This study investigated the presence of phytochemicals, yield of extract, total phenol and flavonoids content of the red seaweed Porteria hornemannii. For the extraction of metabolites from P. hornemannii, two different solvents like methanol and chloroform were used. In the phytochemical test, the methanol extract of P. hornemannii (MEPH) showed superior results in comparison with chloroform. After the crude methanol extract is purified by 86%, it is subjected to a quantitative method which, respectively, determined the total phenol content to be (1.60 ± 0.13 mg.GAE/g) and flavonoid content to be (1.302 ± 0.4 mg.GAE/g). The GC-MS analyses of MEPH revealed 20 compounds, in which, n-hexadeconic acid (Rt-27.385; peak area − 41.88%) and 9, 12, Octadecadienoic acid (Z, Z) (Rt-29.879; peak area − 19.49%) were the major ones. Based on the concentration of MEPH, both the ABTS and the hydroxyl radical scavenging assays showed increased activity. The larvicidal activity of MEPH tested against three mosquito larvae and found that only Culex quinquefasciatus larvae was highly sensitive (100% mortality) with the LC50 and LC90 value of 2.476 ppm and 13.207 ppm, respectively. Finally, the seaweed P. hornemannii could be considered for the future nutraceutical and bio-control agents, which may also be impervious to cancer and vector-borne diseases in human.

The present study focused on proximate composition, moisture, ash, lipid, protein, carbohydrate, dietary fiber and physicochemical properties to determine the water holding capacity, oil holding capacity, and water swelling capacity of H. valentiae red seaweed. The antioxidant properties of methanol extract were performed by superoxide and nitric oxide radical scavenging activity. The superoxide scavenging radical (50-250 μg/mL) was an inhibition of 89.06 ± 0.44μg/mL which is significantly higher than the standard ascorbic acid 75.67 ± 0.20μg/mL. Nitric oxide assay observed that (15-100 μg/mL) exhibited the maximum nitric oxide scavenging was 87.22 ± 0.80μg/mL which is significantly higher than the standard ascorbic acid 74.35 ± 0.67μg/mL. The results were establishing the potential of the seaweed was exploited the nutritional value and pharmaceutical applications.

The proximate composition (Protein, carbohydrate, lipid, ash, moisture and total dietary fiber content) and physicochemical properties of Portieria hornemannii were studied. The proximate composition of protein 33.82 ± 1.48 followed by carbohydrate and lipid the protein is highest activity. Total dietary fiber contained 2.24 ± 0.39 for thr red seaweed of Portieria hornemannii contains neutral sugars corresponded to sulphated galactoans (Carrageen and agar). Insoluble fiber 1.22 ± 0.06 and soluble fiber 1.02 ± 0.05, moisture and ash were 12.96 ± 0.55 and 18.42 ± 1.03 respectively. Followed by WHC and swelling both had strong physicochemical characteristics at high temperatures. The oil retention is very low. Finally the seaweed P.hornemannii is used in anti diabetic activity of α amylase enzyme activity IC50 value 121.68. The P.hornemannii can be effective inhibition of anti diabetic activity and its leads to develop the natural drug in pharmaceutical application