Gunatilaka, A., Sriyani, H., Sotheeswaran, S., & Waight, E. S. (1983). 2,5-dihydroxy-1,6-dimethoxyxanthone and biflavonoids of Garcinia thwaitesii. Phytochemistry, 22(1), 233-235.
Abstract:
The petrol and methanol extracts of the bark and timber of Garcinia thwaitesii have been investigated. In addition to β-amyrin and tirucallol, four biflavonoids and a new xanthone, 2,5-dihydroxy-1,6-dimethoxyxanthone have been isolated and characterized. © 1983.
Gamlath, C. B., Gunaherath, K. B., & Gunatilaka, A. L. (1987). Studies on terpenoids and steroids. Part 10. Structures of four new natural phenolic D:A-friedo-24-noroleanane triterpenoids. Journal of the Chemical Society, Perkin Transactions 1, 2849-2854.
Abstract:
The three new phenolic nortriterpenes, demethylzeylasteral, zeylasteral, and demethylzeylasterone, isolated from Kokoona zeylanica (Celastraceae), have been shown to be 2,3-dihydroxy-6,23-dioxo-D:A-friedo-24-noroleana-1,3,5(10),7- tetraen-29-oic acid (5), its methyl ester (6), and 2,3-dihydroxy-6-oxo-D:A- friedo-24-noroleana-1,3,5(10),7-tetraene-23,29-dioic acid (7), respectively. The structure of the new phenolic (9→8)-D:A-friedo-24-noroleanane triterpene obtained from 'kokum soap' has been established as 23-oxoisopristimerin III (11) on the basis of spectroscopic evidence. The biosynthetic significance of 23-oxoisopristimerin III is discussed.
Gunatilaka, L. -., Xu, Y., Ramirez-Ahumada, M. d., & Valeriote, F. A. (2011). Solid rumor inhibitory and other constituents of Casimiroa tetrameria. Chinese Journal of Natural Medicines, 9(5), 334-337.
Gunatilaka, L., Bashyal, B. P., Wijeratne, K., Tillotson, J., Arnold, E., & Chapman, E. (2017). Chlorinated Dehydrocurvularins and Alterperylenepoxide A from Alternaria sp. AST0039, a Fungal Endophyte of Astragalus lentiginosus. Journal of Natural Products, 80, 427-433. doi:10.1021/acs.jnatprod.6b00960
Mafezoli, J., Oliveira, M. C., Paiva, J. R., Sousa, A. H., Lima, M. A., Júnior, J. N., Barbosa, F. G., Wijeratne, E. M., & Gunatilaka, A. A. (2014). Stereo and regioselective microbial reduction of the clerodane diterpene 3,12-dioxo-15,16-epoxy-4-hydroxycleroda-13(16),14-diene. Natural product communications, 9(6), 759-62.
The biotransformation of the clerodane diterpene, 3,12-dioxo-15,16-epoxy-4-hydroxy-cleroda-13(16),14-diene (1), obtained from Croton micans var. argyroglossum (Baill.) Mill., was investigated for the first time. Whole cells of Cunninghamella echinulata and Rhizopus stolonifer were used as enzymatic systems, and with both fungi the only biotransformation product obtained was the new ent-neo-clerodane diterpene (3R,4S,5S,8S,9R,10S)-3,4-dihydroxy-15,16-epoxy-12-oxo-cleroda-13(16),14-diene (2a). The absolute stereochemistry of 2a was inferred by comparison of its optical rotation with those of the chemical reduction product of 1 and its quasienantiomer 2c.