Author
Mariza Drumond Formiga
Bio: Mariza Drumond Formiga is an academic researcher from Universidade Federal de Minas Gerais. The author has contributed to research in topics: Carbon-13 NMR & Ether. The author has an hindex of 2, co-authored 2 publications receiving 112 citations.
Topics: Carbon-13 NMR, Ether
Papers
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TL;DR: In this article, the 13 C NMR spectra of 15 neolignans of several structural types and two lignans were analyzed and their carbon shifts assigned, and the shifts of pyrogallol ether and ethyl phenyl carbinyl ether models were used in this connection.
96 citations
17 citations
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TL;DR: According to the traditional usage of the plant for antiinflammation and analgesia, Leucas aspera was tested for its prostaglandin (PG) inhibitory and antioxidant activities and LA-8 was determined to be (-)-chicanine, the new antipode of the (+) compound by spectroscopic methods including CD and ORD.
Abstract: According to the traditional usage of the plant for antiinflammation and analgesia, Leucas aspera was tested for its prostaglandin (PG) inhibitory and antioxidant activities. The extract showed both activities, i.e., inhibition at 3 x 10(-4) g/ml against PGE(1)- and PGE(2)-induced contractions in guinea pig ileum and a 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging effect. The separation guided by the activities in these dual assay methods provided eight lignans and four flavonoids, LA-1- -12, among which LA-1- -7 and LA-10- -12 were identified as nectandrin B, meso-dihydroguaiaretic acid, macelignan, acacetin, apigenin 7-O-[6"-O-(p-coumaroyl)-beta-D-glucoside], chrysoeriol, apigenin, erythro-2-(4-allyl-2, 6-dimethoxyphenoxy)-1-(4-hydroxy-3-methoxyphenyl)propan-1-ol, myristargenol B, and machilin C, respectively. LA-8 was determined to be (-)-chicanine, the new antipode of the (+) compound, by spectroscopic methods including CD and ORD. Chiral-HPLC analysis of LA-9 showed that it was a mixture of two enantiomers, (7R, 8R)- and (7S, 8S)-licarin A. All of these components were first isolated from L. aspera. PG inhibition was observed in LA-1, LA-2, and LA-5, and antioxidant activity in LA-1- -3 and LA-8- -12.
209 citations
TL;DR: In this article, the 13 C NMR spectra of 15 flavonoid and 9 isoflavonoid substances of various ring C oxidiation states were analyzed and their carbon shifts assigned.
151 citations
TL;DR: The hexane extract from the roots of Krameria cystisoides yielded besides conocarpan, licarin A, eupomatenoids 6 and 13, and ratanhiaphenol I 16 hitherto unknown lignans, neolignans and nomeoligns, among them toltecol and olmecol as mentioned in this paper.
100 citations
TL;DR: In this article, 13C NMR shielding data for about 300 compounds are tabulated, and critical spectral features are discussed as a guide to the use of the technique in structure elucidation and stereochemical allocations of lignan, neolignan and their derivatives.
Abstract: 13C NMR shielding data for about 300 compounds are tabulated, and critical spectral features are discussed as a guide to the use of the technique in structure elucidation and stereochemical allocations of lignan, neolignan and their derivatives. Unanalysed reported data have been analysed and, wherever necessary, 13C signal assignments have been revised on the basis of more recent evidence and, to obtain consistency throughout the series.
94 citations
TL;DR: An unidentified Streptomyces, designated as Strain H 1051-MY 10, was proved to produce viomycin and two new antibiotics, which inhibited the growth of phytophathogenic fungi and further showed weak antibacterial and antiyeast activities.
Abstract: An unidentified Streptomyces, designated as Strain H 1051-MY 10, was proved to produce viomycin and two new antibiotics. The new antibiotics were extracted from the cultured mycelia with acetone and transferred to ethyl acetate after acetone was removed in vacuo. The extracted antibiotics were separated into two components by alumina column chromatography and named carbazomycins A and B, because both antibiotics were proved to contain a carbazole nucleus. The molecular formulae of carbazomycins A and B were determined to be C16H17NO2 and C15H15NO2, respectively. Further, carbazomycin B was methylated with diazomethane to give carbazomycin A. Carbazomycins inhibited the growth of phytophathogenic fungi and further showed weak antibacterial and antiyeast activities.
91 citations