Yanna Teles

New Sulphated Flavonoids from Wissadula periplocifolia (L.) C. Presl (Malvaceae)

Wissadula periplocifolia (L.) C. Presl (Malvaceae) is commonly used in Brazil to treat bee stings and as an antiseptic. The antioxidant properties of its extracts have been previously demonstrated, thus justifying a phytochemical investigation for its bioactive phenolic constituents. This has yielded five new sulphated flavonoids: 8-O-sulphate isoscutellarein (yannin) (1a); 4′-O-methyl-7-O-sulphate isoscutellarein (beltraonin) (1b); 7-O-sulphate acacetin (wissadulin) (2a); 4′-O-methyl-8-O-sulphate isoscutellarein (caicoine) (2b) and 3′-O-methyl-8-O-sulphate hypolaetin (pedroin) (3b) along with the known flavonoids 7,4′-di-O-methyl-8-O-sulphate isoscutellarein (4), acacetin, apigenin, isoscutellarein, 4′-O-methyl isoscutellarein, 7,4′-di-O-methylisoscutellarein, astragalin and tiliroside. The compounds were isolated by column chromatography and identified by NMR (1H, 13C, HMQC, HMBC and COSY) and LC-HRMS. A cell based assay was carried out to evaluate the preliminary cytotoxic properties of the flavonoids against UVW glioma and PC-3M prostate cancer cells as well as non-tumour cell lines. The obtained results showed that acacetin, tiliroside, a mixture of acacetin + apigenin and the sulphated flavonoids 2a + 2b exhibited inhibitory activity against at least one of the cell lines tested. Among the tested flavonoids acacetin and tiliroside showed lower IC50 values, presenting promising antitumor effects.

Mechanism of the antihypertensive and vasorelaxant effects of the flavonoid tiliroside in resistance arteries

Hypertension is a leading cause of death and disability globally, and its prevalence continues to accelerate. The cardiovascular effects of the flavonoid tiliroside have never been reported. In this work, using complementary in vivo and in vitro approaches, we describe the antihypertensive effect of tiliroside and the underlying mechanisms involved in the reduction of blood pressure. Tiliroside (1, 5 or 10 mg/kg) induced a dose-dependent long-lasting decrease in blood pressure in conscious DOCA-salt hypertensive rats that was accompanied by an increased heart rate. Tiliroside also induced a concentration-dependent vasodilation of mesenteric resistance arteries precontracted with phenylephrine. Removal of the endothelium or pretreatment of the preparation with L-NAME or indomethacin did not modify the vasodilator response for tiliroside. When vessels were precontracted with a high K⁺ (50 mM) solution, tiliroside exhibited a vasodilator effect similar to that observed in vessels precontracted with phenylephrine. Experiments carried out in nominally Ca²⁺-free solution showed that tiliroside antagonized CaCl₂-induced contractions. Moreover, tiliroside reduced the rise in intracellular Ca²⁺ concentration induced by membrane depolarization in vascular smooth muscle cells. Finally, tiliroside decreased the voltage-activated peak amplitude of the L-type Ca²⁺ channel current in freshly dissociated vascular smooth muscle cells from mesenteric arteries. Altogether, our results point to an antihypertensive effect of tiliroside due to a reduction in peripheral resistance through blockage of voltage-activated peak amplitude of the L-type Ca²⁺ channel in smooth muscle cells.

New Alcamide and Anti-oxidant Activity of Pilosocereus gounellei A. Weber ex K. Schum. Bly. ex Rowl. (Cactaceae)

The Cactaceae family is composed by 124 genera and about 1438 species. Pilosocereus gounellei, popularly known in Brazil as xique-xique, is used in folk medicine to treat prostate inflammation, gastrointestinal and urinary diseases. The pioneering phytochemical study of P. gounellei was performed using column chromatography and HPLC, resulting in the isolation of 10 substances: pinostrobin (1), β-sitosterol (2), a mixture of sitosterol 3-O-β-d-glucopyranoside/stigmasterol 3-O-β-d-glucopyranoside (3a/3b), 132-hydroxyphaeophytin a (4), phaeophytin a (5), a mixture of β-sitosterol and stigmasterol (6a/6b), kaempferol (7), quercetin (8), 7′-ethoxy-trans-feruloyltyramine (mariannein, 9) and trans-feruloyl tyramine (10). Compound 9 is reported for the first time in the literature. The structural characterization of the compounds was performed by analyses of 1-D and 2-D NMR data. In addition, a phenolic and flavonol total content assay was carried out, and the anti-oxidant potential of P. gounellei was demonstrated.

Phytochemical investigation of Wissadula periplocifolia (L.) C. Presl and evaluation of its antibacterial activity

A phytochemical study on the aerial parts of Wissadula periplocifolia using chromatographic techniques has led to the isolation of sitosterol (1a), stigmasterol (1b), sitosterol 3-O-β-D-glucopyranoside (2a), stigmasterol 3-O-β-D-glucopyranoside (2b), phaeophytin A (3), 132-hydroxy-(132-S)-phaeophytin A (4), phaeophytin B (5), 173-ethoxyphaeophorbide (6), 3,4-seco-urs-4(23),20(30)-dien-3-oic acid (7), 3-oxo-21β-H-hop-22(29)-ene (8), dammaradienone (9a), and taraxastenone (9b). The isolated compounds were characterised by spectroscopic analysis. A preliminary assay to evaluate the antibacterial activity of W. periplocifolia extracts and fractions showed that the dichloromethane, ethyl acetate, and n-butanol fractions were active against Enterococcus faecalis.

Alkaloids and Phenolic Compounds from Sida rhombifolia L. (Malvaceae) and Vasorelaxant Activity of Two Indoquinoline Alkaloids

The follow-up of phytochemical and pharmacological studies of Sida rhombifolia L. (Malvaceae) aims to strengthen the chemosystematics and pharmacology of Sida genera and support the ethnopharmacological use of this species as hypotensive herb. The present work reports phytoconstituents isolated and identified from aerial parts of S. rhombifolia by using chromatographic and spectroscopic methods. The study led to the isolation of scopoletin (1), scoporone (2), ethoxy-ferulate (3), kaempferol (4), kaempferol-3-O-β-d-glycosyl-6′′-α-d-rhamnose (5), quindolinone (6), 11-methoxy-quindoline (7), quindoline (8), and the cryptolepine salt (9). The alkaloids quindolinone (6) and cryptolepine salt (9) showed vasorelaxant activity in rodent isolated mesenteric arteries.

Sulphated Flavonoids: Biosynthesis, Structures, and Biological Activities

The great diversity of enzymatic reactions in plant secondary metabolism allows the continuous discovery of new natural compounds and derivatives. Flavonoids, for example, can be found as aglycone or as several sorts of glycosylated, acetylated, methylated, and sulphated derivatives. This review focuses on sulphated flavonoids, an uncommon group of flavonoid derivatives found in some plant families. This work presents a compilation of sulphated flavonoids and their natural sources reported in the literature. Biosynthetic aspects and biological activities have also been reviewed, showing that these particular kinds of natural compounds play an interesting role in plant metabolism, as well as being potential candidates for the development of new drugs.

Phenolic constituents from Wissadula periplocifolia (L.) C. Presl. and anti-inflammatory activity of 7,4′-di-O-methylisoscutellarein

Abstract This study reports the first phenolics from Wissadula genus (Malvaceae) and the anti-inflammatory activity of 7,4′-di-O-methylisoscutellarein. Using chromatographic methods, five phenolic compounds were isolated from aerial parts of Wissadula periplocifolia (L.) C. Presl. The compounds were identified as 4-hydroxybenzoic acid, 3-hydroxybenzoic acid, trans-cinnamic acid, tamgermanetin and 7,4′-di-O-methylisoscutellarein using spectroscopic methods. The flavone 7,4′-di-O-methylisoscutellarein showed anti-inflammatory activity by inhibiting neutrophils recruitment in a mice model of pleurisy and by decreasing significantly the production of cytokines IL-1β and TNF-α.

Phytochemistry investigation of Casearia arborea (Rich.) Urb. (Salicaceae) and antimicrobial analysis of its diterpene

Maria D. Leite-Ferreiraa, Maria S. Rocha-Souzaa, Raphael R. de A. Ramireza, Otemberg S. Chavesa, Yanna C. F. Telesb, Fillipe de O. Pereirac, Raimundo Braz-Filhod, Edeltrudes de O. Limaa, Rosangela do Socorro F. R. Sarquise, Tânia Maria Sarmento da Silvaf and Maria de Fátima Vanderlei de Souzaa,* Departamento de Ciências Farmacêuticas, Centro de Ciências da Saúde, Universidade Federal da Paraíba, Campus I, 58051-970 João Pessoa – PB, Brasil Departamento de Química e Física, Centro de Ciências Agrárias, Universidade Federal da Paraíba, Campus I, 58397-000 Areia – PB, Brasil Centro de Educação e Saúde, Universidade Federal de Campina Grande, 58175-000 Cuité – PB, Brasil Departamento de Química, Universidade Estadual do Norte Fluminense, 28013-602 Campos dos Goytacazes – RJ, Brasil Instituto de Pesquisas Científicas e Tecnológicas do Estado do Amapá, 68901-025 Macapá – AP Brasil Departamento de Ciências Moleculares, Universidade Federal Rural de Pernambuco, Campus Dois Irmãos, 52171-900 Recife, Brasil

New Sulphated Flavonoids and Larvicidal Activity of Helicteres velutina K. Schum (Sterculiaceae)

Helicteres velutina K. Schum (Sterculiaceae), commonly known in Brazil as ‘pitó’, 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′-di-hydroxy-7-methoxy-8-O-sulphate flavone (mariahine) (15a) and 5,3′-di-hydroxy-7,4′-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.

Phytoconstituents from Sidastrum micranthum (A. St.-Hil.) Fryxell (Malvaceae) and antimicrobial activity of pheophytin a

Sidastrum micranthum (A. St.-Hil.) Fryxell, a member of the Malvaceae family, is called malva preta in Brazil. As this species is commonly used to treat bronchitis, cough, and asthma, better knowledge of its chemical compounds is important. The phytochemical study of its hexane extract, using chromatographic techniques, led to isolation of six compounds: the triterpene isoarborinol, a mixture of sitosterol and stigmasterol, sitosterol-3-O-β-D-glucopyranoside, pheophytin a, and 132-hydroxy-(132-S)-pheophytin a. Structural identification of these compounds was carried out using spectroscopic methods such as IR and 1D and 2D NMR (HOMOCOSY, HMQC, HMBC, and NOESY). Compounds isolated from S. micranthum were screened for their in vitro antifungal and antibacterial activity against twenty fungal and bacterial standard strains. Pheophytin a exhibited antimicrobial action against all microorganisms tested.