Antonia T. A. Pimenta

Estudo fitoquímico e avaliação da atividade larvicida de Pterodon polygalaeflorus Benth (Leguminosae) sobre Aedes aegypti

Chemical investigation of the hexane and methanol extracts of the fruits of Pterodon polygalaeflorus (Leguminosae) resulted in the isolation and identification of furanic diterpenes: 6-a-acetoxivouacapane, 6-a-hidroxyvouacapane and vouacapane, which is related by the first time as a natural product. The structures of these compounds were established by spectroscopic analysis, including 2D NMR experiments. The 6-a-acetoxivouacapane, the hexane and methanol extracts, and the essential oil were evaluated on 3rd instar larvae of Aedes aegypti and only the hexane extract showed good larvicidal activity with LC50 23.99 ± 0.75 µg/mL.

Rotenoids from Tephrosia toxicaria with larvicidal activity against Aedes aegypti, the main vector of dengue fever

In the search for new larvicides from plants, we have investigated the potential activity of the rotenoids deguelin (1), 12a-hydroxy-α-toxicarol (2) and tephrosin (3), isolated from the bioactive ethanol extract of roots of Tephrosia toxicaria Pers., against Aedes aegypti, the main vector of dengue. The absolute configuration of these compounds was determined by circular dichroism (CD) spectra. The LC50 values of the compounds evaluated justify the potential of T. toxicaria as a new natural larvicide.

Alkaloid and other chemical constituents from Psychotria stachyoides Benth.

The organic extracts of leaves and roots of Psychotria stachyoides provided the new glucoside monoterpenoid indole alkaloid N-demethylcorreantoside, besides bizantionoside B, a-amyrin, alizarine methyl-ether, rubiadine, scopoletin, barbinevic acid and a mixture of b-sitosterol and stigmasterol glucosides. The structural characterization of the isolates was established based on infrared spectroscopy (IR), mass spectrometry (MS) and, particularly, 1D and 2D nuclear magnetic resonance (NMR).

Structure elucidation and NMR assignments of two unusual monoterpene indole alkaloids from Psychotria stachyoides

Two unusual monoterpene indole alkaloids, stachyoside (1) and nor‐methyl‐23‐oxo‐correantoside (2), have been isolated from the aerial parts of Psychotria stachyoides. The structural elucidation of both compounds was performed by the aid of HRESIMS, FT‐IR, and 1D‐ and 2D‐NMR techniques including COSY, HSQC, HMBC, and NOESY. Copyright

New cytotoxic furan from the marine sediment-derived fungi Aspergillus niger

Abstract A fungal strain of Aspergillus niger was recovered from sediments collected in the Northeast coast of Brazil (Pecém’s offshore port terminal). Cultivation in different growth media yielded a new ester furan derivative, 1, along with malformin A1, malformin C, cyclo (trans-4-hydroxy-L-Pro-L-Leu), cyclo (trans-4-hydroxy-L-Pro-L-Phe), cyclo (L-Pro-L-Leu), cyclo (L-Pro-L-Phe), pseurotin D, pseurotin A, chlovalicin, cyclo (L-Pro-L-Tyr) and cyclo (L-Pro-L-Val). Compound 1 was cytotoxic against HCT-116 cell line, showing IC50 = 2.9 μg/mL (CI 95% from 1.8 to 4.7 μg/mL).

Pharmacognostical analysis and protective effect of standardized extract and rizonic acid from Erythrina velutina against 6-hydroxydopamine-induced neurotoxicity in Sh-Sy5Y cells

Background: Erythrina velutina is a tree common in the northeast of Brazil extensively used by traditional medicine for the treatment of central nervous system disorders. Objective: To develop a standardized ethanol extract of E. velutina (EEEV) and to investigate the neuroprotective potential of the extract and rizonic acid (RA) from E. velutina on neuronal cells. Materials and methods: The plant drug of E. velutina previously characterized was used for the production of EEEV. Three methods were evaluated in order to obtain an extract with higher content of phenols. The neuroprotective effect of standardized EEEV (HPLC-PDA) and RA was investigated on SH-SY5Y cell exposure to the neurotoxin 6-hydroxydopamine (6-OHDA). Results: The powder of the plant drug was classified as moderately coarse and several quality control parameters were determined. EEEV produced by percolation gave the highest phenol content when related to others extractive methods, and its HPLC-PDA analysis allowed to identify four flavonoids and RA, some reported for the first time for the species. EEEV and RA reduced significantly the neurotoxicity induced by 6-OHDA in SH-SY5Y cells determined by the MTT assay and the nitrite concentration. EEEV also showed a free radical scavenging activity. Conclusion: This is the first pharmacological study about E. velutina which used a controlled standardized extract since the preparation of the herbal drug. This extract and RA, acting as an antioxidant, presents a neuroprotective effect suggesting that they have potential for future development as a therapeutic agent in neurodegenerative disease as Parkinson. Abbreviations used: ±: More or less, %: Percentage, °C: Degree Celsius, <: Less than, μg: Microgram, μL: Microliter, μM: Micromol, [1D] MNR: One-dimensional nuclear magnetic resonance spectroscopy, [2D] MNR:Two-dimensional nuclear magnetic resonance spectroscopy, 6-OHDA: [6-] Hydroxydopamine. Abs: Absorbance, CFU: Colony forming units, CH2Cl2: Dichloromethane, CHCl3: Chloroform cmCentimeter, DMEM/F12: Dulbeccos Modified Eagles Medium: Nutrient Mixture F-12. DMSO: Dimethyl sulfoxide, DPPH: 1,1-Diphenyl-2-picrylhydrazyl, EAG: Gallic acid equivalents, EEEV: Ethanolic extract of Erythrina velutina, EtOAc: Ethyl acetate, g: Gram, h: Hour, H2O: Water, HPLC: High-performance liquid chromatography, H REIMS: Hydrogen rapid evaporative ionization mass spectrometry, Kg: Kilogram M: Molar, m: Metro, MeOH: Methanol, mg: Milligram, min: Minute, mL: Milliliter, mm: Millimeter, MTT: Bromide 3 [4,5-dimethylthiazol-2-yl] -2,5-diphenyltetrazolium, N: Normal, NBT: Nitroblue tetrazolium, nm: Nanometer, PDA: Photodiode array detector, TPC: Total polyphenol content, RA: Rizonic acid, RP: Reverse phase, SOD: Superoxide dismutase, v/v: Volume per volume, Vs: Versus W: Watts

NOVOS FLAVONOIDES DE Margaritopsis carrascoana COM ATIVIDADE ANTIOXIDANTE

EtOH extracts of the stems and leaves of Margaritopsis carrascoana were found to contain new flavonoids luteolin 7-O-{β-D-apiofuranosil-(1→6)-[β-Lrhamnopyranosyl-( 1→2)]-β-D-glucopyranosyl} (5) and luteolin 7-O-{α-L-rhamnopyranosyl-(1→6)-[β-L-rhamnopyranosyl- (1→2)]-β-D-glucopyranosyl} (6), in addition to the known dihydrodehydrodiconiferyl alcohol 4-O-b-D-glucopyranoside (1), luteolin 7-O-b-L-rhamnopyranosyl-(1→2)-β-D-glucopyranosyl (2), luteolin 7-O-[b-D-apiofuranosyl-(1→6)]-β-D-glucopyranoside (3), and chrysoeriol 7-O-[b-D-apiofuranosyl-(1→6)]-β-D-glucopyranoside (4). All isolated compounds presented higher antioxidant activities than the controls, BHT and quercetin, while the extract of the stems showed strong AChE inhibition.

New Alkaloids from Margaritopsis carrascoana (Rubiaceae)

Two new alkaloids containing Nb-methyl-triptamine units linked to bis-quinoline moieties, N-8”-formyl-calycosidine and N-8”-methyl-N-1’-demethyl-iso-calycosidine, were isolated from the aerial part of Margaritopsis carrascoana, along with known calycosidine and hodgkinsine. The cytotoxicity of the isolated alkaloids has been evaluated against cancer cell lines. The first two compounds showed only weak activity against HL-60 cell line, while hodgkinsine was the most active compound against HCT-116, OVCAR-8, HL-60 and SF-295 cancer cell lines. The structures of the isolated compounds were established by spectroscopic and molecular mechanical methods.

HPLC Quantification of Cytotoxic Compounds from Aspergillus niger

A high-performance liquid chromatography method was developed and validated for the quantification of the cytotoxic compounds produced by a marine strain of Aspergillus niger. The fungus was grown in malt peptone dextrose (MPD), potato dextrose yeast (PDY), and mannitol peptone yeast (MnPY) media during 7, 14, 21, and 28 days, and the natural products were identified by standard compounds. The validation parameters obtained were selectivity, linearity (coefficient of correlation > 0.99), precision (relative standard deviation below 5%), and accuracy (recovery > 96).

NEW FLAVONOIDS FROMMargaritopsis carrascoanaWITH ANTIOXIDANT ACTIVITY

EtOH extracts of the stems and leaves of Margaritopsis carrascoana were found to contain new flavonoids luteolin 7-O-{β-D-apiofuranosil-(1→6)-[β-Lrhamnopyranosyl-( 1→2)]-β-D-glucopyranosyl} (5) and luteolin 7-O-{α-L-rhamnopyranosyl-(1→6)-[β-L-rhamnopyranosyl- (1→2)]-β-D-glucopyranosyl} (6), in addition to the known dihydrodehydrodiconiferyl alcohol 4-O-b-D-glucopyranoside (1), luteolin 7-O-b-L-rhamnopyranosyl-(1→2)-β-D-glucopyranosyl (2), luteolin 7-O-[b-D-apiofuranosyl-(1→6)]-β-D-glucopyranoside (3), and chrysoeriol 7-O-[b-D-apiofuranosyl-(1→6)]-β-D-glucopyranoside (4). All isolated compounds presented higher antioxidant activities than the controls, BHT and quercetin, while the extract of the stems showed strong AChE inhibition.