Biological Evaluation of Essential Oils from Selected Medicinal Plants and Their Main Components against Phytomonas davidi (Kinetoplastea: Trypanosomatidae).

Eight essential oils (EOs) from selected medicinal plants have been tested for their activity against Phytomonas davidi, a plant trypanosomal parasite. In the present research, the EOs have been tested on promastigote forms of P. davidi ATCC® 30287™ strain, along with their major components, both separately and in binary combinations, using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) reduction assay. The EOs with the highest antipromastigote activity were from Origanum virens and Salvia lavandulifolia. Thymol and ß-pinene were the most active pure compounds. The study of the activity of the pure compounds in combination indicated the existence of antagonistic and synergistic effects depending on the concentration tested. In general, the combinations at low concentrations favored the activity.

Chemical Composition and Biological Activities of Artemisia pedemontana subsp. assoana Essential Oils and Hydrolate.

Given the importance of the genus Artemisia as a source of valuable natural products, the rare plant Artemisia pedemontana subspecies assoana, endemic to the Iberian Peninsula, has been experimentally cultivated in the greenhouse and aeroponically, to produce biomass for essential oil (EO) extraction. The chemical composition of the EOs was analyzed, and their plant protection (insects: Spodoptera littoralis, Rhopalosiphum padi, and Myzus persicae; plants: Lactuca sativa and Lolium perenne; fungi: Aspergillus niger; and nematode: Meloidogyne javanica) and antiparasitic (Trypanosoma cruzi, Phytomonas davidi, and antiplasmodial by the ferriprotoporphyrin biocrystallization inhibition test) properties were studied, in addition to the hydrolate by-product. The EOs showed a 1,8-cineole and camphor profile, with quantitative and qualitative chemical differences between the cultivation methods. These oils had moderate insect antifeedant, antifungal, and phytotoxic effects; were trypanocidel; and exhibited moderate phytomonacidal effects, while the hydrolate showed a strong nematicidal activity. Both EOs were similarly antifeedant; the EO from the greenhouse plants (flowering stage) was more biocidal (antifungal, nematicidal, and phytotoxic) than the EO from the aeroponic plants (growing stage), which was more antiparasitic. The major components of the oils (1,8-cineole and camphor), or their 1:1 combination, did not explain any of these effects. We can conclude that these EOs have potential applications as insect antifeedants, and as antifungal or antiparasitic agents, depending on the cultivation method, and that the hydrolate byproduct is a potent nematicidal.

Trypanocidal Effects of Essential Oils from Selected Medicinal Plants. Synergy among the Main Components.

Fourteen essential oils (EOs) from selected live germplasm of medicinal plants have been tested for their antitrypanosomal and cytotoxic activity. These plants have been domesticated and maintained under experimental cultivation. Their EOs were tested on epimastigote forms of Trypanosoma cruzi strain Y and human lung fibroblasts LC5 cell line, along with the major components of the active oils, both separately and in binary combinations. Mentha rotundifolia, Thymus zygis, T. vulgaris and Hyssopus officinalis were the most active EOs against T. cruzi. Among the main components of these EOs (1-8-cineole, thymol, p-cymene, piperitenone oxide, ß-pinene, γ-terpinene, carvacrol and linalool), the most active against the parasite and less toxic to human cells was thymol. In general, the activity of the main components did not exceed that of their origin EO, and the study of the activity of these compounds in combination indicates the existence of antagonistic and synergistic effects depending on the concentration tested.

Antiparasitic Activity of Diterpenoids Against Trypanosoma cruzi.

Twenty-seven diterpenes, including abietanes, labdanes, abeoabietanes, halimanes, and pimaranes, have been evaluated against epimastigote and intracellular amastigote forms of Trypanosoma cruzi and also against LC5 and NCTC cell lines. Royleanones (3, 4, and 5) and a further abietane (12), obtained by purification of Plectranthus spp. extracts, were the most active compounds on epimastigotes, showing IC50 values similar (1.73 µg/mL, 12) or even lower (0.39, 0.99, and 1.20 µg/mL, 3, 4, and 5 respectively) than the positive control nifurtimox (2.3 µg/mL). On intracellular amastigotes, abietanes 3, 4, and 5 showed a significant activity with IC50 values of 0.83, < 0.31, and 0.62 µg/mL, respectively, but were less potent than the positive control nifurtimox (IC50 < 0.16 µg/mL). Compounds 3, 4, and 5 were not cytotoxic to LC5 and NCTC 929 cells at 1 µg/mL.

New Bioactive Semisynthetic Derivatives of 31-Norlanostenol and Obtusifoliol from Euphorbia officinarum.

Fifteen semisynthetic terpenoid derivatives from the major latex components of Euphorbia officinarum have been evaluated against the insect pest Spodoptera littoralis, two species of protozoan parasites, Trypanosoma cruzi and Leishmania infantum, and also against insect Sf9 and mammalian CHO cells to test their selective cytotoxicity. Our results showed that 40% of the test substances were postingestive toxicants to S. littoralis. All the tested derivatives had cytotoxic effects on insect-derived Sf9 cells, whereas mammalian CHO cells were affected by a lower number of compounds (47%). Furthermore, 87% of the test compounds had antiparasitic effects on both L. infantum and T. cruzi, with some of them being selective parasite toxicants.

Antileishmanial, antitrypanosomal, and cytotoxic screening of ethnopharmacologically selected Peruvian plants.

Extracts (34) from eight plant species of the Peruvian Amazonia currently used in traditional Peruvian medicine, mostly as antileishmanial remedies and also as painkiller, antiseptic, antipyretic, anti-inflamatory, antiflu, astringent, diuretic, antipoison, anticancerous, antiparasitic, insecticidal, or healing agents, have been tested for their antileishmanial, antitrypanosomal, and cytotoxic activity. Plant species were selected based on interviews conducted with residents of rural areas. The different plant parts were dried, powdered, and extracted by maceration with different solvents (hexane, chloroform, and 70% ethanol-water). These extracts were tested on promastigote forms of Leishmania infantum strain PB75, epimastigote forms of Trypanosoma cruzi strain Y, and the mammalian CHO cell line. Parasite viability and nonspecific cytotoxicity were analyzed by a modified MTT colorimetric assay method. The isolation and identification of pure compounds from selected extracts were performed by column chromatography, gas chromatography mass spectrometry (GC-MS; mixtures), spectroscopic techniques [MS, infrared (IR), ultraviolet (UV)], and mono and two-dimensional (1)H and (13)C nuclear magnetic resonance (NMR; COSY, HSQC, NOESY) experiments. Chondodendron tomentosum bark and Cedrela odorata were the most active extracts against Leishmania, while C. odorata and Aristoloquia pilosa were the most active against Trypanosoma, followed by Tabebuia serratifolia, Tradescantia zebrina, and Zamia ulei. Six compounds and two mixtures were isolated from Z. ulei [cycasin (1)], T. serratifolia {mixtures 1-2, and naphthoquinones 2-acetyl-4H,9H-naphtho[2,3-b]furan-4,9-dione (2) and 2-(1-hydroxyethyl)-4H,9H-naphtho[2,3-b]furan-4,9-dione (3)}, and C. tomentosum [chondrocurine (4); (S,S')-12-O-methyl(+)-curine (5); and cycleanine (6)]. Four compounds and the two mixtures exhibited significant activity.