Phytochemical Screening and Evaluation of Antidiabetic Activity of the Marine Microalgae: Nannochloropsis Sp.

Abstract

Diabetes  mellitus  is  a  metabolic  disorder  and  is  one  of  the  major  challenges  on  health      of  people  all  over  the  world.  The phytochemicals  of  various  marine  algae  are  found  to  possess  antioxidant,  anti-inflammatory  and  anti-diabetic  properties.  Microalgae  are photosynthetic  organisms  that produce  oxygen  and are capable  of producing  beneficial  secondary  metabolites.  The bioactive  metabolites  like pigments,  phenolics,  amino  acids,  polyunsaturated  fatty acids  etc. produced  by them have a positive  effect  on human  health.   In the present investigation,  the  marine  microalgae  Nannochloropsis  sp.  was  screened  for  phytochemicals  qualitatively  and  quantitatively.  The  evaluation  of antidiabetic activity was determined against the enzymes such as alpha amylase and alpha glucosidase. The extracts were prepared in five different solvents  such as petroleum  ether, aqueous,  isopropanol,  methanol  and ethyl  acetate.  The qualitative  analysis  for  phytochemicals  showed  the presence of alkaloids, phenols, flavonoids, carbohydrates, proteins, cardiac glycosides, sterols, coumarin and tannins. The maximum total phenolic, flavonoid and sterol content was present in ethyl acetate extract of Nannochloropsis  sp. and the values are found to be 42.17 ± 0.12mg GAE/g, 60.23 ± 0.09 mg QE/g, 55.34 ± 0.07 mg cholesterol/g of extract respectively. The ethyl acetate extract showed highest inhibitory effect of 78.52 ±0.56 % (IC50 121.96 µg/ml) on α-amylase and 80.42 ± 0.13 % (IC 50 178.53µg/ml) on α-glucosidase enzyme at a concentration of at 1mg/ml which implies  the microalgae  possess  anti-diabetic  property.  The  results  indicate  that  the phytochemicals  present  in the microalgae  contribute  the antidiabetic activity. Hence Nannochloropsis sp. can be applied in pharmaceuticals for the development of antidiabetic drugs which have the benefits over side effects by the use of synthetic drugs.