Preparation of Topical Cream Containing Sumac (Rhus Coriaria L) Extract and Comparison of its Wound Healing Effects with Phenytoin on Animal Model

Considering the importance of the skin in regulating the temperature and maintaining body fluids and its prominent role in the defense system, it is important to improve any discontinuity in the skin, which is called a wound. Although limited and superficial wounds heal by themselves, the treatment of deep wounds requires drug therapy. Therefore, the aim of this study was to determine and prepare a topical cream containing the extract of the sumac plant (Rhus Coriaria L) and compare its effect with phenytoin in healing skin wounds in an animal model.

 In the present study conducted in 2021-2022, twenty-five New Zealand laboratory rabbits, with the weight range of 2500-3000 grams, were obtained from central animal house, Hamadan University of Medical Sciences. The rabbits were randomly divided into five groups: I) Control Group; II) Receiving Phenytoein cream (1%) as the medical therapy; III) Receiving the placebo cream base; IV) Receiving therapeutic cream containing standardized sumac extract (0.1% of tannic acid); and V) Receiving therapeutic cream containing standardized sumac extract (0.05% of tannic acid). Then, a wound, with dimension of 2*2 cm, was induced in the back of any rabbits and the appropriate topical therapy was administered twice daily on the rabbits. The effectiveness of therapy using creams containing sumac extract was determined using the extent of wound healing and the level of hydroxyproline. The obtained data were statistically analyzed using One-way Analysis of Variance (ANOVA).

It was demonstrated that each one gram of standardized extract contained 2.74±0.86 milligram of tannic acid. The data achieved from the study, including the determination of hydroxyl-proline levels, percentage of wound healing, and the duration of remission, demonstrated significant efficiency in treatment with sumac-containing creams (either 0.1% or 0.05%). Histological studies revealed more condensed collagen fibrils and more reduction of inflammation cells in treatment groups receiving sumac-containing cream (either 0.01% or 0.05%) compared with the control group.

Sumac-containing creams, due to anti-oxidative properties and enhancing synthesis of hydroxyl-proline, can condense collagen fibrils which consequently cause improved wound healing.