Electronic properties of the covalent and noncovalent adsorption of single-walled boron nitride nanotube with vitamins B3 and C and their radicals are investigated through the density functional theory. Results show that noncovalent and covalent adsorption of vitamin B3 on BNNT could make these systems of interest for drug delivery purposes due to the possibility of easily detaching the pristine molecule from the BNNT surface. Noncovalent and covalent adsorption of vitamin C on BNNT result in modification of the electronic properties of BNNT, these results are extremely relevant in identifying the potential application of functionalized BNNT with vitamin C as nano-sensor. The present results are expected to provide useful guidance for the relevant experimental study.