Protective effects of hydroponic Teucrium polium on hippocampal neurodegeneration in ovariectomized rats

Teucrium Polium ameliorates amyloid β-induced brain network disorders in rats: electrophysiological and behavioral studies

Synaptic failure in specific cholinergic networks in rat brains has been implicated in amyloid β-induced neurodegeneration. Teucrium polium is a promising candidate for drug development against Alzheimer's disease (AD) and similar disorders. However, the protective effect of Teucrium polium against amyloid β-induced impairment of short-term synaptic plasticity is still poorly understood. In this study, we used in vivo extracellular single-unit recordings to investigate the preventive efficacy of Teucrium polium on Aβ(25-35)-induced aberrant neuronal activity in the hippocampus and basolateral amygdala of rats, in response to high-frequency stimulation of the cholinergic nucleus basalis magnocellularis (NBM). After 12 weeks of intracerebroventricular administration of Aβ(25-35), alterations such as decreased excitatory responses and increased inhibitory synaptic activity were observed in the NBM-hippocampus and NBM-basolateral amygdala cholinergic circuits. Treatment with Teucrium polium improved the balance of excitatory and inhibitory responses by modulating synaptic transmission strength and restoring short-term plasticity. Acute injection of a therapeutic dose of Teucrium temporarily inhibited spiking activity in single NBM neurons. Open field tests revealed that amyloid-injected rats displayed anxiety and reduced exploratory drive. Treatment with Teucrium polium improved these behaviors, reducing anxiety and increasing exploration. Teucrium polium mitigated amyloid β-induced alterations in cholinergic circuits by enhancing the adaptive capacity of short-term synaptic plasticity. These findings suggest that Teucrium polium could serve as a preventive strategy to delay the progression of cholinergic neurodegeneration.

Teucrium polium L: An updated review of phytochemicals and biological activities

OBJECTIVE

Medicinal plants and their components are potential novel sources for developing drugs against various diseases. Teucrium polium L. (syn Teucrium capitatum L. or felty germander) from the Lamiaceae family, is widely distributed in the dry and stony places of the hills and deserts of almost all Mediterranean countries, southwestern Asia, Europe, and North Africa. Based on traditional Iranian medicine (TIM), T. polium is used for treating many diseases, including abdominal pain, indigestion, and type 2 diabetes.

MATERIALS AND METHODS

In our previous review article published in 2012 and based on 100 articles published from 1970 to 2010, the main compounds purified from T. polium were terpenes, terpenoids, and flavonoids with antioxidant, anticancer, anti-inflammatory, hypoglycemic, hepatoprotective, hypolipidemic, antibacterial, and antifungal activities.

RESULTS

In this article, the phytochemistry and pharmacological activities of the plant reported from 2011 to 2020 have been evaluated. Therefore, a search was done in the databases PubMed, Science Direct and Google Scholar, Scopus, and Web of Science with the terms "T. polium," "T. capitatum." and felty germander', which included about 100 articles published since 2011 about T. polium pharmacological activities and isolated compounds. Most studies of this review focused on the antioxidant and antidiabetic effects of the plant.

CONCLUSION

Considering the position of T. polium in folk medicine, mainly as an antidiabetic agent, purification, structural and biological characterization of the active components appears essential for effective use of the plant.

The Effect of Crude Extract and Fractions of Teucrium polium L. on the Brain, Liver, and Kidney of Male Rats

Background: Teucrium polium (TP) is a medicinal plant with a long history of consumption as a folk remedy for curing many diseases, including diabetes, common cold, obesity, anxiety, etc. Objectives: The present study aimed at investigating the effects of TP crude extracts (TPCE), as well as its diethyl ether (DE) and petroleum ether (PE) fractions, on the brain, kidney, and liver tissue of male rats in the subchronic phase. Methods: In the study, 45 adult male Wistar rats were randomly assigned to five groups as the PBS (receiving phosphate buffer saline), vehicle (receiving dimethyl sulfoxide), as well as CE, PE, and DE receiving 3 mg/kg (100 µL) TPCE, PE, and DE, respectively, for six weeks. Histopathological examinations by hematoxylin and eosin staining investigated morphological changes in all specimens. Also, the brain samples were stained by the immunohistochemistry (IHC) technique with Ki-67, CD31, p53, Nestin, and GFAP markers. Results: The findings showed that the prolonged consumption of TP caused the formation of histological lesions as apoptosis, degeneration, cytoplasmic vacuolization of neurons, and foamy cells in the brain. The liver, displayed cytoplasmic vacuolization, apoptosis, degeneration, and dilated sinusoids. Moreover, TP led to atrophy, vacuolization, and necrosis in renal cells. IHC studies evidenced an increase in the expression of P53, whereas the expression of Ki67 and CD31 decreased. It should be noted that TP crude extract and fractions were toxic; however, the PE fraction was more cytotoxic than others. Conclusions: The study findings indicated that long-term administration of a sublethal dose of TP impairs cellular integrity in vital orangs, including the liver, brain, and kidney, through triggering the cell death mechanisms.

Teucrium polium L. Improves Blood Glucose and Lipids and Ameliorates Oxidative Stress in Heart and Aorta of Diabetic Rats

Background:

Diabetes mellitus (DM) is a prime risk factor for cardiovascular disease. The convincing experimental and clinical evidence indicated that the onset of DM is closely associated with oxidative stress and that the generation of reactive oxygen species increases in both the types of diabetes. The aim of the present study was to evaluate the effect of Teucrium polium (TP) hydroalcoholic extract on the blood glucose, cholesterol, triglyceride, and oxidative stress markers of the heart and aorta in streptozotocin (STZ)-induced diabetic rats.

Methods:

The male Wistar rats assigned into six groups (n = 8 in each group): Control, diabetic, and diabetic rats treated with TP extract (100, 200, and 400 mg/kg) or met and metformin (300 mg/kg) formin (300 mg/kg) group, by daily gavage for 6 weeks. Diabetes was induced by injection of STZ (60 mg/kg, i.p). Serum lipids and glucose, malondialdehyde (MDA) level, total thiol level, and also the activities of Cu, Zn-superoxide dismutase (SOD) in the cardiac and aortic tissues were assessed.

Results:

TP extract reduced serum glucose, triglyceride and cholesterol. The MDA levels were reduced significantly in all TP-treated groups and metformin. Total thiol levels were improved in the heart and aorta of TP extract-treated groups and metformin compared to the diabetic rats. The activity of SOD in the cardiac and aortic tissues of TP extract- and metformin-treated groups was higher than diabetic group.

Conclusions:

The results showed that chronic administration of TP in STZ-induced diabetic rats could decrease blood glucose, cholesterol, and triglyceride and also attenuate the oxidative stress in the aortic and cardiac tissues.