RESUMO
A biosurfactant producing bacterium was identified as Pseudomonas aeruginosa DNM50 based on molecular characterization (NCBI accession no. MK351591). Structural characterization using MALDI-TOF revealed the presence of 12 different congeners of rhamnolipid such as Rha-C8-C8:1, Rha-C10-C8:1, Rha-C10-C10, Rha-C10-C12:1, Rha-C16:1, Rha-C16, Rha-C17:1, Rha-Rha-C10:1-C10:1, Rha-Rha-C10-C12, Rha-Rha-C10-C8, Rha-Rha-C10-C8:1, and Rha-Rha-C8-C8. The radical scavenging activity of rhamnolipid (DNM50RL) was determined by 2, 3-diphenyl-1-picrylhydrazyl (DPPH) assay which showed an IC50 value of 101.8 µg/ ml. The cytotoxic activity was investigated against MDA-MB-231 breast cancer cell line by MTT (4,5-dimethylthiazol-2-yl-2,5-diphenyl tetrazolium bromide) assay which showed a very low IC50 of 0.05 µg/ ml at 72 h of treatment. Further, its activity was confirmed by resazurin and trypan blue assay with IC50 values of 0.01 µg/ml and 0.64 µg/ ml at 72 h of treatment, respectively. Thus, the DNM50RL would play a vital role in the treatment of breast cancer targeting inhibition of p38MAPK.
RESUMO
Prolonged exposure to Ultra Violet Radiation (UVR) adversely alters the functions of many skin cell types causing skin cancer and photoaging, which had led to increase in demand for more safe and natural sunscreens against UVR. The present study focuses on production, structural characterization and evaluation of photoprotective nature of melanin pigment derived from lime dwelling Pseudomonas sp. Melanin was characterized by solubility, UV-Vis, FT-IR, 13C-CPMAS, ESI-MS spectroscopy, including particle size, melting point and elemental analyses. In vitro cytotoxicity and photo-protective effect of Pseudomonas derived melanin (Mel-P) against UV-B (Broad Band-BB) radiations were assessed on mouse fibroblasts NIH 3 T3 cell lines. Reactive Oxygen Species (ROS) generated in NIH 3 T3 cells upon UV-B (BB) exposure was determined and quantified by Fluorescent microscopic and Flow cytometric analyses. A natural melanin obtained from Pseudomonas sp. contains 5,6- dihydroxy indole 2-carboxyic acid (DHICA) as its basic constituent and possess typical properties of eumelanin as revealed by the characterization studies. Mel-P has shown cell viability of 61.33 ± 6.58% at the concentration of 500 µg/mL proving its non-cytotoxic effect. Owing to its anti-oxidant property, melanin efficiently protected the mouse fibroblast cells from UV-B (BB) irradiation in a dose dependant manner demonstrating its potential as an active photoprotective agent.
