ABSTRACT
Phytochemical investigation of the stems of Bridelia stipularis led to the isolation of a new triterpene, 3ß-O-trans-feruloylfriedelinol (1), together with five known compounds, friedelin (2), 3ß-friedelinol (3), lupeol (4), stigmasterol (5), and 4-(1,5-dimethyl-3-oxo-4-hexenyl)benzoic acid (6). Their structures were identified by intensive spectroscopic analysis including 1D and 2D nuclear magnetic resonance, infrared, and mass spectrometry. Compound 1 showed significant α-glucosidase inhibitory activity (IC50 = 337.49 ± 0.59 µM) close to the standard, acarbose. Furthermore, the structure activity relationship of 1 was analyzed by molecular docking studies. In addition, the molecular docking results showed that the interaction between 1 and the active site occurred through hydrophobic forces and hydrogen bonds.
ABSTRACT
We investigated how various drying methods affect the chemical components and microstructure of turmeric. We used freeze drying (FD), hot-air drying (HD) at 50 °C and sun drying (SD). Compared to all dried samples, fresh turmeric had greater amounts of chemical components (curcuminoids, phenolic acids, flavonoids and amino acids) andgreater antioxidantactivity (DPPH and FRAP) except for ABTS.+ values. SD caused a severe decline of three major curcuminoids, resulting from UV and light degradation. Curcumin was decreased the most by SD (72%), followed by HD (61%) and FD (55%), respectively. Curcumin degradation to ferulic acid and vanillin was explored by FTIR analysis. The amino acids were decreased by all drying methods. FD was considered to be most suitable for drying turmeric. Microstructure changes were least after freeze drying, but were still evident compared with fresh turmeric.
