ABSTRACT
Four new 2,3-secodammarane triterpenoids, stellatonins A-D (3-6), together with a new 3,4-secodammarane triterpenoid, stellatonin E (7), and the known silvestrol (1), 5â´-episilvestrol (2), and ß-sitosterol, were isolated from a methanol extract of the stems of Aglaia stellatopilosa through bioassay-guided fractionation. The structures of the new compounds were elucidated using spectroscopic and chemical methods. The compounds were evaluated for their cytotoxic activity against three human cancer cell lines and for their antimicrobial activity using a microtiter plate assay against a panel of Gram-positive and Gram-negative bacteria and fungi.
Subject(s)
Aglaia/chemistry , Antineoplastic Agents, Phytogenic/isolation & purification , Benzofurans/isolation & purification , Plant Stems/chemistry , Triterpenes/isolation & purification , Antineoplastic Agents, Phytogenic/chemistry , Antineoplastic Agents, Phytogenic/pharmacology , Benzofurans/chemistry , Drug Screening Assays, Antitumor , Female , Gram-Negative Bacteria/drug effects , Gram-Positive Bacteria/drug effects , HT29 Cells , Humans , Malaysia , Microbial Sensitivity Tests , Molecular Structure , Nuclear Magnetic Resonance, Biomolecular , Saccharomyces cerevisiae/drug effects , Sitosterols , Triterpenes/chemistry , Triterpenes/pharmacology , DammaranesABSTRACT
Photodynamic therapy (PDT) is a medical treatment that involves the irradiation of an administered photosensitizing drug with light of a particular wavelength to activate the photosensitizer to kill abnormal cells. To date, only a small number of photosensitizers have been clinically approved for PDT, and researchers continue to look for new molecules that have more desirable properties for clinical applications. Natural products have long been important sources of pharmaceuticals, and there is a great potential for discovery of novel chemotypes from under-explored biodiversities in the world. The objective of this study is to mine the terrestrial plants in Sarawak, Borneo Island, for new photosensitizers for PDT. In a screening program from 2004 to 2008, we prepared and studied 2,400 extracts from 888 plants for their photosensitizing activities. This report details the bioprospecting process, preparation and testing of extracts, analysis of the active samples, fractionation of four samples, and isolation and characterization of photosensitizers.