Phytochemical and antiplasmodial investigation of Gardenia thunbergia L. f. leaves

Abstract

Previous results indicated that the methanol extract of Gardenia thunbergia has antiplasmodial activity but no compounds have ever been isolated from the plant. Therefore, this study aimed to investigate the phytochemical and antiplasmodial properties of the plant. The methanol leaf extract of G. thunbergia inhibited Plasmodium falciparum at 50 µg/mL (> 80% inhibition) and was not cytotoxic against HeLa cells. Chromatographic purification of the extract afforded a new saponin and eight other known compounds. The saponin and two flavonoid glycosides displayed non-selective antiplasmodial activity at 50 µg/mL but the activities were diminished at 10 µg/mL. The presence of the isolated compounds in the leaf extract of G. thunbergia could account for the folkloric use of the plant in treating malaria.

Graphical Abstract

Keywords:

• Malaria
• HeLa human cervical cancer cells
• antiplasmodial
• Plasmodium falciparum
• Gardenia thunbergia
• Rubiaceae

Acknowledgment

The authors are grateful to Dr Christina Potgieter of Bews Herbarium, School of Life Sciences, University of KwaZulu-Natal and Ms. Alison young for identifying the plant material. Antimalarial and cytotoxicity evaluations were supported by Rhodes University (Sandisa Imbewu grant) and the South African Medical Research Council.

Disclosure statement

The authors declare that they have no conflict of interest.

Additional information

Funding

NT is grateful to the University of KwaZulu-Natal for the award of a doctoral scholarship. FRVH acknowledges the National Research Foundation (South Africa) Grant [number 98345] for financial support.