In Vitro and In Silico Studies of Two 1,4-Naphthoquinones and Their Topical Formulation in Bigels.

Background: 1,4-Naphthoquinones (1,4-NQs) are secondary plant metabolites with numerous biological activities. 1,4-NQs display low water solubility and poor bioavailability. Bigels are a new technology with great potential, which are designated as drug delivery systems.

Evaluation of in vitro biological activities: antioxidant; anti-inflammatory; anti-cholinesterase; anti- xanthine oxidase, anti-superoxyde dismutase, anti-α-glucosidase and cytotoxic of 19 bioflavonoids.

Pure compounds belonging to phenolic family were studied for their biological potential such as 5,8-dihydroxy-1,4-naphthoquinone (M1), rutin hydrate (M2), 2,3-dichloro-5,8-dihydroxy-1,4-naphthoquinone (M3), taxifolin (M4), myricetin (M5), plumbagin (M6), silibinin (M7), dihydromyricetin (M8), shikonin (M9), quercetin 3-β-D-glucoside (M10), (±)-taxifolin hydrate (M11), cardamonin (M12),(-)-epicatechin (M13), 9-chloro-10-hydroxy-anthracene-1,4-dione (M14), 9-chloro-10-hydroxy-2,3-dimethyl-anthracene-1,4-dione (M15), 2-chloro-3-(2-hydroxy-5-methylanilino)-1,4-naphthoquinone (M16), 2-chloro-3-(4-hydroxy-phenylamino)-(1,4) naphthoquinone (M17), 2-chloro-3-(3,5-di-tert-butyl-4-hydroxy-phenyl)-(1,4)-naphtoquinone (M18), and myricitrin dihydrate (M19). These molecules were chosen based on two reasons; the limited or total absence of their exploitation in several studied activities and the use of other tests for the same activity. The evaluation of the in vitro anti-acetyl-cholinesterase (AChE), anti-5-lipoxygenase (5-LOX), anti-xanthine oxidase (XOD), anti-alpha glucosidase, anti-superoxide dismutase (SOD), anti-oxidant (DPPH (1, 1-diphenyl-2-picrylhydrazyl) and ABTS (2, 2- azinobis-3-ethylbenzothiazoline-6-sulphonate)), and anticancer activities of mentioned 19 molecules was explored during this work.

The antioxidant 2,3-dichloro,5,8-dihydroxy,1,4-naphthoquinone inhibits acetyl-cholinesterase activity and amyloid β aggregation: A dual target therapeutic candidate compound for the treatment of Alzheimer's disease.

Alzheimer's disease is characterized by amyloid β aggregation and cholinergic neurodegeneration. In the present study, pure DDN (2,3-dichloro-5,8-dihydroxy-1,4-naphthoquinone) was examined, for the first time, for its dual potential as inhibitor of acetylcholinesterase (AChE) and Aβ aggregation. Such investigation was encouraged by the in vitro high antioxidant potential of DDN.