کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
30449 | 44478 | 2014 | 6 صفحه PDF | دانلود رایگان |
• HPLC analysis revealed the presence of two MAAs, shinorine and M-307 in Gloeocapsa sp.
• UV-B radiation can induce the biosynthesis of MAAs.
• The MAAs, shinorine and M-307 are highly stable against some abiotic stressors.
• The MAAs (shinorine + M-307) shows strong antioxidant activity.
The biosynthesis of natural sunscreening compounds as influenced by ultraviolet radiation, their stability and antioxidant activity were studied in the cyanobacterium Gloeocapsa sp. CU-2556. An analysis by high-performance liquid chromatography (HPLC) with photodiode-array (PDA) detection revealed the biosynthesis of two MAAs, shinorine (UVλmax 333 nm) and an unknown MAA designated as M-307 (UVλmax 307 nm) with retention times of 5.9 and 6.4 min, respectively. Induction of the synthesis of MAAs was studied under 395 (PAR), 320 (PAR + UV-A) and 295 (PAR + UV-A + UV-B) nm cut-off filters. MAAs induction was significantly increased with an increase in exposure time up to 72 h in the samples covered with 295 nm cut-off filters. Contrary to shinorine, the biosynthesis of M-307 was more dominant in this unicellular cyanobacterium. Both MAAs were highly stable to some physico-chemical stressors such as UV radiation, heat and a strong oxidizing agent. The MAA M-307 was more stable under strong oxidative stress than shinorine. Moreover, UV-C radiation drastically decreased the stability of both MAAs. The MAAs (shinorine + M-307) also exhibited efficient antioxidant activity which was dose-dependent. The results indicate that MAAs may perform a vital role in survival and sustainability of Gloeocapsa sp. CU-2556 in harsh environmental conditions by its ability to absorb/screen short wavelength UV radiation and antioxidant function.
Journal: Journal of Photochemistry and Photobiology B: Biology - Volume 130, 5 January 2014, Pages 287–292