Experimental evaluation of therapeutic properties of ointment based on melanins from natural raw material and a submerged culture of chaga (Inonotus оbliquus)
Authors:   Novosibirsk State Medical University, Novosibirsk, Russia, Stavsky E.A. , Teplyakova T.V. ,   State Research Center of Virology and Biotechnology “Vector”, Novosibirsk Region, Koltsovo village, Russia, Andreeva I.S. ,   State Research Center of Virology and Biotechnology “Vector”, Novosibirsk Region, Koltsovo village, Russia, Davydova E.S. ,   Novosibirsk State Medical University, Novosibirsk, Russia, Stavskaya A.A. ,   Novosibirsk State Medical University, Novosibirsk, Russia, Poteshkina A.L. ,   State Research Center of Virology and Biotechnology “Vector”, Novosibirsk Region, Koltsovo village, Russia
Published: July 2022

Introduction. Due to the acquisition of antibiotic resistance by pyogenic microbiota, the problem of topical (drug) treatment of wounds has worsened. Aim. Experimental evaluation of the antibiotic properties of melanin from natural raw material and a submerged culture of chaga (Inonotus obliquus) in vitro and the therapeutic properties of ointments prepared on the basis of these melanins in vivo. Materials and Methods. Melanins were obtained by alkaline hydrolysis. The antibiotic activity of melanins was determined by co-cultivation in a liquid medium of the studied samples with six cultures of test strains of gram-negative and gram-positive bacteria and two of yeast fungi. Ointments based on melanin from natural raw material and the submerged culture of chaga (Inonotus obliquus F-1244 strain) were obtained using two compositions of ointment base. The wound-healing efficacy of ointments was evaluated on three groups of mice. The control groups were mice untreated and treated with a comparison drug (Levomikon-TFF). The treatment of mice was continued until their incised skin wounds healed. Wound areas, motor activity, appetite, dynamics and character of wound healing were assessed daily in mice of all groups, as well as changes in their body weight every three days. Results. Melanins from natural raw materials and the submerged culture of chaga completely suppressed the growth of gram-positive spore-forming Bacillus cereus bacterium in a co-culture. Melanin from natural raw material of chaga on average suppressed the growth of the Staphylococcus aureus ATCC 6538 strain by an order of magnitude. Melanin from the submerged chaga culture completely suppressed the growth of a clinical isolate of the highly pathogenic Candida sp. Ft-5 strain from a deceased patient with generalized candida infection and, on average, inhibited the growth of the collection strain of yeast Candida albicans 620 by two orders of magnitude more intensively. It was found that ointments based on melanin from natural raw materials and the submerged culture of chaga, as well as ointment containing a fivefold increased concentration of melanin from natural chaga, do not have toxicity to experimental animals. Ointments containing 0.4 mg of melanin from natural raw material and the submerged chaga culture per 0.2 g of a single dose of ointment had the same wound healing efficacy, while not only were not inferior in this indicator to the combined antimicrobial comparison drug Levomikon-TFF, but also showed a tendency to more accelerated wound healing (on the 15–18th day of observation) compared with the process of wound regeneration in the group of animals treated with the drug of comparison. A more accelerated wound healing effect was demonstrated in experimental animals (already on the 12th day of observation) treated with a fivefold increased content of melanin from natural raw material of chaga, compared with mice treated with the comparison drug. Conclusion. Ointments containing melanin of chaga (Inonotus obliquus) have anti-inflammatory, regenerative properties and can be considered promising for topical treatment of wounds.