Caerulines A and B, Flavonol Diacylglycosides from Persea caerulea

Abstract

Two undescribed 4′-O-methylkaempferol-[3″,4″-di-p-coumaroyl]-α-l-rhamnopyranosides, caerulines A and B (1–2), along with three known 4′-O-methylkaempferol diacylrhamnosides isomers (3–5) were isolated from an ethanol extract of the leaves of Persea caerulea, a native plant growing on the Colombian Caribbean coast. The chemical structures of 1 and 2 were elucidated by spectroscopic methods. The effect of compounds 1–5 against four pathogenic microorganisms [i.e., methicillin-resistant Staphylococcus aureus (MRSA), Acinetobacter baumannii, Candida albicans, and Aspergillus fumigatus] was tested in vitro. The compounds exhibited no activity against these pathogens except MRSA (MIC 12–48 μg/mL). Caeruline B (2) was found to be the most active compound with a modest anti-MRSA activity (MIC = 12 μg/mL).

Chemistry and Bioactivity of the Genus Persea ‐ A Review

“…(2021) reported the isolation of five diacylglycosylated flavonoids from P. caerulea leaves, named as careulin A ( 119 ) and B ( 120 ), 4′‐ O ‐methylkaempferol‐[2,4′′‐di( E )‐ p ‐coumaroyl]‐α‐L‐rhamnopyranoside ( 121 ), 4′‐ O ‐methylkaempferol‐[2′′‐( Z )‐ p ‐couymaroyl,4′′‐( E )‐ p ‐coumaroyl]‐α‐L‐rhamnopyranoside ( 122 ) and 4′‐ O ‐methylkaempferol‐[2′′‐( E )‐ p ‐couymaroyl,4′′‐( Z )‐ p ‐coumaroyl]‐α‐L‐rhamnopyranoside ( 123 ). The authors also highlight the action of these flavonoids against multiresistant bacteria being 119 , 120 , 122 and 123 effectives against methicillin‐resistant strain of S. aureus , with MIC ranging from 12–48 μg/mL [68] …”

“…[67] Álvarez-Caballero et al The authors also highlight the action of these flavonoids against multiresistant bacteria being 119, 120, 122 and 123 effectives against methicillin-resistant strain of S. aureus, with MIC ranging from 12-48 μg/mL. [68] (+)-Cathechin (124), (À )-epi-cathechin (125), proantocianidin B1 (126) and B2 (127) were isolated from P. americana, P. caerulea, and P. americana. As observed, these compounds showed protective hair cell function activity.…”

“…Altogether, thirty fatty alcohols were isolated from P. americana (Figure 6), exhibiting different alkyl chain lengths, variations in hydroxyl groups and unsaturation, thereby showing antibacterial activity [49] against Staphylococcus aureus, Saccharomyces cerevisiae, Bacillus subtilis, and Bacillus cereus. The trihydroxy derivative (68), which has only one terminal double bond, showed values of MIC of 2-31 μg/mL. Compounds 69-70 were isolated from P. americana fruits and their insecticidal potential was evaluated.…”

“…[23] P. japonica provided the steroids β-sitosterol (26), stigmasterol (27), β-stigmasterol glucoside (28) and β-sitosterol glucoside (29). [17] Leaves of P. caerulea showed the presence of three [68] 122 4'-O-methylkaempferol-[2''-(Z)-p-couymaroyl,4''-(E)-p-coumaroyl]-α-L-rhamnopyranoside leaves P. caerulea anti-MRSA [68] 123 4'-O-methylkaempferol-[2''-(E)-p-couymaroyl,4''-(Z)-p-coumaroyl]-α-L-rhamnopyranoside leaves P. caerulea anti-MRSA [68] 124 (+)-cathechin bark; leaves P. caerulea P. americana protective hair cell function [29,69] 125 (À )-epi-cathechin 126 proantocianidin B1…”