DPPH Assay

The research aimed at unearthing the total levels of selected phytochemicals and the antioxidant (DPPH) in Annona muricata, Ribes nigrum and manilkara zapota plant extracts, which are widely known for their medicinal properties and locally grown in Manchester Jamaica West Indies. The leaves, bark and stem were collected and identified by an agronomist. They were aseptically treated then dried at room temperature for 4 days after which they were milled by the use of dry blend commercial heavy duty blender. The pulverise samples were stored at room temperature in sealed plastic screw top sterile cups until processed. The plants were tested for the presence of Phytochemicals (total flavonoids, total poly-phenols, and total tannins). DPPH assay was conducted to determine the antioxidant activity of Annona muricata, Ribes nigrum and Manilkara zapota plants respectively. M. zapota had the highest flavonoid content of 2.51 mg/g which was three times that of the A. muricata and more than that from R.nigrum. The highest poly-phenol content was obtained from the R.nigrumwhich produced values of 5.72 mg/g, followed by M. zapota, with A. muricata having the lowest poly phenol content. The lowest total tannins was obtained from A. muricata with the highest content being observed from R.nigrum.M. zapotashowed the highest antioxidantactivities, with the lowest being obtained fromA. muricata.Samples were processed in duplicates.

Objective: To evaluate the immunomodulatory and antioxidant activities of polysaccharides from Callicarpa macrophylla Vahl. leaves. Methods: Three different fractions of polysaccharides (PC, PH, PA) were isolated. The percentage of sugar in the extracted samples was checked by phenol-sulphuric acid method. Lymphocyte proliferation assay was done to evaluate its immunomodulatory activity. 1, 1-Diphenyl-2-picrylhydrazyl (DPPH) assay and total antioxidant assay was done to evaluate its antioxidant property. Results: The total polysaccharide content in PC, PH and PA was found to be 88%, 14% and 87% by the phenol-sulphuric acid method. All the three polysaccharides showed in vitro growth stimulatory effect on isolated normal lymphocytes. The proliferative index of PC, PH, PA was found to be 1.28±0.03, 1.71±0.04 and 1.12±0.01 at a concentration of 500 μg/ml indi­cating immunomodulatory activity. PC, PH, PA showed a % inhibition of DPPH radical at 40.11±0.005 %, 29.18±0.01 % and 16.82±0.00...