TITLE:
A New Ceramide (Rumexamide) and Other Chemical Constituents from Rumex abyssinicus Jacq (Polygonaceae): Isolation, Characterization, Antibacterial Activities and Chemophenetic Significance
AUTHORS:
Léonel Donald Feugap Tsamo, Lorette Victorine Yimgang, Steven Collins N. Wouamba, Pierre Mkounga, Augustin Ephrem Nkengfack, Laurence Voutquenne-Nazabadioko, David Ngnokam, Bruno Ndjakou Lenta, Norbert Sewald
KEYWORDS:
Polygonaceae, Rumex abyssinicus, Rumexamide, Antibacterial Activities, Chemophenetic Significance
JOURNAL NAME:
Advances in Biological Chemistry,
Vol.11 No.5,
October
29,
2021
ABSTRACT: The chemical study of Rumex abyssinicus Jacp (Polygonaceae) led to
the isolation of a new ceramide named (R)-2'-hydroxy-N-[(2S,3S,4R,16E)-1,3,4-trihy- droxyhexacos-16-en-2-yl]hexadecanamide (rumexamide) (1) together
with sixteen known compounds: bis-(2-ethylhexyl)
phthalate (2), chrysophanol (3), physcion (4),
citreorosein (5), emodin (6), chrysophanein (7),
physcionin (8), lupeol (9), 3β,28-dihydroxylup-20(29)-ene (10),
3β-dihydroxylup-20(29)-en-28- oic acid
(11), oleanolic acid (12), ergosta-6,22-diene-3,5,8-triol (13),
stigmastane-3,6-dione (14), a mixture of β-sitosterol (15) and stigmasterol (16), and stigmasterol 3-O-β-D-glucoside (17). Their
structures were determined by interpretation
of their spectroscopic 1D NMR (1H and 13C NMR), 2D NMR (COSY 1H-1H, HSQC and HMBC) data in conjunction with mass
spectrometry (TO- FESIMS
and HR-TOFESIMS) and by comparison with those reported in the literature. Among
all the known compounds, twelve (2, 5, 8-17) were firstly isolated from Rumex abyssinicus, seven (2, 10-14 and 17) from the genus Rumex and three (13, 14, 17) from family Polygonaceae. The in vitro antibacterial activities of extracts (MeOH, n-BuOH
and EtOAc), as well as compounds 9, 11, 12, 15 + 16 and 17 against pathogenic bacteria (Staphylococcus aureus ATCC 43300, Shigella flexneri NR 518, Klebsiella pneumoniae ATCC 700603, Escherichia coli ATCC 25922), were
performed using the broth microdilution method and the results show that, extracts were not
active (MIC > 1000 μg/mL) while compounds were weakly or not
active (MIC ≥ 500 μg/mL) against all bacteria strains. Furthermore, the
chemophenetic relationships of the isolated compounds and their significances were
discussed.