Ginger (Zingiber officinale Rosc.) is both a commonly used spice, and an ingredient of various dietary supplements and medications. Its diverse applications result from the range of health benefits that this plant brings thanks to the presence of active compounds (secondary metabolites) in the matrix. Even if several studies underline a stronger pharmacological activity of fresh ginger rhizomes, the unprocessed plant is relatively rarely used. Ginger rhizomes are subjected to thermal processing, such as boiling, blanching, steam drying and others, at different temperature and time settings. Additionally, freeze-drying of the rhizomes is used as the first step in the preparation of raw material. It was proved that the composition of secondary metabolites of the Zingiber officinale rhizome changes upon the influence of temperature. Therefore, the aim of the review was to put together scientific results on the impact of traditional and unconventional methods of heat treatment on ginger rhizomes and to show the compositional differences that they induce in the plant matrix. Variations in the content and the transformation of some compounds into other metabolites will be also discussed, with particular attention paid to two major groups of secondary metabolites present in the plant, namely, phenolics and terpenes.

Civilization diseases associated with memory disorders are important health problems occurring due to a prolonged life span. The manuscript shows the results of an in vivo study targeting the emergence of two drug candidates with anti-amnestic properties. The preceding quantitative structure–activity relationship (QSAR) studies provided information on the ability of berberine and magnoflorine to cross the blood–brain barrier (BBB). In the light of these findings, both compounds were purified from crude plant extracts of barberries: berberine—from Berberis siberica using a method published earlier, and magnoflorine—from Berberis cretica by centrifugal partition chromatography (solvent system: ethyl acetate:butanol:water-0.6:1.5:3 v/v/v). Both the compounds were evaluated for their memory enhancing and scopolamine inhibitory properties in an in vivo passive avoidance (PA) test on mice towards short-term and long-term memory. Cognition enhancing properties were observed at the following doses: 5 mg/kg (i.p.) for berberine and 20 mg/kg (i.p.) for magnoflorine. In addition, both the tested isoquinolines with the co-administered scopolamine were found to block long-term but not short-term memory impairment. No influence on the locomotor activity was observed for the tested doses. The results confirmed a marked central activity of magnoflorine and showed the necessity to lower the dosage of berberine. Optimized purification conditions have been elaborated for magnoflorine.

In search of novel potential drug candidates that could be used as treatments or prophylactics for memory impairment, an aporphine alkaloid magnoflorine (MAG) isolated from the root of Berberis vulgaris was proven to exhibit beneficial anti-amnestic properties. Its effects on immunoreactivity to parvalbumin in the mouse hippocampus were assessed together with a study on its safety and concentration in the brain and plasma. For this purpose, four experimental groups were created: the MAG10 group—treated with 10 mg MAG/kg b.w. i.p., the MAG20 group—treated with 20 mg MAG/kg b.w. i.p., the MAG50 group—treated with 50 mg MAG/kg b.w. i.p., and a control group—injected with saline i.p. at a volume corresponding to their weight. Our results indicated that the hippocampal fields CA1–CA3 were characterized by an elevated number of parvalbumin-immunoreactive neurons (PV-IR) and nerve fibers in mice at the doses of 10 and 20 mg/kg b.w. (i.p.). No significant changes to the levels of IL-1β, IL-6 or TNF-α were observed for the above two doses; however, the administration of 50 mg/kg b.w. i.p. caused a statistically significant elevation of IL-6, IL-1beta plasma levels and an insignificant raise in the TNF-alpha value. The HPLC–MS analysis showed that the alkaloid’s content in the brain structures in the group treated with 50 mg/kg b.w. did not increase proportionally with the administered dose. The obtained results show that MAG is able to influence the immunoreactivity to PV-IR in hippocampal neurons and might act as a neuroprotective compound.

Cadmium ions (Cd²⁺) penetrate the blood–brain barrier and can, among other effects, influence intracellular calcium metabolism, leading to neurodegeneration. In the presented work, we estimated the effect of Cd²⁺ on the expression of calretinin in the neurons of the rat hippocampus and analyzed the reverse effect of freshly pressed beetroot/carrot juice in this context. In the 12-week lasting experiment, 32 8-week-old male Wistar rats were divided into four experimental groups (n = 8): the control group (C) received pure tap water; the Cd group (Cd)—received Cd²⁺ dissolved in tap water (5 mg Cd²⁺/kg b.w.); and two groups received beetroot/carrot juice: the BCJ group was administered only juice, and the Cd + BCJ group received juice with the addition of Cd²⁺ (5 mg Cd²⁺/kg b.w.). The exposition to low doses of Cd²⁺ caused a significant decrease in calretinin-immunoreactive (Cr-IR) neurons compared to the non-exposed groups. Moreover, the addition of Cd²⁺ to tap water reduced the numbers and length of Cr-IR nerve fibers. The negative effect of Cd²⁺ was significantly attenuated by the simultaneous supplementation of beetroot/carrot juice (Cd + BCJ). The study showed that the bioactive compounds in the beetroot/carrot juice can modulate Ca²⁺ levels in neurons, and thus, potentially act as a neuroprotective factor against neuronal damage.

αCaMKII, widely occurring in the central nervous system, plays a significant role in cognitive processes. It is well known that diabetes is a risk factor that may trigger brain atrophy, cognitive dysfunction and finally lead to memory loss. Antioxidants richly present in bilberry fruits are believed to have significant effects on diabetes-related brain dysfunctions mainly due to their abilities to modulate neurotransmitter release that lead to reduction of the negative impact of free radicals on cognitive processes. The aim of the present research was to immunohistochemically investigate the expression patterns of αCaMKII in hippocampal neurons from non-diabetic, diabetic and diabetic rats fed with an extract of bilberry fruit. The obtained results show that in comparison to the control group, in diabetic rats hippocampal neurons immunoreactive (ir) to αCaMKII were swollen and the lengths of the neuronal fibres were reduced. Further study shows that in diabetic rats fed with bilberry fruit, αCaMKII-positive nerve fibres were significantly longer when compared to the groups of diabetic and control rats. Additionally, we observed statistically significant changes in the average larger diameter of αCaMKII-ir hippocampal neurons between groups of diabetic rats (with vs. without supplement of bilberry fruit). The results of the present work suggest that antioxidants present in bilberry fruits influence the morphology of and possibly exhibit beneficial and neuroprotective effects on hippocampal neurons during diabetes. It is likely that changes in the appearance of αCaMKII-expressed hippocampal neurons may reflect the diabetes-evoked rise in Ca²⁺ level in the cerebral nerve terminals. The present research extends our knowledge of preventive mechanisms for cognitive dysfunctions occurring in the brain during diabetes.

Neurodegenerative diseases associated with memory disturbances are important health issues occurring due to a prolonged life span. This article presents the results of a study targeting the emergence of a drug candidate with antiamnesic properties. The effect of berberine (BBR), an isoquinoline alkaloid isolated from the overground parts of Berberis sibirica Pall., on memory and expression of parvalbumin in the mouse hippocampus proper were determined. High-purity BBR was isolated by centrifugal partition chromatography from a methanolic extract from B. sibirica by using a methyl-tert-butyl ether and water (1:1 v/v) solvent system with 10 mmol/L of triethylamine and hydrochloric acid. In an in vivo study, we assessed the influence of the chronic administration of BBR on different stages of memory-related responses in mice. Our results indicated that the chronic administration of BBR in a higher dose (5 mg/kg) improves long-term memory acquisition in mice, as determined in the passive avoidance test. The hippocampal CA1–CA3 fields showed an increased number of parvalbumin-immunoreactive neurons (PV-IR) and nerve fibers as compared to the control. No significant changes in the dentate gyrus were observed between the groups. The HPLC-ESI-QTOF-MS/MS analysis of the biological material revealed the content of BBR as 363.4 ± 15.0 ng (4.11% of RSD) per brain, 15.06 ± 0.89 ng (5.91% of RSD) per hippocampus, and 54.45 ± 1.40 (4.05% of RSD) ng in 100 µL plasma. The study showed that BBR could be a factor influencing the expression of PV in hippocampal neurons. We speculate that BBR may modulate the level of Ca²⁺ in neurons and thus potentially act as a neuroprotective factor against neuronal damages.