Phytochemical analysis and wound healing properties of Malva parviflora L. ethanolic extract

Scientific publications documented the use of plants from Genus Malva to treat inflammatory diseases and skin disorders by our ancestors. Malva parviflora L. has reported benefits for wound healing in traditional medicine; however, there is a lack of experimental study to validate these claims.

We initiated this study to explore the metabolites and verify the wound healing properties of M. parviflora using in vivo and in vitro models.

Liquid chromatography electrospray ionization tandem mass spectrometry (LC/ESI-MS/MS) was used to identify the ethanolic extract different metabolites. Additionally, total phenolic content was determined using Folin-Ciocalteu reagent. To verify the extract wound healing potential, an in vivo rat wound excision model was employed. Round wounds (5 mm in diameter) were created by a sterile biopsy punch needle. The wounds were treated with plant extracts (2.5% and 5%) as well as a commercially available wound healing product (Mebo®) for 10 days. The results were assessed as follows: 1) Measuring the reduction% in wound area compared to the original wound size. 2) Evaluation of the levels of wound healing biomarkers, namely collagen type I (Col-1), alpha smooth muscle actin (α-SMA), extracellular signal-regulated kinases-1 (ERK1), and matrix metalloproteinase-9 (MMP9) levels. 3) Performing histopathological examination of the wound tissue. The antioxidant properties of the M. parviflora leaves ethanolic extract were investigated using various assays: total antioxidant capacity (TAC), iron reducing power (IRP), 1,1-Diphenyl-2-picryl-hydrazyl (DPPH), and 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radicals scavenging assays. Furthermore, the anti-inflammatory activity was confirmed by calculating the inhibition percentages of protein denaturation and the activity of the proteinase enzyme.

Liquid chromatography tandem mass spectrometry (LC-MS/MS) analysis revealed the presence of various secondary metabolites in M. parviflora ethanolic extract, including phenolic acids (cinnamic and ferulic acids), flavonoids (quercetin and "iso"rhamnetin monoglucuronides), fatty acids (hydroxy-octadecatrienoic and oxo-octadecatrienoic acids), in addition to chlorophyll derivatives and carotenoids (pheophorbide-a and lutein, respectively). Malva extracts significantly reduced wound size compared to untreated control group. The extracts also promoted wound healing by upregulating collagen I, α-SMA, and ERK1 levels, while downregulating MMP9 expression. Notably, the effect of 2.5% and 5% extracts was similar or exceeds those of Mebo®, supported by histopathological results. Finally, M. parviflora ethanolic extract exhibited antioxidant and anti-inflammatory potentials comparable to the used standards.

Our study provides evidence-based support for the wound healing properties of M. parviflora L. leaves ethanolic extract. This is further strengthened by the fact that many of the identified metabolites possess wound healing, antioxidant, and/or anti-inflammatory activities.