Biofilm is a complex microbial community highly resistant to antimicrobials. The formation of biofilms in biotic and abiotic surfaces is associated with high rates of morbidity and mortality in hospitalized patients. New alternatives for controlling infections have been proposed focusing on the therapeutic properties of medicinal plants and their antimicrobial effects. In the present study the antimicrobial and antibiofilm activities of 8 methanolic plant extracts were evaluated against clinical isolated microorganisms. Preliminary screening by diffusion well assay showed the antimicrobial activity of Prosopis laevigata, Opuntia ficus-indica, and Gutierrezia microcephala. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined ranging from 0.7 to >15 mg/mL. The specific biofilm formation index (SBF) was evaluated before and after the addition of plant extracts (MBC × 0.75). Opuntia ficus-indica caused the major reduction on SBF in dose‐dependent manner. Cytotoxic activity of plant extracts was determined using brine shrimp lethality test (Artemia salina L.). Lethal Dose concentration (LD₅₀ values) of the plant extracts was calculated. LD₅₀ values for P. laevigata and G. microcephala were 141.6 and 323.3 µg/mL, respectively, while O. ficus-indica showed a slight lethality with 939.2 µg/mL. Phytochemical analyses reveal the presence of flavonoids, tannins, and coumarines.

Seven medicinal plants from Chiapas, Mexico, used by Native Americans were analyzed, aiming to improve the understanding of their medicinal properties through the evaluation of various biological activities, i.e., bactericidal, antioxidant, α-glucosidase inhibition, and toxicity, to provide a scientific basis for the management of infectious and hyperglycemic diseases in the Mexican southeast. Plant extracts were obtained from Cordia dodecandra, Gaultheria odorata, Heliotropium angiospermum, Justicia spicigera, Leucaena collinsii spp. collinsii, Tagetes nelsonii, and Talisia oliviformis through maceration techniques using methanol and chloroform (1:1). Minimum Inhibitory Concentration (MIC) was employed to determine the antibacterial activity against Staphylococcus aureus, Enterobacter faecalis, Escherichia coli, Enterobacter aerogenes, Enterobacter cloacae, Klebsiella pneumoniae, and Pseudomonas aeuroginosa. The antiradical/antioxidant activity was determined by the 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assays and antihemolytic activity using the 2,2’-Azobis(2-amidinopropane) dihydrochloride radical (APPH). The anti-α-glucosidase activity was evaluated in vitro through the chromogenic PNPG assay. The toxicity was assessed using the brine shrimp lethality assay. The highest antimicrobial activity was displayed by T. nelsonii, mainly against E. faecalis and P. aeuroginosa. The extracts of L. collinsii, J. spicigera, and T. nelsonii possess antioxidant properties with EC₅₀ < 50 μg/mL. J. spicigera and T. nelsonii extracts showed the highest antihemolytic activity with IC₅₀ < 14 μg/mL. T. nelsonii exhibited a remarkable inhibitor effect on the α-glucosidase enzyme and the greatest toxic effect on Artemia salina with IC₅₀ = 193 ± 20 μg/mL and LD₅₀ = 14 ± 1 μg/mL, respectively. According to our results, G. odorata, J. spicigera, T. nelsonii, and T. oliviformis extracts contained active antimicrobial compounds. At the same time, T. nelsonii stands to be a possible source of effective antineoplastic and antihyperglycemic compounds.

Diabetes mellitus (DM) is considered the epidemic of the 21st century. Traditional medicine uses plants to treat DM; many of these have hypoglycemic effects in both animal models and diabetic patients. Our objective was to evaluate the hypoglycemic activity ofTilia americana,Borago officinalis,Chenopodium nuttalliae, andPiper sanctumon diabetic rats. The methanolic extracts of the plants under study were obtained by Soxhlet extraction. Toxicity was evaluated onArtemia salina; the antioxidant potential was evaluated using the DPPH technique. Hypoglycemic capacity at doses of 250 and 500 mg/kg was tested on Wistar rats with diabetes induced by alloxan (120 mg/kg). The toxicity onA. salinawas null for the extracts ofB. officinalisandP. sanctum, moderate forT. americana, and highly toxic forC. nuttalliae. The relevant extract ofT. americanavar. mexicana showed antioxidant activity. Three plants of the studied plants showed hypoglycemic activity:Tilia Americana(p=0.0142),Borago officinalis(p=0.0112), andPiper sanctum(p=0.0078);P. sanctumwas the one that showed the greatest reduction in glucose levels at a lower dose.

The therapeutic potential of medicinal plants is known as an alternative in treatment of human affections; in effect, the conventional application of these medicinal sources has several limitations like low bioavailability, solubility and stability, which affect its pharmacological efficacy. In recent decades, extraordinary advances have been made in new drug delivery systems using nanocarriers. This work consisted in determining the in vitro antifungal activity of the methanolic extract of Euphorbia tirucalli formulated in polymeric nanoparticles. The antifungal activity was determined by the microdilution method in 96-well microplates, applying nanoparticles loaded with plant extract (NP-Ext) obtained by nanoprecipitation on clinical isolates of Trichophyton rubrum and T. interdigitalis. Regarding the nanoparticles, the lots used did not present significant differences in their physicochemical characteristics, with a size of 91.885 ± 1.621nm, polydispersity index of 0.152 ± 0.025 and Z-potential of -6.047 ± 0.987. The quantification of the extract in the polymeric matrix was determined by infrared spectroscopy (FTIR), where an efficiency and encapsulation percentage of 22.15 ± 0.82 and 2.95 ± 0.11, respectively, were obtained. The in vitro antifungal activity of the crude and formulated extract was obtained calculating the Minimum Inhibitory Concentration (MIC) of each one; a MIC of 125 µg/mL was obtained against T. rubrum and T. interdigitalis with the crude extract, while a MIC value of 55.55 and 0.1 µg/mL was obtained with NP-Ext, respectively, against these same. Conclusions: biological activity is closely linked to the phytochemical profile of the extract; while the improvement of said potential with the NP-Ext with the dosage form was directly related to the physicochemical characteristics of the nanocarrier.

There is a trend to use medicinal plants for primary medical care or as dietary supplements; however, the safety of many of these plants has not been studied. The objective of this work was to determine the toxic effect of the aqueous extract of Calea ternifolia (C. zacatechichi), known popularly as “dream herb” in vivo and in vitro in order to validate its safety. In vivo, the extract had moderate toxicity on A. salina. In vitro, the extract induced eryptosis of 73% at a concentration of 100 μg·mL⁻¹ and it inhibited CYP3A by 99% at a concentration of 375 μg/mL. After administering 8.5 mg/kg of C. ternifolia to rats, we found a reduction in platelets and leukocytes and an increase in urea and the liver enzymes alanine aminotransferase (ALT), aspartate aminotransferase (AST), and alkaline phosphatase (ALP). Histological analysis showed spongiform changes in the proximal tubules of renal tissue and a lymphoid infiltrate in liver tissue. This plant is used in the treatment of diabetes, and it is commercialized as a dietary supplement in several countries. Our results show renal and hepatic toxicity; therefore, more profound research on the toxicity of this plant is needed.