Fabrication and characterization of epoxylated zwitterionic copolymer-grafted silica nanoparticle as a new support for lipase immobilization

Trehalose decorated nanostructures stabilize combined cross-linked enzyme aggregates (Combi-CLEAs) of β-galactosidase and glucose isomerase

Combined cross-linked enzyme aggregates (Combi-CLEAs) of β-Galactosidase (β-Gal) and Glucose Isomerase (GI) allow the transformation of d-lactose to lactose-fructose syrup through one-pot cascade biocatalytic reactions. Despite its promise, the low thermostability of β-Gal and high-temperature demands for GI limits this application. Trehalose is a protein-stabilizing disaccharide which has been utilized in immobilized enzyme systems to enhance protein thermostability. In this work, trehalose decorated poly (amidoamine) (PAMAM) dendrimers were synthesized at low and high surface coverage levels (10 % and 50 %) and used to stabilize Combi-CLEAs of β-Gal and GI. Addition of trehalose decorated nanostructures to β-Gal and GI Combi-CLEAs enhanced β-Gal performance at elevated temperatures (58.6 % higher activity and 2.26× higher stability) while maintaining GI performance of Combi-CLEAs. The resulting Combi-CLEAs containing trehalose decorated nanostructures retained ~40 % β-Gal activity following 7 consecutive reaction cycles and exhibited GI activity for 5 consecutive reaction cycles. Overall, this study demonstrates the potential of trehalose decorated nanostructures to stabilize proteins at elevated temperatures typical of bioprocessing applications and storage of therapeutics.

Bioactivity-guided isolation of cyclooxygenase-2 inhibitors from Saussurea obvallata (DC.) Edgew. Using affinity solid phase extraction assay

ETHNOPHARMACOLOGICAL RELEVANCE

Saussurea obvallata (DC.) Edgew. is a traditional Tibetan medicine used for the treatment of inflammation-related diseases, but the scientific validation was very limited.

AIM OF THE STUDY

This study aimed to rapid screen and targeted isolate cyclooxygenase-2 (COX-2) inhibitors from S. obvallata extract.

MATERIALS AND METHODS

An efficient ligand-fishing method based on affinity solid phase extraction (A-SPE) combining with HPLC was developed. The identified COX-2 inhibitors were separated using preparative liquid chromatography. In vitro COX-2 inhibition assays were employed to confirm the inhibitory activities of the isolated compounds. In addition, the effect of the isolated compounds on the production of prostaglandin E2 (PGE2) and the expression of COX-2 in LPS-induced RAW 264.7 were evaluated.

RESULTS

A total of four phenylpropanoids, isolariciresinol, syringaresinol, pinoresinol and balanophonin were targeted isolated as COX-2 inhibitors with IC₅₀ values of 36.4 ± 2.6 μM, 23.1 ± 1.8 μM, 3.6 ± 0.3 μM and 12.1 ± 0.9 μM, respectively. The isolated compounds significantly inhibited LPS-induced NO production in a dose-dependent manner. And, the results of the inhibitory effect on the release of PGE₂ and the expression of COX-2 in LPS-induced macrophages were consistent with A-SPE analysis.

CONCLUSION

The present work demonstrated that the developed A-SPE-HPLC method could successfully targeted isolated COX-2 inhibitors from S. obvallata extract. And, the isolation results indicated that the therapeutic effect of S. obvallata on inflammation-related diseases was partly based on the COX-2 active ingredients.