The role of tannins as antiulcer agents: a fluorescence-imaging based study

Abstract Condensed tannins have been used for many years in folk medicine to treat gastric problems. The mechanism of action that explains why tannins improve gastritis symptoms is based on their ability to chelate metals, antioxidant activity, and their complexation power with other molecules. Even though these uses are well-known, the requirements to become an herbal medicine are much more complex. Herein, we analyzed Stryphnodendron rotundifolium Mart., Fabaceae, extract using MALDI for tannin characterization and carried out a fluorescence-imaging study to prove the gastroprotective effects of tannins as coating agents. Through these methods we show that condensed tannins form a gastroprotective layer. Moreover, we revise and discuss other possible mechanisms of action for phenolic-rich plant extracts and their potential in the development of herbal medicines to treat ulcers and gastritis.

Isovitexin as marker and bioactive compound in the antinociceptive activity of the Brazilian crude drug extracts of Echinodorus scaber and E. grandiflorus

Abstract Echinodorus scaber Rataj and Echinodorus grandiflorus (Cham. & Schltdl.) Micheli, Alismataceae, are popularly used to relieve inflammatory complaints and as diuretic. A study on the antinociceptive effect and selected marker compounds in eleven extracts from different locations was undertaken and their antinociceptive effect was assessed. The fingerprints were compared by HPLC-DAD and the content of vitexin, isovitexin, isoorientin and vitexin-2-O-rhamnoside were determined. All samples presented antinociceptive activity reducing the writhes by 36.4-62.5% and 47.4-79.8% at 10 and 50 mg/kg, respectively; indomethacin (5 mg/kg) reduced writhes by 82.6-90.1%. The content of the flavonoids C-glycosides, however, presented a strong variation. Isovitexin and isoorientin were found in all the samples, with content ranging from traces to 14.70 µg/mg and 2.12-84.27 µg/mg extract, respectively, while vitexin-2-O-rhamnoside occurred in quantifiable amounts only in 3 out of 11 samples ranging from 5.43 to 33.13 µg/mg extract; vitexin was not detected at all or detected in trace amounts. According to the fingerprints, the samples could be arranged in four main groups. All eleven extracts showed antinociceptive activity. Isovitexin was the only flavonoid present in all samples and can be regarded, acting in synergy with the other compounds or not, as the responsible for the antinociceptive activity. Therefore, isovitexin is a good choice as chemical marker when the antinociceptive activity of E. scaber and E. grandiflorus is investigated.

Leaf and Root Extracts from Campomanesia adamantium (Myrtaceae) Promote Apoptotic Death of Leukemic Cells via Activation of Intracellular Calcium and Caspase-3.

Phytochemical studies are seeking new alternatives to prevent or treat cancer, including different types of leukemias. Campomanesia adamantium, commonly known as guavira or guabiroba, exhibits pharmacological properties including antioxidant, antimicrobial, and antiproliferative activities. Considering the anticancer potential of this plant species, the aim of this study was to evaluate the antileukemic activity and the chemical composition of aqueous extracts from the leaves (AECL) and roots (AECR) of C. adamantium and their possible mechanisms of action. The extracts were analyzed by LC-DAD-MS, and their constituents were identified based on the UV, MS, and MS/MS data. The AECL and AECR showed different chemical compositions, which were identified as main compounds glycosylated flavonols from AECL and ellagic acid and their derivatives from AECR. The cytotoxicity promoted by these extracts were evaluated using human peripheral blood mononuclear cells and Jurkat leukemic cell line. The cell death profile was evaluated using annexin-V-FITC and propidium iodide labeling. Changes in the mitochondrial membrane potential, the activity of caspases, and intracellular calcium levels were assessed. The cell cycle profile was evaluated using propidium iodide. Both extracts caused concentration-dependent cytotoxicity only in Jurkat cells via late apoptosis. This activity was associated with loss of the mitochondrial membrane potential, activation of caspases-9 and -3, changes in intracellular calcium levels, and cell cycle arrest in S-phase. Therefore, the antileukemic activity of the AECL and AECR is mediated by mitochondrial dysfunction and intracellular messengers, which activate the intrinsic apoptotic pathway. Hence, aqueous extracts of the leaves and roots of C. adamantium show therapeutic potential for use in the prevention and treatment of diseases associated the proliferation of tumor cell.

Antimicrobial activity of Aspilia latissima (Asteraceae)

Abstract We evaluated the antimicrobial activity of Aspilia latissima - an abundant plant from the Brazilian Pantanal region - against Candida albicans, Candida parapsilosis, Candida krusei, Candida tropicalis, Pseudomonas aeruginosa, Enterococcus faecalis, Escherichia coli and Staphylococcus aureus. The crude extracts and fractions showed activity in all tested microorganisms. The chloroform fraction of the leaves and roots showed the most antimicrobial activity against S. aureus, with an MIC of 500 μg/mL. This fraction was submitted to bioautographic assays to characterize the activity of the compounds. Two bands from the leaves (L-A and L-B) and three bands from the roots (R-C, R-D and R-E) were bioactive. Within the root-derived bands, the terpene derivatives stigmasterol, kaurenoic acid and kaura-9(11), 16-dien-18-oic acid were identified. Antibiotic activity of A. latissima is reported for the first time.

In vitro anti-Leishmania infantum activity of essential oil from Piper angustifolium

Abstract Piper angustifolium Lam., Piperaceae, popularly known as "matito", "pimenta-de-macaco", "pimenta-longa" or "jagurandi" in Brazil, has been commonly used in the treatment of cutaneous leishmaniasis-associated lesions, but there are few studies on the activity against visceral leishmaniasis-associated species. This study demonstrates the first in vitro antileishmanial activity of the P. angustifolium essential oil, of which the phytochemical profile showed the presence of sesquiterpenes and monoterpenes. The main compounds were spathulenol (23.8%) and caryophyllene oxide (13.1%). P. angustifolium essential oil was highly active [the half maximum inhibitory concentration = 1.43 μg/ml] against intracellular amastigotes of Leishmania infantum, the etiological agent of visceral leishmaniasis in the New and Old World. Activity was obtained 24 h after addition of the oil (6.25–50 μg/ml), with a reduction of 100% in the infection index at concentrations of 25 and 50 μg/ml. P. angustifolium essential oil showed low cytotoxicity for mammalian fibroblasts and macrophages (the half maximum inhibitory concentration values of 31.67 and 48.22 μg/ml, respectively), and it was 33 and 22 times more toxic to amastigotes than to mammalian cells, as indicated by selectivity indexes. The results demonstrated that P. angustifolium essential oil is a promising alternative for the study of potential drugs for visceral leishmaniasis.

Control of anthocyanin and non-flavonoid compounds by anthocyanin-regulating MYB and bHLH transcription factors in Nicotiana benthamiana leaves.

Coloration of plant organs such as fruit, leaves and flowers through anthocyanin production is governed by a combination of MYB and bHLH type transcription factors (TFs). In this study we introduced Rosea1 (ROS1, a MYB type) and Delila (DEL, a bHLH type), into Nicotiana benthamiana leaves by agroinfiltration. ROS1 and DEL form a pair of well-characterized TFs from Snapdragon (Antirrhinum majus), which specifically induce anthocyanin accumulation when expressed in tomato fruit. In N. benthamiana, robust induction of a single anthocyanin, delphinidin-3-rutinoside (D3R) was observed after expression of both ROS1 and DEL. Surprisingly in addition to D3R, a range of additional metabolites were also strongly and specifically up-regulated upon expression of ROS1 and DEL. Except for the D3R, these induced compounds were not derived from the flavonoid pathway. Most notable among these are nornicotine conjugates with butanoyl, hexanoyl, and octanoyl hydrophobic moieties, and phenylpropanoid-polyamine conjugates such as caffeoyl putrescine. The defensive properties of the induced molecules were addressed in bioassays using the tobacco specialist lepidopteran insect Manduca sexta. Our study showed that the effect of ROS1 and DEL expression in N. benthamiana leaves extends beyond the flavonoid pathway. Apparently the same transcription factor may regulate different secondary metabolite pathways in different plant species.

Comparative profiles of Achyrocline alata (Kunth) DC. and A. satureioides (Lam.) DC., Asteraceae, applying HPLC-DAD-MS / Perfil comparativo entre Achyrocline alata (Kunth) DC. e A. satureioides (Lam.) DC., Asteraceae, utilizando HPLC-DAD-MS

A comparative analysis between the hydromethanolic extracts of Achyrocline alata (Kunth) DC. and A. satureioides (Lam.) DC., Asteraceae, was performed by the use of HPLC-DAD-MS. Both plants were used without distinction and under the same indications in folk medicine in Mato Grosso do Sul, Brasil. While Achyrocline alata ("jatei-ka-ha") is used in folk medicine of the Brazilian state of Mato Grosso do Sul, A. satureioides is predominantly used in other states. Samples of both plants collected in different periods, 1996 and 2002, showed a very similar chemical profile. The results indicate that A alata could be used in phytotherapeutic preparations as substitue for A. satureioides, since they have similar chemical compositions of the polar extract.

Análises comparativas entre os extratos hidrometanólico de Achyrocline alata (Kunth) DC. e A. satureioides (Lam.) DC., Asteraceae,foram desenvolvidas utilizando HPLC-DAD-MS. Ambas as plantas são utilizadas indistintamente para as mesmas indicações na medicina popular de Mato Grosso do Sul, Brasil, enquanto a A. alata ("jatei-ka-há) é predominante neste estado, a A. satureioides ("marcela") é predominante nos demais estados da Federação. Amostras das duas espécies coletadas em épocas diferentes, 1996 e 2002, apresentaram o mesmo perfil cromatográfico. O presente resultado pode justificar que A. alata possa ser utilizada como sucedânea de A. satureioides, pois apresentam similar composição de metabólitos secundários polares.

Gas-phase dissociation of 1,4-naphthoquinone derivative anions by electrospray ionization tandem mass spectrometry.

Gas-phase dissociation pathways of deprotonated 1,4-naphthoquinone (NQ) derivatives have been investigated by electrospray ionization tandem mass spectrometry (ESI-MS/MS). The major decomposition routes have been elucidated on the basis of quantum chemical calculations at the B3LYP/6-31 + G(d,p) level. Deprotonation sites have been indicated by analysis of natural charges and gas-phase acidity. NQ anions underwent an interesting reaction under collision-induced dissociation conditions, which resulted in the radical elimination of the lateral chain, in contrast with the even-electron rule. Possible pathways have been suggested, and their mechanisms have been elucidated on the basis of Gibbs energy and enthalpy values for the anions previously described at each pathway.

Variação química no óleo essencial das folhas de seis indivíduos de Duguetia furfuracea (Annonaceae) / Chemical variability of the essential oil of the leaves from six individuals of Duguetia furfuracea (Annonaceae)

Duguetia furfuracea, Annonaceae, uma invasora de pastagens, é também usada na medicina tradicional em diversos estados no Brasil. Devido à significante diferença de odor entre dois grupos de indivíduos desta planta em um remanescente de cerrado em Campo Grande, Mato Grosso do Sul, seis amostras foram selecionadas de acordo com a intensidade de odor em suas folhas: In-01, In-03 e In-05: odor pronunciado (Perfil A); In-02, In-04 e In-06: odor fraco ou ausência de odor (Perfil B). As folhas foram coletadas e submetidas a hidrodestilação para obtenção dos óleos essenciais, os quais foram analisados por CG/EM. Uma boa compatibilidade foi encontrada entre os resultados obtidos por CG/EM e a análise olfativa adotada para as amostras: espécimes odor pronunciado apresentaram uma alta porcentagem de monoterpenos e alguns sesquiterpenos: In-01 (β-felandreno, 42,2 por cento; mirceno, 6,8 por cento; α-felandreno, 4,6 por cento); In-03 (terpin-4-ol, 21,6 por cento; sabineno, 17,3 por cento; p-cimeno, 5,6 por cento); In-05 (sabineno, 25,1 por cento; terpin-4-ol, 16,2 por cento; p-cimeno, 8,3 por cento). Apenas sesquiterpenos foram encontrados nos espécimes que apresentaram odor fraco ou ausência do mesmo (com constituinte majoritário biciclogermacreno: 21,4 por cento, 24,0 por cento, and 29,1 por cento, respectivamente, para os In-02, In-04 e In-06).

Duguetia furfuracea, Annonaceae, a pasture weed, is also used in folk medicine in several Brazilian states. Because of the significant difference in odor between two groups of this plant in a remnant patch of savanna in Campo Grande county, Mato Grosso do Sul, six samples were selected according to the odor intensity in the leaves (In-01, In-03, and In-05: pronounced odor; In-02, In-04, and In-06: weak odor or its absence). The leaves were collected and subjected to steam distillation for extraction of essential oils, which were analyzed by GC-MS. A good agreement was found between CG/MS results and olfactory evaluation of the samples: specimens exhibiting leaf scent had a high percentage of monoterpenes and some sesquiterpenes, as follows: In-01 (β-phellandrene, 42.2 percent; myrcene, 6.8 percent; α-phellandrene, 4.6 percent); In-03 (terpin-4-ol, 21.6 percent; sabinene, 17.3 percent; p-cymene, 5.6 percent); In-05 (sabinene, 25.1 percent; terpin-4-ol, 16.2 percent; p-cymene, 8.3 percent). Only sesquiterpenes were found in the specimens having weakly scented or scentless leaves (main constituent bicyclogermacrene: 21.4 percent, 24.0 percent, and 29.1 percent, respectively, for In-02, In-04 and In-06).