Abstract
Microbial natural products serve as a good source for antioxidants. The mangrove‐derived Streptomyces bacteria have been evidenced to produce antioxidative compounds. This study reports the isolation of Streptomyces sp. MUM273b from mangrove soil that may serve as a promising source of antioxidants and UV‐protective agents. Identification and characterization methods determine that strain MUM273b belongs to the genus Streptomyces. The MUM273b extract exhibits antioxidant activities, including DPPH, ABTS, and superoxide radical scavenging activities and also metal‐chelating activity. The MUM273b extract was also shown to inhibit the production of malondialdehyde in metal‐induced lipid peroxidation. Strong correlation between the antioxidant activities and the total phenolic content of MUM273b extract was shown. In addition, MUM273b extract exhibited cytoprotective effect on the UVB‐induced cell death in HaCaT keratinocytes. Gas chromatography–mass spectrometry analysis detected phenolics, pyrrole, pyrazine, ester, and cyclic dipeptides in MUM273b extract. In summary, Streptomyces MUM273b extract portrays an exciting avenue for future antioxidative drugs and cosmeceuticals development.
Highlights
Natural products refer to chemical compounds produced by living organisms, for instance, plants, animals, and microorganisms that benefit the producer (Katz & Baltz, 2016)
This study demonstrated that MUM273b extract suppressed the iron‐induced peroxidation in egg yolk homogenate, suggesting that MUM273b extract could prevent the generation of by‐products of lipid peroxidation which can cause further damage to protein and DNA
This study shows that MUM273b extract was capable of attenuating the UVB‐induced cytotoxicity in HaCaT cells and serves as the first report of Streptomyces strain isolated from Malaysia mangrove soil exhibiting UVB‐protective activity. These findings suggested that the cyto‐ protective effect of MUM273b extract against UVB irradiation might be due to its antioxidant properties, including scavenging free radicals and inhibiting lipid peroxidation
Summary
Natural products refer to chemical compounds produced by living organisms, for instance, plants, animals, and microorganisms that benefit the producer (Katz & Baltz, 2016) Both terrestrial plants and microorganisms portray indispensable sources for bioactive natural products in drug discovery efforts owing to their excep‐ tionally capability in producing a great number of structurally diverse compounds (Cragg & Newman, 2001; Ma et al, 2018; Tan, Lee, et al, 2015; Tang et al, 2016). The natural products that exhibit phar‐ macological properties have been harnessed as clinically important drugs to treat diseases Besides their direct therapeutic use, the fas‐ cinating molecular frameworks of natural products offer a range of diverse unique chemotypes as inspiration for the development of current clinically significant drugs or potential novel drugs (Chan, Tan, Chan, Lee, & Goh, 2016; Nielsen, 2002; Rodrigues, Reker, Schneider, & Schneider, 2016; Tan, Low, et al, 2019). Many has turned their focus toward natural products derived from difficult‐ to‐reach sources/habitats to increase the opportunities for finding novel chemical entities (Desbois, 2014; Xu, 2015)
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