The loss of the ability for learning and memory is a prominent feature of dementia, which affects millions of individuals all over the world, due to either neurodegenerative diseases or brain injury. Although a lot of information is known about the pathology involved, treatment remains elusive at best. The Black Seed of Nigella sativa has been historically and religiously used for thousands of years for preventing and treating many different kinds of diseases. This review article looks at Nigella sativa and its potential role in facilitating learning and memory. The possible use of this seed’s extract or compounds isolated from it, such as thymoquinone, for treating damaged brain neural tissue is discussed. The evidence presented in this paper appears to be supporting the hypothesis that this plant and/or its bioactive constituents can enhance learning and memory in health and disease in animals and humans.

Bergenin (BG) is a naturally occurring C-glycoside with demonstrated anti-arthritic potential. Its therapeutic efficacy is compromised due to its lower absorption and instability at neutral-basic pH. The present study reports fabrication of gum xanthan (GX) stabilized silver nanoparticles (AgNPs) with BG for anti-arthritic activity in a CFA-induced arthritis model targeting ROS, cytokines and TLR expression. NPs were characterized through UV-vis, zetasizer, FT-IR and AFM. Oral administration of BG loaded NPs (1 mg kg⁻¹) exhibited potent anti-arthritic activity with a minimal arthritic score, mild to moderate paw tissue swelling, reduced degenerative changes along with mild articular changes and less influx of inflammatory cells in macroscopic X-ray and histological examination. Administration of BG and its NPs suppressed the levels of reactive oxygen species (ROS) significantly as compared to the arthritic control group. Moreover, increased production of O₂˙⁻ in human neutrophils, stimulated by opsonized zymosan (OZ) and phorbol-12-myristate-13-acetate (PMA) was also suppressed. BG and its loaded NPs were revealed to antagonize the oxidative stress via interference with the NADPH oxidase metabolic pathway. Their anti-oxidant activity was further assessed by their inhibitory effect against TLR (TRL-2 & -4) and cytokine (IL-1β, IL-6 and TNF-α) production. The current investigation validates GX stabilized AgNPs as stable and promising multi-targeted therapeutic nano-cargo for BG delivery with efficient treatment of RA.

Background: Fear, stress, and anxiety-like behaviors originate from traumatic events in life. Stress response is managed by endocannabinoids in the body by limiting the uncontrolled retrieval of aversive memories. Pharmacotherapy-modulating endocannabinoids, especially anandamide, presents a promising tool for treating anxiety disorders. Here, we investigated the effect of kaempferol, a flavonoid, in the extinction of fear related memories and associated anxiety-like behavior. Methods: The ability of kaempferol to inhibit fatty-acid amide hydrolase (FAAH, the enzyme that catabolizes anandamide) was assessed in vitro using an enzyme-linked immunosorbent assay (ELISA) kit. For animal studies (in vivo), the extinction learning was evaluated using contextual fear conditioning (CFC, a behavioral paradigm based on ability to learn and remember aversive stimuli). Furthermore, an elevated plus-maze (EPM) model was used for measuring anxiety-like behavior, while serum corticosterone served as a biochemical indicator of anxiety. Lastly, the interaction of kaempferol with FAAH enzyme was also assessed in silico (computational study). Results: Our data showed that kaempferol inhibited the FAAH enzyme with an IC₅₀ value of 1 µM. In CFC, it reduced freezing behavior in rats. EPM data demonstrated anxiolytic activity as exhibited by enhanced number of entries and time spent in the open arm. No change in blood corticosterone levels was noted. Our computational study showed that Kaempferol interacted with the catalytic amino acids (SER241, PHE192, PHE381, and THR377) of FAAH enzyme Conclusion: Our study demonstrate that kaempferol facilitated the extinction of aversive memories along with a reduction of anxiety. The effect is mediated through the augmentation of endocannabinoids via the inhibition of FAAH enzyme.

Depression is on the rise globally and expected to lead in global burden of diseases by 2030. The current therapy has serious limitations in terms of safety, efficacy, tolerability and therapeutic success. This review, based on the literature of the last decade, is aimed at exploring the preclinical profile of plant-based saponins (the abundant secondary metabolite) as an emerging therapy for depression. Enough scientific evidences reflect that saponins promote neurogenesis, restore monoaminergic tone and enhance neurotrophic factors. In multiple stress models, they have exhibited adaptogenic effects via normalising hypothalamus–pituitary–adrenal axis, corticosterone levels and oxidative stress. Scientific data revealed neuroprotective effect of saponins by inhibiting apoptosis and intraneuronal calcium dynamics. Many plants possessing saponins as their principal antidepressant moiety need investigation at clinical level. Last decade literature revealed numerous preclinical reports supporting the role of saponins as natural cure for depression and justified their inclusion in antidepressant drug discovery programs.