Assessing the Acute Toxicological Effects of Annona muricata Leaf Ethanol Extract on Rats: Biochemical, Histopathological, and Metabolomics Analyses

Annona muricata is a common plant used in Africa and South America to manage various types of disease. However, there is insufficient toxicological information or published standard available regarding repeated dose animal toxicity data. As part of the safety assessment, we exposed Sprague Dawley rats to an acute oral toxicity of A. muricata. The intent of the current study was to use advanced proton nuclear magnetic resonance (1H NMR) in serum and urinary metabolomics evaluation techniques to provide the in vivo acute toxicological profile of A. muricata leaf ethanol extract in accordance with the Organization for Economic Co-operation and Development's (OECD) 423 guidelines. A single 2000 mg/kg dose of A. muricata leaf ethanol extract was administered to Sprague Dawley rats over an observational period of 14 days. The toxicity evaluation (physical and behavior observation, body weight, renal function test, liver function test and 1H NMR analysis) showed no abnormal toxicity. Histopathological analysis manifested mild changes, i.e., the treated kidney manifested mild hypercellularity of mesangial cells and mild red blood cell congestion. In addition, there was mild hemorrhage into tissue with scattered inflammatory cells and mild dilated central vein with fibrosis in the liver. However, the changes were very mild and not significant which correlate with other analyses conducted in this study (biochemical test and 1H NMR metabolomic analysis). On the other hand, urinary 1H NMR analysis collected on day 15 revealed high similarity on the metabolite variations for both untreated and treated groups. Importantly, the outcomes suggest that A. muricata leaf ethanol extract can be safely consumed at a dose of 2000 mg/kg and the LD50 must be more than 2000 mg/kg.

A comprehensive review of drying meat products and the associated effects and changes

Preserving fresh food, such as meat, is significant in the effort of combating global food scarcity. Meat drying is a common way of preserving meat with a rich history in many cultures around the globe. In modern days, dried meat has become a well enjoyed food product in the market because of its long shelf-life, taste and health benefits. This review aims to compile information on how the types of meat, ingredients and the used drying technologies influence the characteristics of dried meat in physicochemical, microbial, biochemical and safety features along with technological future prospects in the dried meat industry. The quality of dried meat can be influenced by a variety of factors, including its production conditions and the major biochemical changes that occur throughout the drying process, which are also discussed in this review. Additionally, the sensory attributes of dried meat are also reviewed, whereby the texture of meat and the preference of the market are emphasized. There are other aspects and concerning issues that are suggested for future studies. It is well-known that reducing the water content in meat helps in preventing microbial growth, which in turn prevents the presence of harmful substances in meat. However, drying the meat can change the characteristics of the meat itself, making consumers concerned on whether dried meat is safe to be consumed on a regular basis. It is important to consider the role of microbial enzymes and microbes in the preservation of their flavor when discussing dried meats and dried meat products. The sensory, microbiological, and safety elements of dried meat are also affected by these distinctive changes, which revolve around customer preferences and health concerns, particularly how drying is efficient in eliminating/reducing hazardous bacteria from the fish. Interestingly, some studies have concentrated on increasing the efficiency of dried meat production to produce a safer range of dried meat products with less effort and time. This review compiled important information from all available online research databases. This review may help the food sector in improving the efficiency and safety of meat drying, reducing food waste, while maintaining the quality and nutritional content of dried meat.

A Comprehensive Review on the Processing of Dried Fish and the Associated Chemical and Nutritional Changes

Fish is a good source of nutrients, although it is easily spoiled. As such, drying is a common method of preserving fish to compensate for its perishability. Dried fish exists in different cultures with varying types of fish used and drying methods. These delicacies are not only consumed for their convenience and for their health benefits, as discussed in this review. Most commonly, salt and spices are added to dried fish to enhance the flavours and to decrease the water activity (aw) of the fish, which further aids the drying process. For fish to be dried effectively, the temperature, drying environment, and time need to be considered along with the butchering method used on the raw fish prior to drying. Considering the various contributing factors, several physicochemical and biochemical changes will certainly occur in the fish. In this review, the pH, water activity (aw), lipid oxidation, and colour changes in fish drying are discussed as well as the proximate composition of dried fish. With these characteristic changes in dried fish, the sensory, microbial and safety aspects of dried fish are also affected, revolving around the preferences of consumers and their health concerns, especially based on how drying is efficient in eliminating/reducing harmful microbes from the fish. Interestingly, several studies have focused on upscaling the efficiency of dried fish production to generate a safer line of dried fish products with less effort and time. An exploratory approach of the published literature was conducted to achieve the purpose of this review. This evaluation gathers important information from all available library databases from 1990 to 2022. In general, this review will benefit the fishery and food industry by enabling them to enhance the efficiency and safety of fish drying, hence minimising food waste without compromising the quality and nutritional values of dried fish.

Srsf7 Establishes the Juvenile Transcriptome through Age-Dependent Alternative Splicing in Mice

The juvenile phase is characterized by continuously progressing physiological processes such as growth and maturation, which are accompanied by transitions in gene expression. The contribution of transcriptome dynamics to the establishment of juvenile properties remains unclear. Here, we investigated alternative splicing (AS) events in postnatal growth and elucidated the landscape of age-dependent alternative splicing (ADAS) in C57BL/6 mice. Our analysis of ADAS in the cerebral cortex, cardiomyocytes, and hepatocytes revealed numerous juvenile-specific splicing isoforms that shape the juvenile transcriptome, which in turn functions as a basis for the highly anabolic status of juvenile cells. Mechanistically, the juvenile-expressed splicing factor Srsf7 mediates ADAS, as exemplified by switching from juvenile to adult forms of anabolism-associated genes Eif4a2 and Rbm7. Suppression of Srsf7 results in “fast-forwarding” of this transcriptome transition, causing impaired anabolism and growth in mice. Thus, juvenile-specific AS is indispensable for the anabolic state of juveniles and differentiates juveniles from adults.

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Age-dependent alternative splicing (ADAS) was determined in mice

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Srsf7 depletion causes loss of cellular juvenescence

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Srsf7 mutation causes a shift from juvenile to adult-type transcriptome

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Srsf7 promotes juvenile growth and anabolism through ADAS

The juvenility-associated long noncoding RNA Gm14230 maintains cellular juvenescence

Juvenile animals possess distinct properties that are missing in adults. These properties include capabilities for higher growth, faster wound healing, plasticity and regeneration. However, the molecular mechanisms underlying these juvenile physiological properties are not fully understood. To obtain insight into the distinctiveness of juveniles from adults at the molecular level, we assessed long noncoding RNAs (lncRNAs) that are highly expressed selectively in juvenile cells. The noncoding elements of the transcriptome were investigated in hepatocytes and cardiomyocytes isolated from juvenile and adult mice. Here, we identified 62 juvenility-associated lncRNAs (JAlncs), which are selectively expressed in both hepatocytes and cardiomyocytes from juvenile mice. Among these common (shared) JAlncs, Gm14230 is evolutionarily conserved and is essential for cellular juvenescence. Loss of Gm14230 impairs cell growth and causes cellular senescence. Gm14230 safeguards cellular juvenescence through recruiting the histone methyltransferase Ezh2 to Tgif2, thereby repressing the functional role of Tgif2 in cellular senescence. Thus, we identify Gm14230 as a juvenility-selective lncRNA required to maintain cellular juvenescence.

Comparable down-regulation of TYR, TYRP1 and TYRP2 genes and inhibition of melanogenesis by tyrostat, tocotrienol-rich fraction and tocopherol in human skin melanocytes improves skin pigmentation

BACKGROUND AND OBJECTIVE

Antioxidant has been recognized to inhibit UV-induced melanogenesis. This study aimed to elucidate the molecular mechanism of tyrostat, tocopherol and tocotrienol-rich fraction in inhibiting melanogenesis in human skin melanocytes.

MATERIALS AND METHODS

Primary culture of melanocytes was exposed to repeated doses of 0.6 J/cm2 UVA for 6 days and treated with tyrostat, tocotrienol-rich fraction or tocopherol alone or in combination.

RESULTS

UVA irradiation increased melanin content and tyrosinase activity and up-regulated TYR, TYRP1 and TYRP2 genes. Treatment with tyrostat, tocotrienol-rich fraction or tocopherol decreased melanin content and down-regulated TYR, TYRP1 and TYRP2 genes with decreased tyrosinase activity. Combined treatment exerted better effects as compared to treatment with single compound in decreasing the melanin content and down-regulating TYR, TYRP1 and TYRP2 genes. These findings indicated that tyrostat, tocotrienol-rich fraction and tocopherol inhibit melanogenesis by modulating the expression of genes involved in the regulation of melanin synthesis and inhibiting tyrosinase activity.

CONCLUSIONS

Tyrostat, tocopherol and tocotrienol-rich fraction possessed anti-melanogenic properties and might be useful in improving skin pigmentation caused by UVA exposure.

Modulation of collagen synthesis and its gene expression in human skin fibroblasts by tocotrienol-rich fraction

INTRODUCTION

Skin aging may occur as a result of increased free radicals in the body. Vitamin E, the major chain-breaking antioxidant, prevents propagation of oxidative stress, especially in biological membranes. In this study, the molecular mechanism of tocotrienol-rich fraction (TRF) in preventing oxidative stress-induced skin aging was evaluated by determining the rate of total collagen synthesis and its gene expression in human skin fibroblasts.

MATERIAL AND METHODS

Primary culture of human skin fibroblasts was derived from circumcision foreskin of 9 to 12 year-old boys. Fibroblast cells were divided into 5 different treatment groups: untreated control, hydrogen peroxide (H(2)O(2))-induced oxidative stress (20 µM H(2)O(2) exposure for 2 weeks), TRF treatment, and pre- and post-treatment of TRF to H(2)O(2)-induced oxidative stress.

RESULTS

Our results showed that H(2)O(2)-induced oxidative stress decreased the rate of total collagen synthesis and down-regulated COL I and COL III in skin fibroblasts. Pre-treatment of TRF protected against H(2)O(2)-induced oxidative stress as shown by increase in total collagen synthesis and up-regulation of COL I and COL III (p<0.05) genes. However, similar protective effects against H(2)O(2)-induced oxidative stress were not observed in the post-treated fibroblasts.

CONCLUSIONS

Tocotrienol-rich fraction protects against H(2)O(2)-induced oxidative stress in human skin fibroblast culture by modulating the expression of COL I and COL III genes with concomitant increase in the rate of total collagen synthesis. These findings may indicate TRF protection against oxidative stress-induced skin aging.