This survey explored the ethnobotanical uses of selected medicinal plants; Adiantum raddianum C. Presl. (Pteridaceae), Lippia alba (Mill.) N. E. Brown (Verbenaceae) and Coronopus didymus (L.) Sm. (Brassicaceae) used for respiratory diseases in Southern Santa Catarina (Brazil). This is timely as the incidence of respiratory disease is increasing in this state. Information was obtained through both interviews using a semi-structured questionnaire administered to 368 people and evaluation of published literature on these plants from scientific peer reviewed journals. The age profile of participants ranged from 20 to over 89 years, with females representing 75% of interviewees. Regarding their use of the medicinal species, 53% reported being users of one of the three plants. Approximately, 52% of users preferred to utilize L. alba, 40% C. didymus and 8% A. raddianum. The primary respiratory diseases reported for use by the plants included cough, flu or cold, lung disorders, bronchitis and asthma. There was also more scientific literature available to support the use of L. alba for treatment of respiratory diseases. This study contributes to the documentation of the medicinal and popular uses of L. alba, C. didymus and A. raddianum in Southern Brazil, in ways that respect and support their conservation. Further studies are warranted to evaluate the biochemical and pharmacological activities of C. didymus and A. raddianum.

Ethnobotanical studies have investigated the use of leaves of Cunila microcephala for respiratory, stomach and gastrointestinal disorders. The essential oil of this plant is mostly composed of menthofuran, which has a hepatotoxic effect. Due to the popular use of this plant in southern Brazil, this study aimed to perform phytochemical profile of C. microcephala to detect and determine the amount of secondary metabolites and to evaluate their microbiological activity in vitro and genetic damage in vivo, indicative of genotoxicity, to ensure safe use of the plant. The leaf extract of C. microcephala was investigated for the presence of phenolic compounds, such as tannins, coumarins and flavonoids. This extract contained 193.23 mg/ml of phenolic compounds. In our in vitro analysis of microbiological activity, the crude leaf extract of C. microcephala showed 6 mm zone of inhibition against Staphylococcus aureus; fractions of dichloromethane and ethyl acetate showed 4 mm zones. In the genotoxic analysis, using the comet assay, no genotoxic effects were observed in blood samples and the liver at 125, 250 and 500 mg/kg. According to the results, C. microcephala presents interesting secondary compounds with biological activity, showing antimicrobial effects in vitro and no genotoxic effects in vivo.