Fig. 2
Inhibition of the multidrug-resistant parasite Plasmodium falciparum (NF54) using leaf extracts of A. annua grown under different artificial light treatments. Microscopic assay of NF54 growth was observed after 0 and 28–30 h of incubation under three conditions. Medium containing 0.05% DMSO and medium containing 100 nM artesunate (ATS) were used as the negative and positive controls, respectively (a). Growth inhibition (%) of NF54 after 28–30 h of incubation with six concentrations (0.001–100 μg mL−1) of leaf extracts (b). Crude extracts were obtained from A. annua leaves grown under different LED spectra as W, white LED light (445, 554 nm), B, blue LED light (445 nm) and R, red LED light (660 nm). Other parameters were kept constant as 200 ± 10 μmol m−2 s−1 PPFD, 16 h photoperiod, 25.0 ± 0.5 °C and 65.0 ± 1.5% RH. Different letters in each group of bars indicate significant difference at p ≤ 0.05 (*) or highly significant difference at p ≤ 0.01 (**) analyzed by Tukey’s HSD test. Error bars represent standard deviation. Microscopic inspection of NF54 further confirmed that inhibition was concentration-dependent (c), in agreement with results shown in b