Alkenylbenzoquinones and other compounds from the fruit of Maesa lanceolata exhibited potent cytotoxic, antibacterial, and antiradical scavenging activities^§

Abstract

A phytochemical study of the methanol extract of the fruit of Maesa lanceolata resulted in the isolation of a new alkenylbenzoquinone (1), alongside the known compounds (Z)-2,5-dihydroxy-6-methyl-3-(pentadec-10’-enyl)-1,4-benzoquinone (2), 2,5-dihydroxy-6-methyl-3-(nonadec-14’-enyl)-1,4-benzoquinone (3), 2,5-dihydroxy-6-methyl-3-(tridecyl)-1,4-benzoquinone (4), (2S,3S,4R,2’R,9E)-[2’-hydroxytetraeicosanoyl]-2-aminooctadec-9-ene-1,3,4-triol (5), monopalmitin (glyceryl palmitate) (6), lupeol (7), and 3-O-(β-D-glucopyranoside)-β-sitosterol (8). The structures of the compounds were established by the means of spectroscopic (1 D- and 2 D-NMR) and spectrometric techniques (MS). The isolated compounds were assessed for their antibacterial, cytotoxic, and antiradical activities. Compound 2 showed moderate activity against Staphylococcus warneri (DSMZ 20036), while the other compounds were inactive. The two quinones 1 and 2 were significantly cytotoxic, with IC₅₀ values of 0.005 µM and 12.5 µM respectively, and were weakly active towards DPPH radical (IC₅₀ >250 µg/mL).

Graphical Abstract

Keywords:

• Benzoquinones
• Maesa lanceolata
• Primulaceae
• antiradical
• cytotoxic
• and antibacterial

Acknowledgements

The authors are grateful to Carmela Michalek, Bielefeld University, for the biological activity testing and to the NMR and MS departments at Bielefeld University for the spectroscopic measurements. The authors gratefully acknowledge financial support from the research grant committees of both the University of Dschang and the Cameroonian Ministry of Higher Education. Authors would like to acknowledge the Yaounde-Bielefeld Graduate School of Natural Products with Antiparasite and Antibacterial Activities (YaBiNaPA, www.yabinapa.de) for the research stay granted at the University of Bielefeld in Germany under the project N° 57316173. BLN is deeply thankful to the International Foundation for Sciences (IFS) and the Organization for the Prohibition of Chemical Weapons (OPCW) for financial support.

Disclosure statement

No conflict of interest was reported by the authors.