Ferric heme b in aqueous micellar and vesicular systems: state-of-the-art and challenges

Evaluation of anti-sickling effects of two varieties of Cajanus cajan (L.) Huth on sickle cell beta thalassemia

ETHNO-PHARMACOLOGICAL RELEVANCE

Globally, the prevalence of sickle cell disease is on the rise, with developing countries experiencing particularly alarming mortality rate compared to developed nations. The World Health Organization (WHO) and United Nations (UN) have acknowledged sickle cell disease as a significant global public health concern. Unfortunately, a cure for this condition is yet to be discovered, and existing allopathic treatments, while offering relief, come with serious side effects. In recent times, there has been a growing interest in exploring the potential of medicinal plants for treating sickle cell disease due to their content of secondary metabolites that may impact the disease's mechanisms. Cajanus cajan, a crucial grain legume in rain-fed agriculture in semi-arid tropics, has been traditionally used in folk medicine to manage various illnesses and is suggested to possess anti-sickling properties.

AIM OF THE STUDY

The present study investigated two varieties of C. cajan for their effectiveness in treating sickle cell beta thalassemia, a variant of sickle cell disease.

MATERIALS AND METHODS

The study was divided into four groups consisting of the untreated group (group 1), group treated with standard drug (group 2), group treated with white C. cajan (group 3) and group treated with brown C. cajan (group 4). The effects of the two variety of C. cajan were measured by polymerization test, reversibility test, osmotic fragility test, deoxygenation and beta globin synthesis test.

RESULT

The results revealed that both varieties of C. cajan demonstrated a reduction in polymerization rates, reversed sickled red blood cells, increased the oxygen affinity of Hb-S/β, elevated the Fe2+/Fe3+ ratio, and maintained the membrane stability of red blood cells. Notably, the white variety exhibited superior anti-sickling properties compared to the brown variety.

CONCLUSION

This suggests that this significant leguminous crop could be utilized for the treatment and management of sickling disorders, particularly in low-income countries where conventional treatments may be financially inaccessible to patients.

Supramolecular assembly-induced electrochemiluminescence enhancement of gold nanoclusters for hemoglobin detection

Gold nanoclusters (Au NCs) with excellent optical properties and biocompatibility have become one of the most promising electrochemiluminescence (ECL) emitters. However, the low efficiency and poor stability of Au NCs restrict their applications in ECL. Herein, by supramolecular assembly of L-arginine (Arg) and 4-hydroxy-2-mercapto-6-methylpyrimidine (MTU) on the surface of Au NCs, Arg/MTU-Au NCs with enhanced ECL efficiency and stability were prepared. Compared with the MTU-stabilized Au NCs (MTU-Au NCs), the ECL efficiency of Arg/MTU-Au NCs increased by 24.8 times. As a proof-of-concept, a sensitive biosensing platform was constructed for sensitive detection of hemoglobin (Hb) in urine using Arg/MTU-Au NCs as ECL emitters. The proposed ECL detection platform provides a feasible strategy for the detection of biomarkers in urine and has broad application prospects in disease screening and clinical marker detection.

Optimization and Enhancement of the Peroxidase-like Activity of Hemin in Aqueous Solutions of Sodium Dodecylsulfate

Iron porphyrins play several important roles in present-day living systems and probably already existed in very early life forms. Hemin (= ferric protoporphyrin IX = ferric heme b), for example, is the prosthetic group at the active site of heme peroxidases, catalyzing the oxidation of a number of different types of reducing substrates after hemin is first oxidized by hydrogen peroxide as the oxidizing substrate of the enzyme. The active site of heme peroxidases consists of a hydrophobic pocket in which hemin is embedded noncovalently and kept in place through coordination of the iron atom to a proximal histidine side chain of the protein. It is this partially hydrophobic local environment of the enzyme which determines the efficiency with which the sequential reactions of the oxidizing and reducing substrates proceed at the active site. Free hemin, which has been separated from the protein moiety of heme peroxidases, is known to aggregate in an aqueous solution and exhibits low catalytic activity. Based on previous reports on the use of surfactant micelles to solubilize free hemin in a nonaggregated state, the peroxidase-like activity of hemin in the presence of sodium dodecyl sulfate (SDS) at concentrations below and above the critical concentration for SDS micelle formation (critical micellization concentration (cmc)) was systematically investigated. In most experiments, 3,3',5,5'-tetramethylbenzidine (TMB) was applied as a reducing substrate at pH = 7.2. The presence of SDS clearly had a positive effect on the reaction in terms of initial reaction rate and reaction yield, even at concentrations below the cmc. The highest activity correlated with the cmc value, as demonstrated for reactions at three different HEPES concentrations. The 4-(2-hydroxyethyl)-1-piperazineethanesulfonate salt (HEPES) served as a pH buffer substance and also had an accelerating effect on the reaction. At the cmc, the addition of l-histidine (l-His) resulted in a further concentration-dependent increase in the peroxidase-like activity of hemin until a maximal effect was reached at an optimal l-His concentration, probably corresponding to an ideal mono-l-His ligation to hemin. Some of the results obtained can be understood on the basis of molecular dynamics simulations, which indicated the existence of intermolecular interactions between hemin and HEPES and between hemin and SDS. Preliminary experiments with SDS/dodecanol vesicles at pH = 7.2 showed that in the presence of the vesicles, hemin exhibited similar peroxidase-like activity as in the case of SDS micelles. This supports the hypothesis that micelle- or vesicle-associated ferric or ferrous iron porphyrins may have played a role as primitive catalysts in membranous prebiotic compartment systems before cellular life emerged.