The present disclosure is in relation to a composition comprising nanosphere and histone acetyltransferase (HAT) activator. The disclosed nanosphere is carbon nanosphere (CSP) which is intrinsically fluorescent and the HAT activator is N-(4-Chloro-3-trifluoromethyl- phenyl)-2-n-propoxy-benzamide [COMPOUND 1]. The said N-(4-Chloro-3-trifluoromethyl- phenyl)-2-n-propoxy-benzamide is covalently conjugated with the carbon nanosphere. The present disclosure further relates to a process for obtaining a composition comprising carbon nanosphere and Histone acetyltransferase (HAT) activator [N-(4-Chloro-3-trifluoromethyl- phenyl)-2-n-propoxy-benzamide]. The composition is capable of crossing blood brain barrier and inducing histone acetylation in brain. Further, the composition is capable of increasing neurogenesis, as well as improving long-term memory formation. The said composition thus provides for managing pathological conditions to a subject in need thereof, such as aging- related, neurodegenerative diseases (Alzheimer's in particular), neurological disorders, depression or other kinds of diseases in which increased HAT activity, neurogenesis and/or memory improvement would benefit.