Most of the deaths from skin cancer are caused by melanoma, a malignancy in which STAT3 plays a crucial role. The inhibition of STAT3 is considered a potential target to induce cell death, tumor regression and metastasis inhibition. The objective of this work was to evaluate the activity of the aqueous extract of Larrea divaricata (Aq), a fraction rich in polyphenols (EA),and the isolated compound quercetin-3-methyl ether (Q3ME) on B16F10 melanoma cells. The effects of Aq, EA and Q3ME were assessed on B16F10 cells by determining the proliferation, viability, apoptosis induction and the expression and phosphorylation of STAT3. The phytochemical composition of the extracts was determined by High Performance Liquid Chromatography. Aq, EA and Q3ME presented antiproliferative activity on B6F10 cells through p-STAT3 inhibition and early and late apoptosis induction (EC 50 EA= ≤0.1 µg/ml; Aq= 316±30 µg/ml; Q3ME= <0.1 µg/ml). L. divaricata could be considered for the development of adjuvant phytotherapies in melanoma treatment.

Urtica circularisis an Argentinean species traditionally used to treat inflammation symptoms and oxidative stress-related diseases. Considering the uses in folk medicine, the purpose of this work was to evaluate and compare the anti-inflammatory and antioxidant activities of two different U. circularisextracts. The contribution of vicenin-2 and vitexin, two compounds identified in the phytochemical analysis, in the biological activity of the extracts was evaluated. The anti-inflammatory activity of the extracts and the isolated compounds was tested on lipopolysaccharide (LPS)-stimulated macrophages, while the antioxidant activity was evaluated through the 2,2 ́ diphenyl-1-picrylhydrazyl (DPPH) radical and 2,2 ́-azinobis(3-ethylbenzthiazoline-6-sulfonic acid) diammonium salt (ABTS) scavenging activities. The popular uses of both extracts were validated, i.e., the use of U. circularisethanol extract for the treatment of inflammation, and the use of the aqueous extract to treat oxidative stress related-diseases. The differences in the biological activities observed between the extracts are probably due to qualitative and/or quantitative differences in the chemical composition and/or the occurrence of synergism between compounds.

Larrea divaricataCav. is an autochthonous South American plant popularly used in inflammatory and infectious diseases with reported anti-inflammatory, immunomodulatory, antimicrobial and antioxidant activities. Covid-19 is an infection caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). This virus can cause pneumonia and even death in about 5% of the cases. The objective of the article was to demonstrate, through a literature review, that L. divaricatahas sufficient attributes to be assayed against SARS-CoV-2. For this, the chemical composition, reported activities and docking studies were taken into account. This review demonstrated that the plant extracts are capable of inhibiting the proliferation of fungi, bacteria and viruses and that they exert anti-inflammatory and immunomodulatory actions in different "in vitro" and "in vivo" models. These results suggest that the plant is a good candidate to be studied for the prevention and/or treatment of SARS -CoV-2.