Chemical Constituents from Aerial Parts of Baccharis sphenophylla and Effects against Intracellular Forms of Trypanosoma cruzi

Evaluation of Anti-Trypanosoma cruzi Activity of Chemical Constituents from Baccharis sphenophylla Isolated Using High-Performance Countercurrent Chromatography

Endemic in 21 countries, Chagas disease, also known as American Trypanosomiasis, is a neglected tropical disease (NTD) caused by the protozoan parasite Trypanosoma cruzi. The available drugs for the treatment of this disease, benznidazole and nifurtimox, are outdated and display severe side effects. Thus, the discovery of new drugs is crucial. Based on our continuous studies aiming towards the discovery of natural products with anti-T. cruzi potential, the MeOH extract from aerial parts of Baccharis sphenophylla Dusén ex. Malme (Asteraceae) displayed activity against this parasite and was subjected to high-performance countercurrent chromatography (HPCCC), to obtain one unreported syn-labdane diterpene - sphenophyllol (1) - as well as the known compounds gaudichaudol C (2), ent-kaurenoic acid (3), hispidulin (4), eupafolin (5), and one mixture of di-O-caffeoylquinic acids (6-8). Compounds 1-8 were characterized by analysis of nuclear magnetic resonance (NMR) and mass spectrometry (MS) data. When tested against trypomastigote forms, isolated labdane diterpenes 1 and 2 displayed potent activity, with EC50 values of 20.1 μM and 2.9 μM, respectively. The mixture of chlorogenic acids 6-8, as well as the isolated flavones 4 and 5, showed significant activity against the clinically relevant amastigotes, with EC50 values of 24.9, 12.8, and 2.7 μM, respectively. Nonetheless, tested compounds 1-8 displayed no cytotoxicity against mammalian cells (CC50 > 200 μM). These results demonstrate the application of HPCCC as an important tool to isolate bioactive compounds from natural sources, including the antitrypanosomal extract from B. sphenophylla, allowing for the development of novel strategic molecular prototypes against tropical neglected diseases.

Chemical Constituents from Leaves of Baccharis sphenophylla (Asteraceae) and Their Antioxidant Effects

Baccharis is one of the largest genera of Asteraceae and its species are used in folk medicine for several medicinal purposes due to the presence of bioactive compounds. We investigated the phytochemical composition of polar extracts of B. sphenophylla. Using chromatographic procedures, diterpenoids (ent-kaurenoic acid), flavonoids (hispidulin, eupafolin, isoquercitrin, quercitrin, biorobin, rutin, and vicenin-2), caffeic acid, and chlorogenic acid derivatives (5-O-caffeoylquinic acid and its methyl ester, 3,4-di-O-caffeoylquinic acid, 4,5-di-O-caffeoylquinic acid, and 3,5-di-O-caffeoylquinic acid and its methyl ester) were isolated from polar fractions and are described. The extract, polar fractions, and fifteen isolated compounds were evaluated in relation to radical scavenging activity using two assays. Chlorogenic acid derivatives and flavonols exhibited higher antioxidant effects, confirming that B. sphenophylla is an important source of phenolic compounds with antiradical properties.

Selective cytotoxicity of ent-kaurene diterpenoids isolated from Baccharis lateralis and Baccharis retusa (Asteraceae)

This study presents the cytotoxic activity evaluation of the natural diterpenes ent-kaurenoic acid (1) and its 15β-hydroxy (2), 15β-senecioyloxy (3), and 15β-tiglinoyloxy (4) derivatives, isolated from Brazilian native plants, Baccharis retusa and B. lateralis (Asteraceae). Using the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) colorimetric assay, it was observed that compound 1 displayed in vitro activity towards the aggressive MDA-MB-231 adenocarcinoma cell line and reduced toxicity against MCF-10A nontumorigenic epithelial cells, indicating expressive selectivity. On the contrary, compounds 2-4 exhibited reduced toxicity and selectivity in both tested cell lines. Based on the chemical structures of compounds 1-4, it is suggested that the presence of additional functional groups at the C-15 position-a hydroxyl group in compound 2 and isomeric isoprene units in compounds 3 and 4-might be responsible for the reduction in the potential/selectivity. In silico studies show, for compounds 1-4, good predictions regarding bioavailability and ADME (absorption, distribution, metabolism, and excretion) properties as well as no alerts for PAINS (pan-assay structures interference). In conclusion, ent-kaurenoic acid (1), a common diterpenoid isolated in high amounts from different plants belonging to the Baccharis genus, has been shown to be a promising cytotoxic agent against an aggressive adenocarcinoma cell line (MDA-MB-23) and, if well exploited, could be used as a scaffold in the development of molecular prototypes for the treatment of breast cancer.