Antibacterial C-Geranylflavonoids from Paulownia tomentosa Fruits

Abstract

Eight C-6-geranylflavonoids ( 1- 8) were isolated from an ethanol extract of Paulownia tomentosa fruits. Tomentodiplacone ( 1), 3'- O-methyl-5'-hydroxydiplacone ( 2), 3'- O-methyl-5'- O-methyldiplacone ( 3), and tomentodiplacone B ( 4) were obtained as new compounds, and 3'- O-methyldiplacol ( 5) was isolated for the first time from a natural source. The structures of these new compounds were determined by using mass spectrometry (including HRMS) and 1D and 2D NMR spectroscopy, and the absolute configurations of the compounds were determined by circular dichroism. The antibacterial activities of 1- 8 against seven bacteria and yeast were evaluated.

Antibacterial activity of flavonoids and their structure–activity relationship: An update review

“…subtilis , Enterococcus faecalis , Listeria monocytogenes , and S . aureus with MIC values of 2–4 μg/ml (Šmejkal et al, ). It has also been demonstrated that abyssione‐V 4′‐O‐methyl ether ( 88 ) from the stem bark of Erythrina caffra inhibit activity of E .…”

“…aureus , and S . epidermidis with MICs ranging from 2 to 4 μg/ml (Šmejkal et al, ). The MIC value of quercetin 3‐O‐methyl ether ( 101 ) isolated from Cistus laurifolius flowers was found to be 3.9 μg/ml against Helicobacter pylori (Ustün, Ozçelik, Akyön, Abbasoglu, & Yesilada, ).Some researchers have reported synergy between naturally occurring flavane‐3‐ols and antibiotic agents.…”

“…Presence of the hydroxy group at different positions of A and B rings has also been reported to improve antibacterial activity. Šmejkal et al () reported that 3′‐O‐methydiplacol ( 100 ) with OH at positions 5, 3′, and 4′ on the A and B rings, respectively, geranyl group at C‐6 and OMe at C‐5′ showed good activity towered S . aureus with MIC value of 4 μg/ml.…”

An In-Silico Investigation of Phytochemicals as Antiviral Agents Against Dengue Fever

“…Silybin (silibinin, silymarin) has shown antiviral activity against hepatitis C virus [63] and chikungunya virus [64]. C -geranylated flavanones from Paulownia tomentosa fruits have shown antibacterial [65, 66], cytotoxic [67], and anti-inflammatory [68] activities as well as SARS-CoV protease inhibitory activity [69]. Diplacone showed excellent docking properties with DENV MTase (Table 3 ) and both 3ʹ- O -methyldiplacone and 3ʹ- O -methyldiplacol docked well with the ATP site of DENV helicase (Table 2 ).…”

Geranylated Flavanones from <i>Paulownia coreana</i> and Their Inhibitory Effects on Nitric Oxide Production

“…The structures of known isolates were elucidated on the basis of their spectroscopic analysis ( 1 H-, 13 C-NMR, and electrospray ionization (ESI)-MS) by comparison with those of published data. Ten known compounds were determined to be 3′-O-methyl-5′-hydroxydiplacone (2), 14) diplacol (3), 15) diplacone (4), 15) 3′-O-methyldiplacol (5), 15) 6-geranyl-4′,5,7-trihydroxy-3′,5′-dimethoxyflavanone (6), 7) mimulone B (7), 16) dihydrotricin (8), 8) 5,7-dihydroxy-3′,4′,5′-trimethoxyflavanone (9), 17) (+)-pinoresinol (10), 18) and (+)-dehydrovomifoliol (11), 19) respectively (Fig. 1).…”