical stretch back to its discovery in Mesoamerica by ancient cultures who cultivated and honored the sweet orchid. European nations also historically valued vanilla for its flavor, its lore as a love potion, and its medicinal uses. While traditional medical uses of vanilla have faded away, its culinary traditions have changed little. Present day advances in basic science research have shed light on the medical benefits of vanillin, vanilla’s active constituent.
Food safety is of extreme importance to human health. Vanillin and ethyl vanillin are the widely used food additives and spices in foods, beverages, cosmetics and drugs. The objective of the present work was to evaluate the impact of vanillin and ethyl vanillin on the activities of CYP2C9, CYP2E1, CYP3A4, CYP2B6 and CYP1A2 in human liver microsomes (HLM) in vitro, and impact on the activities of CYP1A2, CYP2C, CYP3A and CYP2E1 in rat liver microsomes (RLM) in vivo. The in vitro results demonstrated that vanillin and ethyl vanillin had no significant effect on the activity of five human CYP450 enzymes with concentration ranged from 8 to 128 μM. However, after rats were orally administered vanillin or ethyl vanillin once a day for seven consecutive days, CYP2E1 activity was increased and CYP1A2 activity was decreased in RLM. The in vivo results revealed that drug interaction between vanillin/ethyl vanillin and the CYP2E1/CYP1A2-metabolizing drugs might be possible, and also suggested that the application of the above additives in foods and drugs should not be unlimited so as to avoid the adverse interaction.
Normal and sickle erythrocytes were exposed in vitro to millimolar concentrations of 31 different carbonyl compounds. Schiff base (imine) linkages were formed with amino groups of intracellular hemoglobin. Adducts were isolated by gel electrofocusing and could be dissociated by dialysis. Aromatic aldehydes proved more reactive than aliphatic aldehydes, and ketones were unreactive. The influence of various ring substituents on the reactivity of aromatic aldehydes was found to conform closely to traditional concepts regarding electronic and steric effects. Several of the aromatic aldehydes were shown to markedly increase the oxygen affinity of hemoglobins A and S. In particular, 2,4-dihydroxybenzaldehyde and o-vanillin, at concentrations of 5 mM, produced 2- to 3-fold reductions in the P50 (partial pressure of oxygen at half-saturation) of sickle hemoglobin in whole blood. Since low degrees of oxygen saturation promote erythrocyte sickling, compounds of this type significantly inhibit sickling at reduced partial pressures of oxygen.
Vanillin, a food additive, has been evaluated as a potential agent to treat sickle cell anemia. Earlier studies indicated that vanillin had moderate antisickling activity when compared with other aldehydes. We have determined by high performance liquid chromatography that vanillin reacts covalently with sickle hemoglobin (HbS) both in solution and in intact red blood cells. Hemoscan oxygen equilibrium curves show a dose-dependent left shift, particularly at low oxygen tensions. Rheologic evaluation (pO2 scan Ektacytometry) of vanillin-reacted HbS erythrocytes shows a dose-dependent inhibition of deoxygenation-induced cell sickling. Ektacytometry also suggests that vanillin may have a direct inhibitory effect on HbS polymer formation. Vanillin has no adverse effects on cell ion or water content. X-ray crystallographic studies with deoxyhemoglobin (HbA)-vanillin demonstrate that vanillin binds near His 103 alpha, Cys 104 alpha, and Gln 131 beta in the central water cavity. A secondary binding site is located between His 116 beta and His 117 beta. His 116 beta has been implicated as a polymer contact residue. Oxygen equilibrium, ektacytometry, and x-ray studies indicate that vanillin may be acting to decrease HbS polymerization by a dual mechanism of action; allosteric modulation to a high-affinity HbS molecule and by stereospecific inhibition of T state HbS polymerization. Because vanillin is a food additive on the GRAS (generally regarded as safe) list, and because it has little or no adverse effects at high dosages in animals, vanillin is a candidate for further evaluation as an agent for the treatment of sickle cell disease.
A previously uncharacterized type of sickled cell was found in venous blood of patients with sickle cell disease when blood was collected without exposure to air and fixed immediately with 1% glutaraldehyde solution equilibrated with 5% oxygen. These cells were either elongated, resembling irreversibly sickled cells (ISCs), or nonelongated, with a raisin-like shape. Both types assumed a normal discoidal shape upon full oxygenation. Since these cells exist only under partially oxygenated conditions, they are described as partially oxygenated sickled cells (POSCs). POSCs are morphologically distinct from partially deoxygenated sickled cells formed during deoxygenation by having rounded edges, while the latter have sharp edges. Transmission electron microscopy of POSCs revealed various amounts of misaligned Hb S polymers. Investigations in vitro demonstrated the formation of POSC-like cells by partial oxygenation of deoxygenated cells. Since POSCs contain intracellular fibers and sickle readily upon deoxygenation, they may have clinical and pathological significance.
Information on life expectancy and risk factors for early death among patients with sickle cell disease (sickle cell anemia, sickle cell-hemoglobin C disease, and the sickle cell-beta-thalassemias) is needed to counsel patients, target therapy, and design clinical trials.
We followed 3764 patients who ranged from birth to 66 years of age at enrollment to determine the life expectancy and calculate the median age at death. In addition, we investigated the circumstances of death for all 209 adult patients who died during the study, and used proportional-hazards regression analysis to identify risk factors for early death among 964 adults with sickle cell anemia who were followed for at least two years.
Among children and adults with sickle cell anemia (homozygous for sickle hemoglobin), the median age at death was 42 years for males and 48 years for females. Among those with sickle cell-hemoglobin C disease, the median age at death was 60 years for males and 68 years for females. Among adults with sickle cell disease, 18 percent of the deaths occurred in patients with overt organ failure, predominantly renal. Thirty-three percent were clinically free of organ failure but died during an acute sickle crisis (78 percent had pain, the chest syndrome, or both; 22 percent had stroke). Modeling revealed that in patients with sickle cell anemia, the acute chest syndrome, renal failure, seizures, a base-line white-cell count above 15,000 cells per cubic millimeter, and a low level of fetal hemoglobin were associated with an increased risk of early death.
Fifty percent of patients with sickle cell anemia survived beyond the fifth decade. A large proportion of those who died had no overt chronic organ failure but died during an acute episode of pain, chest syndrome, or stroke. Early mortality was highest among patients whose disease was symptomatic. A high level of fetal hemoglobin predicted improved survival and is probably a reliable childhood forecaster of adult life expectancy.
Vanillin, a food additive, has been evaluated as a potential agent to treat sickle cell anemia. Earlier studies indicated that vanillin had moderate antisickling activity when compared with other aldehydes. We have determined by high performance liquid chromatography that vanillin reacts covalently with sickle hemoglobin (HbS) both in solution and in intact red blood cells. Hemoscan oxygen equilibrium curves show a dose- dependent left shift, particularly at low oxygen tensions. Rheologic evaluation (pO2 scan Ektacytometry) of vanillin-reacted HbS erythrocytes shows a dose-dependent inhibition of deoxygenation-induced cell sickling. Ektacytometry also suggests that vanillin may have a direct inhibitory effect on HbS polymer formation. Vanillin has no adverse effects on cell ion or water content. X-ray crystallographic studies with deoxyhemoglobin (HbA)-vanillin demonstrate that vanillin binds near His 103 alpha, Cys 104 alpha, and Gln 131 beta in the central water cavity. A secondary binding site is located between His 116 beta and His 117 beta. His 116 beta has been implicated as a polymer contact residue. Oxygen equilibrium, ektacytometry, and x-ray studies indicate that vanillin may be acting to decrease HbS polymerization by a dual mechanism of action; allosteric modulation to a high-affinity HbS molecule and by stereospecific inhibition of T state HbS polymerization. Because vanillin is a food additive on the GRAS (generally regarded as safe) list, and because it has little or no adverse effects at high dosages in animals, vanillin is a candidate for further evaluation as an agent for the treatment of sickle cell disease.
The hemoglobin types of mouse strains can be distinguished according to patterns observed on cellulose acetate electrophoresis. The two common mouse hemoglobin patterns are single and diffuse. The differences in the patterns result from differences in the β-globin chains of the hemoglobin molecules. Mice with the single hemoglobin pattern have one β-globin type identified as β-single (Hbbs), whereas mice with the diffuse hemoglobin pattern have two different β-globin types identified as β-major (Hbbmaj) and β-minor (Hbbmin). We examined the functional and stability properties in these mouse hemoglobins, and the oxygen binding properties of red blood cells obtained from mice with four different hemoglobin phenotypes: Hbbs/Hbbs, Hbbs/Hbbmin, Hbbmin/Hbbmin and Hbbmaj/Hbbmin. The P50, the partial pressure of oxygen at which hemoglobin is half-saturated, of purified forms of Hbbs, Hbbmin and Hbbmaj was 14.8 ± 0.4 mm Hg, 13.3 ± 0.6 mm Hg and 13.6 ± 0.5 mm Hg, respectively. The n value, determined from the slope of the Hill plot was 2.45 to 2.59 for the mouse hemoglobins. The alkaline Bohr effects of purified HbbS, Hbbmin and Hbbmaj were 0.69, 0.61 and 0.60, respectively. The mechanical stability of Hbbs, Hbbmin and Hbbmaj, expressed by the first order kinetic constant, were 0.098 ± 0.01/min, 0.027 ± 0.013/min and 0.27/min, respectively. The P50 of red blood cell suspensions from lines of mice expressing Hbbs/Hbbs, Hbbmin/Hbbmin, Hbbs/Hbbmin and Hbbmaj/Hbbmin were 40.2 ± 1.8 mm Hg, 40.4 ± 1.5 mm Hg, 38.9 ± 1.4 mm Hg, and 38.7 ± 0.9 mm Hg, respectively.
Oral dosages of 107 synthetic and natural flavourings and structurally-related compounds were administered by intubation to the mouse, rat or guinea-pig. Animals were observed usually for 2 weeks during which time the development of toxic signs was followed and time of death recorded. The acute oral LD50 of each compound was determined.RésuméOn administra par intubation des doses de complexes faits de 107 condiments synthétiques et naturels, de structure chimique voisine, à des souris, des rats et des cobayes. On observa habituellement les animaux pendant 2 semaines, durant lesquelles on suivit le développement de signes toxiques et on nota la date de la mort. Pour chaque complexe on détermina la dose orale limite au-delà de laquelle commence l'intoxication aiguë.Zusammenfassung107 synthetischen un natürliche Geschmackszusätze und strukturverwandte Verbingdungen wurden durch Intubation an Mäuse, Ratten und Meerschweinchen verabreicht. Die Tiere wurden gewöhnlich 2 Wochen lang unter Beobachtung gehalten, während welcher Zeit die Entwicklung toxischer Symptome verfolgt und die Zeit des Todeseintritts registriert wurde. Die akute orale mittlere tödliche Dosis jeder Verbindung wurde festgestellt.
1. The metabolism of vanillin, isovanillin and the corresponding alcohols and acids in rats was investigated using t.l.c., g.l.c. and combined g.l.c.-mass spectrometry. 2. Oral dosage (100 mg/kg) of the aldehyde resulted in urinary excretion of most metabolites within 24 h, mainly as glucuronide and/or sulphate conjugates although the acids formed were also excreted free and as their glycine conjugates. In 48 h 94% of the dose of vanillin was accounted for as follows (%) : vanillin (7), vanillyl alcohol (19), vanillic acid (47), vanilloylglycine (10), catechol (8), 4-methylcatechol (2), guaiacol (0-5) and 4-methylguaiacol (0-6). Similarly, 89% of the dose of isovanillin was accounted for as follows: isovanillin (19), isovanillyl alcohol (10), isovanillic acid (22), vanillic acid (11), isovanilloylglycine (19), catechol(7) and 4-methylcatechol (1). Protocatechuic acid was also formed from both aldehydes. 3. By means of (a) investigation of biliary metabolites, (b) prevention of biliary excretion, (c) suppression of intestinal bacteria with neomycin sulphate and (d) inhibition of intestinal beta-glucuronidase with saccharo-1,4-lactone, it was found that glucuronides of the aldehydes and their respective alcohol and acid derivatives are excreted in the bile and that the conjugates are metabolized by the intestinal bacteria to toluene derivatives and decarboxylated products.
Hydroxyurea has been shown to increase fetal hemoglobin (Hb F) production in patients with sickle cell disease and therefore has the potential to alleviate both the hemolytic and vaso-occlusive manifestations of the disease. Preliminary evidence indicates that recombinant human erythropoietin (rhEpo) may also induce Hb F. Three sickle cell anemia patients were treated with escalating doses of intravenous rhEpo and, subsequently, with daily oral hydroxyurea. After the optimal hydroxyurea dose was attained, rhEpo was added again. Two additional patients were treated with hydroxyurea alone. Treatment with rhEp, either alone or in combination with hydroxyurea, had no significant effect on the percentage of F reticulocytes or F cells. In contrast, hydroxyurea treatment was associated with a 1.5-fold to sevenfold increase in F cells and a 2.3- to 27-fold increase in the percentage of Hb F. In the three patients whose response reached a plateau, hydroxyurea treatment was associated with lessened hemolysis, decreased serum bilirubin and lactate dehydrogenase levels, and prolonged 51chromium-labeled RBC survival. Hydroxyurea treatment also resulted in decreased numbers of irreversibly sickled cells and in decreased sickling at partial oxygen saturation, increased oxygen affinity, increased total RBC cation content, and diminished potassium:chloride co-transport. All five patients treated with hydroxyurea experienced a decrease in severity and frequency of painful sickle crises. This study confirms that hydroxyurea therapy increases Hb F production and provides objective evidence of a significant reduction in hemolytic rate and intracellular polymerization. In contrast, rhEpo, either alone or in combination with hydroxyurea, offered no measurable benefit. Based on these encouraging preliminary data, large-scale, controlled clinical trials are warranted to study the safety and efficacy of hydroxyurea in the treatment of sickle cell disease.
The chapter describes the understanding of the physics and physical chemistry of sickle cell hemoglobin polymerization in solutions and in red cells. The polymerization of sickle cell hemoglobin has probably become the best understood of all protein self-assembly systems. The structure of the hemoglobin S molecule, the structure of the various aggregated forms of hemoglobin S, and the structural analysis of the polymers are discussed in the chapter. The chapter discusses the thermodynamics of hemoglobin S polymerization, and includes a description of the nonideal behavior of concentrated hemoglobin S solutions and the effects of physiologically relevant variables, especially oxygen, and the presence of non-S hemoglobins on the polymerization process. Understanding the polymerization process is not only important for understanding the pathophysiology of sickle cell disease, but is critical to the major problem of developing a specific therapy that could be used in the treatment of patients. The kinetic and thermodynamic studies have played a major role by providing relevant and sensitive assays for potential therapeutic agents. The results of the thermodynamic and kinetic studies of solutions are used to explain various properties of cells, including morphological and rheological properties.
An automated image analysis system was used to characterize the morphology of sickle cells under hypoxic conditions. Images observed by light microscopy were transferred to the image analysis system and were processed to binary (black and white) images, and were then analyzed by area, perimeter, and shape. A circular shape factor (CSF = 4 pi X[area]/[perimeter]2) was found to be useful for elucidating the degree of deformation, but it could not differentiate elongated sickle cells from maple leaf-shaped cells. By combining an elliptical shape factor (ESF = [short axis]/[long axis]) with CSF we could separate deoxygenated homozygous sickle red cells (SS cells) into several morphologically distinct groups, including non-sickled cells, maple leaf-shaped cells, and elongated sickle cells. Using this automated image analysis system, we studied morphologic changes of SS cells exposed to deoxygenation-oxygenation (d-o) cycles between PO2 of 0 and 100 mm Hg (one cycle = 12 minutes) at pHs of 6.9 and 7.4. We found that at both pHs the morphology of sickled cells after the first deoxygenation was predominantly maple leaf-shaped. The number of elongated sickled cells increased as the number of d-o cycles increased, indicating that SS cells changed from maple leaf morphology to classic elongated sickle shape during d-o cycles. Desickling occurred less during the oxygenation phase at pH 6.9 than at pH 7.4 and as the number of d-o cycles increased. These results suggest that during d-o cycles deoxyhemoglobin S fibers may align to form large bundles that do not depolymerize completely even at the arterial oxygen pressure.
Eight subjects with sickle-cell disease in the symptom-free steady-state received a single one-hour infusion of the new anti-sickling agent BW12C on a total of eleven occasions. A dose-dependent increase in wholeblood oxygen affinity was observed, resulting from the action of BW12C in stabilising the oxy-conformation of haemoglobin and causing a left shift of the oxygen saturation curve. At the highest dose given (20 mg/kg bodyweight), up to 23% of haemoglobin was modified to a BW12C-reacted high-affinity form without evidence of tissue hypoxia. There was biochemical and rheological evidence for a transient decrease in haemolytic rate.
The anti-sickling agent BW12C [Beddell, Goodford, Kneen, White, Wilkinson & Wootton (1984) Br. J. Pharmacol. 82, 397-407] was designed to left-shift the oxygen saturation curve of haemoglobin (HbA) by preferential binding to the oxy conformation at a single site between the terminal amino groups of the alpha-chains through Schiff's base formation, ionic and hydrophobic interactions. In the present work, Schiff's base linkages formed with [14C]BW12C were reduced with NaBH4 and the alpha- and beta-globin chains separated. Under oxy conditions at a molar ratio of 2:1, the covalently bound BW12C is localized almost exclusively on a single alpha-chain; tryptic digestion confirms the terminal amino group (alpha 1-valine) as the reaction site, in accord with the design hypothesis. However, about half the labelled BW12C is released on tetramer disruption, suggesting the presence of additional non-covalent binding. Under deoxy conditions, alpha- and beta-chains are labelled approximately equally, and at higher molar ratios additional binding in both oxy and deoxy conditions is seen. Isoelectric-focusing studies under oxy conditions show a complex pattern of modified bands for both HbA and HbA1c (blocked beta-terminal amino groups) but no modification for HbA carbamylated at both alpha- and beta-terminal amino groups or at the alpha-chains only, again confirming the alpha-terminal amino region as the main interaction site. Equilibrium dialysis measurements under oxy conditions indicate two strong binding sites with a binding constant of less than 10(-6) M and a number of weaker binding sites. The present data thus confirm that BW12C binds at the intended locus but reveal additional non-covalent binding at an undefined site, and weaker binding through Schiff's base formation with other amino groups.
BW12C, a potent left-shifting anti-sickling compound in vitro, was administered to normal healthy male Caucasian volunteers. Doses of 2-20 mg kg-1 given by intravenous infusion over 1 h caused a dose-dependent left-shift of the blood-oxygen saturation curve and at the highest dose some 16% of the haemoglobin existed in a high affinity form. Peak left-shift was observed at the end of infusion and decayed thereafter with a mean half-life of approximately 3 h. There were no adverse systemic effects, either clinical, biochemical or haematological, but there was some local irritation at the intravenous infusion site if the infusion was too concentrated. Pharmacokinetic measurements indicated uptake into erythrocytes, low levels in plasma and a volume of distribution not appreciably greater than the blood volume. A pilot radiolabel study indicated extensive metabolism with elimination into the urine.
The relationship between the morphologic characteristics of sickle erythrocytes and the method of deoxygenation was studied using rectangular glass capillary tubes (0.05 X 0.5 X 50 mm). Deoxygenated blood samples were anaerobically collected into the tubes and directly observed under a microscope. A high yield (90%) of sickled red blood cells was observed if the sample was deoxygenated slowly with nitrogen gas. However, rapid deoxygenation by sodium dithionite resulted in low percentages of sickling and high percentages of irregularly shaped cells (mosaic cells). Mosaic cells were also formed upon rapid deoxygenation with nitrogen gas and thus appear to result from the precipitation of intracellular deoxygenated hemoglobin S. Only 20% of the mosaic cells converted to sickle cells with prolonged incubation at 37 degrees C. However, if the mosaic cells were cooled, desickled, and deoxygenated again slowly by nitrogen gas, most could be converted to typical sickle-shaped cells. Further studies on the comparison of sodium dithionite and sodium metabisulfite as reducing agents showed that sodium dithionite reduced intracellular hemoglobin rapidly, and sodium metabisulfite reduced it slowly. This difference explains the high yield of sickling with sodium metabisulfite compared with sodium dithionite.
Substituted benzaldehydes have been designed to bind preferentially to the oxy conformation of human haemoglobin at a site between the amino terminal residues of the α‐subunits. Such compounds should stabilize the oxygenated form of haemoglobin and thereby increase its oxygen affinity.
The compounds produce the expected effect, left‐shifting the oxygen saturation curve of dilute haemoglobin solutions and of whole blood, although the binding pattern to haemoglobin is more complex than envisaged by the design hypothesis.
The predicted best compound is also a potent inhibitor, at low oxygen pressure, of the sickling of erythrocytes from patients homozygous for sickle cell disease, and may prove to be a clinically useful anti‐sickling agent.
Red blood cells (RBC) from patients with sickle cell disease (SCD) are characterized by membrane lesions caused by cell sickling and oxidative damage due to denatured hemichromes. We have developed three lines of transgenic human sickle hemoglobin (Hb S) mice, which produce 30, 50, and 80% human beta sickle globin (h beta S), by crossing transgenic progeny with nonthalassemic, heterozygous, or homozygous beta-thalassemic mice, respectively. Transgenic mice that produce Hb A, developed in a similar fashion, were used as controls. RBC from each transgenic line were examined for pathologic changes. RBC from 50 and 80% h beta S mice sickle upon deoxygenation in vitro while RBC from 30% h beta S mice and all Hb A mice do not. Density gradients of RBC from each Hb S line, including those from 30% h beta S that do not sickle, show broad distributions with increased dense fractions, similar to those of patients with SCD. RBC from Hb S lines exhibit elevated membrane-associated denatured hemoglobin (MADH) levels (0.250 +/- 0.080%) when compared to RBC from nontransgenic (0.073 +/- 0.021%) and transgenic Hb A (0.062 +/- 0.033%) mice. Elevated MADH levels in RBC from the 30% h beta S line suggest that membrane changes occur even though these cells do not sickle. These Hb S-dependent pathologic changes suggest that transgenic Hb S lines may be useful for the study of not only RBC sickling in vivo but also membrane oxidative damage and other chronic changes attributed to abnormal properties of both oxygenated and deoxygenated Hb S.
Changes in the degree of sickling in vitro of reticulocytes and nonreticulocytes from patients with sickle cell disease were studied under complete deoxygenation (PO2 = 0 mm Hg) and partial deoxygenation (PO2 = 30 mm Hg, the average PO2 in the venous circulation) conditions at pH 7.4. Degree of sickling was quantitated by image analysis after identification of reticulocytes by acridine orange staining. Sickling in vitro of reticulocytes and nonreticulocytes under complete deoxygenation was similar and relatively unchanged during a 2-hour incubation. In contrast, under partially deoxygenated conditions, at least two populations of reticulocytes were apparent, one more susceptible to sickling than the other; nonreticulocytes were generally less susceptible to sickling. Many of the severely deformed reticulocytes showed formation of long spicules during incubation. These data suggest that a subset of reticulocytes are more susceptible to sickling than nonreticulocytes, and that the degree of reticulocyte sickling in vitro increases dramatically with time even at constant partial oxygen pressures observed in the venous circulation. Since dehydration in sickled reticulocytes seemed to be proceeding, mechanisms of inhibition were also examined. We found that quinine, an inhibitor of the Ca(++)-activated K+ efflux, inhibited part of the reticulocyte sickling while okadaic acid, a K(+)-Cl- co-transport inhibitor, did not inhibit sickling under our experimental conditions. These phenomena observed at pH and oxygen tension similar to physiological venous conditions may be important in understanding the clinical course and pathophysiology of sickle cell disease.
Hydroxyurea (HU) is the first widely used treatment to have an impact on the severity of disease in adult patients with sickle cell anemia, but limited data are available for younger patients or those with variant genotypes. We reviewed 324 months of experience with HU in 16 patients from 5.3 to 18.4 years of age treated for 6 to 50 months. The major toxicity was reversible neutropenia. Linear growth continued unchanged, and all patients gained weight. Hematologic results were similar to those reported in adults with increases in mean corpuscular volume (MCV) and total and fetal hemoglobin (HbF). We noted that the maximal hematologic effects occurred at less than the maximum dose. Clinically, patients experienced an 80% reduction in episodes of acute chest syndrome and a reduced need for blood transfusion, as well as a 30% decrease in the number of hospitalizations for painful events during HU therapy compared with an equivalent number of months before HU. These highly statistically significant results confirmed the value of HU in ameliorating the severe clinical course of pediatric patients. Similar effects were observed in three patients with sickle beta degrees-thalassemia, sickle beta+-thalassemia, and S-O Arab. Recurrent acute splenic sequestration and progressive symptomatic osteonecrosis were observed during HU. Thus, HU may not prevent the development of complications once organ damage is present. The challenge remains to determine when and to which pediatric patients with sickle cell disease HU should be offered.
Children with sickle cell anemia provide the best opportunity to assess the efficacy of hydroxyurea (HU) in preventing complications and progressive organ damage. The possibility of treating infants with sickle cell disease (SCD) to inhibit the development of organ dysfunction may be the most important future use of HU. The possibility even exists that instituting HU in the neonate may stop the fetal-to-adult globin chain switch and thus markedly change the clinical phenotype of SCD. Recent data suggest HU may also be especially beneficial in children not only by increasing hemoglobin F (HbF), but also by altering the adhesive receptors expressed on red blood cells and vascular endothelium, further increasing the possibility that vasculopathy can be prevented. Six pediatric trials that included small numbers of severely ill patients have been reported recently. All patients received relatively standard HU doses. All studies reported a significant improvement in HbF and mean corpuscular volume and a mild to marked increase in hemoglobin. The clinical response to HU in children with SCD seems to be consistent. The National Institutes of Health pediatric multicenter trial should help answer the question of short-term HU toxicity; however, questions remain concerning long-term risks, such as carcinogenesis, gametogenesis, marrow toxicity, growth retardation, and chromosomal damage. Long-term studies are needed to answer these questions. The future treatment of most children with SCD with HU alone or in combination with other agents looks promising, and long-term trials are warranted.
In a randomized, placebo-controlled clinical trial, treatment with hydroxyurea (HU) reduced crisis rates in adult patients with severe sickle cell anemia. No serious acute toxicity was seen, but the safety of long-term therapy could not be evaluated. The rationale for the use of HU was based on its ability to increase fetal hemoglobin (HbF) synthesis and the inhibitory effect of HbF on polymerization of sickle cell hemoglobin. Surprisingly, final HbF levels in patients assigned to HU did not differ markedly from their pretreatment levels (5% v 9%). As Steinberg et al showed, when HU patients were divided into quartiles based on final HbF levels, those in the highest quartile had an 18% mean HbF, while those in the lowest quartile had a mean of only 4%. Higher HbF levels were associated with lower crisis rates, but the association was not statistically significant. Further analyses suggested noncompliance of patients in the lower HbF quartiles in the later months of the study as a significant factor responsible for the difference in HbF levels. When HU patients were divided into quartiles based on their 2-year crisis rates, those with the fewest crises had lower neutrophil counts and higher mean corpuscular volumes (MCVs) and F-cell counts; similar but less marked changes were seen in patients assigned to placebo. Multivariable analyses showed a significant relationship between crisis rate and, in the early months of the study, F-cell count and, in later months, MCV. Lower neutrophil counts were associated with lower crisis rates in all months of the study. The HbF in F cells inhibits their sickling and decreases the likelihood of vaso-occlusion and infarction. If infarction does occur, lower neutrophil counts may limit the extent of tissue destruction and the severity of pain. Further study is needed to clarify the interplay of these two factors as mediators of the effect of HU in lowering crisis rates in sickle cell anemia.
A simple high-performance liquid chromatographic method was developed for the determination of vanillin and its vanillic acid metabolite in human plasma, red blood cells and urine. The mobile phase consisted of aqueous acetic acid (1%, v/v)-acetonitrile (85:15, v/v), pH 2.9 and was used with an octadecylsilane analytical column and ultraviolet absorbance detection. The plasma method demonstrated linearity from 2 to 100 microg/ml and the urine method was linear from 2 to 40 microg/ml. The method had a detection limit of 1 microg/ml for vanillin and vanillic acid using 5 microl of prepared plasma, red blood cells or urine. The method was utilized in a study evaluating the pharmacokinetic and pharmacodynamic effects of vanillin in patients undergoing treatment for sickle cell anemia.
Among the various potential antisickling agents tested, hydroxyurea (HU) has been the most effective compound used for the treatment of patients with sickle cell disease (SCD). Although HU is effective in many patients, not all patients respond to this drug. In addition, some patients reveal adverse effects, including myelosuppression. In an attempt to find other effective agents with less adverse effects, we investigated the antisickling effect of NIPRISAN (Nix-0699). We found that Nix-0699, an ethanol/water extract from indigenous plants, has a strong antisickling effect. The concentration of Nix-0699 required to inhibit 50% of erythrocyte sickling was about 0.05 mg/ml. As for the kinetics of polymerization, addition of 0.05 microg/ml Nix-0699 caused a sixfold prolongation of the delay time prior to deoxy-Hb S polymerization when compared with that of untreated Hb S samples. The solubility of deoxy-Hb S significantly increased upon treatment with Nix-0699. Analysis of the effect of Nix-0699 on the Hb S oxygen affinity indicated that the drug slightly shifted the oxygen-dissociation curve of Hb S toward the left without any apparent change in the Hill coefficient. These results suggest that the antisickling properties of Nix-0699 may involve direct interaction with Hb molecules. Incubation of red blood cell (RBC) suspensions with various concentrations of Nix-0699 did not dehydrate RBCs, cause haemolysis, increase the amount of denatured Hb, nor form met-Hb. In view of the outcome of this study, Nix-0699 may be a promising option for the treatment of patients with SCD.
The substitution of glutamic acid by valine at the sixth position of the beta-globins of haemoglobin S (Hb S) causes a drastic reduction in the solubility of the deoxy form of Hb S. Under hypoxic conditions, deoxy-Hb S molecules polymerize inside the cells, forming rigid, sickled cells. We studied the effect of Niprisan (Nix-0699), a naturally occurring antisickling agent, on the survival of transgenic (Tg) sickle mice under severe acute hypoxic conditions (60 min). Before hypoxia exposure, the mice were treated by gavage once daily for 7 d with 0 mg/kg (n = 10), 10 mg/kg (n = 5), 50 mg/kg (n = 5), 300 mg/kg (n = 4) or 500 mg/kg (n = 5) of Nix-0699. The mean survival times of the untreated and treated mice were 10, 25, 39, 55 or 60 min respectively. The percentage of sickled cells in the venous blood of the treated mice was lower than that in control mice and was dose dependent. Histological examination of the lungs of the control mice showed entrapment of massive numbers of sickled cells in the alveolar capillaries, although the degree of such entrapment decreased with the increased dose of Nix-0699. Nix-0699 may be a promising option for the treatment and management of patients with sickle cell disease.
Sickle cell dis-ease. In: The Molecular Basis of Blood Disease
- A N Schechter
- C T Noguchi
- G P Rogers
Schechter, A.N., Noguchi, C.T. & Rogers, G.P. (1987) Sickle cell dis-ease. In: The Molecular Basis of Blood Disease (ed. by G. Stanaty-annopoules, A.W. Nienhuis, P. Leder & P. Majerus), p. 179. WB Saunders, Philadelphia.
Sickle Cell Disease: Basic Principles and Clinical Practice
- S H Embury
- R P Hebbel
- N Mohandas
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