نتایج جستجو برای: labdan diterpenoid
تعداد نتایج: 1007 فیلتر نتایج به سال:
The title compound, C(20)H(30)O(2), is an ent-atisane diterpenoid which was isolated from the roots of Euphorbia kansuensis. The mol-ecule contains five six-membered rings, among which three six-membered rings of the bicyclo-[2.2.2]octane unit adopt boat conformations and two cyclo-hexane rings adopt chair conformations. In the crystal structure, mol-ecules are connected by inter-molecular O-H⋯...
Euphorbia species are widely distributed plants, many of which are used in folk medicine. Over the past twenty years, they have received considerable phytochemical and biological attention. Their diterpenoid constituents, especially those with abietane, tigliane, ingenane skeletons, are thought to be the main toxicant and bioactive factors. In this work, the utility of (13)C-NMR spectroscopy fo...
BACKGROUND The genus Salvia is a rich source of structurally diverse terpenoids. Different species of the Salvia have been used in folk medicine of Iran and therefore attracted the attention of researchers for exploring their chemical constituents. In a project directed at structurally interesting bioactive metabolites from Iranian Lamiaceae, we studied Salvia rhytidea. RESULTS Fractionation ...
The Velloziaceae is a family of tropical plants occurring in South America and Africa. The Brazilian species occur in the subtropical regions, especially in the states of Minas Gerais, Bahia, Goiás, Mato Grosso, Rio de Janeiro and Santa Catarina. These plants grow in a characteristic ecosystem fully exposed on mountainsides in rocky or sandy soils. Plants of the family Velloziaceae in spite of ...
The duration of anesthesia (related to protein binding of a drug) and the onset time (determined by the pKa) are important characteristics in assessment of local anesthetic agents. They are known to be affected by a number of factors. Early studies of antiarrhythmic diterpenoid alkaloids from plants Aconitum and Delphinium suggested that they possess local anesthetic activity due to their abili...
A newly reErranged 2(3.20)abeotaxane diterpenoid with a unique 6/1016 skeleton was isolated from the bark of the Chillese yew, Taxus mairei. The structure was established as being 7fi,13(M-diacetoxy-2or,5a,10fi-trihydrexy-9keto-2(3 -20)abeotaxane on the basis of 1-D and 2-D N"M data. The relative stereochemistry was defined from the results of a NOESY experiment. This is the first reported isol...
A new clerodane-type diterpenoid, echinoclerodane A (1), was isolated from a Formosan gorgonian coral Echinomuricea sp. The structure of 1 was elucidated by spectroscopic methods. Echinoclerodane A (1) is the first clerodane-type compound obtained from the marine organisms belonging to the phylum Cnidaria. Echinoclerodane A (1) exhibited moderate cytotoxicity toward MOLT-4, HL-60, DLD-1 and LoV...
The title compound, C(24)H(37)BrO(3), is a tetra-cyclic diterpenoid with a beyerane skeleton, synthesized by esterification of isosteviol. It comprises a fused four-ring system A/B/C/D. Rings A and B have a chair conformation, whereas ring C is an unsymmetrical distorted chair; the remaining five-membered ring D adopts an envelope conformation. The stereochemistry of the A/B and B/C ring juncti...
A rapid resolution liquid chromatography/time-of-flight tandem mass spectrometry (RRLC-TOF/MS) method was developed for qualitative and quantitative analysis of the major chemical constituents in Andrographis paniculata. Fifteen compounds, including flavonoids and diterpenoid lactones, were unambiguously or tentatively identified in 10 min by comparing their retention times and accurate masses ...
The novel diterpenoid taxol (paclitaxel) is now well-established as a potent chemotherapeutic agent. Total synthesis of the drug is not commercially feasible and, in the foreseeable future, the supply of taxol and its synthetically useful progenitors must rely on biological methods of production. The first three steps of taxol biosynthesis have been defined and the responsible enzymes described...
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