R-phycocyanin from porphyra haitanensis influences drosophila melanogaster lifespan in a sex-specific manner

Aging has become a major global public health challenge. Our previous research showed that R-phycocyanin (R-PC) possessed anti-aging activity. Notably, studies already revealed that gender may affect the responses to the anti-aging drug. Therefore, it is worth investigating whether the anti-aging effects and their underlying molecular mechanisms of R-PC differ between genders. Firstly, R-PC was isolated from porphyra haitanensis and its anti-aging mechanisms were explored using the nature aging male and female drosophila melanogaster as model. Next, the regulation pathway of longevity was analyzed by KEGG pathway analysis. The longevity pathways-associated molecules were also examined to explore anti-aging mechanisms of R-PC. The results showed that R-PC increased AMPK activity, thus enhanced the key regulatory factors of autophagy (Atg1, Atg8, Atg5), and consequently induced autophagy. Hence, the longevity activity of R-PC life was related with AMPK/mTOR/S6K autophagic signaling pathways in aging female drosophila melanogaster. Meanwhile, R-PC significantly down-regulated TNF-α, MMP3, IL-1β, IL-6, IL-8 expression levels, and the anti-inflammatory and longevity was associated with R-PC-induced regulation of pI3k/AKT/FOXO3 signaling pathway in aging male drosophila melanogaster. These finding showed that R-PC from porphyra haitanensis might exert the anti-aging actions via different mechanisms in male and female drosophila melanogaste.

Exploring and strengthening the potential of R-phycocyanin from Nori flakes as a food colourant

This study aimed to purify, characterise and stabilise the natural food colourant, R-phycocyanin (R-PC), from the red algae Porphyra spp. (Nori). We purified R-PC from dried Nori flakes with a high purity ratio (A₆₁₈/A₂₈₀ ≥ 3.4) in native form (α-helix content 53%). SAXS measurements revealed that R-PC is trimeric ((αβ)₃) in solution. The thermal denaturation of α-helix revealed one transition (T_m at 52 °C), while the pH stability study showed R-PC is stable in the pH range 4-8. The thermal treatment of R-PC at 60 °C has detrimental and irreversible effects on R-PC colour and antioxidant capacity (22 % of residual capacity). However, immobilisation of R-PC within calcium alginate beads completely preserves R-PC colour and mainly retains its antioxidant ability (78 % of residual capacity). Results give new insights into the stability of R-PC and preservation of its purple colour and bioactivity by encapsulation in calcium alginate beads.

Ultrasound assisted methods for enhanced extraction of phycobiliproteins from marine macro-algae, Gelidium pusillum (Rhodophyta)

Extraction of phycobiliproteins (R-phycoerythrin, R-PE and R-phycocyanin, R-PC) from macro-algae is difficult due to the presence of large polysaccharides (agar, cellulose etc.) present in the cell wall which offer major hindrance for cell disruption. The present study is aimed at developing most suitable methodology for the primary extraction of R-PE and R-PC from marine macro-algae, Gelidium pusillum(Stackhouse) Le Jolis. Such extraction of phycobiliproteins by using ultrasonication and other conventional methods such as maceration, maceration in presence of liquid nitrogen, homogenization, and freezing and thawing (alone and in combinations) is reported for the first time. Standardization of ultrasonication for different parameters such as ultrasonication amplitude (60, 90 and 120µm) and ultrasonication time (1, 2, 4, 6, 8 and 10mins) at different temperatures (30, 35 and 40°C) was carried out. Kinetic parameters were estimated for extraction of phycobiliproteins by ultrasonication based on second order mass transfer kinetics. Based on calorimetric measurements, power, ultrasound intensity and acoustic power density were estimated to be 41.97W, 14.81W/cm² and 0.419W/cm³, respectively. Synergistic effect of ultrasonication was observed when employed in combination with other conventional primary extraction methods. Homogenization in combination with ultrasonication resulted in an enhancement in efficiency by 9.3% over homogenization alone. Similarly, maceration in combination with ultrasonication resulted in an enhancement in efficiency by 31% over maceration alone. Among all the methods employed, maceration in combination with ultrasonication resulted in the highest extraction efficiency of 77 and 93% for R-PE and R-PC, respectively followed by homogenization in combination with ultrasonication (69.6% for R-PE and 74.1% for R-PC). HPLC analysis was carried out in order to ensure that R-PE was present in the extract and remained intact even after processing. Microscopic studies indicated a clear relation between the extraction efficiency of phycobiliproteins and degree of cell disruption in a given primary extraction method. These combination methods were found to be effective for extraction of phycobiliproteins from rigid biomass of Gelidium pusillum macro-algae and can be employed for downstream processing of biomolecules also from other macro-algae.