Tecoma stans (L.) Juss. Ex Kunth is a species belonging to the Bignoniaceae family, popularly known as yellowing, yellow bell, and garden little ipe. Studies with T. stans seeds are scarce and it have potential in the search for natural compounds with biological activities. This study aimed to evaluate the toxicity and antioxidant activity of the ether extract (EE) and fractions from T. stans seeds. The EE was obtained in Soxhlet apparatus with petroleum ether and fractions were obtained by hydrolysis and esterification reactions. Phytochemical screening evaluated the presence of steroids, triterpenoids, alkaloids, coumarins and anthraquinones in EE. The toxicity was evaluated by the A. salina lethality test and antioxidant activity by DPPH method. It was observed the presence of steroids, triterpenoids and alkaloids in EE, which had no toxicity to A. salina (LC50 > 1000 µg/mL). The fractions of seeds exhibited toxicity on A. salina. All samples showed antioxidant activity with EC50 between 0.9 and 1.1 µg/mL. These results indicated potential applications for T. stans seeds.

A 4-hidroxicumarina (4H) é um composto fenólico natural e sintético que apresenta atributos importantes, incluindo propriedades anti-HIV, antitumoral e anticoagulante. Considerando suas importantes atividades biológicas e a utilização da 4H, o objetivo do presente estudo foi investigar as atividades tóxica, mutagênica, antimutagênica e antioxidante da 4H, obtido comercialmente, em experimentos in vivo e in vitro. Os efeitos da administração oral aguda na dose de 200 mg / kg de 4H foram investigados pela triagem hipocrática em animais. O ensaio de micronúcleo em sangue periférico e o teste de Ames foram utilizados para análise de mutagenicidade, enquanto a antimutagenicidade foi testada contra a ciclofosfamida também pelo ensaio de micronúcleo in vivo. Para todos os testes in vivo foram utilizados camundongos Swiss. A atividade antioxidante foi determinada pela capacidade da amostra 4H de sequestrar o radical estável 2,2-difenil-1-picrilhidrazil (DPPH). Os resultados mostraram que o 4H não induziu alterações no comportamento ou na histologia dos animais tratados nem na atividade mutagênica (gênica ou cromossômica). Por outro lado, exibiu efeito protetor contra ciclofosfamida e potencial antioxidante. A 4H é amplamente utilizada clinicamente como uma molécula precursora na síntese de fármacos anticoagulantes sintéticos. Portanto, os resultados obtidos são de extrema importância, pois demonstram ausência de potencial mutagênico e proteção contra danos cromossômicos.

The extract and fractions from flowers of Tecoma stans (Bignoniaceae), an invasive plant in Brazil, were evaluated for their larvicidal potential against Culex quinquesfasciatus larvae and for the toxicity to Artemia salina. The hexane (HEX) fraction caused 100% mortality at 1000 µg mL^-1 in the first 24 h of exposure (LC₅₀ = 118.73 µg mL^-1 and LC₉₀ = 306.06 µg mL^-1). The LC₅₀ and LC₉₀ values for the dichloromethane (DCM) fraction were 399.40 µg mL^-1 and 853.36 µg mL^-1. Only the ethyl acetate (EA) fraction was toxic to A. salina. The results suggest selectivity from the HEX and DCM fractions of T. stans against C. quinquefasciatus and may serve as eco-friendly alternatives to synthetic larvicides.

Extratos vegetais dos diferentes Biomas brasileiros têm sido utilizados como fármacos naturais no tratamento de variadas doenças. Atualmente, nos deparamos com um problema mundial de saúde pública: a resistência microbiana à fármacos tradicionalmente empregados. A maioria das plantas superiores possuem compostos com ação antimicrobiana que as protegem de microrganismos invasores. Neste contexto, o objetivo deste estudo foi avaliar o potencial antimicrobiano de extratos vegetais de espécies coletadas na região de Divinópolis/MG. Obteve-se extratos hidroetanólicos de partes aéreas dos espécimes avaliados. Foram testados extratos de Bidens subalternans, Anadhenantera columbrina, Annona mucosa, Eugenia dysenteryca, Inga vera, Tecoma stans e Crotalaria stipularia. Para os bioensaios foram empregados os testes Disco-Difusão em ágar e CIM/CBM. Utilizaram-se os microorganismos de referência Escherichia coli ATCC 29214, Klebsiella pneumoniae ATCC43816, Enterobacter aerogenes ATCC 13048, Acinetobacter baumannii ATCC19606, Candida albicans ATCC18804 e Candida glabrata ATCC2001. Extratos de B.subalternans apresentaram efeito bactericida frente a E.coli e bacteriostático frente a A.baumanii e E.aerogenes. A. mucosa apresentou efeito bacteriostático frente a E.coli e E. dysenteryca e efeito bacterida frente a S.aureus. T.stans apresentou efeito bactericida frente a E.coli e bacteriostático em A.baumanii e E.aerogenes. Os extratos não apresentaram efeito antifúngico frente a C.albicans e C.glabrata. Os resultados obtidos neste estudo confirmam o grande potencial para o desenvolvimento de novos antimicrobianos baseados em extratos obtidos de partes aéreas de espécies vegetais da região de Divinópolis/MG.

Weed control is mainly carried out using synthetic herbicides, which represent 62.6% of the total pesticides sold. However, some plants produce allelochemicals that inhibit the growth of other plants, and these substances can be isolated and used as natural herbicides. This study aimed to evaluate the allelopathic, cytotoxic, genotoxic, and antigenotoxic potential of the ethanol extract (EE), hexane (HEX), dichloromethane (DCM), ethyl acetate (EA) and hydroethanol (HE) fractions obtained from Tecoma stans flowers. Nuclear magnetic resonance (NMR) was used to characterize the compounds present in the samples. The allelopathic activity was tested using Allium cepa and Lactuca sativa seeds, and the cytotoxicity, genotoxicity and antigenotoxicity were evaluated using A. cepa seeds. The saturated and unsaturated fatty acids ω-3 and ω-6, terpenes, flavonoids, and phenolic acids with coumaroyl or glycosyl derivatives were characterized in the samples. The HEX and DCM fractions significantly inhibited germination and root growth, effects associated with fatty acids and phenolic compounds. The EA fraction exhibits genotoxic potential at higher concentrations tested. The extract and fractions reduced the genotoxicity induced by glyphosate and atrazine, reversing chromosomal abnormalities. These results demonstrate the possible use of the extract and fractions as natural sources of allelochemicals, but safe dosage validation is required.

The species Bidens subalternans DC., belonging to the Asteraceae family, is a native plant of Brazil. The objective of this study was to perform preliminary phytochemical characterization and evaluate the antioxidant activity and acute toxicity of the ethanol extract (EE) and leaf fractions of B. subalternans. Phytochemical screening revealed the presence of steroids, saponins, alkaloids, coumarins, flavonoids and tannins. Analysis of the EE and the dichloromethane fraction (DCMF) by gas chromatography–mass spectrometry (GC-MS) suggested the presence of phytol, ethyl esters, fatty acids, terpenoid compounds, stigmasterol, untriacontane, ketones, and loliolide. The presence of chlorogenic acid, cinnamic acid derivatives, coumaric acid derivatives, caffeic acid derivatives, and flavonoids was putatively assigned using high-performance liquid chromatography coupled with a diode-array detector (HPLC-DAD). The ethyl acetate fraction (EAF) and DCMF showed higher levels of total phenolic compounds and flavonoids compared to the EE and hydroethanol fraction (HEF) (EAF > DCMF > EE > HEF). In antioxidant activity assays, the EAF exhibited the greatest potential, followed by the DCMF, EE, and HEF. The results showed no mortality of Artemia salina larvae, indicating an absence of acute toxicity under the tested conditions. This study contributes to the preliminary chemical characterization of B. subalternans, toxicity and antioxidant activity in vitro, highlighting it as a potential source of natural antioxidants.