Evaluation of in vitro antidiabetic and anti-microbial activity of edible red seaweed Pyropia vietnamensis

Diabetes is one of the top ten leading causes of mortality in the world with an incidence rate of 422 million. The current study aimed to investigate the antidiabetic activity of edible red seaweed Pyropia vietnamensis. Crude extract was subjected to UV–visible light spectroscopy, phytochemical screening, quantification of total tannin content, DPPH free radical scavenging, alpha amylase inhibition assay, antimicrobial activity, and glucose uptake potential by yeast cell assay. The phytochemicals study revealed the presence of alkaloids, glycosides, phenols, lignins, saponins, and further, total tannin content was estimated to be 3.86 ± 0.00378 mg/g. The methanolic extract of Pyropia vietnamensis displayed the highest DPPH free radical scavenging activity of 35.19% at 100 µg/mL. The alpha-amylase inhibition potential of the extract showed 11.5% at 400 and 13.5% at 500 µg/mL. Glucose utilization of yeast cells treated with extract with different (5, 15, and 25 mM) glucose concentrations showed a linear increase in the glucose uptake percent. The minimum inhibitory concentration (MIC) of Pyropia vietnamensis extract against E. coli MTCC-443 and S. aureus MTCC-96 was found to be 250 mg/mL and 125 mg/mL respectively. The uptake percent was 31.7, 29.5, and 38.27% for 5, 15, and 25 mM glucose concentrations respectively, exhibiting its ability to transport glucose across the yeast cell membrane. The toxicity study resulted in a more than 60% cell survival rate in all the concentrations, proving its safety for human consumption. The result of the study concludes that Pyropia vietnamensis could be utilized as a functional food due to its dietary source for treating diabetic conditions naturally. Further research can be done to evaluate the potential of diabetic mouse (in vivo) conditions.