Immuno-modulation effect of sulphated polysaccharide (porphyran) from Porphyra vietnamensis.

Our investigation explores the immuno-efficiency of sulphated polysaccharides enriched Porphyra vietnamenis. Isolated polysaccharide fraction (17.1-25.8%) was characterized by FTIR and NMR spectroscopy which showed the presence of typical linear backbone structure called as porphyran. Oral administration of porphyran (200-500 mg/kg) evoked a significant (P ≤ 0.05) increase in weight of the thymus, spleen and lymphoid organ cellularity. The total leucocyte and lymphocyte count was increased significantly (P<0.005). The increase in the percent neutrophil adhesion to nylon fibres as well as a dose-dependent increase in antibody titre values was observed. A decreased response to DTH reaction induced by SRBC was recorded. A potential phagocytic response was seen and significant changes were observed in the formation of formazone crystals. It also prevented myelosuppression in cyclophosphamide drug treated rats. The results indicated that P. vietnamenis possesses potential immunomodulatory activity and has therapeutic potential for the prevention of autoimmune diseases.

Broad-spectrum sun-protective action of Porphyra-334 derived from Porphyra vietnamensis.

There are enormous UV-protective compounds present in the current world market, out of which 98% give protection against UV-B range and the remaining 2% are potent against far UV-A range only. Furthermore, these synthetic compounds have various problems related to photo-stability and cross-stability. There is a vital need of sunscreen agents that will remain stable for prolonged periods and provide broad-spectrum protection against harmful UV range. The Indian Ocean contains large amounts of macro-algae which synthesize varied amount of mycosporine amino acids, "sun-protective compounds" by shikmic acid pathway. In the present study, we have evaluated the sunscreen protection provided by Porphyra-334, a mycosporine amino acid isolated from Indian sp. of Porphyra. Furthermore, the isolated compound was detected by high performance thin layer chromatography (HPTLC) fingerprinting, high performance liquid chromatography (HPLC) and ultraviolet (UV), whereas nuclear magnetic resonance (NMR) spectroscopy and infrared spectrometry were used for its structural characterization. Stability studies were performed under different storage and pH conditions. Ultimately a sunscreen formulation was developed and its potential against marketed Aloe vera gel was evaluated by in vitro sunscreen protection method. It was observed that sunscreen potential of Porphyra-334 was 5.11-fold greater than that of the marketed Aloe vera gel preparation.

Biosorption characteristics of uranium(VI) from aqueous medium onto Catenella repens, a red alga.

The biosorption characteristics of uranium(VI) onto Catenella repens (a red alga), were evaluated as a function of pH, biosorbent size, time, biomass dosage, initial uranium concentration and temperature. Within the pH range studied (1.5-7.5), 4.5 was the optimum pH for the uptake of uranium(VI) by C. repens. Reduction in particle size did not increase the biosorption capacity. The metal removal was rapid, with more than 90% of total biosorption taking place in 30 min, and equilibrium was attained in 45 min. The maximum metal loading capacity of the alga was 303 mg/g. Within the temperature range studied (15-55 degrees C), there was no significant change in biosorption, under optimal conditions. Adsorption process could be well defined by both the Langmuir and Freundlich isotherms with r(2) of 0.94 and 0.96, respectively. The kinetic data fitted the pseudo-second-order kinetic model with the r(2) value of 0.99. At a low pH of 2.5, where most of the biomasses show either no or less metal uptake, a good (>15%) metal loading capacity of 25% was achieved. Therefore biosorption characteristics were also evaluated at pH 2.5.