Glycolipids and sphingolipids are well known for their diverse biological activities like anticancer, anti-inflammatory, antistress, anti-HIV, hepatoprotective and antimicrobial. The present study deals with the activity-guided isolation and characterization of two antihyperglycemic glycolipids, (2S)-1,2-di-O-octadecanoyl-3-O-[α-d-galctopyranosyl-(1'' → 6')-O-β-d-galactopyranosyl] glycerol (1) and 1-O-β-d-glucopyranosyl-(2S,3S,4R,8E)-2-[(2R)-2-hydroxy-tetracosanoylamino]-2,3,4-octadecanetriol-8-ene (2) from Oplismenus burmannii and the development of a simple and validated reverse-phase HPLC analytical method for their quantification in the methanolic extracts of O. burmannii. The marker compounds 1 and 2 were isolated from the methanolic extract of O. burmannii and characterized on the basis of their spectroscopic data. Their antihyperglycemic potential was evaluated by determining their glucose uptake-stimulating potential in L6-GLUT4myc myotube cells. Finally, these analytes were separated on a Waters Spherisorb ODS 2 column with a binary gradient of methanol and water at a constant flow rate of 0.8 mL/min and detected using a photodiode array detector at 230 nm. The calibration curve was linear (r(2) > 0.999) over 1.2 orders of magnitude with acceptable accuracy, reproducibility and recovery (98.16-100.50%). The limits of detection and quantification for 1 and 2 were 1.36, 4.11 and 1.11, 3.35 µg/mL respectively. The method is simple, accurate, precise and selective and may be routinely used for the quality control analysis of whole plant extract of O. burmannii for these two glycolipids.

Herein, we describe the enantioselective C­(sp3)–H bond functionalizations of 2-alkyl azaarenes using a cooperative dual Lewis acid catalysis. An achiral Lewis acid activates the unactivated azaarene partner without the need for a strong base. Orthogonally, a chiral-at-metal Lewis acid catalyst enables LUMO lowering and induces chirality. This method tolerates a range of complex molecular scaffolds and exhibits good to excellent yields and selectivity while accepting a wide variety of functional groups.