In vitro antimalarial activity of Garcinia parvifolia Miq. Stem extracts and fractions on Plasmodium falciparum lactate dehydrogenase (LDH) assay

Abstract

Objectives: The rapid spread of antimalarial drug resistance is becoming a problem in the treatment of malaria. The fact was indicated the importance of finding new antimalarial drugs. The genus Garcinia is well known to be a rich source of bioactive prenylated xanthones and triterpenes reported for their antimalarial activity. Garcinia parvifolia is one of the Garcinia genera that can be explored for the search of new antimalarial drugs. This study was aimed to determine the antimalarial activities of G. parvifolia extracts and fractions.

Methods: Garcinia parvifolia Miq. stem was collected from Balikpapan Botanical Garden in East Kalimantan, Indonesia, was extracted gradually with n-hexane, dichloromethane, and methanol by ultrasonic assisted method. The most active extract was further separated using the open column chromatography method. All extracts and fractions were tested against Plasmodium falciparum 3D7 using lactate dehydrogenase (LDH) assay and followed by IC₅₀ determination.

Results: The results showed that all extracts inhibit P. falciparum growth by LDH assay. The highest inhibition was showed by dichloromethane stem extract (BP12-S-D) with the IC₅₀ value of 6.61 ± 0.09 μg/mL. Further fractionation of BP12-S-D has obtained 10 fractions. All of them were identified by TLC, and a brownish-yellow spot (fraction-1) appears after spraying with 10% H₂SO₄. Fraction-1 (F1) performed the highest parasite growth inhibition with the IC₅₀ value of 6.00 ± 0.03 μg/mL compared with other fractions. This fraction was classified as having a promising activity of antimalarial. The fraction-1 was identified using HPLC, and two major peaks were observed (A and B). The UV-Vis spectra showed the absorption at wavelengths 250 and 278 (A), 243, 281, and 317 nm (B). Based on the profile of TLC, HPLC, and UV-Vis spectra of F1, it was expected that the active compounds are flavonoid (A) and xanthone (B).

Conclusions: The fraction-1 of dichloromethane extract of G. parvifolia Miq. stem has the highest antimalarial activity. It might be a potential candidate for the new antimalarial drug.

Keywords: Garcinia parvifolia Miq.; antimalarial activity; lactate dehydrogenase (LDH).