Jayshree, et al.: Microalgae: Effective Health MediatorsAlgae are rich sources of structurally novel and biologically active metabolites. Primary and secondary metabolites produced by these organisms have drawn interest of the pharmaceutical industries. In this regard we have put forth an investigation to evaluate phenolic and flavonoid content in methanol extract of fresh algal biomass followed by antioxidant, antimicrobial and anticancer activities. Determination of total phenol and flavonoid content was followed by the 2,2-diphenyl-1-picrylhydrazyl radicals scavenging, phosphomolybdate and reducing power assay for evaluating antioxidant potency. Agar well diffusion method for antibacterial activity and trypan blue test along with MTT assay was done for anticancer activity. Among two microalgae, Chlorella vulgaris had efficiently high amount of total phenol and flavonoid content. Chlorella vulgaris is a single-celled eukaryotic green micro algae, known to be first form of a plant with a well-defined nucleus emerged over 2 billion years ago [1] . Chlorella contains the highest amount of chlorophyll of any known plant. Chlamydomonas reinhardtii, another unicellular algae though not much explored as nutrient supplement; it is well known model organism with its three genomes (nuclear, plastidial and mitochondrial) completely sequenced [2] . It finds its application mostly in molecular biology especially in studies involving flagellar motility, chloroplast dynamics, biogenesis and genetics [3] . C. vulgaris is well determined nutrientdense superfood containing 60% protein, 18 amino acids, 20 vitamins and minerals like iron, calcium, potassium, magnesium and phosphorous [4] . One of its unique properties is a phytonutrient called Chlorella Growth Factor [1] . These two microalgae are known for high volume production of β-carotene.Besides being food supplements microalgae, Chlorella sp., Chlamydomonas sp. have been proved to have antibacterial activity in vitro against both Gram positive and Gram negative bacteria [5] . The production of extracellular antibiotic metabolites by marine algae has been well studied in recent years. They are also been reported that a wide range of antifungal activities were obtained from extracts of green microalgae [6] . Eventually, microalgae are almost an untapped resource of natural antioxidants due to their enormous biodiversity, much more diverse than higher plants. They contain various biologically active compounds that are been used as source of food, feed and medicine [7] . Microalgae are

Scientific research has always been concerned with aspects of human health. There are several systems of medicines besides the globally accepted allopathy, which are based on compounds originating from natural products. Recent research has been centred around validation of the traditional knowledge on medicinal products. The traditional systems in India, China and forklore medicines in other parts of the world have indicated the potential of natural products consist of various chemical compounds that could be used as drugs. The search for drugs against five major dreadful diseases namely, cancer, AIDS, heart disease, diabetes and pulmonary disorders that attack the present day human from natural products has been in progress for some time. Microbes, plants and animals are the sources of natural products. In the past five decades, the research on bioactive chemicals from marine algae has been incited and several compounds with biological activity were isolated from algae. Generally, these are secondary metabolites produced for chemical defence against the biotic pressure of predators, consumers and epibionts. These potential drugs are now attracting considerable attention from the pharmaceutical industries due to the necessity of identifying substances that could be utilized for novel therapeutic purposes. Several compounds such as alginate, carrageenans, sulphated and halogenated polysachcharise and other derivatives have been shown to provide drugs that could be antiviral, anticancer and antimicrobial. The present account is on the potential of marine macro-algae for medicinally important products.

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Natural antioxidants are found in algae, are important biologically active compounds that involve in protecting the cells from oxidation thereby used in defense mechanism on ageing processes and various diseases. In this study, R-Phycoerythrin (R-PE) was extracted from Spyridia filamentosa and was assessed for their antioxidant properties. The antioxidising property of decontaminated R-PE has been evaluated by measuring the free radical scavenging activity by DPPH radical scavenging assay, ABTS radical scavenging activity, hydroxyl radical scavenging activity, superoxide radical (O2) scavenging assay, nitric oxide scavenging activity and phosphomolybdenum reduction assay. The purified R-PE extract was subjected to structural analysis by UV-Visible spectroscopy, fluorescence emission spectroscopy and infrared spectroscopy. The UV-Visible spectrum showed a peak at 496 nm, 543 nm and 564 nm and fluorescence emission spectrum of R-PE was measured 575 nm which confirmed the presence of R-Phycoerythrin. The IR spectral data showed the presence of aromatic constituents containing amide group in the protein. DPPH radical scavenging assay showed the highest antioxidant potential with an IC50 value of 128.25 μg/ml. The radical scavenging activity of Nitric oxide showed an IC50 value of 87.85 μg/ml, Phosphomolybdenum reduction assay showed an RC50 value of 61.45 μg/ml. The hydroxyl radical scavenging activity showed IC50 value of 34.56 μg/ml and Superoxide radical (O2) scavenging assay showed IC50 value of 18.58 μg/ml. The ABTS radical scavenging activity showed the lowest antioxidant potential of 3.13 μg/ml. The free radical scavenging property of R-Phycoerythrin (R-PE) concentrate of Spyridia filamentosa demonstrate that it has high antioxidant potency and it could be considered as utilitarian nourishment with essential pharmaceutical and biological importance.