Two edible seaweeds, Sargassum polycystum and Sargassum wightii, were investigated for their antidiabetic potential using in vitro enzyme inhibitory assays. Among the various extracts, petroleum ether and ethyl acetate extracts of S. wightii showed significant inhibitory effects against α-amylase (IC 50 378.3 μg/ml) and α-glucosidase (IC 50 314.8 μg/ml). Methanol extract of S. wightii showed the highest inhibition against dipeptidyl peptidase-IV (DPP-IV) (IC 50 38.27 μg/ml) and moderate antioxidant activity was observed in acetone extract of S. wightii (44%). Similarly, ethyl acetate extract of S. polycystum showed the highest inhibition against α-amylase (IC 50 438.5 μg/ml) and methanol extract of S. polycystum showed maximum inhibition against α-glucosidase (IC 50 289.7 μg/ml) and DPP-IV (36.94 μg/ml). The antioxidant activity was poor (22%). The extracts were investigated for in vitro cytotoxicity, DNA fragmentation in macrophages and haemolytic activity against erythrocytes, but no notable toxicity was observed with any of the tested extracts. Gas chromatography-mass spectrometry revealed the presence of the antidiabetic compound fucosterol and other major bioactive compounds, giving an insight into the antidiabetic and antioxidant properties of these algae. This study reveals the possible mechanisms of antidiabetic action in vitro, and these two seaweeds may also have an antidiabetic action in vivo.

One of the therapeutic approaches in treating diabetes is to reduce postprandial hyperglycemia by inhibiting major carbohydrate hydrolyzing enzymes. In the present study, crude extracts of marine seaweed, Turbinaria ornata, were tested for their antidiabetic potential using enzyme inhibitory assays (α-amylase, α-glucosidase, and dipeptidyl peptidase-IV). Among the tested extracts, methanol and acetone extracts showed significant inhibitory effects on α-amylase (IC50 250.9 μg/mL), α-glucosidase (535.6 μg/mL), and dipeptidyl peptidase-4 (55.2 μg/mL), respectively. Free radical scavenging activity of these extracts was analyzed using DPPH assay (65%). Extracts were tested for in vitro toxicity using DNA fragmentation assay, haemolytic assay, and MTT assay. None of the extracts showed toxicity in tested models. Furthermore, GC-MS analysis of lead extracts showed the presence of major compounds, hentriacontane, z, z-6, 28-heptatriactontadien-2-one, 8-heptadecene, and 1-heptacosanol. Our findings suggest that Turbinaria ornata can be used as a potential source for further in vivo studies in controlling hyperglycemia.

Plant-derived extracts have been used as folk remedies for Type 2 diabetes mellitus (T2DM) for many centuries, and offer the potential of cheap and readily available alternatives to conventional pharmaceuticals in developing countries. Extracts of Costus pictus (CP), a plant belonging to the Costaceae family, are reported to have antidiabetic activity in vivo. The exact molecular mode of action(s) of CP is unclear but the antihyperglycemic effect seen in animal studies was associated with dramatic increases in insulin secretion so in our study we have measured the effect of aqueous CP extract on insulin secretion in vitro from the MIN6 Β-cell line and isolated mouse and human islets. Our data demonstrate that CP has a direct stimulatory effect on insulin secretion at basal but not stimulatory glucose concentrations which was not associated with compromised membrane integrity or decrease Β-cell viability. Single cell calcium microfluorimetry measurements showed that CP caused elevations in Β-cell intracellular Ca²⁺ concentrations ([Ca²⁺]_i), an effect which was completely abolished by the removal of extracellular Ca²⁺ or blockade of voltage-gated Ca²⁺ channels (VGCC). These in vitro observations suggest that one mode of action of CP is through stimulating insulin secretion which may be mediated, in part, by the ability of CP to increase [Ca²⁺]_i levels through VGCC. CP extracts may provide an affordable and inexpensive alternative for treating patients with T2DM.

Magnetosomes are nanosized iron oxide particles surrounded by lipid membrane synthesized by magnetotactic bacteria (MTB). Magnetosomes have been exploited for a broad range of biomedical and biotechnological applications. Due to their enormous potential in the biomedical field, its safety assessment is necessary. Detailed research on the toxicity of the magnetosomes was not studied so far. This study focuses on the toxicity assessment of magnetosomes in various models such as Human RBC's, WBC's, mouse macrophage cell line (J774), Onion root tip and fish (Oreochromis mossambicus). The toxicity in RBC models revealed that the RBC's are unaltered up to a concentration of 150 lg/ml, and its morphology was not affected. The genotoxicity studies on WBC's showed that there were no detectable chromosomal aberrations up to a concentration of 100 lg/ml. Similarly, there were no detectable morphological changes observed on the magnetosome-treated J774 cells, and the viability of the cells was above 90% at all the tested concentrations. Furthermore, the magnetosomes are not toxic to the fish (O. mossambicus), as no mortality or behavioural changes were observed in the magnetosome-treated groups. Histopathological analysis of the same reveals no damage in the muscle and gill sections. Overall, the results suggest that the magnetosomes are safe at lower concentration and does not pose any potential risk to the ecosystem.

No abstract