Polymethylated Phloroglucinol Meroterpenoids from Rhodomyrtus tomentosa and Their Antibacterial and Acetylcholinesterase Inhibitory Effects

Abstract

Rhotomentodiones CÀ E, three new polymethylated phloroglucinol meroterpenoids with diverse configurations, were isolated from the twigs and leaves of Rhodomyrtus tomentosa. Their structures and absolute configurations were established mainly by means of comprehensive spectroscopic data and electron circular dichroism (ECD) calculation. Among them, Rhotomentodione D (2) exhibited both antibacterial activity with an MIC value of 12.5 μg/mL against Propionibacterium acnes and AChE inhibitory activity with an IC 50 value of 22.9 μM.

Non-Alkaloid Cholinesterase Inhibitory Compounds from Natural Sources

“…Several terpenoids from natural sources have been reported as cholinesterase inhibi-tors [ 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 ]. The compounds 1 – 11 , as shown in Supplementary Material ( Table S1 ), are of the Abietane-type diterpene skeletons isolated from Salvia austriaca , Salvia glutinosa , Caryopteris mongolica, and Perovskia atriplicifolia [ 14 , 15 , 16 ].…”

Phloroglucinol and Its Derivatives: Antimicrobial Properties toward Microbial Pathogens

“…58 Rhotomentodiones C−E were extracted from Rhodomyrtus tomentosa leaves and twigs and exhibited the highest antibacterial activities against Propionibacterium acnes, with MIC and MBC values of 12.5−50 μg/mL and 25.0−100.0 μg/mL, respectively. 59 Aspidin BB, a phloroglucinol derivative derived from Dryopteris f ragrans (L.) Schott, has the highest bactericidal activity against S. epidermidis, S. aureus, and P. acnes. 53,55 In particular, the presence of aspidin BB (1) impaired the permeability of the bacterial membrane, (2) degraded the DNA and proteins, and (3) inhibited lipase activity in P. acnes 55 (Figure 2).…”

“…Furthermore, as shown in 3,3-dipropylthiacarbocyanine and SYTOX green assays and scanning electron microscopy (SEM), the potency of callistemonols A and B was considered to be a result of (1) depolarization of the bacterial membrane, (2) concentration-dependent permeability effects, and (3) bacterial cell lysis (Figure ). Rhotomentodiones C–E were extracted from Rhodomyrtus tomentosa leaves and twigs and exhibited the highest antibacterial activities against Propionibacterium acnes , with MIC and MBC values of 12.5–50 μg/mL and 25.0–100.0 μg/mL, respectively . Aspidin BB, a phloroglucinol derivative derived from Dryopteris fragrans (L.) Schott, has the highest bactericidal activity against S. epidermidis , S. aureus , and P. acnes . , In particular, the presence of aspidin BB (1) impaired the permeability of the bacterial membrane, (2) degraded the DNA and proteins, and (3) inhibited lipase activity in P. acnes (Figure ).…”