Thevetia peruviana (Pers.) K. Schum or Cascabela peruviana (L.) Lippold (commonly known as ayoyote, codo de fraile, lucky nut, or yellow oleander), native to Mexico and Central America, is a medicinal plant used traditionally to cure diseases like ulcers, scabies, hemorrhoids and dissolve tumors. The purpose of this study was to evaluate the cytotoxic, antiproliferative and apoptotic activity of methanolic extract of T. peruviana fruits on human cancer cell lines. The cytotoxic activity of T. peruviana methanolic extract was carried out on human breast, colorectal, prostate and lung cancer cell lines and non-tumorigenic control cells (fibroblast and Vero), using the MTT assay. For proliferation and motility, clonogenic and wound-healing assays were performed. Morphological alterations were monitored by trypan blue exclusion, as well as DNA fragmentation and AO/EB double staining was performed to evaluate apoptosis. The extract was separated using flash chromatography, and the resulting fractions were evaluated on colorectal cancer cells for their cytotoxic activity. The active fractions were further analyzed through mass spectrometry. The T. peruviana methanolic extract exhibited cytotoxic activity on four human cancer cell lines: prostate, breast, colorectal and lung, with values of IC50 1.91 ± 0.76, 5.78 ± 2.12, 6.30 ± 4.45 and 12.04 ± 3.43 μg/mL, respectively. The extract caused a significant reduction of cell motility and colony formation on all evaluated cancer cell lines. In addition, morphological examination displayed cell size reduction, membrane blebbing and detachment of cells, compared to non-treated cancer cell lines. The T. peruviana extract induced apoptotic cell death, which was confirmed by DNA fragmentation and AO/EB double staining. Fractions 4 and 5 showed the most effective cytotoxic activity and their MS analysis revealed the presence of the secondary metabolites: thevetiaflavone and cardiac glycosides. T. peruviana extract has potential as natural anti-cancer product with critical effects in the proliferation, motility, and adhesion of human breast and colorectal cancer cells, and apoptosis induction in human prostate and lung cancer cell lines, with minimal effects on non-tumorigenic cell lines.

The toxins of Bacillus thuringiensis (Bt) have shown great potential in the control of harmful insects affecting human health and agriculture, used as the main biological agent for the formulation of bioinsecticides due to its specificity to target different insects’ orders. This has led Bt-based products to become the best-selling biological insecticides in the world since the genes encoding insecticidal proteins have been successfully used in novel insecticidal formulation, genetically engineered (GE) crops, and development of transgenic rice that produce insecticidal toxins derived from Bacillus thuringiensis. It has been proven that insecticidal activity of Bt protein crystals can prolong their toxicity in shelf life or field under specific conditions, and this can improve the use of special strains and formulations to control insect vectors of diseases. Bt toxins have shown well-documented toxicity against lepidopterans, coleopterans, hemipterans, dipterans, nematodes, Rhabditida and human cancer cells of various origins. These crystal toxins may be responsible for other novel biological properties suggesting a pluripotential nature with different specificities.

Actinomycetes are a group of bacteria that have been reported as potential controllers of several plant pathogens and plant growth-promoting agents. This study focused on the isolation of 60 actinobacterial strains from the Cuatro Cienegas Basin, Coahuila, Mexico, with an emphasis on evaluating their potential as biocontrol agents against plant pathogens. Among the strains tested, the isolate PR69 exhibited significant in vitro antagonistic activity against eight plant pathogens, with inhibition rates ranging from 44% to 73%, including Phytophthora capsici. The genome of PR69 was sequenced and assembled. It was identified as Streptomyces by phylogenetic analysis based on concatenated multiple sequence alignments of 81 core bacterial genes. Additionally, volatile compounds produced by PR69 enhanced the growth of Arabidopsis thaliana seedlings in vitro, increasing seedling weight, primary root length, and the number of secondary roots. Furthermore, the soil treated with Streptomyces sp. PR69 effectively controlled the infection caused by the pathogen P. capsici in bell pepper plants, reducing mortality by 47% compared to plants inoculated solely with the pathogen. PR69-treated plants also showed 30% increase in fresh weight compared to untreated controls. These findings suggest that Streptomyces sp. PR69 holds promise as a bioinoculant for promoting pepper plant growth and controlling P. capsici populations.