Wijeratne, K., Oliviera, M., Mafazoli, J., Xu, Y., Minguzzi, S., Batista, P., Pessoa, O., Whitesell, L., & Gunatilaka, L. (2017). Withaferin A and Withanolide D Analogues with Dual Heat-Shock-Inducing and Cytotoxic Activities: Semisynthesis and Biological Evaluation. Journal of Natural Products.
Gunatilaka, A. L., Nanayakkara, N. D., & Uvais, M. (1979). Irradiation of friedelan-21-ones: Structure determination of novel friedelane triterpenes from kokoona zeylanica. Journal of the Chemical Society, Chemical Communications, 434-436.
Abstract:
Formation of the photoproducts (10) and (12) and chemical and spectroscopic evidence suggest that kokoononol obtained from Kokoona zeylanica is 27-hydroxyfriedelane-3,21-dione (1); kokoondiol and kokoonol have been identified as 21α,27-dihydroxyfriedelan-3-one (2) and 27-hydroxyfriedelan- 3-one (3), respectively, by chemical conversions.
A., A., Ramdayal, F. D., Sarragiotto, M. H., G., D., Sackett, D. L., & Hamel, E. (1999). Synthesis and biological evaluation of novel paclitaxel (Taxol) D-ring modified analogues. Journal of Organic Chemistry, 64(8), 2694-2703.
Abstract:
The semisynthesis and biological activity of paclitaxel (Taxol) analogues in which the oxygen atom in ring D is substituted by a sulfur or a selenium atom is presented. These derivatives were synthesized and tested in order to make more transparent the role of the oxetane ring in the biological activity of paclitaxel. The sulfur derivatives were found to be less active than paclitaxel in biological assays, while the selenium derivative could not be converted to its 4-acyl analogue. The results with the sulfur analogues suggest that the oxygen atom in the oxetane ring plays an important role in the mechanism by which paclitaxel exhibits its anticancer activity.
Liang, J., Huang, K., & Gunatilaka, A. L. (1998). A new 1,2-deoxytaxane diterpenoid from Taxus chinensis. Planta Medica, 64(2), 187-188.
PMID: 17253235;Abstract:
The bark of Taxus chinensis yielded a new taxane diterpenoid, 2- deacetoxy-7,9-dideacetyltaxinine J (1) together with several known taxoids. 1H- and 13C-NMR data of 1 are reported.
Carbonezi, C. A., Hamerski, L., A., A., Cavalheiro, A., Castro-Gamboa, I., Helena, D., Furlan, M., Claudia, M., Lopes, M. N., & Da, V. (2007). Bioactive flavone dimers from Ouratea multiflora (Ochnaceae). Brazilian Journal of Pharmacognosy, 17(3), 319-324.
Abstract:
Chromatographic fractionation of the organic extract from leaves of Ouratea multiflora afforded the flavone dimers heveaflavone, amentoflavone-7′, 4‴-dimethyl eter, podocarpusflavone-A and amentoflavone. Their structures were elucidated from spectral data, including 2D-NMR experiments of the natural substances. Biological activities of all isolates were evaluated, using antimicrobial assay against Gram-positive bacteria Staphylococcus aureus and Bacillus subtilis, cytotoxicity assay against mouse lymphoma (L5178) and KB cell lines, TLC screening for acetylcholinesterase inhibitors and antioxidant activity measured by DPPH test.