RESUMEN
Two C25 steroids with bicyclic [4.4.1] A/B rings were successfully separated from the marine fungus Aspergillus sp. LS116 by a two-step high-speed counter current chromatography (HSCCC). Petroleum ether/ethyl acetate/methanol/water (5.5:11:5:7, v/v) and petroleum ether/ethyl acetate/methanol/water (5:6:5:7, v/v) were selected as two optimum two-phase systems to purify two C25 steroids, neocyclocitrinol B (1) and threo-23-O-methylneocyclocitrinol (2). The purity of two compounds was over 94%. Their structures were determined by comprehensive spectroscopic techniques. This is the first report about rapid separation and identification of C25 steroids with bicyclic [4.4.1] A/B rings by HSCCC.
Asunto(s)
Distribución en Contracorriente , Metanol , Aspergillus , Cromatografía Líquida de Alta Presión/métodos , Distribución en Contracorriente/métodos , Hongos , Solventes/química , Esteroides , AguaRESUMEN
Methicillin-resistant Staphylococcus aureus (MRSA) and its biofilms infection is still a serious threat to global health. It is urgent to develop efficient drugs by repositioning or designing drugs to solve this problem. In this study, the antibacterial/biofilm activity and mechanisms of ivermectin (D) and its 4â³-position amino substitution derivative (D4) against MRSA were investigated. The minimum inhibitory concentration (MIC) of D was 20 µg/mL, which is four times higher than D4 (MIC = 5 µg/mL). The mechanism research demonstrated that D4 was more potent than D at destroying bacterial cell wall, permeating cell membrane (6.25-36.0% vs 1.92-6.04%) and binding to MRSA genomic DNA. Moreover, after incubation with 10-40 µg/mL D4 for 24 h, the percentages of biofilm decreased by 21.2-92.9%, which was more effective than D (no significant change at 40 µg/mL). The antibiofilm effect is achieved by regulating the expression of related genes (RSH, relQ, rsbU, sigB, spA, and icaD). Additionally, though the higher hemolysis makes D4 a safety risk for intravenous injection, other administration options could be considered as well. Therefore, all the results have indicated that D4 may be a potential candidate compound for the treatment of MRSA and its biofilm infections.
RESUMEN
A series of novel N-phenylbenzamide-4-methylamine acridine derivatives were designed and synthesized based initially on the structure of amsacrine (m-AMSA). Molecular docking suggested that the representative compound 9a had affinity for binding DNA topoisomerase (Topo) II, which was comparable with that of m-AMSA, and furthermore that 9a could have preferential interactions with Topo I. After synthesis of 9a and analogues 9b-9f, these were all tested in vitro and the synthesized compounds displayed potent antiproliferative activity against three different cancer cell lines (K562, CCRF-CEM and U937). Among them, compounds 9b, 9c and 9d exhibiting the highest activity with IC50 value ranging from 0.82 to 0.91⯵M against CCRF-CEM cells. In addition, 9b and 9d also showed high antiproliferative activity against U937 cells, with IC50 values of 0.33 and 0.23⯵M, respectively. The pharmacological mechanistic studies of these compounds were evaluated by Topo I/II inhibition, western blot assay and cell apoptosis detection. In summary, 9b effectively inhibited the activity of Topo I/II and induced DNA damage in CCRF-CEM cells and, moreover, significantly induced cell apoptosis in a concentration-dependent manner. These observations provide new information and guidance for the structural optimization of more novel acridine derivatives.