Hexaricins, Pradimicin-like Polyketides from a Marine Sediment-Derived Streptosporangium sp. and Their Antioxidant Effects

Abstract

Seven pradimicin-like polyketides were isolated from the dichloromethane extract of the marine sediment-derived Streptosporangium sp. CGMCC 4.7309, including five new hexaricins, D-H (1-5), and known hexaricins A (6) and C (7). Their structures were determined by HRESIMS, 1D and 2D NMR, and other spectroscopic analyses. The absolute configurations of compounds 1-5 were determined on the basis of circular dichroism and specific rotation data. All isolated compounds 1-7 were tested for their antioxidant capacities by DPPH scavenging, OH scavenging, andO̅ scavenging assays. Compounds 3 and 4 displayed stronger antioxidant activities than the positive control ( tert-butylhydroquinone). The relationship between structure and antioxidant activity is discussed. These compounds could be effective natural antioxidants with considerable pharmaceutical value.

Salumycin, a New Pyrazolequinone from a Streptomyces albus J1074 Mutant Strain

“…The antioxidant activity of ( 1 ) was evaluated by the DPPH free radical scavenging assay [ 17 ]. Compared with the high DPPH free radical scavenging activity of tert -butylhydroquinone (EC50 = 4.7 ± 0.3 μM), ( 1 ) showed moderate activity (EC50 = 46.3 ± 2.2 μM).…”

“…The assay was performed as described by Gao et al [ 17 ]. The compounds were dissolved in MeOH to form a concentration gradient of 3.125–100 μg/mL.…”

Overexpression of Global Regulator PbrlaeA Leads to the Discovery of New Polyketide in Fungus Penicillium Brocae HDN-12-143

“…The cytotoxicity assays were evaluated by the MTT method against the K562 and HL-60 cancer cell lines, and the SRB method against the H975, MGC803, and HO-8910 cancer cell lines. All of the biological evaluations were carried out as previously reported in the References (Yu et al, 2016;Gao et al, 2018).…”

“…Compounds 1 and 2 exhibited weak activities against HL-60 with IC 50 of 18.63 and 24.83 µM (Table S2). Besides, compounds 1 and 2 were also tested for the antimicrobial activity against Bacillus subtilis and antioxidant capacities by DPPH free radical scavenging assay, but no activity was observed (IC 50 > 100 µM) (Yu et al, 2016;Gao et al, 2018).…”

Bioactive Compounds Isolated from Marine-Derived Microbes in China: 2009–2018

“…Recently, a series of pradimicin-like polyketides, the hexaricins, including five new compounds 35 – 39 , were obtained from a marine sediment that is derived Streptosporangium sp. Of these, hexaricins F ( 37 ) and G ( 38 ) showed potent antioxidant activity, even stronger than the positive control [39]. Some researchers commonly employ co-culture as a strategy for producing novel chemistry: in a 2018 study, Zhang et al isolated janthinopolyenemycins A ( 40 ) and B ( 41 ), which are two novel antifungal polyketides, from the co-culture of two marine-sourced bacteria Janthinobacterium spp.…”