The first phytochemical investigation from the stems of Croton krabas resulted in the isolation of three new ent-clerodane diterpenoids, crotonkrabases A-C (1-3), along with two known compounds, 12-oxohardwickiic acid (4) and crotonpyrone B (5). Their structures were elucidated using extensive spectroscopic methods. The structure of 3 was unambiguously proven by X-ray crystallography. Furthermore, the absolute configurations of compounds 1-3 were identified by NOESY and the comparison of their experimental ECD spectra with those of calculated ECD spectra reported in the literature. Compounds 1, 2, and 5 showed antibacterial activities against two Gram-positive bacteria (Bacillus cereus and Bacillus subtilis); whereas compound 4 exhibited weak antibacterial against B. cereus. In addition, compound 4 showed potent α-glucosidase inhibitory activity, which was lower than the reference standard acarbose.
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http://dx.doi.org/10.1016/j.fitote.2021.104912 | DOI Listing |
Nat Prod Res
December 2024
School of Life Sciences, Pharmacy and Chemistry, Kingston University, Kingston, UK.
Phytochemical analysis of the twigs and leaves of , endemic to Kenya, yielded known compounds 3-(3',4'-dimethoxyphenyl)-prop-1-ene (, 3-(3',4'-dimethoxyphenyl)-propenal (), lupeol () and -trachyloban-19-oic acid (), and a tentatively new -clerodane diterpenoid, crotokinondoenolide (). -Trachy-loban-19-oic acid () showed good activity against a panel of drug-resistant strains of and spp with MIC -values of 25 g/mL.
View Article and Find Full Text PDFPhytochemistry
December 2024
Key Laboratory of Phytochemistry and Natural Medicines, Kunming Institute of Botany, Chinese Academy of Sciences, and Yunnan Key Laboratory of Natural Medicinal Chemistry, Kunming, 650201, PR China. Electronic address:
Scoparodane C (1), a diterpenoid with a rare 3,4-seco-3-nor-2,11-epoxy-ent-clerodane scaffold, was obtained from the aerial parts of Isodon scoparius, along with isocopariusines A-E (2-6), five ent-clerodanoids featuring a 5/6-fused ring system, and isocopariusines F-H (7-9), three common ent-clerodanoids. The structures of these previously undescribed compounds were established by a combination of spectroscopic analysis, X-ray diffraction, chemical derivatization, and quantum chemical calculation. Remarkably, isocopariusine B (3) showed strong resistance reversal activity against fluconazole-resistant Candida albicans.
View Article and Find Full Text PDFACS Omega
April 2024
Institute of Pharmacognosy, Faculty of Pharmacy, University of Szeged, 6720 Szeged, Hungary.
Fourteen diterpenes were isolated from methanol extracts of the aerial parts of, "Marginatus", and . The compounds belong to the abietane (-, -, and ), -clerodane (-), and -kaurane (, ) classes. Three new compounds were isolated from , including 3--acetylornatin G (), 3,12-di--acetylornatin G (), ornatin B methyl ester (), and ornatin F (), for which we proposed a revised structure.
View Article and Find Full Text PDFJ Nat Prod
May 2023
State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zuchongzhi Road, Shanghai 201203, People's Republic of China.
Laeviganoids A-T (-), 20 new -clerodane-type diterpenoids featuring a 2-furanone (-) or a furan (-) ring, as well as six analogues (-), were isolated from the roots of . Their structures were determined by spectroscopic data analysis, experimental electronic circular dichroism measurements, and X-ray crystallographic studies. Compounds -, , -, and could influence the anti-inflammatory protumoral phenotype of macrophages.
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.
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