Thermal‑denatured PDRN exhibits increased in vitro pharmacological activities: A functional role of single‑stranded DNA random coils

Polydeoxyribonucleotide (PDRN) is a DNA‑based remedy that is broadly utilized for the treatment of wounds, inflammatory diseases and other diverse disorders. The present study aimed to clarify which conformational state of PDRNs, single‑stranded DNA (ssDNA) random coil or double‑stranded DNA (dsDNA) helical form, was responsible for its in vitro pharmacological properties, such as antioxidant, anti‑inflammatory, skin whitening and anti‑wrinkling properties. A PDRN solution was subjected to thermal denaturation at a high temperature, which generated heated PDRN (PDRN‑H) with augmented ssDNA random coils. Skin in vitro beneficial properties of PDRN and PDRN‑H were analyzed and compared using the non‑celled in vitro models. PDRN itself was shown to exhibit positive effects, such as a scavenging or inhibitory effect, in all tests done, such as 2,2‑diphenyl‑1‑picrylhydrazyl (DPPH), [2,2'‑azino‑bis(3‑ethylbenzothiazoline‑6‑sulfonic acid)] (ABTS), superoxide and nitrite scavenging assays, and tyrosinase, elastase and collagenase inhibition assays. However, PDRN‑H exhibited 10.3‑ and 1.6‑fold higher activities in the DPPH and ABTS scavenging assays compared with PDRN, respectively. PDRN‑H showed 2.2‑ and 4.7‑fold higher activities in the superoxide and nitrite scavenging assays compared with PDRN, respectively. PDRN‑H also displayed 2.3‑ and 1.8‑fold higher activities compared with PDRN in the inhibition assays of L‑tyrosine hydroxylase and L‑DOPA oxidase activities of tyrosinase, respectively. PDRN‑H was able to suppress elastase and collagenase activities and the degrees of their inhibition activities were 3.9‑ and 2.2‑fold higher than those of PDRN, respectively. Although both PDRN and PDRN‑H demonstrate in vitro beneficial properties for the skin, such as antioxidant, anti‑inflammatory, skin whitening and antiwrinkle properties, PDRN‑H exerts remarkably higher skin beneficial properties than PDRN due to its augmented single‑stranded DNA random coils. Overall, these findings suggest that the single‑stranded DNA random coils of PDRNs serve as an active player for the in vitro pharmacological properties.