Isolation and structural characterization of sulfated polysaccharide from Spirulina platensis and its bioactive potential: In vitro antioxidant, antibacterial activity and Zebrafish growth and reproductive performance.

In this study, the sulfated polysaccharide (SPs) was isolated from Spirulina platensis. The isolated SPs contains carbohydrate, sulfate, protein and uronic acid at 38.7 ±â€¯0.30%, 21.3 ±â€¯0.87%, 7.1 ±â€¯0.15% and 7.9 ±â€¯0.4% respectively. The elemental analysis confirmed the presence of carbon (18.01 ±â€¯0.10%), hydrogen (1.83 ±â€¯0.02%) and nitrogen (3.43 ±â€¯0.01%). The monosaccharide composition and molecular weight of SPs were analyzed by high-performance liquid chromatography and size exclusion chromatography respectively. The monosaccharide composition analysis showed the existence of glucose, rhamnose, xylose, fucose, mannose, galactose and the molecular weight of SPs was 1016 kDa. Further, the characterization of SPs was done by UV-visible spectroscopy, X-ray diffraction, FT-IR, 1H NMR and 13C NMR analysis. The obtained SPs exhibited potent antioxidant activity in DPPH (76.45 ±â€¯0.49%), reducing power (absorbance: 1.3 ±â€¯0.02), hydrogen peroxide scavenging (66.3 ±â€¯1.16%), hydroxyl scavenging (68.6 ±â€¯3.2%), nitric oxide (81.36 ±â€¯1.85%) and total antioxidant (absorbance:1.66 ±â€¯0.02) activities at 5 mg/ml. In addition, SPs revealed the highest antibacterial efficacy against the pathogenic bacteria Vibrio vulnificus in disc diffusion, agar bioassay and protein leakage assays at 100 µg/ml. Furthermore, the supplementation of 2% SPs through a feed to the Danio rerio fish enhances the growth and reproductive performances. This finding confirmed that the isolated SPs from S. platensis possess pharmaceutical as well as nutritional properties.

Exploitation of chemical, herbal and nanoformulated acaricides to control the cattle tick, Rhipicephalus (Boophilus) microplus - A review.

The tick Rhipicephalus (Boophilus) microplus is a key vector of bacterial and protozoan diseases causing heavy economic losses directly and indirectly in animal husbandry. In the past decades, the control of ticks faced some major issues, such as the rapid development of resistance in targeted vectors and non-target effects on human health and the environment, due to the employ of synthetic acaricides and repellents. Eco-friendly pesticides for treating and controlling animal parasites such as ticks were mainly from medicinal plants and thus they form the richest entity for manufacturing resources for drugs. Even though there are efforts made to discover reliable plant-based acaricides to control ectoparasites in animal husbandry, the effective control of R. (B.) microplus ticks still represent a major challenge in current veterinary entomology. Recently, a wide number of promising attempts have been conducted to use herbal preparations and green-fabricated nanoparticles for the control of R. (B.) microplus. The aim of this review is to critically summarize and discuss the use of herbal preparations used in ethno-veterinary as well as green-fabricated nanoparticles as novel acaricides for the control of the cattle tick R. (B.) microplus.

In vitro and in vivo efficacy of rosmarinic acid on quorum sensing mediated biofilm formation and virulence factor production in Aeromonas hydrophila.

Rosmarinic acid (RA) was assessed for its quorum sensing inhibitory (QSI) potential against Aeromonas hydrophila strains AH 1, AH 12 and MTCC 1739. The pathogenic strains of A. hydrophila were isolated from infected zebrafish and identified through biochemical analysis and amplification of a species-specific gene (rpsL). The biofilm inhibitory concentration (BIC) of RA against A. hydrophila strains was found to be 750 µg ml-1. At this concentration, RA reduced the QS mediated hemolysin, lipase and elastase production in A. hydrophila. In FT-IR analysis, RA treated A. hydrophila cells showed a reduction in cellular components. Gene expression analysis confirmed the down-regulation of virulence genes such as ahh1, aerA, lip and ahyB. A. hydrophila infected zebrafish upon treatment with RA showed increased survival rates. Thus, the present study demonstrates the use of RA as a plausible phytotherapeutic compound to control QS mediated biofilm formation and virulence factor production in A. hydrophila.