Impact of Chlorella pyrenoidosa on the attenuation of hyperglycemia-mediated oxidative stress and protection of kidney tissue in streptozotocin-cadmium induced diabetic nephropathic rats

Potential benefits of microalgae intake against metabolic diseases: beyond spirulina-a systematic review of animal studies

CONTEXT

Microalgae are a diverse source of bioactive molecules, such as polyphenols, carotenoids, and omega-3 fatty acids, with beneficial properties in biomarkers of metabolic diseases. Unlike the rest of the microalgae genera, Arthrospira sp., commonly called spirulina, has been widely studied.

OBJECTIVE

This review aims to describe the current knowledge about microalgae, besides spirulina, focusing on their beneficial properties against metabolic diseases.

DATA SOURCES

A systematic research of MEDLINE (via PubMed), Cochrane, and Scopus databases was conducted to identify relevant studies published after January 2012. In vivo animal studies including microalgae consumption, except for spirulina, that significantly improved altered biomarkers related to metabolic diseases were included. These biomarkers included body weight/composition, glucose metabolism, lipid metabolism, oxidative damage, inflammation markers, and gut microbiota.

DATA EXTRACTION

After the literature search and the implementation of inclusion and exclusion criteria, 37 studies were included in the revision out of the 132 results originally obtained after the application of the equation on the different databases.

DATA ANALYSIS

Data containing 15 microalgae genera were included reporting on a wide range of beneficial results at different levels, including a decrease in body weight and changes in plasma levels of glucose and lipoproteins due to molecular alterations such as those related to gene expression regulation. The most reported beneficial effects were related to gut microbiota and inflammation followed by lipid and glucose metabolism and body weight/composition.

CONCLUSIONS

Microalgae intake improved different altered biomarkers due to metabolic diseases and seem to have potential in the design of enriched foodstuffs or novel nutraceuticals. Nevertheless, to advance to clinical trials, more thorough/detailed studies should be performed on some of the microalgae genera included in this review to collect more information on their molecular mechanisms of action.

A sulfated exopolysaccharide derived from Chlorella sp. exhibiting in vitro anti-α-D-Glucosidase activity

There is a great scientific curiosity to discover all environments sheltering microalgae, especially those with exceptional characteristics from coldest to hottest ones, the purpose remains to explore the potential of the native microalgae flora and the research for new bioactive compounds. This study aimed to isolate a polysaccharide-producing microalga from an extreme ecosystem and to evaluate its capacity to inhibit the α-D-glucosidase enzyme. Chlorella strain is isolated from hypersaline Lake in the Algerian desert. The exopolysaccharide extraction was performed by the concentration of free-cell supernatant in a rotary evaporator. The infrared analysis showed a characteristic footprint of carbohydrates with particular functional groups, such as sulfate. Gas chromatography-mass spectrometry has revealed a hetero-exopolysaccharide composed of galactose 35.75%, glucose 21.13%, xylose 16.81%, fructose 6.96%, arabinose 5.10%, and glucuronic acid 2.68%. The evaluation of the anti-hyperglycemic activity demonstrated a significant α-D-glucosidase inhibition of 80.94 ± 0.01% at 10 mg mL-1 with IC50 equal to 4.31 ± 0.20 mg mL-1. This study opens a vast prospect to use exopolysaccharides as natural nutraceutical or food additive.

Microalgal bioactive metabolites as promising implements in nutraceuticals and pharmaceuticals: inspiring therapy for health benefits

The rapid increase in global population and shrinkage of agricultural land necessitates the use of cost-effective renewable sources as alternative to excessive resource-demanding agricultural crops. Microalgae seem to be a potential substitute as it rapidly produces large biomass that can serve as a good source of various functional ingredients that are not produced/synthesized inside the human body and high-value nonessential bioactive compounds. Microalgae-derived bioactive metabolites possess various bioactivities including antioxidant, anti-inflammatory, antimicrobial, anti-carcinogenic, anti-hypertensive, anti-lipidemic, and anti-diabetic activities, thereof rapidly elevating their demand as interesting option in pharmaceuticals, nutraceuticals and functional foods industries for developing new products. However, their utilization in these sectors has been limited. This demands more research to explore the functionality of microalgae derived functional ingredients. Therefore, in this review, we intended to furnish up-to-date knowledge on prospects of bioactive metabolites from microalgae, their bioactivities related to health, the process of microalgae cultivation and harvesting, extraction and purification of bioactive metabolites, role as dietary supplements or functional food, their commercial applications in nutritional and pharmaceutical industries and the challenges in this area of research.

Graphical abstract

Antihyperglycemic, antihyperlipidemic, and renoprotective effects of Chlorella pyrenoidosa in diabetic rats exposed to cadmium

OBJECTIVE

The objective of the present study is to evaluate the antihyperlipidemic effect of Chlorella pyrenoidosa in diabetic rats exposed to cadmium (Cd).

MATERIALS AND METHODS

Group 1 and 2 rats were treated as control and C. pyrenoidosa control. Group 3 and 4 rats were given single injection of streptozotocin (40 mg/kg b.w; i.p) followed by Cd (0.6 mg/kg b.w; s.c) for 5 days per week for a total period of 90 days. In addition, group 4 rats alone were treated with C. pyrenoidosa throughout the study period of 90 days. Assessments of plasma glucose, insulin, lipid profile and renal function markers were performed in control and experimental rats along with histological examination of kidney tissues.

RESULTS

Diabetic rats exposed to Cd showed increased levels of plasma glucose and decreased levels of plasma insulin accompanied by the significantly elevated levels of tissue lipids viz., total cholesterol, triglyceride, free fatty acid, and phospholipids compared with control rats. Alterations in lipoproteins (low density lipoprotein-C, very low density lipoprotein-C, and high density lipoprotein-C) levels were also observed.

DISCUSSION

Elevated levels of urinary albumin, creatinine, and blood urea nitrogen confirmed the onset of renal dysfunction in unsupplemented diabetic rats exposed to Cd.

CONCLUSION

C. pyrenoidosa (100 mg/kg body weight) supplemented diabetic nephropathic rats showed near normal biochemical profile and well preserved renal histology that substantiate the antihyperglycemic, antihyperlipidemic, and renoprotective effects of C. pyrenoidosa in diabetic rats exposed to Cd.