The Effects of Cassava Cyanide on the Antioxidant (Glutathione) Status and Some Clinically Important Enzymes of Rats

Quercetin upregulates CREM gene expression in cyanide-induced endocrine dysfunction

Cyanide is among the ubiquitous chemicals that humans are usually exposed to and it is well documented that cyanide induces infertility in humans and experimental rodents. However, the pathogenesis remains unknown. Likewise, quercetin is an important nutraceutical that detoxifies reactive oxygen species, but its effects on testicular damage is not clear. The present study investigated the role of nutraceutical, quercetin on cyanide-induced testicular toxicity and probable involvement of cAMP-response-element modulator (CREM) which is a transcription factor necessary for the process of spermatogenesis. Thus, this work hypothesized that quercetin will mitigate endocrine dysfunction induced by cyanide. Seventy-two adult male Wistar rats were divided into seven groups (A to G). Groups A, B, C, F and G comprised of eight (8) rats per group while groups D and E comprised of sixteen (16) rats per group. Group A was designated as control while Groups B and C were given 0.5 and 1 mg/kg of cyanide respectively for 56 days. Group D and E received 0.5 and 1 mg/kg body weight cyanide respectively for 30 days. At day 30, eight animals were sacrificed from Group D and E and the remaining eight (8) rats were subdivided into sub-groups (D1 and E1) and were given 20 and 40 mg/kg of quercetin respectively for twenty-six (26) days. Group F and G were given concurrent administration of cyanide and quercetin at a dose of 0.5 + 20 mg/kg and 1 + 40 mg/kg respectively for 56 days. Body and testicular weight were significantly reduced in cyanide treated groups while quercetin modulates the reduction. Significant down-regulation of CREM gene and reduction in serum level of follicle stimulating hormone (FSH), Luteinizing hormone (LH), testosterone, glutathione peroxidase (GPx) and zinc in cyanide-treated groups, whereas administration of quercetin concomitantly with cyanide exposure or post-treated significantly reversed the alterations.

Protective properties of Spondias mombin Linn leaves on redox status, cholinergic dysfunction and electrolyte disturbance in cyanide-intoxicated rats

Cyanide is an environmental neurotoxin which has been reported to arrest the normal functioning of the brain. This study investigated the protective properties of methanol and flavonoid-rich extracts of the leaves of Spondias mombin on redox status, cholinergic dysfunction and electrolyte disturbance in cyanide-induced neurotoxicity in rats. Male Wistar rats were orally pre-treated with Spondias mombin methanol leaf extract (SMC) (50, 100 and 150 mg/kg), flavonoid-rich extract (SMF) (25, 50 and 75 mg/kg) or quercetin (20 mg/kg), followed by intraperitoneal administration of 2 mg/kg potassium cyanide. Cyanide intoxication caused brain damage in rats as echoed in the deleterious alterations to activities/levels of endogenous antioxidants and biomarkers/enzymes linked with electrolyte imbalance and neurotoxicity. Pre-treatment with SMC and SMF significantly attenuated these KCN-induced imbalances (p < 0.05). The results suggested that the protection conferred by SMC and SMF probably involves attenuation of oxidative stress and regulation of ionic homeostasis. SMF displayed a better apparent ameliorative activity than SMC and 75 mg/kg SMF offered the best protection suggesting that flavonoids probably contributed to the protective effect of Spondias mombin leaf.

Biochemical pathways to α-ketoglutarate, a multi-faceted metabolite

α-Ketoglutarate (AKG) also known as 2-oxoglutarate is an essential metabolite in virtually all organisms as it participates in a variety of biological processes including anti-oxidative defence, energy production, signalling modules, and genetic modification. This keto-acid also possesses immense commercial value as it is utilized as a nutritional supplement, a therapeutic agent, and a precursor to a variety of value-added products such as ethylene and heterocyclic compounds. Hence, the generation of KG in a sustainable and environmentally-neutral manner is a major ongoing research endeavour. In this mini-review, the enzymatic systems and the metabolic networks mediating the synthesis of AKG will be described. The importance of such enzymes as isocitrate dehydrogenase (ICDH), glutamate dehydrogenase (GDH), succinate semialdehyde dehydrogenase (SSADH) and transaminases that directly contribute to the formation of KG will be emphasized. The efficacy of microbial systems in providing an effective platform to generate this moiety and the molecular strategies involving genetic manipulation, abiotic stress and nutrient supplementation that result in the optimal production of AKG will be evaluated. Microbial systems and their components acting via the metabolic networks and the resident enzymes are well poised to provide effective biotechnological tools that can supply renewable AKG globally.

In vivo studies on hepato-renal impairments in freshwater fish Cyprinus carpio following exposure to sublethal concentrations of sodium cyanide

Reactive oxygen species is an inevitable composite of aerobic systems that could channelize their lethality by imparting oxidative stress under a stressful environment. Cyanide is an important environmental toxicant that could be responsible in the resulting detrimental health issues of aquatic fauna. The present effort investigates the possibilities of hepato-renal damage in freshwater fish Cyprinus carpio following exposure to sublethal concentrations of sodium cyanide (NaCN). Fish were exposed to 0.1 mg/L of NaCN for 10 days (E1) and 20 days (E2) and were further subjected to recovery for 14 days (R) in NaCN-free medium. Liver tissue exhibited a significant decline in activity of catalase, superoxide dismutase, glutathione peroxidase, and glutathione S-transferase enzymes in exposed fish, unlike in control (C). Subsequent levels of lipid peroxidation elevation at 'E1' and 'E2' suggested oxidative damage to hepatocytes. This was further confirmed through a histopathological evaluation which indicated important findings like lymphocytic infiltration and necrosis in liver and tubular and glomerular degeneration in renal organ. The investigation suggests biochemical and histopathological alterations in fish following exposure to NaCN. Nevertheless, fish upon the recovery period were known to exhibit incomplete recuperation which was indicated by partial restoration tendencies under biochemical and histopathological factions. The study clearly implicated the role of NaCN in emphasizing its toxicity to C. carpio, further suggesting lack of recovery transition at a limited tenure of 14 days. The study might contribute in the course of regulatory surveillance and monitoring of aquatic bodies and may also reflect the possibilities of NaCN contamination during aquaculture practices. Graphical Abstract ᅟ.

The Metabolic Effects of Consumption of Yellow Cassava (Manihot esculenta Crantz) on Some Biochemical Parameters in Experimental Rats

The metabolism of yellow cassava (variety TMS 01/1368) was investigated in male albino rats fed a diet containing yellow cassava for 7 to 28 days. There were significant increases (P < 0.05) in total and free cyanide and thiocyanate in the sera and urine samples of the experimental rats compared with the control, significant increases (P < 0.05) in serum glucose, alanine aminotransaminase, aspartate aminotransaminase, and alkaline phosphatase levels of the experimental rats compared with the control, significant decreases (P < 0.05) in serum albumin of the experimental rats compared with the control, but no significant differences (P > 0.05) in the serum total proteins of the experimental rats compared with the control. The experimental rats treated for 7, 14, 21, or 28 days exhibited body weight decreases of 5.11%, 11.10%, 19.16%, and 24.18%, respectively, whereas the control group showed 9.17% gain in body weight. Total and free cyanide concentrations were detected in the liver, kidney, and heart of most of the rats in both the experimental and control groups, except for free cyanide in the control group that was not detected. Metabolism of the yellow cassava variety in experimental rats was capable of exposing the animals to cyanide, underscoring the need for its proper processing before consumption by humans.