A new furanonapthoquinone from the stems of Thunbergia laurifolia.

α-Glucosidase inhibitory assay-guided purification of Thunbergia laurifolia L. stems yielded a new compound named 5-acetoxyfuranonapthoquinone (1) along with nineteen known compounds (2-20). The structures of the isolated compounds were elucidated by the analysis of multiple spectroscopic data. The isolated compounds were evaluated for α-glucosidase inhibition. Syringaresinol (7), rosmarinic acid (11), 1,2,8-trihydroxyxanthone (16), and isojacareubin (18) showed the most potent inhibitory activity among isolated compounds. Kinetic study indicated that syringaresinol (7), 1,2,8-trihydroxyxanthone (16) and isojacareubin (18) could inhibit maltase and sucrase function by non-competitive manner, and rosmarinic acid (11) was identified as a non-competitive inhibitor against maltase and a mixed-manner inhibitor against sucrase.

Efficient Self-Assembly of mPEG End-Capped Porous Silica as a Redox-Sensitive Nanocarrier for Controlled Doxorubicin Delivery.

Porous nanosilica (PNS) has been regarded as a promising candidate for controlled delivery of anticancer drugs. Unmodified PNS-based nanocarriers, however, showed a burst release of encapsulated drugs, which may limit their clinical uses. In this report, PNS was surface conjugated with adamantylamine (ADA) via disulfide bridges (-SS-), PNS-SS-ADA, which was further modified with cyclodextrin-poly(ethylene glycol) methyl ether conjugate (CD-mPEG) to form a core@shell structure PNS-SS-ADA@CD-mPEG for redox triggered delivery of doxorubicin (DOX), DOX/PNS-SS-ADA@CD-mPEG. The prepared PNS-SS-ADA@CD-mPEG nanoparticles were spherical in shape with an average diameter of 55.5 ± 3.05 nm, a little larger than their parentally PNS nanocarriers, at 49.6 ± 2.56 nm. In addition, these nanoparticles possessed high drug loading capacity, at 79.2 ± 3.2%, for controlled release. The release of DOX from DOX/PNS-SS-ADA@CD-mPEG nanoparticles was controlled and prolonged up to 120 h in PBS medium (pH 7.4), compared to less than 40 h under reducing condition of 5 mM DTT. Notably, the PNS-SS-ADA@CD-mPEG was a biocompatible nanocarrier, and the toxicity of DOX was dramatically reduced after loading drugs into the porous core. This redox-sensitive PNS-SS-ADA@CD-mPEG nanoparticle could be considered a potential candidate with high drug loading capacity and a lower risk of systemic toxicity.