The Effect of Andrographis paniculata Nees on Oxidative Stress and Parasitemia Levels of Plasmodium berghei Infected Rats

Abstract

Background: During malaria infection, oxidative stress arises due to the high metabolic rate of the multiplying parasite within the erythrocyte. Malondialdehyde (MDA), a product of lipid peroxidation and glutathione (GSH) has been suggested as a biomarker of oxidative stress. The Ethyl acetate (EA) fraction from the ethanol extract of Andrographis paniculata was shown to inhibit Plasmodium berghei in vivo. However, the antimalarial mechanism of the EA fraction, specifically on oxidative stress has not been investigated previously. Therefore, this study aimed to investigate the effects of the EA fraction on parasitemia levels, GSH and MDA levels of P. berghei infected rats. Methods: Female Wistar rats infected with P. berghei were divided into three groups. Group one received no treatment (negative control), group two was treated with 1.4 mg/200 g body weight of chloroquine diphosphate as positive control, and group three was treated with the EA fraction at a dose equal to andrographolide 3.5 mg/200 g body weight. The treatments lasted for four days (day 0 to day 3) and parasitemia was observed from day 0 to day 4. Rats were sacrificed and blood taken intracardially on day 4 after parasitemia observation. GSH was measured using an ELISA reader at a wavelength of 415 nm. MDA was observed via spectrophotometry at a wavelength of 532 nm. Results: The EA fraction at a dose equal to andrographolide 3.5 mg/200 g body weight was able to inhibit parasite growth by 81.97±9.14%. The GSH levels of the negative control, positive control and EA fraction treated group were 139.30±75.93 μMol/mL, 81.06±53.26 μMol/mL and 105.71±76.00 μMol/mL, respectively. Furthermore, the MDA level of negative control, positive control and EA fraction treated group were 11.18±0.70 nMol mL, 8.81±1.26 nMol/mL and 9.40±0.74 nMol/mL, respectively. No significant differences were detected between treatment groups regarding their GSH levels. Additionally, there was a significant difference in MDA levels between the negative control and positive control groups; as well as a significant difference between the negative control and the EA treated group. However, no significant difference in MDA levels between the EA fraction treated group and positive control group. Interestingly, a correlation was found between parasite growth inhibition and MDA levels among groups (p<0.05). Conclusion: The EA fraction of A. paniculata significantly decreased MDA levels which correlated significantly with parasitemia levels of P. berghei infected rats. The antimalarial activity of the EA fraction may have been correlated with oxidative stress mechanisms and this correlation could be explained in part by the decreased production of MDA.