Long-Lasting Silver Nanoparticles Synthesized with Tagetes erecta and Their Antibacterial Activity against Erwinia amylovora, a Serious Rosaceous Pathogen.

A rapid, eco-friendly, and simple method for the synthesis of long-lasting (2 years) silver nanoparticles (AgNPs) is reported using aqueous leaf and petal extracts of Tagetes erecta L. The particles were characterized using UV-Visible spectrophotometry and the analytical and crystallographic techniques of transmission electron microscopy (TEM). The longevity of the AgNPs was studied using UV-Vis and high-resolution TEM. The antibacterial activity of the particles against Erwinia amylovora was evaluated using the Kirby-Bauer disk diffusion method. The results were analyzed using ANOVA and Tukey's test (p ≤ 0.05). Both the leaf and petal extracts produced AgNPs, but the leaf extract (1 mL) was long-lasting and quasi-spherical (17.64 ± 8.87 nm), with an absorbance of UV-Vis λmax 433 and a crystalline structure (fcc, 111). Phenols, flavonoids, tannins, and terpenoids which are associated with -OH, C=O, and C=C were identified in the extracts and could act as reducing and stabilizing agents. The best antibacterial activity was obtained with a nanoparticle concentration of 50 mg AgNPs L-1. The main contribution of the present research is to present a sustainable method for producing nanoparticles which are stable for 2 years and with antibacterial activity against E. amylovora, one of most threatening pathogens to pear and apple productions.

Cytotoxic and Antitumor Effects of the Hydroalcoholic Extract of Tagetes erecta in Lung Cancer Cells.

Among all cancers, lung cancer is the one with the highest mortality rate, and it also has limited therapeutics. Antitumor agents based on medicinal plants have gained importance as a source of bioactive substances. Tagetes erecta is a plant of great cultural value, and recent reports have suggested its cytotoxic effects in tumor cells. Our objective was to evaluate the antitumor activity of Tagetes erecta extract in a lung carcinoma model. Hydroalcoholic extracts were obtained from fresh flowers and leaves of T. erecta; both extracts did not exert toxicity on Artemia salina. We observed cytotoxic effects induced by the floral extract in Lewis lung carcinoma (LLC) and breast tumor cell line (MCF7), but not by the leaf extract. In vivo, a xenograft lung carcinoma model was performed with LLC cells implanted on C57BL/6 mice, which showed that the floral extract reduced tumor growth and improved the effect of etoposide. Microscopic analysis of tumors showed a reduction in mitoses and an increase in necrotic areas with the extract and the etoposide. The main phytochemical compounds found are 2,3-dihydro-benzofuran, octadecanoic acid, benzenacetic acid, oleic acid, linoleic acid, and acetic acid. We conclude that the hydroalcoholic extract of T. erecta flowers has cytotoxic effects in lung carcinoma cells and enhances the effect of etoposide.

The complete chloroplast genome of Mexican marigold (Tagetes erecta L., Asteraceae).

Tagetes erecta is an important ornamental and medicinal plant indigenous to Mexico and Guatemala. The complete chloroplast genome of T. erecta was newly sequenced in this study. The total chloropalst genome size of T. erecta was 152,055 bp. In total, 123 genes were indetified, including 79 protein-coding genes, 8 rRNA genes, and 37 tRNA genes. Twelve genes are containing introns (ycf3 and clpP contained two introns). The overall GC content of this genome was 37.4%. A further phylogenomic analysis of Asteraceae, including 23 taxa, was conducted for the placement of genus Tagetes. The complete plastome of T. erecta will provide a valuable resource for further genetic conservation, evolution, and molecular breading studies in Asteraceae.

Carotenoids and xanthophyll esters of yellow and red nance fruits (Byrsonima crassifolia (L.) Kunth) from Costa Rica.

Carotenoid profiles, by means of HPLC-PDA-MSn, and CIE-L*C*h° colour values of yellow and red nance fruits from Costa Rica were elucidated. Among 16 carotenoids detected, (all-E)-lutein was the most abundant accounting for >80% of the total carotenoids, followed by (all-E)-zeaxanthin (9-11%) and (all-E)-ß-carotene (2-9%). Minor constituents were (Z)-isomers of lutein and ß-carotene, as well as diverse lutein diesters. Among the esters, lutein dimyristate was the most abundant as substantiated by the comparison with a marigold flower extract. Total carotenoids in the peel (616.2 µg/100 g of FW in yellow nance and 174.2 µg/100 g of FW in red nance) were higher than in the pulp (39.4 µg/100 g of FW in yellow nance and 31.4 µg/100 g of FW in red nance). Since carotenoid profiles of yellow and red varieties were qualitatively similar, although the colour values showed significant differences (77.2 and 88.6 h° in peel and pulp of yellow nance, versus 32.7 and 67.3 h° in peel and pulp of red nance, respectively), pigments other than carotenoids may impart the colour of red nance. High lutein content renders nance fruit as a nutritionally relevant source of this micronutrient.

Anthelmintic effect of Psidium guajava and Tagetes erecta on wild-type and Levamisole-resistant Caenorhabditis elegans strains.

ETHNOPHARMACOLOGICAL RELEVANCE: Psidium guajava and Tagetes erecta have been used traditionally to treat gastrointestinal parasites, but their active metabolites and mechanisms of action remain largely unknown. AIM OF THE STUDY: To evaluate the anthelmintic potential of Psidium guajava and Tagetes erecta extracts on Levamisole-sensitive and Levamisole-resistant strains of the model nematode Caenorhabditis elegans. MATERIALS AND METHODS: Aqueous extracts of Psidium guajava (PGE) and Tagetes erecta (TEE) were assayed on locomotion and egg-laying behaviors of the wild-type (N2) and Levamisole-resistant (CB193) strains of Caenorhabditis elegans. RESULTS: Both extracts paralyzed wild-type and Levamisole-resistant nematodes in a dose-dependent manner. In wild-type worms, TEE 25mg/mL induced a 75% paralysis after 8h of treatment and PGE 25mg/mL induced a 100% paralysis after 4h of treatment. PGE exerted a similar paralyzing effect on N2 wild-type and CB193 Levamisole-resistant worms, while TEE only partially paralyzed CB193 worms. TEE 25mg/mL decreased N2 egg-laying by 65% with respect to the untreated control, while PGE did it by 40%. CONCLUSIONS: Psidium guajava leaves and Tagetes erecta flower-heads possess hydrosoluble compounds that block the motility of Caenorhabditis elegans by a mechanism different to that of the anthelmintic drug Levamisole. Effects are also observable on oviposition, which was diminished in the wild-type worms. The strong anthelmintic effects in crude extracts of these plants warrants future work to identify their active compounds and to elucidate their molecular mechanisms of action.

In vitro schistosomicidal effects of the essential oil of Tagetes erecta

The in vitro schistosomicidal effects of the essential oil obtained from Tagetes erecta L. Asteraceae, leaves (TE-EO) collected in Brazil against Schistosoma mansoni worms are reported in this paper. The oil caused a significant decrease in the motor activity at 50 µg/mL as minimal concentration after 24 h. This oil also caused death of all the parasites and the separation of coupled pairs into individual male and female at 100 µg/mL after 24 h. The viability of adult worm groups treated with the TE-EO at 100 µg/mL was similar to that of groups treated with praziquantel (positive control). In addition, the oil promoted the inhibition of eggs development at all the tested concentrations. These data indicate that the TE-EO could be considered as a promising source for the development of new schistosomicidal agents.