Prevention of short-term memory impairment by Bryophyllum pinnatum (Lam.) Oken and its effect on acetylcholinesterase changes in CCl4-induced neurotoxicity in rats

Silymarin pretreatment protects against ethanol-induced memory impairment: Biochemical and histopathological evidence

BACKGROUND

Ethanol (Eth.) abuse induces memory impairment. Oxidative damage and apoptosis are considered the likely causes of memory impairment. Silymarin (Sil.) is a flavonoid isolated from the plant Silymarin marianum (milk thistle). While studies have reported the neuroprotective effect of Sil. against neurodegenerative processes, the precise mechanism of action of Sil. in Eth.-induced memory impairment remains unclear.

METHODS

Twenty-eight rats were equally divided into four groups: Control (saline 1 ml/rat); Sil. (200 mg/kg for 30 days); Eth. (2 g/kg/day for 30 days); and Sil. + Eth. Behavioral tests including inhibitory avoidance and open field were used to investigate memory and locomotion. Brain antioxidant parameters, including catalase, superoxide dismutase, total antioxidant capacity and total thiol group, plus oxidative parameters, including malondialdehyde and total oxidant status, followed by hippocampal apoptosis (Bax/Bcl2, cleaved caspase) and histopathological changes were evaluated in the groups.

RESULTS

While the administration of Eth. impaired memory, Sil. significantly reversed Eth-induced memory deficits. Eth. administration also augmented brain oxidative and hippocampal apoptosis parameters. In contrast, a marked reduction in brain antioxidant and anti-apoptotic parameters was observed in the Eth. group. At the tissue level, hippocampal sections from Eth.-treated animals revealed severe neuronal damage. The administration of Sil. to Eth.-treated rats remarkably alleviated all the said Eth.-induced biochemical and histopathological effects. On the contrary, Sil. alone did not change the behavior and biochemical/molecular parameters.

CONCLUSION

The memory-enhancing effect of Sil. in Eth.-induced demented rats may be partly mediated by the augmented antioxidant effects and amelioration of apoptotic and histopathological changes.

Neuroprotective effect of Bryophyllum pinnatum flavonoids against aluminum chloride-induced neurotoxicity in rats

Toxic metals such as aluminum accumulation in the brain have been associated with the pathophysiology of several neurodegenerative disorders. Bryophyllum pinnatum leaves contain a vast array of polyphenols, particularly flavonoids, that may play a role in the prevention of toxic and degenerative effects in the brain. This study assessed the neuro-restorative potential of leaves of B. pinnatum enriched flavonoid fraction (BPFRF) in aluminum-induced neurotoxicity in rats. Neurotoxicity was induced in male Wistar rats by oral administration of 150 mg/kg body weight of aluminum chloride (AlCl₃) for 21 days. Rats were grouped into five (n = 6); Control (untreated), Rivastigmine group, AlCl₃ group and BPFRF group (50 and 100 mg/kg b.wt.) for 21 days. Neuronal changes in the hippocampus and cortex were biochemically and histologically evaluated. Expression patterns of acetylcholinesterase (AChE) mRNA were assessed using semi-quantitative reverse-transcription-polymerase chain reaction protocols. Molecular interactions of BPFRF compounds were investigated in silico. The results revealed that oral administration of BPFRF ameliorated oxidative imbalance by augmenting antioxidant systems and decreasing lipid peroxidation caused by AlCl₃. BPFRF administration also contributed to the down-regulation of AChE mRNA transcripts and improved histological features in the hippocampus and cortex. Molecular docking studies revealed strong molecular interactions between BPFRF compounds, catalase, superoxide dismutase and glutathione peroxidase Overall, these findings suggest the neuroprotective effect of Bryophyllum pinnatum against aluminum-induced neurotoxicity.

Toxicity of carbon tetrachloride, free radicals and role of antioxidants

Several chemicals, including environmental toxicants and clinically useful drugs, cause severe cellular damage to different organs of our body through metabolic activation to highly reactive substances such as free radicals. Carbon tetrachloride is an organic compound of which chemical formula is CCl₄. CCl₄ is strong toxic in the kidney, testicle, brain, heart, lung, other tissues, and particularly in the liver. CCl₄ is a powerful hepatoxic, nephrotoxic and prooxidant agent which is widely used to induce hepatotoxicity in experimental animals and to create hepatocellular carcinoma, hepatic fibrosis/cirrhosis and liver injury, chemical hepatitis model, renal failure model, and nephrotoxicity model in recent years. The damage-causing mechanism of CCl₄ in tissues can be explained as oxidative damage caused by lipid peroxidation which starts after the conversion of CCl₄ to free radicals of highly toxic trichloromethyl radicals (•CCl₃) and trichloromethyl peroxyl radical (•CCl₃O₂) via cytochrome P450 enzyme. Complete disruption of lipids (i.e., peroxidation) is the hallmark of oxidative damage. Free radicals are structures that contain one or more unpaired electrons in atomic or molecular orbitals. These toxic free radicals induce a chain reaction and lipid peroxidation in membrane-like structures rich in phospholipids, such as mitochondria and endoplasmic reticulum. CCl₄-induced lipid peroxidation is the cause of oxidative stress, mitochondrial stress, endoplasmic reticulum stress. Free radicals trigger many biological processes, such as apoptosis, necrosis, ferroptosis and autophagy. Recent researches state that the way to reduce or eliminate these CCl₄-induced negative effects is the antioxidants originated from natural sources. For normal physiological function, there must be a balance between free radicals and antioxidants. If this balance is in favor of free radicals, various pathological conditions occur. Free radicals play a role in various pathological conditions including Pulmonary disease, ischemia / reperfusion rheumatological diseases, autoimmune disorders, cardiovascular diseases, cancer, kidney diseases, hypertension, eye diseases, neurological disorders, diabetes and aging. Free radicals are antagonized by antioxidants and quenched. Antioxidants do not only remove free radicals, but they also have anti-inflammatory, anti-allergic, antithrombotic, antiviral, and anti-carcinogenic activities. Antioxidants contain high phenol compounds and antioxidants have relatively low side effects compared to synthetic drugs. The antioxidants investigated in CCI₄ toxicity are usually antioxidants from plants and are promising because of their rich resources and low side effects. Data were investigated using PubMed, EBSCO, Embase, Web of Science, DOAJ, Scopus and Google Scholar, Carbon tetrachloride, carbon tetrachloride-induced toxicity, oxidative stress, and free radical keywords. This study aims to enlighten the damage-causing mechanism created by free radicals which are produced by CCl₄ on tissues/cells and to discuss the role of antioxidants in the prevention of tissue/cell damage. In the future, Antioxidants can be used as a therapeutic strategy to strengthen effective treatment against substances with high toxicity such as CCl₄ and increase the antioxidant capacity of cells.

Analysis of silymarin-modulating effects against acrylamide-induced cerebellar damage in male rats: Biochemical and pathological markers

BACKGROUND

Acrylamide (ACR) is a well-proven neurotoxin and potential food carcinogen in humans and rodent models. Silymarin (SIL) is a flavonoid mixture isolated from seeds, leaves, and fruits of Silymarin marianum (milk thistle) that possesses a free-radical scavenging effect.

OBJECTIVE

In this work, the primary focus was to investigate the efficacy of SIL to mitigate ACR-induced subacute neurotoxic effects and oxidative changes in rat cerebellum.

METHODS

Adult male rats were treated intraperitoneally with ACR (50 mg/kg) with or without SIL (160 mg/kg). The neuropathology and biochemical parameters viz. lipid peroxidation (measured as levels of malondialdehyde or MDA), catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx), serotonin (5-hydroxytryptamine; 5-HT), dopamine (DA), and cathepsin D (CTSD) in the cerebellum have been evaluated.

RESULTS

The data showed that ACR induced redox disruptions as measured by increased MDA levels and inhibition of CAT, SOD, and GPx antioxidant enzyme activities. Besides, cerebellar monoamine neurotransmitters, 5-HT and DA, were depleted in ACR-treated rats. Furthermore, ACR administration caused a significant elevation of CTSD activity, indicating that ACR could trigger apoptosis or apoptosis-like death. At the tissue level, cerebellar cortex sections from ACR-treated animals were characterized by severe neuronal damage. The administration of SIL to ACR-treated rats remarkably alleviated all the aforementioned ACR-induced effects.

CONCLUSION

SIL has a potent therapeutic effect against ACR-induced cerebellar neurotoxicity in experimental rats via the attenuation of oxidative/antioxidative responses and the inhibition of CTSD-activity.

Evaluation of Phytochemical, Antioxidant, and Memory-Enhancing Activity of Garuga pinnata Roxb. Bark and Bryophyllum pinnatum (Lam) Oken. Leaves

Garugapinnata Roxb. (Burseraceae) is a medium-sized tree widely available all over the tropical regions of Asia. Bryophyllum pinnatum (Lam) Oken. (Crassulaceae) is an indigenous and exotic plant grown in tropical regions. Both plants have been used for their anti-inflammatory, antioxidant, anticancer, wound healing, antidiabetic activities, etc. This investigation was designed to explore the result shown by methanolic extract of Garuga pinnata bark and Bryophyllum pinnatum leaves, on cognitive power and retention of the memory in experimental mice along with quantification of phenolic compounds and DPPH radicals neutralizing capacity. The memory-enhancing activity was determined by the elevated plus-maze method in Scopolamine-induced amnesic mice, using Piracetam as allopathic and Shankhpushpi as ayurvedic standard drugs. Two doses (200 and 400 mg/kg p.o.) of both extracts were administered to mice up to 8 consecutive days; transfer latency of individual group was recorded after 45 minutes and memory of the experienced things was examined after 1 day. DPPH assay method and the Folin–Ciocalteu method were employed to determine antioxidant potency and total phenol amount, respectively. 400 mg/kg of the methanolic B. pinnatum bark extract significantly improved memory and learning of mice with transfer latency (TL) of 32.75 s, which is comparable to that of standard Piracetam (21.78 s) and Shankhpushpi (27.83 s). Greater phenolic content was quantified in B. pinnatum bark extract (156.80 ± 0.33 µg GAE/mg dry extract) as well as the antioxidant potency (69.77% of free radical inhibition at the 100 µg/mL concentration). Our study proclaimed the scientific evidence for the memory-boosting effect of both plants.