Ten lignans (1 – 10) were isolated from the hexane-ethyl acetate extract of Phyllanthus amarus leaves. Three of them, cubebin dimethyl ether (3), urinatetralin (4), and lintetralin (7) are described for the first time in this species, while phyllanthin (1), niranthin (2), 5-demethoxyniranthin (5), isolintetralin (6), hypophyllanthin (8), nirtetralin (9), and phyltetralin (10) have been already reported from P. amarus. Among the lignans tested against Trypanosoma cruzi intracellular amastigotes, 2 was the most active with an EC₅₀ of 35.28 µM. Lignans 2, 5, 7, and 9 showed inhibitory effects against Leishmania amazonensis promastigotes with EC₅₀ of 56.34, 51.86, 23.57, and 43.27 µM, respectively. During in vitro infection assays, 5 reduced amastigotes by 91% at 103.68 µM concentration, whereas 7 and 9 reduced amastigotes by approximately 84% at 47.5 and 86.04 µM, respectively. Lignans 5, 7, and 9 were more potent in intracellular amastigotes with EC₅₀ of 2.76, 8.30, and 15.83 µM, respectively, than in promastigotes. CC₅₀ for all samples was > 100 µg/mL, thus revealing low cytotoxicity against macrophages, and selectivity against the parasite. L. amazonensis promastigotes treated with compounds 2 and 9 showed decreased respiratory control of 38% and 25%, respectively, suggesting a change in mitochondrial membrane potential and lower ATP production.

Seborrheic dermatitis is a chronic inflammatory disease caused by Malassezia yeast species that affects the regions of the body where the sebaceous glands are present. The combined use of different essential oils (EOs) can increase their spectrum of action. Thus, the present study aimed to evaluate the action of EOs alone and in combination with each other on M. furfur, in planktonic and biofilm form, and their anti-inflammatory and mutagenic potential, in addition to the effects on the viability of cells lines. Of the 40 evaluated EOs, 22 showed activity against M. furfur at 0.5 – 2.0 mg/mL concentrations. Among the most active species, a blend of essential oils (BEOs) composed of Cymbopogon martini (Roxb.) Will. Watson (MIC = 0.5 mg/mL) and Mentha × piperita L. (MIC = 1.0 mg/mL) was selected, which showed a synergistic effect against yeast when evaluated through the checkerboard assay. The fungicidal activity was maintained by the addition of anti-inflammatory oil from Varronia curassavica Jacq. to BEOs. The BEOs also showed activity in the inhibition of biofilm formation and in the eradication of the biofilm formed by M. furfur, being superior to the action of fluconazole. Furthermore, it did not show mutagenic potential and did not interfere with the cell viability of both evaluated cell lines (HaCaT and BMDMs). TNF-α levels were reduced only by C. martini; however, this property was maintained when evaluating BEOs. BEOs had no effect on IL-8 levels. Thus, the BEOs may be indicated for alternative treatments against seborrheic dermatitis.

Chloroform extract (CE) and fractions obtained from Aldama arenaria roots were evaluated for their in vitro antiproliferative activity against 10 human tumor cell lines [leukemia (K-562), breast (MCF-7), ovary expressing a multidrug-resistant phenotype (NCI/ADR-RES), melanoma (UACC-62), lung (NCI-H460), prostate (PC-3), colon (HT29), ovary (OVCAR-3), glioma (U251), and kidney (786-0)]. CE presented weak to moderate antiproliferative activity (mean log GI50 1.07), whereas fractions 3 and 4, enriched with pimarane-type diterpenes [ent-pimara-8(14),15-dien-19-oic acid and ent-8(14),15-pimaradien-3β-ol], presented moderate to potent activity for most cell lines, with mean log GI50 of 0.62 and 0.59, respectively. The results showed promising in vitro antiproliferative action of the samples obtained from A. arenaria, with the best results for NCI/ADR-RES, HT29, and OVCAR-3, and TGI values ranging from 5.95 to 28.71 µg.mL-1, demonstrating that compounds of this class may be potential prototypes for the discovery of new therapeutic agents.