The objective of the present investigation was to evaluate ability of the novel self-assembled phospholipid- based cationic nanocarriers (LeciPlex) in improving the therapeutic efficacy of a poorly water-soluble natural polyphenolic agent, quercetin (QR), on oral administration. Quercetin loaded LeciPlex (QR-LeciPlex) were successfully fabricated using a biocompatible solvent Transcutol HP. The QR-LeciPlex were characterized for particle size, encapsulation efficiency, zeta potential, and particle morphology by cryo-TEM. UV and fluorescence spectral characterization was carried out to find out the association of QR with LeciPlex. Small angle neutron scattering studies (SANS) were carried out to understand the internal structure of Leciplex and to evaluate the influence of the incorporation of QR in the LeciPlex. Anti-inflammatory and antitumorigenic activity of QR-LeciPlex was determined in comparison to QR suspension to evaluate the potential of LeciPlex in improving oral delivery of QR. QR-LeciPlex exhibited a particle size of ∼400 nm and had excellent colloidal stability. The QR-LeciPlex had a zeta potential greater than +30 mV and exhibited very high encapsulation efficiency of QR (>90%). UV and fluorescence spectral characterization indicated the interaction/association of QR with LeciPlex components. Cryo-TEM studies showed that LeciPlex and QR-LeciPlex have a unilamellar structure. SANS confirmed the unilamellar structure of LeciPlex and indicated that the incorporation of QR does not have any effect on the internal structure of the LeciPlex. QR-LeciPlex exhibited significantly higher anti-inflammatory and antitumorigenic activity (p < 0.01) as compared to that of QR suspension on oral administration.