Silvana Maria de Oliveira Santin

This study reports the first phytochemical and anticancer investigation of the Brazilian orchid Epidendrum cristatum. Classical chromatography led to the isolation of the steroids sitosterol (1) and stigmasterol (2), the phenolic compound vanillin (3), and the flavone tricin (4). Additionally, the compounds moupinamide (5), corchoionoside (6), phytosphingosine (7), syringaresinol (8), and 4-(2,6,6-trimethyl-4-oxo-2-cyclohexen-1-yl)-2-butanyl β-D-glucopyranoside (9) were putatively identified using ultra-high-performance liquid chromatography coupled with high-resolution tandem time-of-flight mass spectrometry (UHPLC-QToF-HR-MS/MS) analyses. Cytotoxicity assays were conducted against HeLa (human colon cancer cells modified by HPV) and VERO (non-cancerous green monkey kidney cells) cell lines. The crude extract of the plant (CE), the acid chloroform fraction (CAF), and the basic chloroform fraction (CBF) were tested. These fractions exhibited activity against HeLa cells, with cytotoxic concentrations (CC50) of 1.88, 5.69, and 5.04 µg mL-1, respectively, and showed activity against non-cancerous VERO cells, with CC50 values of 1.33, 0.75, and 1.46 µg mL-1, respectively. Finally, the chemophenetic and ecological relevance of the isolated and putatively identified compounds from E. cristatum was discussed based on the available literature.

Herbicides selects resistant weed populations, such as morning glory (Ipomoea triloba L.) and sourgrass (Digitaria insularis (L.) Fedde). Natural compounds represent an alternative control method for weeds. Released into the environment, those metabolites can influence other organisms by allelochemical interactions. Alecrim-de-campinas (Holocalyx balansae Micheli) produces cyanogenic glycosides, which are toxic metabolites. Therefore, can crude extract, aqueous extracts, and H. balansae metabolites affect the germination and growth of morning glory, sourgrass, and lettuce? Crude extract (CE) and the ethyl acetate fraction (EAF) were obtained and their allelochemical potential evaluated by lettuce germination. Aqueous extracts (EAq) were tested on the germination and growth of lettuce, morning glory, and sourgrass. The HB-1 compound was isolated from EAF and its effect was tested on the growth of the weeds and on the germination and growth of lettuce. CE, EAF, and EAq reduced germination and inhibited growth, especially affecting root elongation. This study found no difference in lettuce germination under HB-1 solutions. The compound reduced seedling elongation, the bioassays caused the emergence of abnormal seedlings with root necrosis, yellowish and poorly expanded cotyledons and eophylls. The evaluated seedlings showed reduced growth and weight and morphological changes.

Weeds pose a problem, infesting areas and imposing competition and harvesting difficulties in agricultural systems. Studies that provide the use of alternative methods for weed control, in order to minimize negative impacts on the environment, have intensified. Native flora represents a source of unexplored metabolites with multiple applications, such as bioherbicides. Therefore, we aimed to carry out a preliminary phytochemical analysis of crude extracts and fractions of Miconia auricoma and M. ligustroides and to evaluate these and the isolated metabolites phytotoxicity on the growth of the target species. The growth bioassays were conducted with Petri dishes with lettuce, morning glory, and sourgrass seeds incubated in germination chambers. Phytochemical analysis revealed the presence of flavonoids, isolated myricetin, and a mixture of quercetin and myricetin. The results showed that seedling growth was affected in a dose-dependent manner, with the root most affected and the seedlings of the lettuce, morning glory, and sourgrass as the most sensitive species, respectively. Chloroform fractions and myricetin were the most inhibitory bioassays evaluated. The seedlings showed structural changes, such as yellowing, nonexpanded cotyledons, and less branched roots. These results indicate the phytotoxic potential of Miconia allelochemicals, since there was the appearance of abnormal seedlings and growth reduction.

Aspidosperma macrocarpon Mart., popularly known as 'guatambu' or 'peroba', is found from North American (Mexico) to South American (Argentina) continents and in Brazil. Two indole alkaloids were isolated from leaves of A. macrocarpon, kopsanone (1) and unreported N(4)-oxide-kopsanone (2). [GRAPHICS] .

Allelopathy is analyzed as an alternative to herbicides due to the inhibitory or beneficent activities of its compounds with other organisms. Current paper discusses the effects of Aeschynomene fluminensis Vell. fractions on cultivated plant species, Lactuca sativa L. and Glycine max (L.) Merril, and on weeds, Ipomoea grandifolia (Dammer) O’Donnel and Digitaria insularis (L.) Fedde. Aqueous fractions at 0.80; 0.40; 0.20 and 0.10 mg mL-1 concentrations were employed for initial growth tests. Seeds were pre-germinated in distilled water and transferred to petri plates with separate fractions at different concentrations. Plates were maintained for 48 h in a germination chamber at 25°C for L. sativa and I. grandifolia and at 30°C for G.max and D. insularis. The length of hypocotyl (LH) and root (LR) was measured and LR and foliar length (LF) were taken for D. insularis seedlings. Parameters were employed to calculated inhibition percentage. Plants with morphological changes were fixed and analyzed anatomically. Results revealed LH and LR inhibition of lettuce seedlings in fractions with highest concentration rates. The same has been reported in the case of I. grandifolia. Butanolic, methanolic and chloroform fractions did not affect negatively soybean seedlings but they inhibited D. insularis seedlings´ LR. A. fluminensis fractions, especially at higher concentrations, inhibited seedlings´ growth and confirmed their phytotoxic capacity.

Palicourea species has been used in folk medicine in the treatment of some diseases including cancer and inflammatory disorders. This work aimed to evaluate the in vitro antiproliferative and in vivo topical anti-inflammatory activities of the methanolic extract, fractions and two major alkaloids isolated from Palicourea minutiflora. Methanolic extract, non-alkaloidal and alkaloidal fractions exhibited strong growth inhibition for ovarian cell lines (OVCAR-3, GI₅₀ = 3.8 at 16.3 µg mL⁻¹) and the vincosamide alkaloid revealed selective effect on the growth of glioma cell lines (U251, GI₅₀ = 33.0 µg mL⁻¹) compared with doxorubicin (DOX, GI₅₀ = 0.42 and 0.025 µg mL⁻¹, respectively) anticancer drug. Methanolic extract, fractions and strictosidinic acid showed significant inhibitory effect with 62.7% at 77.5% (p < 0.05) to ear edema induced by croton oil and 81% at 100% (p < 0.05) to myeloperoxidase assay compared with indomethacin (positive control) 68.4% and 91.3% (p < 0.05), respectively.