Stanhopea tigrina Bateman ex Lindl. (Orchidaceae) is an orchid endemic to Mexico, known as “Calavera” or “calaverita”, in the Huasteca Potosina (central region of Mexico). This plant species is used for the folk treatment of mental disorders and urological kidney disorders, according to the ethnomedicinal information obtained in this study. Ethanolic extracts of leaves (HE) and pseudobulb (PE) were obtained by microwave-assisted extraction (MAE). Gas Chromatography coupled with Mass Spectrometry (GC-MS) was used to carry out the chemical characterization of HE and PE. The pharmacological effects (antioxidant, diuretic, anxiolytic, locomotor, hypnotic, and sedative) of HE and PE were evaluated. The possible mechanism of action of the anxiolytic-like activity induced by HE was assessed using inhibitors of the GABAergic, adrenergic, and serotonergic systems. The possible mechanism of the diuretic action of HE was assessed using prostaglandin inhibitory antagonists and nitric oxide synthase (NOS) blockers. HE at 50 and 100 mg/kg exerted anxiolytic-like activity without inducing hypnosis or sedation. Flumazenil, prazosin, and ketanserin inhibited the anxiolytic-like activity shown by HE, which suggests the participation of GABA, α₁-adrenergic receptors, and 5-HT₂ receptors, respectively. The diuretic effect was reversed by the non-selective NOS inhibitor L-NAME, which caused the reduction in nitric oxide (NO). These results demonstrate that the ethanolic extract of S. tigrina leaves exhibited anxiolytic-like activity and diuretic effects without inducing hypnosis or sedation. This work validates the medicinal uses of this orchid species.

The contamination of rivers by potentially toxic elements (PTEs) is a problem of global importance. The Valles River is Ciudad Valles’ (Central Mexico) main source of drinking water. During the four seasons of the year, water samples (n = 6), sediment samples (n = 6), and Phragmites australis plants (n = 10) were taken from three study sites selected based on the presence of anthropogenic activities in the Valles River. A graphite atomic absorption spectrophotometer estimated elements in the water, and an energy-dispersive X-ray fluorescence spectrometer quantified elements in sediments and plant samples. Phragmites australis accumulated metal(loid)s mainly in the roots during all seasons of the year. Water samples from all sites recorded PTEs (As, Pb, Cd, and Hg), with primary sources identified as the sugar industry, urban and industrial wastewater, and the combustion of fossil fuels. Sediment samples showed concentrations of Hg, Mn, Ni, Zn, Pb, V, Cu, Cr, and Cd, attributed to agricultural practices, industrial activity, and urbanization. P. australis is an alternative for in situ phytoremediation because this macrophyte can bioaccumulate different elements in its roots, such as Mn, Rb, V, Sr, Cu, Zn, Pb, Ni, and As.