Mutagenic activity promoted by amentoflavone and methanolic extract of Byrsonima crassa Niedenzu

Byrsonima crassa is a plant pertaining to the Brazilian central savannah-like belt of vegetation and popularly used for the treatment of gastric dysfunctions and diarrhoea. The methanol extract contains catechin, tannins, terpenes and flavonoids; both mutagenic potential and antioxidant properties have been ascribed to flavonoids. The mutagenicity of some flavonoids is believed to be associated with the formation of reactive oxygen species and seems to depend on the number and position of hydroxyl groups. In the present study the mutagenic activity of the methanol, chloroform and 80% aqueous methanol extracts, as well as acetate and aqueous sub-fractions, of this medicinal plant were evaluated by Salmonella typhimurium assay, using strains 100, TA98, TA102 and TA97a, and in mouse reticulocytes. The results showed mutagenic activity of the methanolic extract in the TA98 strain without S9, but no mutagenicity to mouse cells in any of the extracts. The acetate fraction showed strong signs of mutagenicity without S9, suggesting that in this enriched fraction were concentrated the compounds that induced mutagenic activity. The aqueous fraction showed no mutagenic activity. The TLC and HSCCC analyses of the acetate fraction with some standard compounds permitted the isolation of the quercetin-3-O-beta-D-galactopyranoside, quercetin-3-O-alpha-L-arabinopyranoside, amentoflavone, methyl gallate and (+)-catechin, of which only the amentoflavone exhibited positive mutagenicity to TA98 (+S9, -S9). (c) 2006 Elsevier B.V.. All rights reserved.

Constituents and antiulcer effect of Alchornea glandulosa: Activation of cell proliferation in gastric mucosa during the healing process

Alchornea glandulosa (Euphorbiaceae) is a plant used in folk medicine as an antiulcer agent. Rats pretreated with methanolic extract obtained from the leaves of A. glandulosa (AG) showed a dose-dependent effect and significant reduction of gastric ulcers induced by absolute ethanol at the doses of 500 (57%) and 1000 mg/kg (35%) in relation to the control group. Pretreatment of mice with AG (500, 1000 mg/kg, p.o.) showed dose-dependent activity and significantly decreased the severity of lesions caused by HCl/ethanol and by non steroidal anti inflammatory drug-induced gastric lesions. Pretreatment with AG also induced antisecretory action via local and systemic routes and a significant decrease in the total gastric acid content. The gastroprotective effects of AG involved the participation of nitric oxide and increased levels of endogenous sulfhydryl compounds, which are defensive mechanisms of the gastrointestinal mucosa against aggressive factors. The ability of AG to heal gastric ulcers was evaluated after 14 consecutive days of treatment. The results showed that single oral administrations of AG (250 mg/kg/once daily) potently stimulates gastric epithelial cell proliferation that contributes to the accelerated healing of gastric ulcers induced by acetic acid. In addition, no subacute toxicity (body weight gain, vital organs, and serum biochemical parameters) was observed during treatment with AG. Phytochemical investigation of AG led to the isolation of myricetin-3-O-alpha-L-rhamnopyranoside, quercetin-3-O-alpha-L-arabinopyranoside, quercetin-3-O-beta-D-galactopyranoside, quercetin, amentoflavone, methyl gallate, gallic acid, and pterogynidine. We also established the phytochemical profile of AG with the quantification of total phenolic compounds. These compounds may contribute to the observed antiulcerogenic effects of AG.

In vitro allelopathic potential of Leonurus sibiricus L. leaves

The chemical interaction between plants is known as allelopathy and it is related to the release of substances into the environment. The present study aimed at the evaluation of the allelopathic activity of the leaves of Leonurus sibiricus against the germination and initial growth of Raphanus sativus, Lactuca sativa, and Lepidium sativum. Chemical analyses showed the presence in the leaves of four major flavonoids (quercetin-3-O-alpha-L-rhamnopyranosyl-(1 > 6)-beta-D-galactopyranoside; rutin; hyperin, and isoquercetrin) and of three minor flavonoidic compounds (genkwanin, 3'-hydroxy genkwanin, and quercetin). Extracts, their chromatographic fractions and pure isolated flavonoids showed different biological activities. A methanol extract of leaves of Leonurus sibiricus caused significant reduction only in the germination of Lactuca sativa, with no effects on the germinative processes of Raphanus sativus and Lepidium sativum. Some chromatographic fractions, containing the flavonoids, showed inhibitory activity on the initial stages of root growth of all tested seeds. The isolated flavonoids, at the higher concentration tested (10(-4) M) seemed to be responsible for the inhibition of the germination, as well as the radical elongation. Among pure compounds, 3'-OH-genkwanin and quercetin showed the stronger antigerminative activity at the concentration of 10(-4) M, whereas the radical elongation was reduced by rutin, isoquercetrin and 3'-OH-genkwanin. All compounds, tested at concentrations ranging between 10(-5) and 10(-7) M, showed stimulatory activities.

Flavonoids and antiulcerogenic activity from Byrsonima crassa leaves extracts

Byrsonima crassa Niedenzu (IK) (Malpighiaceae) is used in Brazilian folk medicine for the treatment of diseases related mainly to gastric ulcers. In this study, we evaluated the potential antiulcerogenic effect of three different extracts obtained from the leaves of Byrsonima crassa namely hydromethanolic (80% MeOH), methanolic (MeOH) and chloroformic extracts (CHCl3). The oral administration (250, 500 and 1000 mg/kg) of all the extracts reduced the formation of lesions associated with HCl/ethanol administration in mice. The 80% MeOH extract significantly reduced the incidence of gastric lesions by 74, 78 and 92% at doses of 250,500 and 1000 mg/kg, respectively (P < 0.01). The MeOH extract reduced the ulceration by 93 and 99% only at the doses of 500 and 1000 mg/kg (P < 0.01). The lower gastroprotective action (69%) was observed when animals were treated with CHCl3 extract at the dose of 1000 mg/kg (P < 0.01). Phytochemical investigation of Byrsonima crassa afforded five known substances: quercetin-3-O-beta-D-galactopyranoside, quercetin-3-O-alpha-L-arabinopyranoside, the biflavonoid amentoflavone, (+)-catechin and (-)-epicatechin. The presence of these phenolic compounds may probably explain the antiulcerogenic effect of the extracts of Byrsonima crassa leaves. (C) 2004 Elsevier B.V.. All rights reserved.

Application of preparative high-speed counter-current chromatography for the separation of flavonoids from the leaves of Byrsonima crassa Niedenzu (IK)

The methanolic extract of the leaves of the medicinal plant Byrsonima crassa (Malpighiaceae) contain flavonoids with antioxidant activity. They were separated in a preparative scale using high-speed counter-current chromatography. The optimum solvent system used was composed of a mixture of ethyl acetate-n-propanol-water (140:8:80 (v/v/v)) and led to a successful separation between monoglucosilated flavonoids (quercetin-3-O-alpha-L-arabinoside, quercetin-3-O-beta-D-galactoside) and the biflavonoid amentoflavone in only 3.5 h. The purities of quercetin-3-O-alpha-L-arabinoside (95 mg), quercetin-3-O-beta-D-galactoside (16 mg) and the biflavonoid amentoflavone (114 mg) were all isolated at purity over 95%. Identification was performed by H-1 NMR, C-13 NMR and UV analyses. (C) 2004 Published by Elsevier B.V.

Preparative separation of flavonoids from the medicinal plant Davilla elliptica St. Hill. by high-speed counter-current chromatography

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Relative antioxidant activity of Brazilian medicinal plants for gastrointestinal diseases

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Isolation and structure elucidation of two new flavonoid glycosides from the infusion of Maytenus aquifolium leaves. Evaluation of the antiulcer activity of the infusion

Droplet countercurrent chromatography and high-performance liquid chromatography fractionation of the aqueous infusion from Maytenus aquifolium Martius leaves afforded two flavonoid tetrasaccharides: quercetin 3-O-alpha-L-rhamnopyranosyl(1-->6)-O-[beta-D-glucopyranosyl(1-->3)-O-alpha-L-rhamnopranosyl( 1-->2)-O-beta-D-galactopyranoside and kaempferol 3-O-alpha-L-rhamnopyranosyl(1-->6)-O-[beta-D-glucopyranosyl( 1-->3)-O-alpha-L-rhamnopyranosy(1-->2-2)-O-beta-D-galactopyranoside. All structures were elucidated by spectroscopic methods. Pharmacological essays of the infusion showed antiulcer activity in rats.

Preparative isolation of a novel flavonoid from an infusion of Byrsonima basiloba leaves by high-speed counter-current chromatography

A method for the isolation of three compounds from the infusion of leaves of Byrsonima basiloba A. Juss. by high-speed counter-current chromatography (HSCCC) was developed. This technique led to the separation of a novel compound, quercetin 3-O-alpha-L-rhamnopyranosyl-(1 -> 3)-O-[alpha-L-rhamnopyranosyl-(1 -> 6)]-beta-D-allopyranoside, and two known compounds quercetin3-O-(X-L-rhamnopyranosyl-(1 -> 6)-beta-D-galactopyranoside and (+)-catechin in 4 h with purities of over 92%. The structures of the compounds were determined by one- and two-dimensional NMR spectroscopy and HPLC.

An unusual C-6-C-6 '' linked flavonoid from Miconia cabucu (Melastomataceae)

Chromatographic fractionation of the methanolic extract from the leaves of Miconia cabucu Hoehne (Melastomataceae) afforded the first example of a C-6-C-6 linked flavone dimer, 5-hydroxy-4',7-dimethoxyflavone-(6-C-6)-5-hydroxy-3 4',7-trimethoxyflavone as well as the known compounds, quercetin- 3-O-alpha-L- rhamnopyranosyl-(2 -> 1)-O-beta-D-xylopyranoside, quercetin-3-O-alpha-L-rhamnopyranoside, myricetin-3-O-alpha-L-rhamnopyranoside, quercetin-3-O-beta-D-glucopyranoside, kaempferol -3-O-beta-D-(6-coumaroyl) -glucopyranoside and gallic acid. Their chemical identities were established by application of NMR spectroscopic methods including 2D-NMR, as well as UV and ESI-MS analyses. (c) 2007 Elsevier Ltd. All rights reserved.

Modulatory effect of Byrsonima basiloba extracts on the mutagenicity of certain direct and indirect-acting mutagens in Salmonella typhimurium assays

Byrsonima basiloba A. Juss. species is a native arboreal type from the Brazilian cerrado (tropical American savanna), and the local population uses it to treat diseases, such as diarrhea and gastric ulcer. It belongs to the Malpighiaceae family, and it is commonly known as murici. Considering the popular use of B. basiloba derivatives and the lack of pharmacological potential studies regarding this vegetal species, the mutagenic and antimutagenic effect of methanol (MeOH) and chloroform extracts were evaluated by the Ames test, using strains TA97a, TA98, TA100, and TA102 of Salmonella typhimurium. No mutagenic activity was observed in any of the extracts. To evaluate the antimutagenic potential, direct and indirect mutagenic agents were used: 4 nitro-o-phenylenediamine, sodium azide, mitomycin C, aflatoxin B1, benzo[a]pyrene, and hydrogen peroxide. Both the extracts evaluated showed antimutagenic activity, but the highest value of inhibition level (89%) was obtained with the MeOH extract and strain TA100 in the presence of aflatoxin B1. Phytochemical analysis of the extracts revealed the presence of n-alkanes, lupeol, ursolic and oleanolic acid, (+)-catechin, quercetin-3-O-α-L-arabinopyranoside, gallic acid, methyl gallate, amentoflavone, quercetin, quercetin-3-O-(2″-O-galloyl)-β-D- galactopyranoside, and quercetin-3-O-(2″-O-galloyl)-α-L- arabinopyranoside. © 2008 Mary Ann Liebert, Inc.

Evaluation of the toxicity of Virola sebifera crude extracts, fractions and isolated compounds on the nest of leaf-cutting ants

The phytochemical study of Virola sebifera leaves led to the isolation of three lignans: (+)-sesamin, (-)-hinokinin, and (-)-kusunokinin and three flavonoids: quercetin-3-O - L-rhamnoside, quercetin-3-O - D-glucoside, and quercetin-3-methoxy-7-O - D-glucoside by using techniques as high-speed counter-current chromatography and high-performance liquid chromatography. The crude extracts, fractions, and isolated compounds were evaluated for their insecticidal and fungicidal potential against Atta sexdens rubropilosa and its symbiotic fungus Leucoagaricus gongylophorus. The bioassay results showed a high insecticidal activity for the methanol crude extract of the leaves of V. sebifera and its n-hexane, dichloromethane and ethyl acetate fractions. The fungicidal bioassay revealed high toxicity of the lignans against L. gongylophorus. © 2012 Keylla Utherdyany Bicalho et al.

A new tropane alkaloid and other constituents of Erythroxylum rimosum (Erythroxylaceae)

A new tropane alkaloid, named the 7β-acetoxy-3β,6β- dibenzoyloxytropane (1), was isolated from a methanol extract of Erythroxylum rimosum O.E. Schulz leaves. Other known compounds were detected, including quercetin, kaempferol-3-O-α-l-arabinofuranoside, (+)-catechin, epicatechin, quercetin-3-O-α-arabinofuranoside, quercetin-3-O-α- arabinopyranoside, quercetin-3-O-β-arabinopyranoside, quercetin-3-β- glucopyranoside, kaempferol, quercetin-3-O-β-galactopyranoside, β-sitosterol, α-amyrin, β-amyrin, and the ester derivatives of these two amyrins. Compound 1 exhibited weak inhibition of acetylcholinesterase. Structural identification was performed using IR, ESIHRMS and one- and two-dimensional NMR data analyses and confirmed by comparison with literature data. © 2013 Phytochemical Society of Europe.

Effect of Byrsonima crassa and Phenolic Constituents on Helicobacter pylori-Induced Neutrophils Oxidative Burst

Byrsonima crassa Niedenzu (Malpighiaceae) is used in Brazilian folk medicine for the treatment of diseases related mainly to gastric ulcers. In a previous study, our group described the gastric protective effect of the methanolic extract from the leaves of B. crassa. The present study was carried out to investigate the effects of methanolic extract and its phenolic compounds on the respiratory burst of neutrophils stimulated by H. pylori using a luminol-based chemiluminescence assay as well as their anti-H. pylori activity. The suppressive activity on oxidative burst of H. pylori-stimulated neutrophils was in the order of methyl gallate > (+)-catechin > methanol extract > quercetin 3-O-alpha-L-arabinopyranoside > quercetin 3-O-beta-D-galactopyranoside > amentoflavone. Methyl gallate, compound that induced the highest suppressive activity with IC50 value of 3.4 mu g/mL, did not show anti-H. pylori activity. B. crassa could be considered as a potential source of natural antioxidant in gastric ulcers by attenuating the effects on the damage to gastric mucosa caused by neutrophil generated reactive oxygen species, even when H. pylori displays its evasion mechanisms.

A Validated Chromatographic Method for the Determination of Flavonoids in Copaifera langsdorffii by HPLC

Hydroethanolic extracts of C. langsdorffii leaves have therapeutic potential. This work reports a validated chromatographic method for the quantification of polar compounds in the hydroethanolic extract of C. langsdorffii leaves. A reliable HPLC method was developed using two monolithic columns linked in series (100 x 4.6 mm - C-18), with nonlinear gradient elution, and UV detection set at 257 nm. A procedure for the extraction of flavonols was also developed, which involved the use of 70% aqueous ethanol and the addition of benzophenone as the internal standard. The developed method led to a good detection response as the values for linearity were between 10.3 and 1000 mu g/mL, and those for recovery between 84.2 and 111.1%. The detection limit ranged from 0.02 to 1.70 mu g/mL and the quantitation limit from 0.07 to 5.1 mu g/mL, with a maximum RSD of 5.24%. Five compounds, rutin, quercetin-3-O-alpha-L-rhamnopyranoside, kaempferol-3-O-alpha-L-rhamnopyranoside, quercetin and kaempferol, were quantified. This method could, therefore, be used for the quality control of hydroethanolic extracts of Copaifera leaves and their cosmetic and pharmaceutical products.