Pharmacological validation of Solanum mammosum L. as an anti-infective agent: Role of solamargine.

ETHNOPHARMACOLOGICAL RELEVANCE: Fungal and bacterial infections remain a major problem worldwide, requiring the development of effective therapeutic strategies. Solanum mammosum L. (Solanaceae) ("teta de vaca") is used in traditional medicine in Peru to treat fungal infections and respiratory disorders via topical application. However, the mechanism of action remains unknown, particularly in light of its chemical composition. MATERIALS AND METHODS: The antifungal activity of TDV was determined against Trichophyton mentagrophytes and Candida albicans using bioautography-TLC-HRMS to rapidly identify the active compounds. Then, the minimum inhibitory concentration (MIC) of the fruit crude extract and the active compound was determined to precisely evaluate the antifungal activity. Additionally, the effects of the most active compound on the formation of Pseudomonas aeruginosa biofilms and pyocyanin production were evaluated. Finally, a LC-HRMS profile and a molecular network of TDV extract were created to characterize the metabolites in the fruits' ethanolic extract. RESULTS: Bioautography-TLC-HRMS followed by isolation and confirmation of the structure of the active compound by 1D and 2D NMR allowed the identification solamargine as the main compound responsible for the anti-Trichophyton mentagrophytes (MIC = 64 µg mL-1) and anti-Candida albicans (MIC = 64 µg mL-1) activities. In addition, solamargine led to a significant reduction of about 20% of the Pseudomonas aeruginosa biofilm formation. This effect was observed at a very low concentration (1.6 µg mL-1) and remained fairly consistent regardless of the concentration. In addition, solamargine reduced pyocyanin production by about 20% at concentrations of 12.5 and 50 µg mL-1. Furthermore, the LC-HRMS profiling of TDV allowed us to annotate seven known compounds that were analyzed through a molecular network. CONCLUSIONS: Solamargine has been shown to be the most active compound against T. mentoagrophytes and C. albicans in vitro. In addition, our data show that this compound affects significantly P. aeruginosa pyocyanin production and biofilm formation in our conditions. Altogether, these results might explain the traditional use of S. mammosum fruits to treat a variety of fungal infections and respiratory disorders.

Antiprotozoal activity of medicinal plants used by Iquitos-Nauta road communities in Loreto (Peru).

ETHNOPHARMACOLOGICAL RELEVANCE: In the Peruvian Amazon, the use of medicinal plants is a common practice. However, there is few documented information about the practical aspects of their use and few scientific validation. The starting point for this work was a set of interviews of people living in rural communities from the Peruvian Amazon about their uses of plants. Protozoan diseases are a public health issue in the Amazonian communities, who partly cope with it by using traditional remedies. Validation of these traditional practices contributes to public health care efficiency and may help identify new antiprotozoal compounds. AIMS OF STUDY: to inventory and validate the use of medicinal plants by rural people of Loreto region. MATERIALS AND METHODS: Rural mestizos were interviewed about traditional medication of parasite infections with medicinal plants. Ethnopharmacological surveys were undertaken in two villages along Iquitos-Nauta road (Loreto region, Peru), namely 13 de Febrero and El Dorado communities. Forty-six plants were collected according to their traditional use for the treatment of parasitic diseases, 50 ethanolic extracts (different parts for some of the plants) were tested in vitro on Plasmodium falciparum (3D7 sensitive strain and W2 chloroquine resistant strain), Leishmania donovani LV9 strain and Trypanosoma brucei gambiense. Cytotoxic assessment (HUVEC cells) of the active extracts was performed. Two of the most active plants were submitted to preliminary bioguided fractionation to ascertain and explore their activities. RESULTS: From the initial plants list, 10 were found to be active on P. falciparum, 15 on L. donovani and 2 on the three parasites. The ethanolic extract from Costus curvibracteatus (Costaceae) leaves and Grias neuberthii (Lecythidaceae) bark showed strong in vitro activity on P. falciparum (sensitive and resistant strain) and L. donovani and moderate activity on T. brucei gambiense. CONCLUSIONS: The Amazonian forest communities in Peru represents a source of knowledge on the use of medicinal plants. In this work, several extracts with antiprotozoal activity were identified. This work contributes to validate some traditional uses and opens subsequent investigations on active compounds isolation and identification.