Bioaktivitas Ekstrak Metanol Alga Merah (Gracilaria sp.) sebagai Antimalaria terhadap Plasmodium falciparum Strain 3D7 secara In Vitro

Abstract

Malaria remains a major global health challenge due to the increasing resistance to antimalarial drugs. One potential alternative approach is the utilization of natural products, such as the red algae Gracilaria sp., which contains secondary metabolites with potential antimalarial activity. This study aimed to identify the secondary metabolites and evaluate the antimalarial activity of the methanolic extract of Gracilaria sp. The study was conducted using an experimental design with a completely randomized design approach through an in vitro assay against Plasmodium falciparum strain 3D7 at the ring stage with an initial parasitemia of approximately 1%. The assay was performed at concentrations of 0.01–100 µg/mL in duplicate, with a negative control (dimethyl sulfoxide, DMSO) and a positive control (standard antimalarial drug). Cultures were incubated for 48 hours at 37°C and subsequently examined using Giemsa staining. Data were analyzed using analysis of variance (ANOVA) followed by the least significant difference (LSD) test, and probit analysis was applied to determine the 50% inhibitory concentration (IC₅₀). Phytochemical screening revealed the presence of alkaloids, saponins, flavonoids, tannins, and steroids. The IC₅₀ value of 2.00 µg/mL indicates that the methanolic extract of Gracilaria sp. exhibits highly active antimalarial activity against Plasmodium falciparum.