Chemical constituents, antioxidant and antimicrobial activities of Pavonia glazioviana Gurke (Malvaceae)

Species from Pavonia genus (Malvaceae) are traditionally used as antioxidant, n anti inflammatory and antimicrobial remedies. Previous studies have revealed their diversity of specialized metabolites widely used in the development of new medicines. This is the first study on Pavonia glazioviana Gurke, a Brazilian species known as “Malva da Chapada”. The research led to identify fifteen compounds: 132 (S) hydroxy pheophytin a; and 132(S) hydroxy 173 ethoxyphaeophorbide, n decanol, cycloart 23Z ene 3β,25 diol, cycloart 24S 25 ene 3β,24 diol, sitosterol 3 O β D glucopyranoside, stigmasterol 3 O β D glucopyranoside, quercetin, acacetin, kaempferol, tiliroside, 5 hydroxy 3,7,8,4’ tetramethoxyflavone, 5,7 dihydroxy 3,8,4’ trimethoxyflavone, 5,7 dihydroxy 4’ methoxyflavone, 5,7,4’ trihydroxy 3,8 dimethoxyflavone and 5,7,4’ trihydroxy 3 methoxyflavone. The major flavonoids were tested for their antimicrobial activity, and the compound 5,7 dihydroxy 3,8,4’ trimethoxyflavone showed strong activity against Escherichia coli (MIC = 512 μg mL1), Pseudomonas aeruginosa (MIC = 512 μg mL1), Candida albicans (MIC = 512 μg mL1), Candida tropicalis (MIC = 512 μg mL1), Candida parapsilosis (MIC = 512 μg mL1), Aspergillus flavus (MIC = 512 μg mL1) and A. fumigantus (MIC = 512 μg mL1). The total phenolic content, flavonoid content, and radical scavenging potential were determined showing its great production of phenolics and flavonoids, along with interesting radical scavenging potential (DPPH EC50 = 6.36 ± 0.029 mg mL 1). Our findings contributed to characterize P. glazioviana as a source of methoxylated flavonoids with antimicrobial potential

New Sulphated Flavonoids and Larvicidal Activity of <i>Helicteres velutina</i> K. Schum (Sterculiaceae)

Helicteres velutina K. Schum (Sterculiaceae), commonly known in Brazil as &#8216;pit&#243;&#8217;, is traditionally used by indigenous peoples as insecticides and repellents. The present work reports on the the phytoconstituents from aerial parts of H. velutina and evaluation of the larvicidal potential of its extract. The compounds were isolated using chromatographic techniques and identified by NMR, IR and LC-HRMS. This study led to the isolation of a fatty acid, one aliphatic alcohol, four chlorophyll derivatives, one steroid, triterpenes, a lignan, and flavonoids, highlighting the new compounds in the literature, 5,4&#8242;-di-hydroxy-7-methoxy-8-O-sulphate flavone (mariahine) (15a) and 5,3&#8242;-di-hydroxy-7,4&#8242;-dimethoxy-8-O-sulphate flavone (condadine) (15b). The work presented here contributes to the chemotaxonomic knowledge of the Sterculiaceae family by describing the occurrence of sulphated flavonoids in this family for the first time. The crude ethanolic extract of H. velutina featured robust larvicidal activity against Aedes aegypti larvae, showing that the extract can be useful as a domestic larvicide, just as indicated by traditional use, to combat A. aegypti, a vector insect of severe viral diseases, such as dengue and Zika