Antimicrobial Rubrolides from a South African Species of Synoicum Tunicate

Abstract

The CH2Cl2-MeOH extract of a South African tunicate described as the new Synoicum globosum Parker-Nance sp. nov. (Ascidiacea, Aplousobranchia) was subjected to 1H NMR-guided fractionation. This resulted in the identification of new 3″-bromorubrolide F (1), 3′-bromorubrolide E (2), 3′-bromorubrolide F (3) and 3′, 3″-dibromorubrolide E (4), and reisolation of known rubrolides E (5) and F (6), based on NMR spectroscopic and mass spectrometric data. Biological testing of both new and known members of this reported antimicrobial family of halogenated, aryl-substituted furanones indicated moderate antibacterial properties for 3′-bromorubrolide E (2), 3′, 3″-dibromorubrolide E (4), and rubrolide F (6) against methicillin-resistant Staphylococcus aureus (MRSA) and S. epidermidis.

Synthesis and Characterization of Fluorescent Brightening Agents with Chiral 2(5H)-Furanone and Bis-1,2,3-triazole Structure

“…The structures of the target compounds 6a and 6b are systematically characterized by Fourier transform infrared (FTIR) spectroscopy, UV, 1 H NMR, 13 According to the literature on stilbene sulfonate, 1,7,8 both 1 H and 13 C NMR spectra of compounds 6a and 6b are determined. In 1 H NMR, there is a singlet peak in the region of 5.30−5.31 ppm, which is the characteristic peak of 5-H in 2(5H)-furanone structure.…”

“…Herein, based on our previous research, 23,26,27 we take advantage of the Click reaction 17,19,28−30 to build bis-1,2,3-triazole moiety, with the intent to combine stilbene sulfonate with 2(5H)-furanone moiety (see Scheme 1). For the first time, the novel FBA (6) forms simultaneously possessing chiral 2(5H)-furanone and bis-1,2,3-triazole moieties are synthesized, and their structures and properties are characterized by infrared (IR) spectroscopy, 1 H nuclear magnetic resonance ( 1 H NMR), 13 C NMR, mass spectroscopy (MS), elemental analysis, ultraviolet (UV) analysis, scanning electron microscopy (SEM), and UV protection factor (UPF) testing.…”

Rubrolides as Model for the Development of New Lactones and Their Aza Analogs as Potential Photosynthesis Inhibitors

“…, 207 (26), 110 (22), 109 (100), 107 (14), 101 (17), 96 (17), 83 (45), 75 (31),63 (29), 57 (19), 51 (23 (7)); 3.53 (AB, J AB ¼ 14.1,H b ÀC(7)); 3.79 (s,M eO); 6.15 (s, NH); 7. 11 (d, J(3',4') ¼ 9.0, HÀC(3'));7 .36 (d, J(2'',3'') ¼ J(6'',5'') ¼ 8.4, HÀC(2'',6''));7 .46 (dd, J(4',3') ¼ 9.0, J(4',6') ¼ 2.7,H ÀC(4'));7 .67 (d, J(6',4') ¼ 2.7,HÀC(6'));8.01 (d, J(3'',2'') ¼ J(5'',6'') ¼ 8.4, HÀC(3'',5'')).…”

“…13 C-NMR((D 6 )acetone): 41.6 (C(7)); 55.2 (MeO); 93.8 (C(4));113.2 (C(3'));120.6 (C(1'));121.5 (C(6)); 122.6(C(3'',5''));124.5 (C(5'));128.9 (C(6'));130.8 (C(4'));131.7 (C(2'',6''));143.1 (C(1''));147.1 (C(4'')); 149.6 (C(5)); 155.4 (C(2'));158.1 (C(3)). MS:453 (14 (7)); 3.49 (AB, J AB ¼ 14.1,H b ÀC (7)); 3.77 (s,MeO);…”

Physicochemical characterization of Theobroma cacao L. mucilage, in Ecuadorian coast

“…The main raw materials used to produce xylitol are corncob, soybean stalk, sugarcane bagasse and light woods (Dhar et al, 2016). Rubrolide C is rarely found in natural sources (Tale et al, 2012) and reports biological activity against S. aureus, B. subtiliis B. megaterium, Escherichia coli, Clostridium perfringens and Micrococcus tetragenus (Sikorska et al, 2012;Zhai et al, 2016).…”