Sida cordifolia accelerates wound healing process delayed by dexamethasone in rats: Effect on ROS and probable mechanism of action.

Sida cordifolia is used commonly in traditional systems of medicine (TSM) and as folk remedies for treating the wounds (both external and internal), infected area, rheumatic disorders, muscular weakness, tuberculosis, heart problems, bronchitis, neurological problems etc. Therefore, in order to authenticate the claims, a mechanism-oriented investigation of the wound healing properties of this plant is essential.

The overall aim of the present research is to understand the precise unknown cellular and molecular mechanism by which S. cordifolia accelerates wound healing delay caused by the steroidal drug dexamethasone. Here, we have also tried to quantify intracellular superoxide with the help of a unique fluoroprobe MitoSOX based on fluorescence measurements in yeast MATERIALS AND METHODS: Wound healing property of successive extracts (ethyl acetate, methanol and aqueous) of S. cordifolia against dexamethasone-induced retardation of wound healing in rats was studied. The various extracts of S. cordifolia were characterised by determining the various phytochemicals and quantifying the total phenolic content and flavonoidal content by High throughput assays. In order to know the probable mechanism of action of the successive fractionates, assessed the antioxidant activity both by in-vitro (DPPH-assay) and in-vivo methods in wild-type Saccharomyces cerevisiae BY 4743 (WT) and knock-out strain (Δtrx2) against H₂O₂-induced stress mediated damages. The cell survival was evaluated after exposure to the oxidizing reagent (4 mM H₂O₂) by two methods which included the ability of cells to proliferate on solid or liquid medium. The cell membrane integrity/amount of mitochondrial ROS was determined by treating the strains with extract/standard in presence of H₂O₂ and propidium iodide (PI)/MitoSOX Red RESULTS: During the preliminary in-vivo wound healing study, the period for complete re-epithelialization of the wound tissue was reduced significantly (pin the treatment groups as compared to the negative control group. The formulation HF₃ containing aqueous extract of S. cordifolia (SCA) showed highest wound healing potential against dexamethasone-retarded wounds in rats which justifies its traditional use. In the growth curve assay, the H₂O₂-induced growth arrest was restored by aqueous extract of S. cordifolia (SCA) in a concentration-dependent(pmanner both in the WT and Δtrx2 strains similar to the standard (ascorbic acid), H₂O₂ after 24 hours incubation which was also confirmed by the findings of CFU method. We got almost similar results of cell viability when stained with PI. The lower level of mitochondrial superoxide was indicated by a significant (preduction in the amount of MitoSOX stained cells, in the extract-treated group in contrast to the H₂O₂-stressed group.

It was concluded that HF₃ can be applied topically in hydrogel form in the case of delayed wound healing caused by the steroidal drug-dexamethasone, aptly justifying its traditional use. Regarding its mechanism of action, our findings report that the potent adaptive response of SCA-treated WT and Δtrx2 strains towards intracellular ROS specifically mitochondrial-ROS confirms its antioxidant potential. Moreover, as SCA was able to rescue the Δtrx2 strains from stress, it can be inferred that it might be able to induce the enzyme thioredoxin-II to restore redox homeostasis. The findings with the conditional mutant ∆trx2 are the first proof linking SCA action related to particular cellular pathways which may be because of the phenols and flavonoids and their synergistic effect.