Comparative evaluation of hepatoprotective activity of carotenoids of microalgae

Innovative Bioactive Products with Medicinal Value from Microalgae and Their Overall Process Optimization through the Implementation of Life Cycle Analysis-An Overview

Microalgae are being recognized as valuable sources of bioactive chemicals with important medical properties, attracting interest from multiple industries, such as food, feed, cosmetics, and medicines. This review study explores the extensive research on identifying important bioactive chemicals from microalgae, and choosing the best strains for nutraceutical manufacturing. It explores the most recent developments in recovery and formulation strategies for creating stable, high-purity, and quality end products for various industrial uses. This paper stresses the significance of using Life Cycle Analysis (LCA) as a strategic tool with which to improve the entire process. By incorporating LCA into decision-making processes, researchers and industry stakeholders can assess the environmental impact, cost-effectiveness, and sustainability of raw materials of several approaches. This comprehensive strategy will allow for the choosing of the most effective techniques, which in turn will promote sustainable practices for developing microalgae-based products. This review offers a detailed analysis of the bioactive compounds, strain selection methods, advanced processing techniques, and the incorporation of LCA. It will serve as a valuable resource for researchers and industry experts interested in utilizing microalgae for producing bioactive products with medicinal properties.

Effect of the Emulsifier Used in Dunaliella salina-Based Nanoemulsions Formulation on the β-Carotene Absorption and Metabolism in Rats

SCOPE

Microalgae such as Dunaliella salina are a potential sustainable source of natural β-carotene due to their fast growth and high adaptability to environmental conditions. This work aims to evaluate the effect of the incorporation of β-carotene from this alga into different emulsifier-type nanoemulsions (soybean lecithin [SBL], whey protein isolate [WPI], sodium caseinate [SDC]) on its absorption, metabolization, and biodistribution in rats.

METHODS AND RESULTS

Nanoemulsions formulated with different emulsifiers at 8% concentration are obtained by five cycles of microfluidization at 130 mPa, then expose to an in vitro digestion or orally administer to rats. Feeding rats with nanoemulsions improves β-carotene uptake compared to control suspension, especially using SDC and WPI as emulsifiers. A greater presence of β-carotene and retinol in the intestine, plasma, and liver is observed, being the liver the tissue that shows the highest accumulation. This fact can be a consequence of the smaller droplets that protein-nanoemulsions present compared to that with SBL in the intestine of rats, which promote faster digestibility and higher β-carotene bioaccessibility (35%-50% more) according to the in vitro observations.

CONCLUSIONS

Nanoemulsions, especially those formulated with protein emulsifiers, are effective systems for increasing β-carotene absorption, as well as retinol concentration in different rat tissues.

The Extraction of β-Carotene from Microalgae for Testing Their Health Benefits

β-carotene, a member of the carotenoid family, is a provitamin A, and can be converted into vitamin A (retinol), which plays essential roles in the regulation of physiological functions in animal bodies. Microalgae synthesize a variety of carotenoids including β-carotene and are a rich source of natural β-carotene. This has attracted the attention of researchers in academia and the biotech industry. Methods to enrich or purify β-carotene from microalgae have been investigated, and experiments to understand the biological functions of microalgae products containing β-carotene have been conducted. To better understand the use of microalgae to produce β-carotene and other carotenoids, we have searched PubMed in August 2021 for the recent studies that are focused on microalgae carotenoid content, the extraction methods to produce β-carotene from microalgae, and the bioactivities of β-carotene from microalgae. Articles published in peer-reviewed scientific journals were identified, screened, and summarized here. So far, various types and amounts of carotenoids have been identified and extracted in different types of microalgae. Diverse methods have been developed overtime to extract β-carotene efficiently and practically from microalgae for mass production. It appears that methods have been developed to simplify the steps and extract β-carotene directly and efficiently. Multiple studies have shown that extracts or whole organism of microalgae containing β-carotene have activities to promote lifespan in lab animals and reduce oxidative stress in culture cells, etc. Nevertheless, more studies are warranted to study the health benefits and functional mechanisms of β-carotene in these microalgae extracts, which may benefit human and animal health in the future.

Hepatoprotective efficacy of Spirulina platensis against lead-induced oxidative stress and genotoxicity in catfish; Clarias gariepinus

Lead (Pb) is a toxic environmental pollutant that induces a broad range of biochemical and physiological hazards in living organisms. We investigated the possible hepatoprotective effects of Spirulina platensis (SP) in counteracting the Pb-induced oxidative damage. Ninety-six adult African catfish were allocated into four equal groups. The 1st group (control) fed basal diet while the 2nd group (Pb-treated) fed on basal diet and exposed to 1mg Pb(NO₃)₂/L. The 3rd and 4th groups fed SP-supplemented basal diets at levels of 0.25% and 0.5%, respectively and exposed to Pb. Serum samples were used to analyze hepatic function biomarkers, electrolytes, and oxidant and antioxidant status. Lipid peroxidation and DNA fragmentation were determined in the liver tissues. Pb exposure induced hepatic dysfunction, electrolytes (Na⁺, K⁺, Ca⁺², and Cl^-) imbalance, as well a significant decrease in GSH content, and LDH, AChE, SOD, CAT and GST enzymes activity. SP supplementation reverted these biochemical and genetic alterations close to control levels. This amelioration was higher with 0.5% SP and at the 4th week of exposure, showing concentration- and time-dependency. Thus, the current study suggests that SP could protect the catfish liver against lead-induced injury by scavenging ROS, sustaining the antioxidant status and diminishing DNA oxidative damage. The dietary inclusion of SP can be used as a promising protective agent to counteract oxidative stress-mediated diseases and toxicities.

Evaluation of hepatoprotective and antioxidant activity of astaxanthin and astaxanthin esters from microalga-Haematococcus pluvialis

Effect of isolated astaxanthin (ASX) and astaxanthin esters (ASXEs) from green microalga-Haematococcus pluvialis on hepatotoxicity and antioxidant activity against carbon tetrachloride (CCl4) induced toxicity in rats was compared with synthetic astaxanthin (SASX). ASX, ASXEs, and SASX, all dissolved in olive oil, fed to rats with 100 and 250 μg/kg b.w for 14 days. They were evaluated for their hepatoprotective and antioxidant activity by measuring appropriate enzymes. Among the treated groups, the SGPT, SGOT and ALP levels were decreased by 2, 2.4, and 1.5 fold in ASXEs treated group at 250 μg/Kg b.w. when compared to toxin group. Further, antioxidant enzymes catalase, glutathione, superoxide dismutase and lipid peroxidase levels were estimated in treated groups, their levels were reduced by 30-50 % in the toxin group, however these levels restored by 136.95 and 238.48 % in ASXEs treated group at 250 μg/kg. The lipid peroxidation was restored by 5.2 and 2.8 fold in ASXEs and ASX treated groups at 250 μg/kg. The total protein, albumin and bilirubin contents were decreased in toxin group, whereas normalized in ASXEs treated group. These results indicates that ASX and ASXEs have better hepatoprotection and antioxidant activity, therefore can be used in pharmaceutical and nutraceutical applications and also extended to use as food colorant.

Review of natural products with hepatoprotective effects

The liver is one of the most important organs in the body, performing a fundamental role in the regulation of diverse processes, among which the metabolism, secretion, storage, and detoxification of endogenous and exogenous substances are prominent. Due to these functions, hepatic diseases continue to be among the main threats to public health, and they remain problems throughout the world. Despite enormous advances in modern medicine, there are no completely effective drugs that stimulate hepatic function, that offer complete protection of the organ, or that help to regenerate hepatic cells. Thus, it is necessary to identify pharmaceutical alternatives for the treatment of liver diseases, with the aim of these alternatives being more effective and less toxic. The use of some plants and the consumption of different fruits have played basic roles in human health care, and diverse scientific investigations have indicated that, in those plants and fruits so identified, their beneficial effects can be attributed to the presence of chemical compounds that are called phytochemicals. The present review had as its objective the collecting of data based on research conducted into some fruits (grapefruit, cranberries, and grapes) and plants [cactus pear (nopal) and cactus pear fruit, chamomile, silymarin, and spirulina], which are consumed frequently by humans and which have demonstrated hepatoprotective capacity, as well as an analysis of a resin (propolis) and some phytochemicals extracted from fruits, plants, yeasts, and algae, which have been evaluated in different models of hepatotoxicity.

Red Sea Suberea mollis Sponge Extract Protects against CCl4-Induced Acute Liver Injury in Rats via an Antioxidant Mechanism

Recent studies have demonstrated that marine sponges and their active constituents exhibited several potential medical applications. This study aimed to evaluate the possible hepatoprotective role as well as the antioxidant effect of the Red Sea Suberea mollis sponge extract (SMSE) on carbon tetrachloride- (CCl₄-) induced acute liver injury in rats. In vitro antioxidant activity of SMSE was evaluated by 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH) assay. Rats were orally administered three different concentrations (100, 200, and 400 mg/kg) of SMSE and silymarin (100 mg/kg) along with CCl₄ (1 mL/kg, i.p., every 72 hr) for 14 days. Plasma aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), and total bilirubin were measured. Hepatic malondialdehyde (MDA), reduced glutathione (GSH), nitric oxide (NO), superoxide dismutase (SOD), glutathione peroxidase (GPx), and catalase (CAT) were also measured. Liver specimens were histopathologically examined. SMSE showed strong scavenging activity against free radicals in DPPH assay. SMSE significantly reduced liver enzyme activities. Moreover, SMSE significantly reduced hepatic MDA formation. In addition, SMSE restored GSH, NO, SOD, GPx, and CAT. The histopathological results confirmed these findings. The results of this study suggested a potent protective effect of the SMSE against CCl₄-induced hepatic injury. This may be due to its antioxidant and radical scavenging activity.

Hepatoprotection by carotenoids in isoniazid–rifampicin induced hepatic injury in rats

This study evaluates the hepatoprotective effect of carotenoids against isoniazid (INH) and rifampicin (RIF). Thirty-six adult rats were divided into the following 4 groups: (1) control group treated with normal saline; (2) INH + RIF group treated with 50 mg·(kg body mass)–1·day–1 of INH and RIF each; (3) INH + RIF+ carotenoids group treated with 50 mg·(kg body mass)–1·day–1 of INH and RIF each and 10 mg·(kg body mass)–1·day–1 of carotenoids; and (4) carotenoids group treated with 10 mg·(kg body mass)–1·day–1 of carotenoids for 28 days intragastrically. Oxidative stress and antioxidant levels in liver and blood, liver histology and change in transaminases were measured in all the above-mentioned groups. There was an increase in lipid peroxidation with a reduction in thiols, catalase, and superoxide dismutase (SOD) in the liver and blood of rats accompanied by an increase in transaminases, bilirubin, and alkaline phosphatase. Treatment with carotenoids along with INH + RIF partially reversed lipid peroxidation, thiols, catalase, and SOD in the liver and blood of rats. Elevated levels of the enzymes in serum were also reversed partially by this treatment. The degree of necrosis, portal triaditis, and inflammation were also lowered in the carotenoids group. In conclusion, carotenoids supplementation in INH + RIF treated rats showed partial protection.

Effects of Aulosira fertilisima against cisplatin-induced nephrotoxicity and oxidative stress in rats

Oxidative stress due to abnormal production of reactive oxygen molecules (ROM) is believed to be involved in the etiology of toxicities of many xenobiotics. Evidence suggested that ROM is involved in the nephrotoxicity of a widely used synthetic anticancer drug cisplatin. The nephroprotective effects of ethanol extract of Aulosira fertilisima Ghose (EEA) was evaluated using cisplatin (5 mg/kg(-1) i.p.)-induced renal damage in rats. EEA showed higher significant effect on DPPH radical scavenging activity as compared with methanol extract of A. fertilisima (MEA) and water extract of A. fertilisima (WEA). Thus, EEA was selected for further in vivo studies. The serum urea and creatinine levels in the cisplatin alone-treated group were significantly elevated with respect to normal group of animals. The levels were reduced in the EEA (100 mg/kg, p.o) plus cisplatin-treated groups. Renal oxidative stress was determined by renal TBARS, CD and reduced glutathione levels, and by enzymatic activity of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX), and glutathione transferase (GST). A single dose of cisplatin-produced marked renal oxidative and nitrosative stress and significantly deranged renal functions. Chronic EEA treatment significantly and dose-dependently restored renal functions, reduced lipid peroxidation, and enhanced reduced glutathione levels, superoxide dismutase, and catalase activities. The results of the study indicated that A. fertilisima significantly and dose-dependently protected the nephrotoxicity induced by cisplatin. This protection is mediated either by preventing the cisplatin-induced decline of renal antioxidant defense system or by their direct free radical scavenging activity.

Evaluation of renoprotective effect of Aphanizomenon flos-aquae on cisplatin-induced renal dysfunction in rats

Cisplatin is an effective chemotherapeutic agent used in the treatment of a wide array of both pediatric and adult malignancies. Dose-dependent and cumulative nephrotoxicity is the major toxicity of this compound, sometimes requiring a reduction in dose or discontinuation of treatment. Recent evidence has implicated oxidative and nitrosative stress in cisplatin-induced nephrotoxicity. Aphanizomenon flos-aquae (AFA), blue-green algae, is claimed to be a potential antioxidant. The present study was designed to explore the renoprotective potential of AFA against cisplatin-induced oxidative stress and renal dysfunction. The ethanolic extract of Aphanizomenon flos-aquae (EEAFA) (25, 50, 100 mg/kg(-1) p.o.) was administered two days before through three days after cisplatin challenge (5 mg/kg(-1) i.p.). Renal injury was assessed by measuring serum creatinine, blood urea nitrogen, creatinine and urea clearance, and serum nitrite levels. Renal oxidative stress was determined by renal TBARS levels, reduced glutathione levels, and enzymatic activity of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX), and glutathione transferase (GST). A single dose of cisplatin produced marked renal oxidative and nitrosative stress and significantly deranged renal functions. Chronic EEAFA treatment significantly and dose-dependently restored renal functions, reduced lipid peroxidation, and enhanced reduced glutathione levels, superoxide dismutase, and catalase activities. The results of the present study clearly demonstrate the pivotal role of reactive oxygen species and their relation to renal dysfunction and point to the therapeutic potential of AFA in cisplatin-induced nephrotoxicity.

Beta-carotene isomer composition of sub- and supercritical carbon dioxide extracts. Antioxidant activity measurement

In the present work sub- and supercritical extraction conditions using carbon dioxide were studied in order to obtain extracts with different compositions from the green microalgae Dunaliella salina. Different compositions of beta-carotene isomers were identified in the extracts by using HPLC-DAD. Also, antioxidant activity of the extracts was measured using a TEAC assay. An experimental design was applied considering two factors, extraction pressure and temperature, in a wide range of values, trying to maximize the extraction yield. Higher yields were obtained at high pressures and low temperatures, that is, at higher CO2 densities. Attempts were made to correlate the antioxidant activity of the extracts with their chemical composition by means of principal component analysis. A certain relationship was found between their antioxidant activity and the isomeric composition of beta-carotenes. As a result, an original equation is proposed to predict the antioxidant activity of extracts from D. salina in terms of the ratio 9-cis-beta-carotene/all-trans-beta-carotene, the concentration of alpha-carotene, and, especially, the concentration of 9-cis-beta-carotene.