White clover (Trifolium repens) and Wounds: evidence and sources

Trifolium repens is a well-known herbaceous, perennial herb and has been extensively used in the traditional medicine system over the years. Various parts of the plant are traditionally used as a curative agent against several health ailments such as skin problems, wound healing, stomach disorders, sedative, fever, antiseptic, analgesic, expectorant, psoriasis and eczema. To maximise the plant's potential for usage in the future, the review also aims to update information about its significant pharmacological properties. The ethnomedicinal benefits of T. repens have been well studied; however, the facets of the plant have not been explored yet. The current review outlines several bioactive compounds quantified from T. repens and a few of them namely quercetin, kaempferol, myricetin, acacetin and linamarin, have been reported to have biological activities such as antibacterial, antifungal, antileishmanial, anti-inflammatory, antiaging and anti-hepatotoxic activities. A significant number of in vitro studies have been done on the plant extract, but little is known about the isolation and efficacy of the potent natural bioactive compounds of T. repens . The bioactive compounds in T. repens can be used for advanced drug development against various health disorders.

Introduction Natural agents with antioxidant and anti-inflammatory properties are safer than synthetic agents and may improve wound healing. Objective The purpose of this study is to evaluate the in vivo wound healing potential of an ointment prepared from Trifolium repens hydroethanolic extract (T repens) concerning excisional wounds in a rat model. Materials and methods Seventy-two adult Wistar rats were divided into 4 groups: a control group and 3 groups of animals treated with 1.5% T repens, 3% T repens, and 6% T repens. A full-thickness wound with an area of 314 mm2 was created in each rat. To investigate the effect of T repens on wound healing, the wound area, histological analyses (eg, angiogenesis, fibroblast, fibrocyte, mast-cell distribution), intracytoplasmic carbohydrate storage, and B-cell lymphoma 2-like protein 4 (BAX), B-cell lymphoma 2 (Bcl-2), and p53 gene expression in the wound tissue were evaluated for 21 days. Antioxidant activity was further measured by 2,20-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) and 2,2-Di(4-tert-octylphenyl)-1-picrylhydrazyl (DPPH) assays. Results The animals in the treated groups showed higher wound contraction ratios (P ⟨ .05), angiogenesis, fibroblast, fibrocyte, and mast-cell distribution and intracytoplasmic carbohydrate storage compared with the control group (P ⟨ .05). Moreover, the topical administration of T repens increased the messenger ribonucleic acid (mRNA) level of Bcl-2 and reduced the BAX and p53 mRNA levels (P ⟨ .05). These findings further revealed the strong antioxidant activity of T repens. Conclusions The topical administration of T repens accelerated wound healing by increasing angiogenesis; fibroblast, fibrocyte, and mast-cell distribution; intracytoplasmic carbohydrate storage; and modulation in genes involved in apoptosis in a rat model.

Trifolium species are used in Turkish folk medicine as a wound healing agent, expectorant, antiseptic, sedative and to alleviate pain in rheumatism. In the present study, the aqueous methanolic extracts (80%) of 13 Trifolium species (Trifolium ambigum, Trifolium arvense var. arvense, Trifolium campestre, Trifolium canescens, Trifolium hybridum var. anatolicum, Trifolium hybridum var. hybridum, Trifolium pannonicum, Trifolium pratense var. pratense, Trifolium purpureum var. purpureum, Trifolium repens var. repens, Trifolium resupinatum var. microcephalum, Trifolium spadiceum and Trifolium trichocephalum) collected from different regions of Anatolia were evaluated for their in vivo wound healing effects. In vivo wound healing activities of the plant aqueous methanolic extracts were evaluated by linear incision and circular excision wound models subsequent to histopathological analysis. Active constituents were determined by a validated high performance liquid chromatographic method. Precision of the method was performed by the evaluation of intra-day and inter-day variations of the each standard at limits of quantification (LOQ) levels. The aqueous methanolic extracts of Trifolium canescens and Trifolium pretense var. pratense possessed better wound healing activity compared to the other extracts and control groups. The animal groups treated with the Trifolium canescens extract demonstrated increased contraction (48.96%) on excision and a significant increase in wound tensile strength (35.6%) on incision models. The main compounds were detected as genistein and biochanin A for Trifolium canescens. The results of the present study revealed the wound healing potential of Trifolium canescens. This might be due to the combined effect of the isoflavones genistein, formononetin, daidzein, and biochanin A present in the extract.