Neolignans isolated from twigs of Nectandra leucantha Ness & Mart (Lauraceae) displayed in vitro antileishmanial activity

The therapeutic arsenal for the treatment of Leishmaniasis is limited and includes toxic compounds (antimonials, amphotericin B, pentamidine and miltefosine). Given these aspects, the search for new compounds based on floristic biodiversity is crucial. In the present work, we report the isolation, characterization and antileishmanial activity of six related neolignans (1­6) of bioactive extract from Nectandra leucantha (Lauraceae) twigs. Methods: Dried and powdered twigs of N. leucantha were exhaustively extracted using n-hexane. The crude extract was dereplicated by HPLC/HRESIMS and subjected to column chromatography to yield pure compounds 1­6. Their chemical structures were identified via NMR and comparison of obtained data with those previously published in the literature. Biological assays of compounds 1­6 and their respective monomers (eugenol and methyleugenol) were performed using promastigote and amastigote forms of Leishmania (L.) infantum. Results: Dereplication procedures followed by chemical characterization of isolated compounds by NMR enabled the identification of related neolignans 1­6. Neolignans 2, 4 and 6 showed potential against amastigote forms of L. (L.) infantum (EC50 values of 57.9, 67.7 and 13.7 µM, respectively), while compounds 1 and 3 were inactive. As neolignans 2­4 are chemically related, it may be suggested that the presence of the methoxyl group at C4 constitutes an important structural aspect to increase antileishmanial potential against amastigote forms. Compound 6, which consists of a methylated derivative of compound 5 (inactive) showed antileishmanial activity similar to that of the standard drug miltefosine (EC50 =16.9 µM) but with reduced toxicity (SI = 14.6 and 7.2, respectively). Finally, two related monomers, eugenol and methyleugenol, were also tested and did not display activity, suggesting that the formation of dimeric compounds by oxidative coupling is crucial for antiparasitic activity of dimeric compounds 2, 4 and 6. Conclusion: This study highlights compound 6 against L. (L.) infantum amastigotes as a scaffold for future design of new compounds for drug treatment of visceral leishmaniasis.(AU)

Chemical constituents from Zanthoxylum setulosum (Rutaceae) / Costituyentes químicos de Zanthoxylum setulosum (Rutaceae)

Following our phytochemical studies of Costa Rican plants, in this work we report the isolation and identification of eight compounds from aerial parts of Zanthoxylum setulosum (Rutaceae). They were identified as the alkaloid skimmianine, the lignans savinin, kusunokinin, sesamin, syringaresinol and the isopentenyl ether of pluviatol, the amide aurantiamide acetate, and the triterpen lupeol. This is the first report of isolation of skimmianine from the leaves of Z. setulosum and its presence confirm that quinoline and benzophenanthridine alkaloids, can be considered as chemotaxonomic markers of this genus. All the isolated compounds were characterized by spectroscopic methods (including 1H-NMR, 13C-NMR, , HMQC, HMBC and NOESY) and comparison with the literature data.

Continuando con el estudio fitoquímico de plantas de Costa Rica, en este trabajo informamos el aislamiento e identificación de ocho compuestos de las partes aéreas de Zanthoxylum setulosum (Rutaceae). Los compuestos fueron identificados como el alcaloide skimmianina, los lignanos savinina, kusunokinina, sesamina, siringaresinol y el éter isopentílico del pluviatol, la amida conocida como acetato de aurantiamida, y el triterpeno lupeol. Este es el primer informe del aislamiento de skimmianina en las hojas de Z. setulosum, lo cual confirma que alcaloides quinolínicos y benzofenantridinicos pueden ser considerados marcadores quimiotaxonómicos en éste género. La estructura de los compuestos aislados fue caracterizada por métodos espectroscópicos (incluyendo 1HNMR, 13C-NMR, HMQC, HMBC y NOESY) y comparación con datos de la literatura.

Compuestos fenólicos presentes en las hojas de la especie colombiana Polygonum segetum Kunth / Fenolic compounds in the leaves of Polygonum segetum Kunth

The flavonoids 5-hydroxy-7,8,4'-trimethoxy isoflavone and 5,3',4'-trihydroxy-7-methoxyflavanon ,the tannin derivate Ethyl gallate and lignang homoegonol 5-(3''-Hydroxypropyl)-7-methoxy-2-(3',4'-dimethoxyphenyl)benzofuran were isolated and purified from Polygonum segetum Kunth leaves using column chromatography and thin layer chromatography methods. These substances were identified on the basis of their physical properties (melting point and Rf value), qualitative chemical reactions and spectroscopic techniques UV and NMR (experiments 1H, 13C, 1H-1H COSY, HMQC) and spectrometric techniques GC-MS according to their complexity.

El presente estudio se encaminó a determinar los metabolitos secundarios presentes en las hojas de la especie vegetal: Polygonum segetum Kunth, colectada del humedal Juan Amarillo (Bogotá-Colombia). Como resultado se aislaron e identificaron a partir de propiedades físicas y técnicas espectroscópicas de UV, 1HRMN, COSY, DEPT 135, HMQC y APT, la 5-hidróxi-7,8,4´-trimétoxi isoflavona, el galato de etilo (derivado de taninos) y la 5,3´,4´-trihidróxi-7-metóxi flavanona. Además, por análisis GC-MS se identifico el lignano 5-(3,4-dimetóxifenil)-7-metóxibenzofuranpropanol homoegonol.

Antimycobacterial neolignans isolated from Aristolochia taliscana

Tuberculosis (TB - Mycobacterium tuberculosis) is an ancient infectious disease that has appeared once again as a serious worldwide health problem and now comprises the second leading cause of death resulting from a single infection. The prevalence of multidrug resistance (MDR) TB is increasing and therapeutic options for treatment are not always accessible; in fact, some patients do not respond to the available drugs. Therefore, there is an urgent need to develop novel anti-TB agents. The aim of the present study was to screen extracts of Aristolochia taliscana, a plant used in traditional Mexican medicine to treat cough and snake bites, for antimycobacterial activity. The hexanic extract of A. taliscana was tested by microdilution alamar blue assay against Mycobacterium strains and bioguided fractionation led to the isolation of the neolignans licarin A, licarin B and eupomatenoid-7, all of which had antimycobacterial activity. Licarin A was the most active compound, with minimum inhibitory concentrations of 3.12-12.5 ìg/mL against the following M. tuberculosis strains: H37Rv, four mono-resistant H37Rv variants and 12 clinical MDR isolates, as well as against five non-tuberculous mycobacteria (NTM) strains. In conclusion, licarin A represents a potentially active anti-TB agent to treat MDR M. tuberculosis and NTM strains.

Antioxidant isolated from Schisandra propinqua (Wall. ) Baill

Schisandra propinqua (Wall.) Baill.(Schisandraceae) is widely used as a Chinese folk medicine. In this study, activity-guided fractionation of the ethanol extract from the stem of Schisandra propinqua led to the isolation of four extracts. Subsequently, a neolignan 4,4-di(4-hydroxy-3-methoxyphenly)-2,3-dimethylbutanol was isolated from the EtOAc part of the stem of Schisandra propinqua, the free radical scavenging activities of which were researched in vitro. The present work demonstrated that extracts and pure compound possessed scavenging activities to DPPH, superoxide anions and hydroxy radical, and could depress lipid peroxidation reaction induced by oxygen radical produced by the Fe2+/cysteine system in vitro. This suggests that the traditional application of Schisandra propinqua in China may be related to its antioxidant activities, and the EtOAc part of the stems of Schisandra propinqua can be utilized as an effective source of antioxidants.

Bioactivity of the extract and isolation of lignansand a sesquiterpene from the aerial parts of centaurea pamphlica[Asteraceae]

Centaurea pamphylica Boiss. and Heldr. [Family: Asteraceae], commonly known as "pamphylia daisy", is a Turkish endemic species of the genus Centaurea that comprises ca. 500 species, many of which have been used as traditional medicines. The n-hexane, dichloromethane [DCM] and methanol [MeOH] extracts of the aerial parts of C. pamphylica were assessed for antioxidant activity and general toxicity using, respectively, the 2, 2-diphenyl-1-picrylhydrazyl [DPPH], and the brine shrimp lethality assays. The reversed-phase preparative HPLC and PTLC were used to isolate compounds from the extracts. The structures of these compounds [1-4] were elucidated by spectroscopic means, and also by direct comparison with the respective published data. Both the DCM and the MeOH extract showed significant levels of antioxidant activities with the RC[50] values of 72.6 x 10[-2] and 47.3 x 10[-2] mg/mL, respectively. The MeOH extract exhibited low levels of toxicity towards brine shrimps [LD[50] = 125.0 x 10[-2] mg/mL]. Three major bioactive components of the MeOH extract were matairesinoside [1], arctiin [2] and matairesinol [3]. An eudesmane-type sesquiterpene, pterodontriol [4], was also isolated from the DCM extract. Since reactive oxygen species are important contributors to various ailments, the antioxidant properties of the extracts as well as the isolated compounds may be of medicinal significance. This is the first report on the occurrence of 1-4 in C. pamphylica, and 4 in the genus Centaurea