The human gastrointestinal tract is populated with a diverse microbial community. The vast genetic and metabolic potential of the gut microbiome underpins its ubiquity in nearly every aspect of human biology, including health maintenance, development, aging, and disease. The advent of new sequencing technologies and culture-independent methods has allowed researchers to move beyond correlative studies toward mechanistic explorations to shed light on microbiome–host interactions. Evidence has unveiled the bidirectional communication between the gut microbiome and the central nervous system, referred to as the “microbiota–gut–brain axis”. The microbiota–gut–brain axis represents an important regulator of glial functions, making it an actionable target to ameliorate the development and progression of neurodegenerative diseases. In this review, we discuss the mechanisms of the microbiota–gut–brain axis in neurodegenerative diseases. As the gut microbiome provides essential cues to microglia, astrocytes, and oligodendrocytes, we examine the communications between gut microbiota and these glial cells during healthy states and neurodegenerative diseases. Subsequently, we discuss the mechanisms of the microbiota–gut–brain axis in neurodegenerative diseases using a metabolite-centric approach, while also examining the role of gut microbiota-related neurotransmitters and gut hormones. Next, we examine the potential of targeting the intestinal barrier, blood–brain barrier, meninges, and peripheral immune system to counteract glial dysfunction in neurodegeneration. Finally, we conclude by assessing the pre-clinical and clinical evidence of probiotics, prebiotics, and fecal microbiota transplantation in neurodegenerative diseases. A thorough comprehension of the microbiota–gut–brain axis will foster the development of effective therapeutic interventions for the management of neurodegenerative diseases.

Supercritical fluid technologies offer a propitious method for drug discovery from natural sources. Such methods require relatively short processing times, produce extracts with little or no organic co-solvent, and are able to extract bioactive molecules whilst minimising degradation. Supercritical fluid extraction (SFE) provides a range of benefits, as well as offering routes to overcome some of the limitations that exist with the conventional methods of extraction. Unfortunately, SFE-based methods are not without their own shortcomings; two major ones being: (1) the high establishment cost; and (2) the selective solvent nature of CO₂, i.e., that CO₂ only dissolves small non-polar molecules, although this can be viewed as a positive outcome provided bioactive molecules are extracted during solvent-based SFE. This review provides an update of SFE methods for natural products and outlines the main operating parameters for extract recovery. Selected processing considerations are presented regarding supercritical fluids and the development and application of ultrasonic-assisted SFE methods, as well as providing some of the key aspects of SFE scalability.

Oxidative stress is a result of disruption in the balance between antioxidants and pro-oxidants in which subsequently impacting on redox signaling, causing cell and tissue damages. It leads to a range of medical conditions including inflammation, skin aging, impaired wound healing, chronic diseases and cancers but these conditions can be managed properly with the aid of antioxidants. This review features various studies to provide an overview on how Carica papaya help counteract oxidative stress via various mechanisms of action closely related to its antioxidant properties and eventually improving the management of various oxidative stress-related health conditions. Carica papaya is a topical plant species discovered to contain high amounts of natural antioxidants that can usually be found in their leaves, fruits and seeds. It contains various chemical compounds demonstrate significant antioxidant properties including caffeic acid, myricetin, rutin, quercetin, α-tocopherol, papain, benzyl isothiocyanate (BiTC), and kaempferol. Therefore, it can counteract pro-oxidants via a number of signaling pathways that either promote the expression of antioxidant enzymes or reduce ROS production. These signaling pathways activate the antioxidant defense mechanisms that protect the body against both intrinsic and extrinsic oxidative stress. To conclude, Carica papaya can be incorporated into medications or supplements to help manage the health conditions driven by oxidative stress and further studies are needed to investigate the potential of its chemical components to manage various chronic diseases.

The shrimp farming industry is receiving increasing attention globally. However, extending the frontiers of the industry has been a challenge as high stocking density often increases susceptibility to diseases and compromises shrimp quality. There has been a huge adoption of bacterial‐derived additives in recent decades, particularly in Asia. Accumulating evidence demonstrates the modulatory effect of these functional additives on the animal gut microbiota composition, thus making them potential alternatives to antibiotics in controlling infectious diseases, such as acute hepatopancreatic necrosis disease (AHPND). These functional additives could be introduced in various forms, such as probiotics, synbiotics, paraprobiotics, and postbiotics. This article aims to critically review previous studies that investigated the effects of these bacterial derivatives, particularly on shrimp species. The surge of research in recent years indirectly attested to the immense potentialities of these functional additives. Generally, the introduction of bacterial derivatives not only helped in disease control but also demonstrated encouraging outcomes, including better survival rate, immune enhancement, and growth promotion effects. It is interesting to note that the effectiveness of probiotics extended beyond the viability of the bacteria, thus leading to concepts such as paraprobiotics and postbiotics. Although this is a relatively new research area with limited information, this review aims to consolidate available data and provide a comprehensive overview of the state of the art of this research arena. The challenges in each research domain were also discussed towards the end of this review to provide insights into potential future research niches.