Two new β-carboline alkaloids, variabines A (1) and B (2), were isolated from the Indonesian marine sponge Luffariella variabilis. Their structures were elucidated from spectral data, and 1 was found to be a sulfonated derivative of 2. Although numerous β-carboline alkaloids have been isolated from natural sources to date, 1 is the first β-carboline derivative containing a sulfate group. Compound 2 inhibited chymotrypsin-like activity of the proteasome and Ubc13 (E2)-Uev1A interaction with IC50 values of 4 and 5 μg/mL, respectively, whereas 1 had little effect on the activity or interaction.
Our blepahro-tensiometer can obtain repeatable measurements of the eyelid pressure and can be used to evaluate the pressure of the eyelids on the ocular surface in normal and diseased eyes.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.