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Materials and Methods S. officinalis oil, the mixture of alpha-and beta-thujone and chlorhexidine were used as received. All other chemical products were of analytical grade or better. Plant material and oil analyses: S. desoleana and S. sclarea plants came from the Decimoputzu experimental station (Sardinia). Samples of these species, identified by Professor A. D. Atzei, are kept in the Herbarium of the Dipartimento di Scienze del Farmaco; SASSA 1090 bis and 1086, respectively. Oil isolation was performed in a steel steam distiller with a recycling system, using the upper part in toto of plants gathered during the flowering season. Oil yields were measured in a Clevenger-type apparatus in conformity with F.U.I. standards (18). Statistical analyses were performed by ANOVA followed by Student's t test. P < 0.05 was considered significant.

Chromatographic separation of a methanol extract prepared from the whole plant of Dendrobium brymerianum led to the isolation of eight phenolic compounds. Among the isolated compounds (1–8), moscatilin (1), gigantol (3), lusianthridin (4), and dendroflorin (6) showed appreciable cytotoxicity against human lung cancer cell lines with IC50 values of 196.7, 23.4, 65.0, and 125.8 μg/mL, respectively, and exhibited antimigratory property at nontoxic concentrations. This study is the first report on the biological activities of this plant.

Oxyresveratrol (2,4,3 1 ,5 1 -tetrahydroxystilbene, 1), a phytoalexin present in large amounts in the heartwood of Artocarpus lacucha Buch.-Ham., has been reported to possess a wide variety of biological activities. As part of our continuing studies on the structural modification of oxyresveratrol, a library of twenty-six compounds was prepared via O-alkylation, aromatic halogenation, and electrophilic aromatic substitution. The two aromatic rings of the stilbene system of 1 can be chemically modulated by exploiting different protecting groups. Such a strategy allows for selective and exclusive modifications on either ring A or ring B. All compounds were evaluated in vitro for a panel of biological activities, including free radical scavenging activity, DNA protective properties, antiherpetic activity, inhibition of α-glucosidase and neuraminidase, and cytotoxicity against some cancer cell lines. Several derivatives were comparably active or even more potent than the parent oxyresveratrol and/or the appropriate positive controls. The partially etherified analogs 5 1 -hydroxy-2,3 1 ,4-trimethoxystilbene and 3 1 ,5 1 -dihydroxy-2,4-dimethoxystilbene demonstrated promising anti-herpetic and DNA protective activities, offering new leads for neuropreventive agent research, whereas 5 1 -hydroxy-2,3 1 ,4,-triisopropoxystilbene displayed anti-α-glucosidase effects, providing a new lead molecule for anti-diabetic drug development. 3 1 ,5 1 -Diacetoxy-2,4-diisopropoxystilbene showed potent and selective cytotoxicity against HeLa cancer cells, but the compound still needs further in vivo investigation to verify its anticancer potential.

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