A wound refers to an injury to the skin or underlying tissues or organs . Dermal wounds are often caused by surgery, trauma, and chemicals or as a result of diseases [1, 2]. Intentionally created dermal wounds can be incisional, whereby the wound is brought about by surgical cutting into the skin with a scalpel or excision wound created when a part of the skin is cut off . The process of tissue repair after an insult to the tissue (wound) is called ‘wound healing’ . Wound healing is an intricate process in which usually the skin repairs itself . The process involves four overlapping phases: haemostasis (ceasation of bleeding), inflammation, proliferation, and remodeling [4, 5].
In haemostasis, thromboxane synthase (TXS) converts prostaglandin H2 into thromboxane A2 which causes vasoconstriction and platelet aggregation . Failure of the haemostatic process is prevented by plasminogen activator inhibitor type 1 (PAI-1), an inhibitor of fibrinolysis . In the inflammation phase, neutrophils release free radicals to kill wound contaminating bacteria [8, 9]. Heme and heme proteins which accumulate at the local site of the wound have prooxidative and proinflammatory properties by inducing the expression of adhesion molecules, causing vascular permeability and leukocyte infiltration. These actions initiate wound healing process . Conversely, heme oxygenase-1 (HO-1) has anti-inflammatory and antioxidant activities and is responsible for a wide range of wound healing functions. It converts heme into biliverdin/bilirubin, iron and carbon monoxide, which are potent antioxidant products . In proliferation phase, overexpression of HO-1 helps to accelerate wound healing such as amelioration of inflammation, proliferation and protection against endothelial cell apoptosis . In remodeling phase, matrix metalloproteinases (MMPs) plays a major role in wound healing by extracellular matrix (ECM) remodeling .
The length of time it takes for wound healing process to be complete is dependent on the rate of availability of biochemical substances required for each phase to occur. To shorten the duration of the healing process and minimize complications (such as overwhelming bacterial wound contamination) of natural healing, medical professionals use orthodox medications (which increase the rate of healing process and/or control secondary microbial wound contamination) to treat wounds . But, the prices of these orthodox medications are exorbitant and many wound contaminating bacteria are becoming increasingly resistant to their effects .
In traditional medicine, medicinal plants are used in the preparation of decoctions which are applied to dermal wounds to enable healing . The efficacies of these plants in wound healing have been experienced and passed on from one generation to the other. One of these medicinal plants widely used traditionally in Nsukka Southeast, Nigeria in treating wounds is Pupalia lappacea (Family Amaranthaceae). The common name is forest Burr or creeping cork’s comb. It is an erect or straggling under shrub with flowers in spicate clusters, and it usually grows along hedges . It is used in agrihorticulture as a fodder . Traditional practitioners including those in Nsukka, claim that foliage parts of P. lappacea are used in form of poultices and decoctions to treat different ailments such as bone fractures and inflammatory conditions, boils, cough, fever, leprosy sores, flatulence, jaundice, abdominal colic, cephalgia, diarrhoea, paralysis, erectile dysfunction, vomiting, toothache, cuts, chronic wounds, fever and malaria [13, 16–20]. For the treatment of wounds, the leaf paste and the fruit juice is applied externally . Scientific investigations have validated some of these claims such as antimalaria , anticancer , antinociceptive and antipyretic  activities of the P. lappacea extract. No study has been done to evaluate its wound healing and antibacterial activities.
Moreover, chemical investigations of P. lappacea leaf extract revealed that it consists of 8 compounds which included: 1-docosanol, stearic acid, stigmasterol, sitosterol, N-benzoyl-L-phenyl alaninol acetate, setosterol-3-O-D-glucopyranoside, stigmasterol-3-O-D-glucopyranoside and 20-hydroxyl ecdysone . These biochemical compounds have been shown to promote wound healing process in animals and humans. Stigmaesterol have been shown to exhibit haemostatic  and anti-inflammatory activities [5, 23]. The 20-hydroxyl ecdysyne promoted protein synthesis and wound healing in animals and humans . Docosanol was used by to treat herpes simplex virus cutaneous wounds in mice . Plant extract that contains N-benzoyl-L-phenyl alaninol exhibited antibacterial activity . Since some of the compounds contained in P. lappacea leaf extract showed activities involved in wound healing process, the plant extract may exhibit wound healing activities in animals and humans as claimed by the traditional practitioners. The objective of this study was therefore to evaluate the wound healing and antibacterial activities of P. lappacea methanolic leaf extract in rats.