Crotofolane Diterpenoids and Other Constituents Isolated from Croton kilwae

Abstract
Six new crotofolane diterpenoids (1–6) and 13 known compounds (7–19) were isolated from the MeOH–CH2Cl2 (1:1, v/v) extracts of the leaves and stem bark of Croton kilwae. The structures of the new compounds were elucidated by extensive analysis of spectroscopic and mass spectrometric data. The structure of crotokilwaepoxide A (1) was confirmed by single-crystal X-ray diffraction, allowing for the determination of its absolute configuration. The crude extracts and the isolated compounds were investigated for antiviral activity against respiratory syncytial virus (RSV) and human rhinovirus type-2 (HRV-2) in HEp-2 and HeLa cells, respectively, for antibacterial activity against the Gram-positive Bacillus subtilis and the Gram-negative Escherichia coli, and for antimalarial activity against the Plasmodium falciparum Dd2 strain. ent-3β,19-Dihydroxykaur-16-ene (7) and ayanin (16) displayed anti-RSV activities with IC50 values of 10.2 and 6.1 μM, respectively, while exhibiting only modest cytotoxic effects on HEp-2 cells that resulted in selectivity indices of 4.9 and 16.4. Compounds 2 and 5 exhibited modest anti-HRV-2 activity (IC50 of 44.6 μM for both compounds), while compound 16 inhibited HRV-2 with an IC50 value of 1.8 μM. Compounds 1–3 showed promising antiplasmodial activities (80–100% inhibition) at a 50 μM concentration.
Language
English
Published in
Journal of Natural Products
Citation
  • Mahambo, E. T., Uwamariya, C., Miah, M., Clementino, L. D. C., Alvarez, L. C. S., Di Santo Meztler, G. P., Trybala, E., Said, J., Wieske, L. H. E., Ward, J. S., Rissanen, K., Munissi, J. J. E., Costa, F. T. M., Sunnerhagen, P., Bergström, T., Nyandoro, S. S., & Erdelyi, M. (2023). Crotofolane Diterpenoids and Other Constituents Isolated from Croton kilwae. Journal of Natural Products, 86(2), 380-389. https://doi.org/10.1021/acs.jnatprod.2c01007
License
CC BY 4.0Open Access
Additional information about funding
Financial support from the Swedish Research Council (2018- 03918, 2019-03715), University of Dar es Salaam (CoNASCH 18035), and the São Paulo Research Foundation (FAPESP, grant 2017/18611-7), and the Center for Antibiotics Resistance Research (CARe) at the University of Gothenburg is highly appreciated. E.T.M. is thankful to UDSM for postgraduate studies sponsorship. This study made use of the NMR Uppsala infrastructure that is funded by the Department of Chemistry - BMC and the Disciplinary Domain of Medicine and Pharmacy. Mr. Frank Mbago (University of Dar es Salaam) is acknowledged for locating and identifying the plant species in the field, Katarzyna Palica (Uppsala University) for assistance with chiral compound HPLC separation, and Andreas Orthaber (Uppsala University) for initial X-ray diffraction experiments. L.C.C. and L.C.S.A. are grateful to the National Council for Scientific and Technological Development (CNPq), and G.P.D.S.M. is grateful to the Sven and Lilly Lawski Foundation for fellowships.
Copyright© 2023 the Authors

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