Cyanobacterial Pigments as Natural Anti-Hyperglycemic Agents: An In vitro Study

Abstract

Traditional medicines for controlling postprandial hyperglycemia includes herbs and plant extracts as well as synthetic drugs like acarbose. Synthetic drug molecules frequently have side effects such as flatulence and diarrhea. Cyanobacterial pigments have excellent anti-oxidant and free radical scavenging properties. Thus, α-amylase and α-glucosidase inhibiting activities of purified pigments and crude extracts from three cyanobacterial species, Lyngbya, Microcoleus, and Synechocystis sp., were investigated. Lyngbya extract had the highest total anti-oxidant activity (TAC) before digestion (48.26 ± 0.04 µg AAE ml −1 ) while purified lycopene had the highest TAC after digestion (154.16 ± 0.96 µg AAE ml −1 ). The Microcoleus extract had the highest ABTS scavenging activity before digestion (98.23 ± 0.25%) while purified C-phycocyanin (C-PC) had the highest ABTS scavenging after digestion (99.69 ± 0.04%). None of the digested or undigested extracts performed better than acarbose in inhibiting α-amylase but the digested Microcoleus extract was able to inhibit its activity by ∼35%. The purified pigments gave inhibitory activities ranging from ∼8 to 16%. The Lyngbya extract had the highest inhibitory activity against α-glucosidase both before and after digestion (62.22 ± 0.02 and 97.82 ± 0.03%, respectively). Purified C-phycoerythrin (C-PE), C-PC, lycopene and myxoxanthophyll could inhibit α-glucosidase in a range of ∼83-96%. Considering the potent inhibitory activities of purified pigments against both α-amylase and α-glucosidase, cyanobacterial pigments could be used as food additives for their dual advantage of anti-oxidant and anti-hyperglycemic activities.

Glucosidase Inhibitors Screening in Microalgae and Cyanobacteria Isolated from the Amazon and Proteomic Analysis of Inhibitor Producing Synechococcus sp. GFB01

“…With occurrence in animals, plants and microorganisms [ 24 , 25 , 26 , 27 ], the bioprospection of glucosidase inhibitors in sustainable natural sources was once concentrated on macroalgae [ 28 , 29 , 30 ] but it is interesting to look for alternatives with cheaper cultivation and that require less area, such as microalgae, including cyanobacteria [ 31 , 32 , 33 , 34 , 35 , 36 , 37 ]. The possibility of associating the production of these inhibitors with other metabolites of biotechnological interest produced by cyanobacteria, such as antioxidants [ 38 ]; pigments [ 39 ], acids and polysaccharides of cosmetic and pharmacological interest [ 40 , 41 ] in addition to joint production with polyhydroxybutyrate (PHB) [ 42 , 43 ] and biofuels [ 44 , 45 , 46 ], while mitigating CO 2 [ 43 , 44 ], is yet another advantage of this bacterial phylum.…”

Studies on Extraction and Stability of C-Phycoerythrin From a Marine Cyanobacterium

“…Repeated freezing at sub-zero temperatures followed by instant thawing is intended to shock and rupture the fragile cell walls and is considered to be one of the gentler techniques from the point of view of the proteins, since there is no heat generation involved. As such, it is one of the most common methods used for phycobiliprotein extraction (Soni et al, 2010;Mishra et al, 2011;Parmar et al, 2011;Ghosh et al, 2016Ghosh et al, , 2018Patel et al, 2018; with recoveries ranging from ∼29 to 102 mg g −1 of cell dry weight in the crude extract.…”

“…C-phycoerythrin (CPE) is a water soluble, light harvesting accessory pigment found in some strains of cyanobacteria and is responsible for absorption of wavelengths inaccessible to chlorophyll. In addition to its role as a light harvesting protein, it is widely studied for its applications as a natural food colorant, anti-oxidant and anti-hyperglycemic agent, fluorescent tag, and small ion sensor (Sekar and Chandramohan, 2007;Ghosh et al, 2016Ghosh et al, , 2018.…”

Cyanotherapeutics: an emerging field for future drug discovery

“…Thus, they proposed an antihyperglycaemic effect of Spirulina. Further, an in vitro study by Ghosh et al (2016) demonstrated the antihyperglycaemic effect of cyanobacterial pigments such as Figure 2. Anti-cancer activity associated with cyanobacteria (Luesch et al, 2001;Xiong et al, 2006;Yonezawa et al, 2012;Marquez et al, 2002;Drew et al, 2002).…”

“…In recent years several pharmaceutical companies have been working on "nutraceuticals", the term being a combination of the words "nutrition" and "pharmaceuticals" (Defelice, 1989) which can be defined as a food or food product that possesses health benefits and has medicinal properties in the prevention/treatment of disease (Dominguez, 2013;Kalra, 2003). Cyanobacteria are an important target due to their cosmopolitan availability and their bioactive compounds such as polyunsaturated fatty acids (PUFAs), phycobiliproteins (PBPs), carotenoids, several enzymes and vitamins, with a long history of use (Ciferri & Tiboni, 1985;Ghosh et al, 2016) due to their beneficial properties (Burja, Banaigs, Abou-Mansour, Burgess, & Wright, 2001;Nunnery, Mevers, & Gerwick, 2010;Singh, Kate, & Banerjee, 2005). Available evidence suggests that cyanobacteria have been used since 1500 BC to treat gout, fistula and forms of cancer (Abarzua, Jakubowski, Eckert, & Fuchs, 1999;Bhadury & Wright, 2004;Dahms, Ying, & Pfeiffer, 2006).…”