Phytochemicals, Antioxidant Activities, and Toxicological Screening of Native Australian Fruits Using Zebrafish Embryonic Model

Toxicological screening of jambolan hydroalcoholic extract (Syzygium cumini (L.) Skeels) in zebrafish (Danio rerio)

Jambolan (Syzygium cumini (L.) Skeels) is an important source of phenolic compounds, especially anthocyanins, known for their biological properties. This study investigated the acute toxicity of jambolan hydroalcoholic extract (JE) in zebrafish (Danio rerio) at different life stages. JE, obtained from freeze-dried fruits, was analyzed by high-performance liquid chromatography (HPLC) and found to be rich in total phenolic compounds (TPC). A total of 15 phenolic compounds were identified in the HPLC extracts, mainly anthocyanins (≈ 82 % of TPC), and JE presented relevant antioxidant properties in in vitro tests. Exposure to concentrations between 50 and 200 µg/ml resulted in increased malformations and mortality in both embryos and adult zebrafish, and doses of 300 and 400 µg/ml were lethal to the animals. Lethal concentrations (LC50) were estimated at 118.4 µg/ml for embryos and 68.86 µg/ml for adults. Despite no significant cardiovascular or neurological toxicities, behavioral impacts were observed at lower concentrations (10 µg/ml), indicating a nonmonotonic concentration-response curve. Our findings suggest that moderate JE doses (around 25 µg/ml) are safe for zebrafish; however, further studies are needed to ensure its safety and efficacy under different health conditions and exposure regimes.

Phytoceutical isoquercitrin and ethanolic extracts from pequi (Caryocar coriaceum Wittm) reverse alcohol withdrawal-induced anxiety in adult zebrafish (Danio rerio)

Pharmacotherapy in Alcohol Withdrawal Syndrome (AWS), which is a mental disorder, generally involves benzodiazepines due to their action via GABA, but their side effects, such as excessive sedation, mental confusion and risk of dependence, are considerable. It is important to investigate the anxiolytic potential of plants such as Caryocar coriaceum, due to the presence of secondary metabolic compounds, such as isoquercitrin, capable of promoting the reduction of anxiety during AWS. We evaluated the anxiolytic-like potential of ethanolic extracts from the leaves (EEPL) and pulp (EEPP) of C. coriaceum, and its major compound, isoquercitrin (IsoQuer), in adult zebrafish (Danio rerio) during alcohol withdrawal. Adult zebrafish (n = 8 per group) were treated (20 µL; p.o) with EEPL, or EEPP or IsoQuer (0.01 or 0.05 or 0.1 or 0.5 or 1.0 mg/mL) and submitted to the 96-hour acute toxicity test. Flumazenil in adult zebrafish and molecular Docking of IsoQuer were used to investigate the GABAergic involvement. Finally, the anxiolytic-like activity was evaluated during alcohol withdrawal in adult zebrafish. The results indicated that EEPL, EEPP and IsoQuer are safe and have no sedative effect on adult zebrafish. Furthermore, they demonstrated a pharmacological potential in the treatment of alcohol withdrawal-induced anxiety, mediated by the GABAergic system, evidenced in the in-silico study by the stable isoquercitrin-GABAA complex, the main constituent of the extracts. These findings suggest an anxiolytic herbal potential of C. coriaceum and isoquercitrin, providing an alternative for the treatment of anxiety associated with AWS.

A review on the role of deep eutectic solvents in mango (Mangifera indica) extraction

The present review attempts to evaluate the applicability of deep eutectic solvents (DES) as a green technique for the extraction of phytochemicals from Mangifera indica L. and their therapeutic potential. Mango has been reported to show numerous therapeutic activities, which are attributed to its abundant source of bioactive compounds. Thus, the therapeutic potential of phytochemicals in mangoes is reviewed based on different reported bioactivity tests. The use of DESs is considered a green approach for the extraction of bioactive compounds from natural sources utilizing two or more components and a safe alternative for application in the nutritional, pharmaceutical and other sectors. The trends in the extraction of phytochemicals from mango using different DES components and different extraction parameters of the optimum protocol are reviewed. Hence, DESs are considered potential solvents with selective and efficient properties for extracting bioactive ingredients from mango. However, there are several knowledge gaps that need to be assessed for DES-based bioactive compound extraction from mango such as information on the local and specific varieties of mangoes, standardization of the extraction protocols and use of other parts of the mango plant as alternatives to its peel as bioactive sources. Accordingly, the extraction of bioactive compounds from mango using DESs will provide useful information for subsequent agricultural, pharmaceutical and nutraceutical applications in the future.

Phytochemical Composition and Toxicological Screening of Anise Myrtle and Lemon Myrtle Using Zebrafish Larvae

Plants are an immense source of drugs, and 50% of modern pharmacopeia has a plant origin. With increasing life expectancy in humans, many age-related degenerative diseases converge on oxidative cellular stress pathways. This provides an opportunity to develop broad treatments by targeting the cause of common pathologic cell degeneration. Toxicological effects can be readily assessed in a live animal model system to establish potential fauna for clinical use. Here, we characterized and evaluated the antioxidant potential and toxicological effects of anise myrtle (Syzygium anisatum) and lemon myrtle (Backhousia citriodora) leaves. Using zebrafish larvae, a model for high-throughput pre-clinical in vivo toxicology screening, we identified safe levels of extract exposures for development of future therapeutics. The antioxidant capacity and toxicity were very similar in these two myrtles. The LC50-96h for anise myrtle was 284 mg/L, and for lemon myrtle, it was 270 mg/L. These measurements are comparable to ongoing studies we are performing using the same criteria in zebrafish, which allow for robust testing and prioritization of natural fauna for drug development.

Astragalin from Thesium chinense: A Novel Anti-Aging and Antioxidant Agent Targeting IGFR/CD38/Sirtuins

Astragalin (AG), a typical flavonoid found in Thesium chinense Turcz (T. chinense), is abundant in various edible plants and possesses high nutritional value, as well as antioxidant and antibacterial effects. In this study, we initially predicted the mechanism of action of AG with two anti-aging and antioxidant-related protein targets (CD38 and IGFR) by molecular docking and molecular dynamics simulation techniques. Subsequently, we examined the anti-aging effects of AG in Caenorhabditis elegans (C. elegans), the antioxidant effects in zebrafish, and verified the related molecular mechanisms. In C. elegans, AG synergistically extended the lifespan of C. elegans by up-regulating the expression of daf-16 through inhibiting the expression of daf-2/IGFR and also activating the AMPK and MAPK pathways to up-regulate the expression of sir-2.1, sir-2.4, and skn-1. In oxidatively damaged zebrafish embryos, AG demonstrated a synergistic effect in augmenting the resistance of zebrafish embryos to oxidative stress by up-regulating the expression levels of SIRT1 and SIRT6 within the zebrafish embryos system via the suppression of CD38 enzymatic activity and then inhibiting the expression of IGFR through high levels of SIRT6. These findings highlight the antioxidant and anti-aging properties of AG and indicate its potential application as a supplementary ingredient in aquaculture for enhancing fish health and growth.

Comparative Study of Condensed and Hydrolysable Tannins during the Early Stages of Zebrafish Development

In this study, we present data on the effects of condensed tannins (CTs) and hydrolysable tannins (HTs), polyphenols extracted from plants, at different concentrations on zebrafish development to identify the range of concentrations with toxic effects. Zebrafish embryos were exposed to CTs and HTs at two different concentration ranges (5.0-20.0 μgL-1 and 5.0-20.0 mgL-1) for 72 h. The toxicity parameters were observed up to 72 h of treatment. The uptake of CTs and HTs by the zebrafish larvae was assessed via HPLC analysis. A qRT-PCR analysis was performed to evaluate the expressions of genes cd63, zhe1, and klf4, involved in the hatching process of zebrafish. CTs and HTs at 5.0, 10.0, and 20.0 μgL-1 were not toxic. On the contrary, at 5.0, 10.0, and 20.0 mgL-1, HTs induced a delay in hatching starting from 48 h of treatment, while CTs showed a delay in hatching mainly at 48 h. The analysis of gene expression showed a downregulation in the group exposed to HTs, confirming the hatching data. We believe that this study is important for defining the optimal doses of CTs and HTs to be employed in different application fields such as the chemical industry, the animal feed industry, and medical science.

LC-ESI-QTOF-MS/MS Identification and Characterization of Phenolic Compounds from Leaves of Australian Myrtles and Their Antioxidant Activities

Phenolic compounds, present in plants, provide substantial health advantages, such as antioxidant and anti-inflammatory properties, which enhance cardiovascular and cognitive well-being. Australia is enriched with a wide range of plants with phytopharmacological potential, which needs to be fully elucidated. In this context, we analyzed leaves of aniseed myrtle (Syzygium anisatum), lemon myrtle (Backhousia citriodora), and cinnamon myrtle (Backhousia myrtifolia) for their complex phytochemical profile and antioxidant potential. LC-ESI-QTOF-MS/MS was applied for screening and characterizing these Australian myrtles' phenolic compounds and the structure-function relation of phenolic compounds. This study identified 145 and quantified/semi-quantified 27 phenolic compounds in these Australian myrtles. Furthermore, phenolic contents (total phenolic content (TPC), total condensed tannins (TCT), and total flavonoids (TFC)) and antioxidant potential of phenolic extracts from the leaves of Australian myrtles were quantified. Aniseed myrtle was quantified with the highest TPC (52.49 ± 3.55 mg GAE/g) and total antioxidant potential than other selected myrtles. Catechin, epicatechin, isovitexin, cinnamic acid, and quercetin were quantified as Australian myrtles' most abundant phenolic compounds. Moreover, chemometric analysis further validated the results. This study provides a new insight into the novel potent bioactive phenolic compounds from Australian myrtles that could be potentially useful for functional, nutraceutical, and therapeutic applications.

Screening and Characterization of Phenolic Compounds from Selected Unripe Fruits and Their Antioxidant Potential

The food sector's interest in sustainability and the demand for novel bioactive compounds are increasing. Many fruits are wasted every year before ripening due to various climatic conditions and harsh weather. Unripe mangoes, grapes, and black lemons could be rich sources of phenolic compounds that need to be fully elucidated. Using fruit waste as a source of bioactive chemicals has grown increasingly appealing as it may have significant economic benefits. Polyphenols are beneficial for human health to inhibit or minimize oxidative stress and can be used to develop functional and nutraceutical food products. In this context, this study aimed to characterize and screen unripe mangoes, grapes, and black lemons for phenolic compounds using LC-ESI-QTOF-MS/MS and their antioxidant activities. Unripe mangoes were quantified with higher total phenolic content (TPC, 58.01 ± 6.37 mg GAE/g) compared to black lemon (23.08 ± 2.28 mg GAE/g) and unripe grapes (19.42 ± 1.16 mg GAE/g). Furthermore, unripe mangoes were also measured with higher antioxidant potential than unripe grapes and black lemons. A total of 85 phenolic compounds (70 in black lemons, 49 in unripe grapes, and 68 in unripe mango) were identified, and 23 phenolic compounds were quantified using LC-MS/MS. Procyanidin B2, gallic acid, epicatechin, caffeic acid, quercetin, and chlorogenic acid were measured with higher concentration in these selected unripe fruits. A positive correlation was found between phenolic contents and the antioxidant activities of unripe fruits. Furthermore, chemometric analysis was conducted to validate the results. This study will explore the utilization of these unripe fruits to develop functional and therapeutic foods.

Optimized Extraction of Polyphenols from Unconventional Edible Plants: LC-MS/MS Profiling of Polyphenols, Biological Functions, Molecular Docking, and Pharmacokinetics Study

Plant bioactive phenolic metabolites have recently attracted the attention of researchers due to their numerous health advantages. Therefore, this study aimed to investigate with advanced techniques the bioactive metabolites and antioxidant and antidiabetic capacity of four unconventional edible plant leaves: lemongrass (Cymbopogon citratus (DC.) Stapf), chicory (Cichorium intybus L.), moringa (Moringa oleifera Lam.), and ryegrass (Lolium perenne L.). The extraction process was optimized using different solvents. These plants' phenolic composition, identification, and characterization have been determined herein using LCESI-QTOF-MS/MS. This research identified 85 phenolic compounds, including 24 phenolic acids, 31 flavonoids, 7 stilbenes and lignans, and 17 other metabolites. Moreover, the study determined that moringa has the highest total phenolic content (TPC; 18.5 ± 1.01 mg GAE/g), whereas ryegrass has the lowest (3.54 ± 0.08 mg GAE/g) among the selected plants. It seems that, compared to other plants, moringa was found to have the highest antioxidant potential and antidiabetic potential. In addition, twenty-two phenolic compounds were quantified in these chosen edible plants. Rosmarinic acid, chlorogenic acid, chicoric acid, ferulic acid, protocatechuic acid, and caffeic acid were the most abundant phenolic acids. In silico molecular docking was also conducted to investigate the structure-function relationship of phenolic compounds to inhibit the alpha-glucosidase. Finally, the simulated pharmacokinetic characteristics of the most common substances were also predicted. In short, this investigation opens the way for further study into these plants' pharmaceutical and dietary potential.

Characterization, Antioxidant Potential, and Pharmacokinetics Properties of Phenolic Compounds from Native Australian Herbs and Fruits

In recent decades, plant bioactive phenolic compounds gained much attention due to their various health benefits. Therefore, this study aimed to analyze native Australian river mint (Mentha australis), bush mint (Mentha satureioides), sea parsley (Apium prostratum), and bush tomatoes (Solanum centrale) for their bioactive metabolites, antioxidant potential, and pharmacokinetics properties. LC-ESI-QTOF-MS/MS was applied to elucidate these plants' composition, identification, and quantification of phenolic metabolites. This study tentatively identified 123 phenolic compounds (thirty-five phenolic acids, sixty-seven flavonoids, seven lignans, three stilbenes, and eleven other compounds). Bush mint was identified with the highest total phenolic content (TPC-57.70 ± 4.57 mg GAE/g), while sea parsley contained the lowest total phenolic content (13.44 ± 0.39 mg GAE/g). Moreover, bush mint was also identified with the highest antioxidant potential compared to other herbs. Thirty-seven phenolic metabolites were semi-quantified, including rosmarinic acid, chlorogenic acid, sagerinic acid, quinic acid, and caffeic acid, which were abundant in these selected plants. The most abundant compounds' pharmacokinetics properties were also predicted. This study will develop further research to identify these plants' nutraceutical and phytopharmaceutical potential.

Antioxidant, Alpha-Glucosidase Inhibition Activities, In Silico Molecular Docking and Pharmacokinetics Study of Phenolic Compounds from Native Australian Fruits and Spices

Native Australian fruits and spices are enriched with beneficial phytochemicals, especially phenolic compounds, which are not fully elucidated. Therefore, this study aimed to analyze native Australian mountain-pepper berries (Tasmannia lanceolata), rosella (Hibiscus sabdariffa), lemon aspen (Acronychia acidula), and strawberry gum (Eucalyptus olida) for phenolic and non-phenolic metabolites and their antioxidant and alpha-glucosidase inhibition activities. Liquid chromatography-mass spectrometry-electrospray ionization coupled with quadrupole time of flight (LC-ESI-QTOF-MS/MS) was applied to elucidate the composition, identities, and quantities of bioactive phenolic metabolites in Australian native commercial fruits and spices. This study identified 143 phenolic compounds, including 31 phenolic acids, 70 flavonoids, 10 isoflavonoids, 7 tannins, 3 stilbenes, 7 lignans, 10 other compounds, and 5 limonoids. Strawberry gum was found to have the highest total phenolic content (TPC-36.57 ± 1.34 milligram gallic acid equivalent per gram (mg GAE/g), whereas lemon aspen contained the least TPC (4.40 ± 0.38 mg GAE/g). Moreover, strawberry gum and mountain pepper berries were found to have the highest antioxidant and anti-diabetic potential. In silico molecular docking and pharmacokinetics screening were also conducted to predict the potential of the most abundant phenolic compounds in these selected plants. A positive correlation was observed between phenolic contents and biological activities. This study will encourage further research to identify the nutraceutical and phytopharmaceutical potential of these native Australian fruits.