Phytochemical screening, antimalarial activities, and genetic relationship of 16 indigenous Thai Asteraceae medicinal plants: A combinatorial approach using phylogeny and ethnobotanical bioprospecting in antimalarial drug discovery

Emergence of artemisinin resistance leads the people to discover the new candidate for antimalarial drug. Combinatorial phylogeny and ethnobotanical approach may be useful to minimize the expenditure and time in laboratory testing. Seven hundred and thirty-three ethnomedicinal plants were listed from literature search. Obtained 340 internal transcribed spacer (ITS) sequences of plant list which met criteria were retrieved from GenBank NCBI and analyzed by MUSCLE and maximum likelihood phylogenetic test to generate the phylogenetic tree. Interactive phylogenetic tree was generated by Interactive Tree of Life (ITOL, https://itol.embl.de) and showed strong clustered pattern on Asteraceae. Afterward, 16 species of Asteraceae were selected to investigate the antimalarial activity, phytochemical, and genetic diversity. The presence of phytochemical was determined by standard method. DNA fluorescence-based assay was performed to determine the antimalarial activity against 3D7 Plasmodium falciparum. IC(50)μg/mL was used to categorize antimalarial activity. On the other hand, ITS universal primer was used to amplify and sequence the obtained extracted DNA of tested plant by cetyltrimethylammonium bromide method. Phylogenetic analyses were performed by MAFFT and RAxML with automatic bootstrapping. ITOL and Adobe Illustrator were used to generate interactive phylogenetic tree. All species tested showed the presence of phenolics and flavonoids, whereas alkaloids and terpenoids were shown vary among tested extracts. Among 16 species tested, 1 species exhibited good-moderate (Sphaeranthus indicus, IC(50)6.59 μg/mL), 4 weak (Artemisia chinensis, Artemisia vulgaris, Tridax procumbens, and Blumea balsamifera), and 3 very weak (Eupatorium capillifolium, Wedelia trilobata, and Vernonia cinerea). Generated phylogenetic tree by ITS data was able to separate the tested species into their tribal classification. In addition, new medicinal properties of A. chinensis were discovered. Combining phylogeny approach with ethnobotanical data is useful to narrow down the selection of antimalarial plants candidate.