Molecular interactions and binding dynamics of Alpelisib with serum albumins: insights from multi-spectroscopic techniques and molecular docking

Alpelisib (ALP) is a potent anti-cancer drug showing promising activity against advanced breast cancers. Hence, profound understanding of its binding dynamics within the physiological system is vital. Herein, we have investigated interaction of ALP with human serum albumin (HSA) and bovine serum albumin (BSA) using spectroscopic techniques like absorption, fluorescence, time-resolved, synchronous and 3D-fluorescence, FRET, FT-IR, CD, and molecular docking studies. The intrinsic fluorescence of both BSA and HSA quenched significantly by ALP with an appreciable red shift in its emission maxima. Stern-Volmer analysis showed increase in Ksv with temperature indicating involvement of dynamic quenching process. This was further validated by no significant change in absorption spectrum of BSA and HSA (at 280 nm) upon ALP interaction, and by results of fluorescence time-resolved lifetime studies. ALP exhibited moderately strong binding affinity with BSA (of the order 106 M−1) and HSA (of the order 105 M−1), and the major forces accountable for stabilizing the interactions are hydrophobic forces. Competitive drug binding experiments and molecular docking suggested that ALP binds to site I in subdomain IIA of BSA and HSA. The Förster distance r was found to be less than 8 nm and 0.5 Ro r Ro which suggests possible energy transfer between donors BSA/HSA and acceptor ALP. Synchronous and 3D-fluoresecnce, FT-IR and CD studies indicated that ALP induces conformational changes of BSA and HSA upon interaction. Communicated by Ramaswamy H. Sarma</p

Sulphonated biomass-based catalyst for solketal synthesis by acetalization of glycerol – A byproduct of biodiesel production

Research on biomass-based catalyst is beneficial for the sustainability of biodiesel industry owing to its wide availability of feedstock, non-toxicity and biodegradability. Cellulose based heterogeneous solid carbon catalyst was prepared from cellulose by treating cellulose with concentrated sulphuric acid in innocuous hydrothermal conditions. It shows promising potential as a suitable catalyst for the synthesis of solketal (a biofuel additive) by acetalization of glycerol, the waste product of biodiesel production. 97.1 ± 0.4% of solketal was produced under the optimum conditions of 1:5 M ratio of glycerol and acetone, catalyst loading of 7 wt% at 70 °C in 10 min. 90% of catalytic activity was retained even after five catalytic cycles making the catalyst highly efficient. With further investments; this method may be used for the preparation of biofuel additive in an industrial level