Phytochemical analysis and investigation of analgesic, anti-inflammatory, and antispasmodic activities of hydroethanolic extracts of Alternanthera dentata, Ocimum carnosum, and Plectranthus barbatus, three species with vernacular names derived from analgesic drugs

Plant vernacular names can provide clues about the popular use of a species in different regions and are valuable sources of information about the culture or vocabulary of a population. Several medicinal plants in Brazil have received names of medicines and brand-name products. The present work aimed to evaluate the chemical composition and pharmacological activity in the central nervous system of three species known popularly by brand names of analgesic, anti-inflammatory, antispasmodic, and digestive drugs. Hydroethanolic extracts of Alternanthera dentata (AD), Ocimum carnosum (OC), and Plectranthus barbatus (PB) aerial parts were submitted to phytochemical analysis by HPLC-PAD-ESI-MS/MS and evaluated in animal models at doses of 500 and 1000 mg/kg. Mice were tested on hot plate, acetic acid-induced writing, formalin-induced licking, and intestinal transit tests. Aspirin and morphine were employed as standard drugs. The three extracts did not change the mice's response on the hot plate. Hydroethanolic extracts of AD and PB reduced the number of writhes and licking time, while OC was only effective on the licking test at dose of 1000 mg/kg. In addition, AD and OC reduced intestinal transit, while PB increased gut motility. Pharmacological tests supported some popular uses, suggesting peripheral antinociceptive and anti-inflammatory effects, while the phytochemical analysis showed the presence of several flavonoids in the three hydroethanolic extracts and steroids in PB, with some barbatusterol derivatives described for the first time in the species. [Display omitted] •Several species have been called by names of analgesic and anti-inflammatory drugs.•A. dentata, O. carnosum and P. barbatus induced antinociceptive effect in animal models.•A. dentata and O. carnosum extracts reduced the intestinal transit, while P. barbatus produced the opposite effect.•Steroids such as barbatusterol derivatives are new to the Plectranthus genus.