Garcinia kola aqueous suspension prevents cerebellar neurodegeneration in long-term diabetic rat - a type 1 diabetes mellitus model

Alteration of Aquaporins 1 and 4 immunohistochemical and gene expression in the cerebellum of diabetic albino rat

Aquaporins (AQPs) are a family of transmembrane channel proteins. AQP1 and AQP4 are expressed in cerebellum amongst others. This study was designed to assess the effect of diabetes on AQP1 and AQP4 expression in cerebellum of rats. Diabetes was induced by a single intraperitoneal injection of Streptozotocin 45 mg/kg in 24 adult male Sprague Dawley rats. Six rats from control and diabetic groups were sacrificed at one, four, and eight weeks post diabetic confirmation. After eight weeks, measurement of malondialdehyde (MDA), reduced glutathione (GSH) concentrations, and cerebellar mRNA expression for AQP1 and AQP4 genes were performed. Immunohistochemical evaluation of AQP1, AQP4, and glial fibrillary acidic protein (GFAP) for cerebellar sections was performed for all groups. Diabetes caused degenerative changes in Purkinje cells with a significant increase in the cerebellar level of MDA and AQP1 immunoreactivity and a significant decrease in GSH level and AQP4 expression levels. However, the alteration in the AQP1 mRNA level was not statistically significant. GFAP immunoreactivity was increased in 8 W diabetic rats following its decrease in 1 W diabetic rats. Diabetes caused some alteration in the AQPs 1 and 4 expression in the cerebellum of diabetic rats which may contribute to diabetes-induced cerebellar complications.

An Eluate of the Medicinal Plant Garcinia kola Displays Strong Antidiabetic and Neuroprotective Properties in Streptozotocin-Induced Diabetic Mice

Materials and Methods

G. kola methanolic extract was fractionated using increasingly polar solvents. Fractions were administered to streptozotocin (STZ)-induced diabetic mice until marked motor signs developed in diabetic controls. Fine motor skills indicators were measured in the horizontal grid test (HGT) to confirm the prevention of motor disorders in treated animals. Column chromatography was used to separate the most active fraction, and subfractions were tested in turn in the HGT. Gas chromatography-mass spectrometry (GC-MS) technique was used to assess the components of the most active subfraction.

Results

Treatment with ethyl acetate fraction and its fifth eluate (F5) preserved fine motor skills and improved the body weight and blood glucose level. At dose 1.71 mg/kg, F5 kept most parameters comparable to the nondiabetic vehicle group values. GC-MS chromatographic analysis of F5 revealed 36 compounds, the most abundantly expressed (41.8%) being the β-lactam molecules N-ethyl-2-carbethoxyazetidine (17.8%), N,N-dimethylethanolamine (15%), and isoniacinamide (9%).

Conclusions

Our results suggest that subfraction F5 of G. kola extract prevented the development of motor signs and improved disease profile in an STZ-induced mouse model of diabetic encephalopathy. Antidiabetic activity of β-lactam molecules accounted at least partly for these effects.

Garcinia kola treatment exhibits immunomodulatory properties while not affecting type 1 diabetes development in an experimental mouse model

Objective

T cells orchestrate an inflammatory response that destroys pancreatic insulin-producing β cells during the development of autoimmune type 1 diabetes (T1D). Garcinia kola Heckel (GK) is a plant widely exploited in West African traditional medicine. Some of the therapeutic effects of GK nut’s extract (GKE) have been suggested to be due to its anti-inflammatory potential. Since GKE has never been investigated in a T1D experimental model, nor in the T cells’ context, we aimed to determine whether GKE exhibits antidiabetic properties and affects T cells by its anticipated anti-inflammatory action.

Methods

The effect of aqueous GKE (aGKE) ingestion, 100 mg/kg daily by drinking water over the period of 6 weeks, has been tested in a low-dose streptozotocin-induced (LDSTZ) mouse model of autoimmune T1D. T cells were studied in vitro and in vivo in mice treated by aGKE.

Results

The results showed that aGKE treatment, which started a week before induction of disease, neither delayed the development of T1D, nor reduced glycemia severity. Interestingly, aGKE treatment did affect T cells and their function, significantly decreasing the frequency of helper (T_H) and cytotoxic (T_C) T cells, while elevating the levels of pro-inflammatory cytokines, TNF-α, IL-6, and IFN-γ, and suppressing IL-2.

Conclusion

In conclusion, our results did not confirm the antidiabetic property of GKE, while suggesting its therapeutic exploration in T_H2-dependent pathologies that benefit from an aggravated T_H1 response, such as allergies.

A review on garcinia kola heckel: traditional uses, phytochemistry, pharmacological activities, and toxicology

PURPOSE

Garcinia kola is a medicinal plant commonly known as bitter kola. It is utilised in ethnomedicine for the treatment of diarrhoea, bronchitis, bacterial infection, cough, hepatitis, gonorrhoea, laryngitis, food poison, liver and gastric diseases.

OBJECTIVE

This study reviewed the phytochemistry, pharmacological activities, and ethnomedicinal potentials of G. kola.

MATERIALS AND METHODS

An extensive review was performed using electronic literature collated from ScienceDirect, Springer, Wiley, and PubMed databases.

RESULTS

Phytochemical analysis revealed the isolation of several chemical compounds including 9-octadecenoic acid, linoleic acid, 14-methylpentadecanoic acid, 1-butanol, hexadecanamide, I-4',II-4',I-5,II-5,I-7,II-7-hexahydroxy-I-3,II-8-biflavanone, lanost-7-en-3-one, kolaflavanone (8E)-4-geranyl-3,5-dihydroxybenzophenone, glutinol, Garcinia biflavonoid (GB-2a-II-4'-OMe), 9,19-cyclolanost-24-en-3-ol, 24-methylene, tirucallol, lupeol, β-amyrin, obtusifoliol and Kolaviron. Diverse pharmacological in-vivo and in vitro investigations revealed that G. kola has anti-inflammatory, antimalarial, hepatoprotective, cardioprotective, anti-asthmatic, neuroprotective, antioxidant, and antidiabetic activities.

CONCLUSION

The present study revealed that G. kola has preventive and therapeutic potentials against various diseases in both in vivo and in vitro studies and therefore can be utilised as a raw material in the pharmaceutical industries for the development of therapeutic products. However, there is a need for clinical trial experiments to validate and provide accurate and substantial information on the required safe dosage and efficacy for the treatment of several diseases.

Garcinia kola improves cognitive and motor function of a rat model of acute radiation syndrome in the elevated plus maze

We reported recently that the elevated plus maze is a good tool for evaluating cognitive and motor functional changes in gamma-irradiated rats as a model for new drug evaluation and monitoring. The capacity of Garcinia kola to mitigate radiation-induced brain injury is currently unknown. We therefore assessed the effects of the neuroprotective medicinal plant Garcinia kola, on the cognitive and motor changes in this murine model of acute radiation syndrome. Wistar rats exposed once to an ionizing dose of Tc99m-generated Gamma radiation were treated with an ethyl acetate fraction of methanolic extract of Garcinia kola seeds (content of 100 mg/kg of extract) for 9 weeks. Cognitive and motor function indicators were assessed in the elevated plus maze in these animals and compared with irradiated control groups (vitamin C- and vehicle-treated groups) and the non-irradiated control rats. The irradiated control group displayed cachexia, shaggy and dirty fur, porphyrin deposits around eyes, decreased exploratory activity, reduced social interactions and a loss of thigmotaxis revealed by a marked decrease in rearing episodes and stretch attend posture episodes close to the walls of elevated plus maze closed arm, an increased central platform time, and decreases in open arm time and entries. This group further displayed a decrease in head dips and grooming episodes. Treatment with Garcinia kola, and in a lesser extent vitamin C, significantly prevented the body weight loss (P < 0.001) and mitigated the development of elevated plus maze signs of cognitive and motor affections observed in the irradiated control group (P < 0.05). Altogether, our data suggest for the first time that Garcinia kola seeds have protective properties against the development of cognitive and motor decline in the acute radiation syndrome-like context. Future studies are warranted to characterize the molecular mechanisms and neuronal networks of this action.

Evaluation of metabolic, antioxidant and anti-inflammatory effects of Garcinia kola on diabetic rats

Garcinia kola (G. kola), is a plant characterized by its hypoglycemic properties. We recently reported our findings on the extracts of G. kola, in which we found that it prevented the loss of inflammation-sensible neuronal populations in streptozotocin (STZ)-induced rat models of type 1 diabetes mellitus (T1DM).

In the present study we assessed the effect of G. kola bioactive compounds extracted successively with water, hexane, methylene chloride, ethyl acetate, and butanol. through analyzing biochemical markers of oxidative stress, inflammation, and metabolic function in STZ-induced diabetic animals.

Animals made diabetic by a single injection with STZ (60 mg/kg, i.p.), were treated daily with either vehicle solution, insulin, or G. kola extracts and its fractions from the first to the 6th-week post-injection. Biochemical markers; glucose, insulin, C-peptide, neuron-specific enolase (NSE), creatinine kinase, glutathione peroxidase, malondialdehyde (MDA), resistin, soluble E-selectin (SE-Selectin), and C-reactive proteins (CRP) levels in the sera were determined in the study groups. A marked increase in blood glucose (209.26% of baseline value), and a decrease in body weight (−12.37%) were observed in diabetic control animals but not in animals treated with either insulin or G. kola extracts and its fractions. The sub-fraction F5, G. kola ethyl acetate had the highest bioactive activities, with a maintenance of blood sugar, malondialdehyde, C-peptide, E-selectin, C-reactive protein (CRP) and neuron-specific enolase (NSE) to levels and responses comparable to healthy non-diabetic vehicle group and the positive control diabetic insulin-treated group.

Our findings suggest that G. kola may have a strong therapeutic potential against T1DM and its microvascular complications.

Evaluation of the safety of conventional lighting replacement by artificial daylight

Background

Short morning exposure to high illuminance visible electromagnetic radiations termed as artificial daylight is beneficial for the mental health of people living in geographical areas with important seasonal changes in daylight illuminance. However, the commercial success of high illuminance light sources has raised the question of the safety of long hour exposure.

Methods

We have investigated the effect of the replacement of natural daylight by artificial daylight in Swiss mice raised under natural lighting conditions. Mice were monitored for neurotoxicity and general health changes. They were submitted to a battery of conventional tests for mood, motor and cognitive functions' assessment on exposure day (ED) 14 and ED20. Following sacrifice on ED21 due to marked signs of neurotoxicity, the expression of markers of inflammation and apoptosis was assessed in the entorhinal cortex and neurons were estimated in the hippocampal formation.

Results

Signs of severe cognitive and motor impairments, mood disorders, and hepatotoxicity were observed in animals exposed to artificial daylight on ED20, unlike on ED14 and unlike groups exposed to natural daylight or conventional lighting. Activated microglia and astrocytes were observed in the entorhinal cortex, as well as dead and dying neurons. Neuronal counts revealed massive neuronal loss in the hippocampal formation.

Conclusions

These results suggest that long hour exposure to high illuminance visible electromagnetic radiations induced severe alterations in brain function and general health in mice partly mediated by damages to the neocortex-entorhinal cortex-hippocampus axis. These findings raise caution over long hour use of high illuminance artificial light.