Examination of Changes in Enzyme Activities of Erythrocyte Glucose 6-Phosphate Dehydrogenase and 6-Phosphogluconate Dehydrogenase in Rats Given Naringenin and Lead Acetate

Lead toxicity and potential therapeutic effect of plant-derived polyphenols

BACKGROUND

Due to its unique physical and chemical properties, lead is still used worldwide in several applications, especially in industry. Both environmental and industrial lead exposures remain a public health problem in many developing and rapidly industrializing countries. Plant polyphenols are pleiotropic in their function and have historically made a major contribution to pharmacotherapy.

PURPOSE

To summarize available pre-clinical and limited clinical evidence on plant polyphenols as potential antidotes against lead poisoning and discuss toxic mechanisms of lead.

METHOD

A comprehensive search of peer-reviewed publications was performed from core collections of electronic databases such as PubMed, Web of Science, Google Scholar, and Science Direct. Articles written in English-language from inception until December 2022 were selected.

RESULTS

In this review, we review key toxic mechanisms of lead and its pathological effects on the neurological, reproductive, renal, cardiovascular, hematological, and hepatic systems. We focus on plant polyphenols against lead toxicity and involved mechanisms. Finally, we address scientific gaps and challenges associated with translating these promising preclinical discoveries into effective clinical therapies.

CONCLUSION

While preclinical evidence suggests that plant polyphenols exhibit bioprotective effects against lead toxicity, scant and equivocal clinical data highlight a need for clinical trials with those polyphenols.

Role of geraniol against lead acetate-mediated hepatic damage and their interaction with liver carboxylesterase activity in rats

In this study, the effect of geraniol (50 mg/kg for 30 d), a natural antioxidant and repellent/antifeedant monoterpene, in a rat model of lead acetate-induced (500 ppm for 30 d) liver damage was evaluated. Hepatic malondialdehyde increased in the lead acetate group. Reduced glutathione unchanged, but glutathione S-transferase, glutathione reductase, as well as carboxylesterase activities decreased in geraniol, lead acetate and geraniol + lead acetate groups. 8-OhDG immunoreactivity, mononuclear cell infiltrations and hepatic lead concentration were lower in the geraniol + lead acetate group than the lead acetate group. Serum aspartate aminotransferase and alanine aminotransferase activities increased in the Pb acetate group. In conclusion, lead acetate causes oxidative and toxic damage in the liver and this effect can reduce with geraniol treatment. However, we first observed that lead acetate, as well as geraniol, can affect liver carboxylesterase activity.

Investigation of the effect of naringenin on oxidative stress-related alterations in testis of hydrogen peroxide-administered rats

Testis tissue is prone to oxidation because its plasma membrane contains many polyunsaturated fatty acids. Naringenin is a plant-derived natural flavonoid. We investigated the possible ameliorative role of naringenin on the hydrogen peroxide (H₂ O₂ )-induced testicular damage in Wistar rats. Animals received 12 mg/kg H₂ O₂ by intraperitoneal injection, and 50 mg/kg naringenin via orogastric gavage for 4 weeks. In the H₂ O₂ group, the testis malondialdehyde level increased, while the amount of reduced glutathione, glutathione transferase activities, and the testis weight decreased. There were severe testicular damages in the H₂ O₂ group otherwise their grade were less in the naringenin + H₂ O₂ group. However, the serum testosterone concentrations decreased in both the H₂ O₂ and the naringenin + H₂ O₂ groups. The testicular zinc and calcium levels reduced in the H₂ O₂ -treated rats. In conclusion, the administration of H₂ O₂ caused oxidative stress in the testes and naringenin supplementation decreased the H₂ O₂ -induced effects, except for changes in testosterone levels.

In Vivo Effects of Naringenin and Lead on Rat Erythrocyte Carbonic Anhydrase Enzyme

Objectives

Carbonic anhydrase (CA) enzyme catalyses the reversible reactions of CO₂ with water and takes part in metabolically important events such as systemic acid-base regulation and respiration. In this study, in vivo effects of lead, which is a heavy metal and to which living beings are exposed by different ways, with naringenin, a flavanone, were investigated.

Materials and Methods

For this purpose, four different rat groups were established and one of them was chosen as the control group. The other three groups were given lead, naringenin and lead+naringenin substances to analyze the changes in the CA enzyme of rat erythrocytes.

Results

The research findings showed that the enzyme activity in the control group was higher than that in the other groups. The naringenin group showed the highest inhibition effect, while the lead group showed the lowest inhibition.

Conclusion

Therefore, it can be said that naringenin is a strong inhibitor of the CA enzyme.

Purification of glucose-6-phosphate dehydrogenase and glutathione reductase enzymes from the gill tissue of Lake Van fish and analyzing the effects of some chalcone derivatives on enzyme activities

Glucose-6-phosphate dehydrogenase (G6PD) and glutathione reductase (GR) are metabolically quite important enzymes. Within this study, these two enzymes were purified for the first time from the gills of Lake Van fish. In the purifying process, ammonium sulfate precipitation and 2',5'-ADP Sepharose 4B affinity column chromatography techniques for glucose-6-phosphate dehydrogenase, temperature degradation and 2',5'-ADP Sepharose 4B affinity column chromatography for glutathione reductase enzyme were used. The control of the enzyme purity and determination of molecular weight were done with sodium dodecyl sulfate polyacrylamide gel electrophoresis. K(M) and V(max) values were determined with Lineweaver-Burk plot. Besides, the effects of some chalcone derivatives on the purified enzymes were analyzed. For the ones showing inhibition effect, % activity-[I] figures were drawn and IC50 values were determined. K(i) value was calculated by using Cheng-Prusoff equation.