Antileishmanial anthraquinones from the rhyzomes of Rumex abyssinicus Jacq (Polygonaceae)

Abstract

Phytochemical investigation of the rhyzomes of Rumex abyssinicus (Polygonaceae) afforded six anthraquinones viz chrysophanol (1), physcion (2), emodin (3), mixture of physcion-8-O-β,D-glucopyranoside (4) and chrypsophanol-8-O-β,D-glucopyranoside (5), and emodin-8-O-β,D-glucopyranoside (6). All the compounds were characterised and identified by comparison of their MS and NMR data with available literature data. The isolated compounds were evaluated for their antileishmanial activity. Emodin (3) was the most active compounds with IC₅₀ 13.82 and 0.26 µg/mL against Leishmania donovani amastigotes and promastigotes, respectively. Emodin-8-O-β,D-glucopyranoside (6) also showed a moderate activity with IC₅₀ 27.53 and 37.08 µg/mL. This is the first report of antileishmanial compounds from R. abyssinicus and the antileishmanial activities of compounds 2, 4, 5 and 6 are here reported for the first time.

Graphical Abstract

Keywords:

• Rumex abyssinicus
• anthraquinones
• antileishmanial activity

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The authors are grateful to Bill and Melinda Gates Foundation through the postdoctoral fellowship training program in Infectious Diseases at Noguchi Memorial Institute for Medical Research, Ghana (Global Health Grant number OPP52155), for the financial support to LRTY to carry out biological activities.