A new rearranged clerodane-type diterpene (1), tinobaenzigeride, and a new rearranged clerodane glucoside (2) were isolated from the stems of Tinospora baenzigeri, along with four known compounds (3‒6). Their structures were elucidated by spectroscopic data analysis. In addition, the structure and configuration of 1 was confirmed by single-crystal X-ray diffraction analysis. Compound 1 are a rare example of rearranged clerodanes, since it contains a fully oxygenated tetrahydrofuran moiety. The isolated compounds were evaluated for their cytotoxicity against Hep-G2 and MCF-7 cancer cells, none of them did show any significant activity at 25 μM.
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http://dx.doi.org/10.1007/s11418-020-01450-5 | DOI Listing |
Chem Biodivers
December 2023
Key Laboratory of Medicinal Chemistry for Natural Resource of Ministry of Education, Yunnan Characteristic Plant Extraction Laboratory, Yunnan Research & Development Centre for Natural Products, School of Chemical Science and Technology and School of Pharmacy, State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming, 650500, P. R. China.
J Nat Prod
August 2023
Research Center for Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou 510006, People's Republic of China.
Twelve new -clerodane diterpenoids, eight undescribed methoxy/ethoxy acetal analogues, and one new -iridane monoterpenoid were isolated from . Their structures were elucidated using a combination of spectroscopic data, quantum chemical calculations, and X-ray crystallography. This research reveals the distinctive structural features of diterpenes, including distinct C rings and 4,18-double bonds, distinguishing them from diterpenes of other plants in the genus.
View Article and Find Full Text PDFPlants (Basel)
November 2022
Departamento de Biomacromoléculas, Instituto de Química, Universidad Nacional Autónoma de México, Av. Universidad 3000, Circuito Exterior S/N, Coyoacán, Ciudad Universitaria, Mexico City 04510, Mexico.
Phytochemical screening of an ethanol-water extract (EWE) from the bark of led to the isolation and identification of eight compounds, among them: five -clerodane diterpenoids [junceic acid (), 6()-acetoxy-15,16-diepoxy--cleroda-3,13(16),14-trien-20-oic acid (crotoguatenoic acid A) (), 6()-hydroxyoxy-15,16-diepoxy--cleroda-3,13(16),14-trien-20-oic acid (crotoguatenoic acid B) (), formosin F (), bartsiifolic acid ()], and three flavonoids [rutin (), epicatechin (), and quercetin ()]. Of these, and are reported here for the first time. Structures were established through conventional spectroscopy methods and their absolute configurations were determined by optical rotation and comparison of experimental electronic circular dichroism (ECD) and theoretical calculated ECD spectra.
View Article and Find Full Text PDFChemistryOpen
October 2022
Institut für Organische Chemie, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 18, 72076, Tübingen, Germany.
The generation of the quaternary stereocenter at the C9 position of salvinorin A precursors by the Claisen rearrangement was investigated. The required allyl alcohol was prepared from a Wieland-Miescher ketone using a known γ-hydroxylation, reduction of the enone double bond, cyanohydrin formation, and elimination, yielding an unsaturated nitrile. A two-step reduction led to the required allyl alcohol.
View Article and Find Full Text PDFSci Rep
April 2021
Department of Pharmacognosy, College of Pharmacy, King Saud University, P.O. Box. 2457, Riyadh, 11451, Kingdom of Saudi Arabia.
Teucrium yemense, a medicinal plant commonly grown in Saudi Arabia and Yemen, is traditionally used to treat infections, kidney diseases, rheumatism, and diabetes. Extraction of the dried aerial parts of the plant with methanol, followed by further extraction with butanol and chromatography, gave twenty novel neoclerodanes. Their structures, relative configurations and some conformations were determined by MS and 1-D and 2-D NMR techniques.
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