Phenolic content of Terminalia catappa L. leaf and toxicity evaluation on red hybrid tilapia (Oreochromis sp.)

Despite the use of Terminalia catappa (TC) leaf by traditional fish farmers around the world to improve the health status of cultured fish, there is a paucity of information on comprehensive metabolite profile and the maximum safe dose of the plant. This study aims at profiling the methanol leaf extract of T. catappa, quantifying total phenolic content (TPC) as well as the total flavonoid content (TFC) and evaluating its acute toxicity on blood, plasma biochemical parameters and histopathology of some vital organs in red hybrid tilapia (Oreochromis sp.). The experimental fish were acclimatised for 2 weeks and divided into six groups. Group (1) served as a control group and was administered 0.2 ml,g^-1 of phosphate buffer saline (PBS). Groups 2-6 were orally administered T. catappa leaf extracts (0.2 ml.50 g^-1 ) in the following sequence; 31.25, 62.5, 125, 250 and 500 mg.kg^-1 body weight. The metabolites identified in T. catappa using liquid chromatography-tandem mass electrospray ionisation spectrometry (LC-ESI-MS/MS) revealed the presence of organic acids, hydrolysable tannins, phenolic acids and flavonoids. Phenolic quantification revealed reasonable quantity of phenolic compounds (217.48 μg GAEmg^-1 for TPC and 91.90 μg. QCEmg^-1 for TFC). Furthermore, there was no significant difference in all the tested doses in terms of blood parameters and plasma biochemical analysis except for the packed cell volume (PCV) at 500 mg.kg^-1 when compared to the control. Significant histopathological changes were observed in groups administered with the extract at 125, 250 and 500 mg.kg^-1 doses. To a very large extent it is therefore safe to administer the extract at 31.25 and 62.5 mg.kg^-1 in tilapia.

The Ethyl Acetate Extract of Leaves of Ugni molinae Turcz. Improves Neuropathological Hallmarks of Alzheimer's Disease in Female APPswe/PS1dE9 Mice Fed with a High Fat Diet

The most common type of dementia is Alzheimer's disease (AD), a progressive neurodegenerative disease characterized by impairment in cognitive performance in aged individuals. Currently, there is no effective pharmacological treatment that cures the disease due to the lack of knowledge on the actual mechanisms involved in its pathogenesis. In the last decades, the amyloidogenic hypothesis has been the most studied theory trying to explain the origin of AD, yet it does not address all the concerns relating to its development. In the present study, a possible new preclinical treatment of AD was evaluated using the ethyl acetate extract (EAE) of leaves of Ugni molinae Turcz. (synonym Myrtus ugni Molina Family Myrtacea). The effects were assessed on female transgenic mice from a preclinical model of familial AD (APPswe/PS1dE9) combined with a high fat diet. This preclinical model was selected due to the already available experimental and observational data proving the relationship between obesity, gender, metabolic stress, and cognitive dysfunction; related to characteristics of sporadic AD. According to chemical analyses, EAE would contain polyphenols such as tannins, flavonoid derivatives, and phenolic acids, as well as pentacyclic triterpenoids that exhibit neuroprotective, anti-inflammatory, and antioxidant effects. In addition, the treatment evidenced its capacity to prevent deterioration of memory capacity and reduction of progression speed of AD neuropathology.

Anti-Oxidant Activity of Gallotannin-Enriched Extract of Galla Rhois Can Associate with the Protection of the Cognitive Impairment through the Regulation of BDNF Signaling Pathway and Neuronal Cell Function in the Scopolamine-Treated ICR Mice

The antibacterial, anti-inflammatory, anti-metastatic/anti-invasion activities and laxative activity of Galla Rhois (GR) are well-known, although the neuropreservation effects of their extracts are still to be elucidated. To investigate the novel therapeutic effects and molecular mechanism of GR on alleviation of cognitive impairment, two different dosages of gallotannin-enriched GR (GEGR) were administered to Korl:ICR mice for three weeks, and to induce memory impairment, scopolamine (SP) was administered during the last seven days of the GEGR treatment period. GEGR showed the high level of the free radical scavenging activity to DPPH and suppressive activity to reactive oxygen species (ROS) in B35 cells as well as enhanced SOD and CAT activity in brains of the SP-induced model. Latency time for memory impairment assessed by the passive avoidance test significantly protected in the SP+GEGR treated group as compared to the SP+Vehicle treated group. Moreover, similar protective effects were observed on the secretion of BDNF in SP+GEGR treated mice. The expression of TrkB receptor, and phosphorylation of PI3K on the TrkB receptor signaling pathway were dramatically protected in the SP-induced model after GEGR treatment, whereas the expression of p75^NTR receptor, the phosphorylation of JNK, and expression of Bax/Bcl-2 on the p75^NTR receptor signaling pathway was significantly protected in the same group. Furthermore, the GEGR treated SP-induced model showed decreased number of dead neural cells and suppressed acetylcholine esterase (AChE) activity and inhibited inflammatory responses. Taken together, these results indicate that the anti-oxidant activity of GEGR contributes to improving the neuronal cell function and survival during cognitive impairment in the SP-induced model through regulation of BDNF secretion and their receptor signaling pathway.

Mitigating Alzheimer’s Disease with Natural Polyphenols: A Review

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According to Alzheimer’s Disease International (ADI), nearly 50 million people worldwide were living with dementia in 2017, and this number is expected to triple by 2050. Despite years of research in this field, the root cause and mechanisms responsible for Alzheimer’s disease (AD) have not been fully elucidated yet. Moreover, promising preclinical results have repeatedly failed to translate into patient treatments. Until now, none of the molecules targeting AD has successfully passed the Phase III trial. Although natural molecules have been extensively studied, they normally require high concentrations to be effective; alternately, they are too large to cross the blood-brain barrier (BBB).

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In this review, we report AD treatment strategies, with a virtually exclusive focus on green chemistry (natural phenolic molecules). These include therapeutic strategies for decreasing amyloid-β (Aβ) production, preventing and/or altering Aβ aggregation, and reducing oligomers cytotoxicity such as curcumin, (-)-epigallocatechin-3-gallate (EGCG), morin, resveratrol, tannic acid, and other natural green molecules. We also examine whether consideration should be given to potential candidates used outside of medicine and nutrition, through a discussion of two intermediate-sized green molecules, with very similar molecular structures and key properties, which exhibit potential in mitigating Alzheimer’s disease.