Bioassay-Guided Isolation of Antimicrobial Components and LC/QToF Profile of Plumeria obtusa: Potential for the Treatment of Antimicrobial Resistance

Abstract

The methanolic fraction (M-F) of the total extract (TE) of Plumeria obtusa L. aerial parts showed promising antibacterial effects against the MDR (multidrug-resistant) gram-negative pathogens Klebsiella pneumoniae and Escherichia coli O157:H7 [Shiga toxin-producing E. coli (STEC)]. In addition, M-F had a synergistic effect (in combination with vancomycin) against the MDR gram-positive strains MRSA (methicillin-resistant Staphylococcus aureus) and Bacillus cereus. After treating the K. pneumoniae- and STEC-infected mice with M-F (25 mg/kg, i.p.), the level of IgM and TNF-α was decreased and the severity of pathological lesions were reduced better than that observed after administration of gentamycin (33 mg/kg, i.p.). Thirty-seven compounds including 10 plumeria-type iridoids and 18 phenolics, 7 quinoline derivatives, 1 amino acid, and 1 fatty acid were identified in TE using LC/ESI-QToF. Furthermore, five compounds; kaempferol 3-O-rutinoside (M1), quercetin 3-O-rutinoside (M2), glochiflavanoside B (M3), plumieride (M4), and 13-O-caffeoylplumieride (M5) were isolated from M-F. M5 was active against K. pneumoniae (MIC of 64 μg/mL) and STEC (MIC of 32 μg/mL). These findings suggested that M-F and M5 are promising antimicrobial natural products for combating MDR K. pneumoniae and STEC nosocomial infections.

Plumieride as a novel anti-fungal and anti-inflammatory iridoid against superficial candidiasis in mice

“…1 ) by comparing 1 H- and 13 CNMR spectral data with those previously reported (Figs. S1 and S2) [ 11 , 13 ].…”

“…Using LC/ESI-QToF, 37 compounds were identified in the methanolic extract of P. obtusa aerial parts (10 plumeria-type iridoids, 6 quinoline derivatives, 18 phenolics, 2 amino acids, and one fatty acid). We recently reported that the methanolic extract of the leaves and plumieride-type iridoids isolated thereof demonstrated promising antibacterial activity against multidrug-resistant Gram-negative strains; Klebsiella pneumoniae and Shiga-toxin producing Escherichia coli (STEC) [ 11 ]. According to the results of molecular docking studies, 13- O -coumaroyl plumieride was found to exhibit superior binding affinity for both iNOS and prostaglandin E synthase-1 target receptors and suggest its potential for targeting and modulating the activity of both enzymes [ 12 ].…”

9-Methoxyellipticine: Antibacterial Bioactive Compound Isolated from Ochrosia elliptica Labill. Roots

“…The antibacterial research community must incessantly search together to develop new and safer medications to resolve the increasing drug resistance, along with toxicity challenges [ 8 , 9 , 10 ]. Historically, natural compounds have been a rich source of antibacterial therapies [ 11 , 12 , 13 , 14 ].…”