Solventless extraction methods for immature fruits: Evaluation of their antioxidant and cytoprotective activities

Green Extraction of Orange Peel Waste Reduces TNFα-Induced Vascular Inflammation and Endothelial Dysfunction

Orange peel waste (OPW) is known to contain an abundant amount of polyphenols compounds such as flavonoids, well-reported for their antioxidant and anti-inflammatory properties. While OPW is generally regarded as a food waste, the opportunity to extract bioactive compounds from these “wastes” arises due to their abundance, allowing the investigation of their potential effects on endothelial cells. Hence, this study aims to use a green extraction method and pressurized hot water extraction (PHWE) to extract bioactive compounds from OPW. Liquid chromatography with UV detection (LC/UV) and liquid chromatography mass spectrometry (LC/MS) were subsequently used to identify the bioactive compounds present. Through the optimization of the extraction temperature for PHWE, our results demonstrated that extraction temperatures of 60 °C and 80 °C yield distinct bioactive compounds and resulted in better antioxidant capacity compared to other extraction temperatures or organic solvent extraction. Despite having similar antioxidant capacity, their effects on endothelial cells were distinct. Specifically, treatment of endothelial cells with 60 °C OPW extracts inhibited TNFα-induced vascular inflammation and endothelial dysfunction in vitro, suggesting that OPW possess vasoprotective effects likely mediated by anti-inflammatory effects.

Valorization of avocado seeds with antioxidant capacity using pressurized hot water extraction

The pulp of avocado (Persea Americana) is widely consumed as the primary food source, while the seed is often discarded as food waste. Increased consumption of avocado would inevitably results in production of waste by-products such as avocado seeds, hence the ability to extract phytochemicals from such waste, and upcycling to potential nutraceutical products is of great interest. The overall aim of this study is to explore avocado seeds as potential functional food through the combined use of a green extraction method, chemical standardization and pattern recognition tools, and biological characterization assays. Specifically, this study utilized an organic solvent-free extraction method, pressurized hot water extraction (PHWE) to extract phytochemicals from avocado seeds and liquid chromatography mass spectrometry (LCMS) was used to identify the phytochemicals present in the avocado seeds. Our results demonstrated that avocado seed extracts have antioxidant activity and inhibited oxidative stress-induced metabolomics changes in endothelial cells, suggesting that avocado seed extracts have vasoprotective actions.

Nutritional status, antioxidant activity and total phenolic content of different fruits and vegetables' peels

The present study assessed nutritional status, antioxidant activity, and total phenolic content in fruits, i.e., mango (Mangifera indica), apple (Malus domestica), and vegetable, i.e., bottle gourd (Lagenaria siceraria), and ridge gourd (Luffa acutangula) peels. The antioxidant activity and total phenolic content (TPC) were evaluated by using methanol extracts along with 2, 2-diphenyl-1-picrylhydrazyl (DPPH), Folin-Ciocalteu (FC) assay, respectively having Butylated hydroxytoluene (BHT) and Gallic acid (GA) as standard. The TPC and antioxidant activity in the peels ranged from 20 mg GAE/g to 525 mg GAE/g and 15.02% to 75.95%, respectively, which revealed that investigated fruit and vegetable peels are rich source of phytochemical constituents. Bottle gourd peels exhibited the highest value of DPPH compared to the rest of the peels included in the study. Likewise, mango peels had the highest TPC as compared to the rest of the fruit peels. This research showed that the utilization of agricultural wastes should be promoted at commercial level to achieve the nutritional benefit at zero cost and minimize the generation of biological waste.

Insights into the release mechanisms of antioxidants from nanoemulsion droplets

The therapeutic effects of antioxidant-loaded nanoemulsion can be often optimized by controlling the release rate in human body. Release kinetic models can be used to predict the release profile of antioxidant compounds and allow identification of key parameters that affect the release rate. It is known that one of the critical aspects in establishing a reliable release kinetic model is to understand the underlying release mechanisms. Presently, the underlying release mechanisms of antioxidants from nanoemulsion droplets are not yet fully understood. In this context, this review scrutinized the current formulation strategies to encapsulate antioxidant compounds and provide an outlook into the future of this research area by elucidating possible release mechanisms of antioxidant compounds from nanoemulsion system.

Protein Hydrolysis by Subcritical Water: A New Perspective on Obtaining Bioactive Peptides

The importance of bioactive peptides lies in their diverse applications in the pharmaceutical and food industries. In addition, they have been projected as allies in the control and prevention of certain diseases due to their associated antioxidant, antihypertensive, or hypoglycemic activities, just to mention a few. Obtaining these peptides has been performed traditionally by fermentation processes or enzymatic hydrolysis. In recent years, the use of supercritical fluid technology, specifically subcritical water (SW), has been positioned as an efficient and sustainable alternative to obtain peptides from various protein sources. This review presents and discusses updated research reports on the use of subcritical water to obtain bioactive peptides, its hydrolysis mechanism, and the experimental designs used for the study of effects from factors involved in the hydrolysis process. The aim was to promote obtaining peptides by green technology and to clarify perspectives that still need to be explored in the use of subcritical water in protein hydrolysis.

Dietary natural products as a potential inhibitor towards advanced glycation end products and hyperglycemic complications: A phytotherapy approaches

Natural products exist in various natural foods such as plants, herbs, fruits, and vegetables. Furthermore, marine life offers potential natural products with significant biological activity. The biochemical reaction is known as advanced glycation end products (AGEs) occurs in the human body. On the other hand, foods are capable of a wide range of processing conditions resulting in the generation of exogenous AGEs adducts. Protein glycation and the formation of advanced glycation end products both contribute to the pathogenesis of hyperglycemic complications. AGEs also play a pivotal role in microvascular and macrovascular complications progression by receptors for advanced glycation end products (RAGE). RAGE activate by AGEs leads to up-regulation of transcriptional factor NF-kB and inflammatory genes. Around the globe, researchers are working in various approaches for therapeutical implications on controlling AGEs mediated disease complications. In this regard, one of the potential promising agents observed with a wide range of AGEs inhibition by food-derived natural products. Current biotechnological tools have been turned to natural products or phytochemicals to manufacture the molecules without compromising their functionality. Metabolic engineering and bioinformatics perspectives have recently enabled the generation of a few potent metabolites with anti-diabetic activity. As the primary focus, this review article will also discuss multidisciplinary approaches that emphasize current advances in anti-diabetic therapeutic action and future perspectives of natural products.

Pressurized Hot Water Extraction of Okra Seeds Reveals Antioxidant, Antidiabetic and Vasoprotective Activities

Abelmoschus esculentus L. Moench (okra) is a commonly consumed vegetable that consists of the seeds and peel component which are rich in polyphenolic compounds. The aim of this study is to utilize pressurized hot water extraction (PHWE) for the extraction of bioactive phytochemicals from different parts of okra. A single step PHWE was performed at various temperatures (60 °C, 80 °C, 100 °C and 120 °C) to determine which extraction temperature exhibits the optimum phytochemical profile, antioxidant and antidiabetic activities. The optimum temperature for PHWE extraction was determined at 80 °C and the biological activities of the different parts of okra (Inner Skin, Outer Skin and Seeds) were characterized using antioxidant (DPPH and ABTS), α-glucosidase and vasoprotective assays. Using PHWE, the different parts of okra displayed distinct phytochemical profiles, which consist of primarily polyphenolic compounds. The okra Seeds were shown to have the most antioxidant capacity and antidiabetic effects compared to other okra parts, likely to be attributed to their higher levels of polyphenolic compounds. Similarly, okra Seeds also reduced vascular inflammation by downregulating TNFα-stimulated VCAM-1 and SELE expression. Furthermore, metabolite profiling by LC/MS also provided evidence of the cytoprotective effect of okra Seeds in endothelial cells. Therefore, the use of PHWE may be an alternative approach for the environmentally friendly extraction and evaluation of plant extracts for functional food applications.

Antioxidant and Cytoprotective Effect of Quinoa (Chenopodium quinoa Willd.) with Pressurized Hot Water Extraction (PHWE)

Quinoa is widely noted for its nutritional value. The seed is the main edible part of the plant and exists in at least three different colors: white, red and black. This study utilized a pressurized hot water extraction (PHWE) for the extraction of phytochemicals from quinoa. Chemical fingerprints with LC/UV and LC/MS using a targeted approach and pattern recognition tools were used to evaluate the quinoa extracts. The antioxidant properties for various types of quinoa were evaluated using DPPH assay, ABTS assay and the cytoprotective effect of quinoa extracts were investigated in HMEC-1 cell line. Distinctive chemical profiles obtained from black and red quinoa were well correlated with the antioxidant activities and cytoprotective effects. The combination of PHWE, chemical standardization with LC/UV and LC/MS, pattern recognition tools and biological assay provided an approach for the evaluation and eventual production of quinoa extracts for functional food.

A Glimpse into the Extraction Methods of Active Compounds from Plants

Naturally active compounds are usually contained inside plants and materials thereof. Thus, the extraction of the active compounds from plants needs appropriate extraction methods. The commonly employed extraction methods are mostly based on solid-liquid extraction. Frequently used conventional extraction methods such as maceration, heat-assisted extraction, Soxhlet extraction, and hydrodistillation are often criticized for large solvent consumption and long extraction times. Therefore, many advanced extraction methods incorporating various technologies such as ultrasound, microwaves, high pressure, high voltage, enzyme hydrolysis, innovative solvent systems, adsorption, and mechanical forces have been studied. These advanced extraction methods are often better than conventional methods in terms of higher yields, higher selectivity, lower solvent consumption, shorter processing time, better energy efficiency, and potential to avoid organic solvents. They are usually designed to be greener, more sustainable, and environment friendly. In this review, we have critically described recently developed extraction methods pertaining to obtaining active compounds from plants and materials thereof. Main factors that affect the extraction performances are tuned, and extraction methods are chosen in line with the properties of targeted active compounds or the objectives of extraction. The review also highlights the advancements in extraction procedures by using combinations of extraction methods to obtain high overall yields or high purity extracts.

Pear Extract and Malaxinic Acid Reverse Obesity, Adipose Tissue Inflammation, and Hepatosteatosis in Mice

SCOPE

Obesity and diabetes are major public health problems and are emerging as pandemics. Considerable evidence suggests that pear fruit consumption is associated with a lower risk of obesity-related complications. Thus, the present study is conducted to investigate the therapeutic potential of pear extract (PE) for reversing obesity and associated metabolic complications in high-fat diet-induced obese mice.

METHODS AND RESULTS

Obesity is induced in male C57BL/6 mice fed a high-fat diet for 11 weeks. After the first 6 weeks on the diet, obese mice are administered vehicle or PE for 5 weeks. PE treatment decreases body weight gain, expands white adipose tissue (WAT), and causes hepatic steatosis in obese mice, as well as inhibits adipogenesis and lipogenesis. Impaired glucose tolerance and insulin resistance are improved by PE. In addition, PE reduces macrophage infiltration and expression of pro-inflammatory genes and deactivates mitogen-activated protein kinases in WAT. Finally, malaxinic acid is identified as an active component responsible for the anti-obesity effects of PE in mice.

CONCLUSION

The results demonstrate that PE supplementation ameliorates diet-induced obesity and associated metabolic complications and suggest the health-beneficial effects of both pear fruits and malaxinic acid in counteracting these diseases.

A comparative study on subacute toxicity of arsenic trioxide and dimethylarsinic acid on antioxidant status in Crandell Rees feline kidney (CRFK), human hepatocellular carcinoma (PLC/PRF/5), and epithelioma papulosum cyprini (EPC) cell lines

Arsenic (As) is a global contaminant of terrestrial and aquatic environments posing concern for environmental and human health. The effects of subacute concentrations of arsenic trioxide (As^III) and dimethylarsinic acid (DMA^V) were examined using Crandell Rees feline kidney (CRFK), human hepatocellular carcinoma (PLC/PRF/5), and epithelioma papulosum cyprini (EPC). Whole monolayer with suffering cells (confluence 100%, pyknosis and refractive cells; value scale = 2) led to identification of subacute As concentrations for the three cell lines. The selected As^III concentrations were 1.33 µM for CRFK and 33.37 µM for PLC/PRF/5 and EPC, at 48 hr time point. The selected DMA^V concentrations were 0.67 mM for PLC/PRF/5, 1.33 mM for CRFK, and 2.67 mM for EPC for 48 hr. Unlike the As^III test, the three cell lines did not exhibit marked susceptibility to DMA^V-mediated toxicity. Several oxidative stress biomarker levels, directly or indirectly associated with reactive oxygen species (ROS) elimination including superoxide dismutase, catalase, glutathione peroxidases, glutathione reductase, glutathione S-transferase, glyoxalase I, glyoxalase II, and total glutathione, were determined in the three cell lines at 24 and 48 hr. Antioxidant responses in metal-treated cells were significantly altered compared to controls, suggesting a perturbation of redox state. The weakening of antioxidant pathway in either healthy or tumoral cells was greater using As^III than DMA^V. Differences in level of several oxidative stress biomarkers suggest that the oxidative stress mechanism induced by As^III is distinctly different from DMA^V. Multifaceted mechanisms of action underlying ROS generation in tumor and nontumor cells versus As^III and DMA^V exposure are thus involved. Since As-mediated toxicity is quite complex, more data regarding both oxidant-enhancement and oxidant-lowering strategies may be useful to improve knowledge regarding the influence of As on human and animal cells.