A Potential New Source of Therapeutic Agents for the Treatment of Mucocutaneous Leishmaniasis: The Essential Oil of Rhaphiodon echinus.

Weeds are an important source of natural products; with promising biological activity. This study investigated the anti-kinetoplastida potential (in vitro) to evaluate the cytotoxicity (in vitro) and antioxidant capacity of the essential oil of Rhaphiodon echinus (EORe), which is an infesting plant species. The essential oil was analyzed by GC/MS. The antioxidant capacity was evaluated by reduction of the DPPH radical and Fe3+ ion. The clone Trypanosoma cruzi CL-B5 was used to search for anti-epimastigote activity. Antileishmanial activity was determined using promastigotes of Leishmania braziliensis (MHOM/CW/88/UA301). NCTC 929 fibroblasts were used for the cytotoxicity test. The results showed that the main constituent of the essential oil was γ-elemene. No relevant effect was observed concerning the ability to reduce the DPPH radical; only at the concentration of 480 µg/mL did the essential oil demonstrate a high reduction of Fe3+ power. The oil was active against L. brasiliensis promastigotes; but not against the epimastigote form of T. cruzi. Cytotoxicity for mammalian cells was low at the active concentration capable of killing more than 70% of promastigote forms. The results revealed that the essential oil of R. echinus showed activity against L. brasiliensis; positioning itself as a promising agent for antileishmanial therapies.

Anti-Trypanosoma, anti-Leishmania and cytotoxic activities of natural products from Psidium brownianum Mart. ex DC. and Psidium guajava var. Pomifera analysed by LC-MS.

Neglected diseases are those that are prevalent in developing countries, even with a rich biodiversity. These diseases still persist because of the lack of scientific studies, government negligence or failures of the public health system. This study aims to identify the composition of extracts and fractions from Psidium brownianum and Psidium guajava through LC-MS, to evaluate its in vitro anti-parasitic and cytotoxic activity against Trypanosoma cruzi, Leishmania brasiliensis and L. infantum epismastigote and promastigote forms, as well as mammalian cells. The results showed the presence of chemical constituents in the two Psidium species as quercetin, myricetin and gallic acid derivatives. The P. brownianum extract and fractions showed low toxicity at all tested concentrations and all samples were effective at the concentration of 1000µg/mL against the parasites, with the extract being the most efficient against the L. infantum promastigote form. The ethanolic extract, and the flavonoid and tannic fractions, from P. guajava showed low toxicity for the fibroblasts. All samples showed effectiveness at the highest concentration tested and the extract was more effective against the promastigote forms tested. The results showed that the species Psidium brownianum and Psidium guajava demonstrated an anti-parasitic activity against the T. cruzi, L. brasiliensis and L. infantum parasite cell lines indicating these species as an alternative therapy given their efficacy in the in vitro assays performed, opening the possibility for new biological studies to further this knowledge through in vivo assays.

Safety assessment and antioxidant activity of Lantana montevidensis leaves: Contribution to its phytochemical and pharmacological activity.

Lantana camara, the widely studied species, and L. montevidensis, the less studied species of the genus Lantana are both used in traditional medicine for the same purpose (anti-asthma, anti-ulcer, anti-tumor, etc). However, little is known about the toxicity of L. montevidensis and there is limited information on its chemical constituents. Here, we investigated for the first time the genotoxicity and cytotoxicity of the ethanolic (EtOH) and aqueous extracts from the leaves of Lantana montevidensis in human leukocytes, as well as their possible interaction with human erythrocyte membranes in vitro. The antioxidant activities of both extracts were also investigated in chemical and biological models. Treatment of leukocytes with EtOH or aqueous extracts (1-480 µg/mL) did not affect DNA damage index, but promoted cytotoxicity at higher concentrations (240-480 µg/mL). Both extracts did not modify the osmotic fragility of human erythrocytes. The extracts scavenged DPPH radical and prevented Fe2+-induced lipid peroxidation in rat's brain and liver homogenates, and this was likely not attributed to Fe (II) chelation. The HPLC analysis of the extracts showed different amounts of polyphenolic compounds (isoquercitrin, gallic acid, catechin, ellagic acid, apigenin, kaempferol, caffeic acid, rutin, quercitrin, quercetin, chlorogenic acid, luteolin) that may have contributed to these effects. These results supported information on the functional use of L. montevidensis in folk medicine.