Anti-plasmodial and anti-inflammatory activities of cyclotide-rich extract and fraction of  Oldenlandia affinis(R. & S.) D.C. (Rubiaceae).

Chukwuemeka Sylvester Nworu, Tochukwu Ifenyinwa Ejikeme, Adaobi Chioma Ezike, Okechukwu Ndu,
Theophine Chinwuba Akunne, Collins Azubuike Onyeto, Paul Okpalanduka, Peter Achunike Akah
Department of Pharmacology & Toxicology, Faculty of Pharmaceutical Sciences, University of Nigeria, Nsukka,
410001, Enugu State, Nigeria

Abstract
Background: Oldenlandia affinis, commonly called ‘kalata-kalata’, a versatile plant used locally to treat malaria fever in some parts  of sub-Saharan Africa was investigated for anti-plasmodial and anti-inflammatory activities.

Objective: The study was designed to evaluate the antiplasmodial as well as anti-inflammatory activities of whole extract and  cyclotide-rich fraction of Oldenlandia affinis

Method:The dichloromethane-methanol extract (ODE) of the plant, O. affiniswas investigated for suppressive and curative antiplasmodial activities against Plasmodium bergheiin mice. ODE and the cyclotide-rich fraction (CRF) was investigated for chronic  and acute anti-inflammatory activities in rat models of inflammation. Inhibition of pro-inflammatory mediators was studied in  RAW264.7 macrophages.

Results: ODE exhibited significant (p<0.05) reduction in mean parasitaemia in both the suppressive and curative models  of Plasmodium berghei infection in mice.Administration of ODE(100, 200, or 400 mg/kg) and CRF (100, 200, or 400 mg/kg)  produced significant inhibition of rodent models of acute and chronic inflammation . This observation is supported by the  significant (P<0.05) inhibition of pro-inflammatory mediators, inducible nitric oxide (iNO) and tumour necrosis factor-alpha  (TNF-α), and the reactive radical scavenging activities in RAW264.7 macrophages.

Conclusion: These findings could explain, at least in part, the successes reported in the use of the herb, Oldenlandia affinisin the  traditional treatment of malaria fever.

Keywords: Oldenlandia affinis, Reactive oxygen/nitrogen species, Plasmodium berghei, pro-inflammatory mediators, parasitemia.