Role of Flavonoids as Wound Healing Agent

Pharmacognostic characterization, wound healing and toxicity assessment of the stem bark of Xylia evansii Hutch (Leguminosae)

Xylia evansii is widely used in traditional medicine to stop bleeding gums and treat wounds. This study was undertaken to assess the wound healing activity and toxicity profile of the stem bark methanol extract of X. evansii (XES). Wound healing activity was determined by the dermal excision model in rats. The free radical scavenging capacity, antioxidant activity, total phenolic and flavonoid contents were evaluated by the 1, 1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging, total antioxidant capacity (TAC), aluminum chloride colorimetric and Folin Ciocalteu methods respectively. Acute and sub-acute oral toxicity assessment was performed following the Organization for Economic Co-operation and Development guidelines. Significant (p < 0.05) dose-dependent wound healing effect, similar to that of 1 % silver sulphadiazine was elicit by the 10, 15 and 20 %w/w XES ointments. The highest effect was demonstrated by XES 20 %w/w which resulted in 98.3 % wound surface closure by day 9 of treatment (p < 0.0001). The total phenolic and flavonoid contents were determined to be 381.2 ± 12.57 mg/g gallic acid equivalent (GAE) and 460 ± 29.07 mg/g quercetin equivalent respectively. XES exhibited remarkable free radical scavenging effect (IC50 = 68.13 ± 1.87 μg/mL) and had a total antioxidant capacity of 279.2 ± 32.08 mg/g GAE. The LD50 of XES was estimated to be > 5000 mg/kg. In sub-acute toxicity, 28 days treatment with XES (250, 500, 1000 mg/kg body weight) did not result in any significant (p > 0.05) change in the body weight or weight of the heart, lung, spleen, liver and kidneys. The haematological and biochemical profiles of XES-treated rats were not significantly (p > 0.05) affected after 4-weeks treatment with XES, except for platelet count which increased significantly (p < 0.0001) in a non-dose-dependent manner. Histopathological examination did not reveal any toxic effect to liver cells, however at 1000 mg/kg XES, slight abnormalities were identified in the glomeruli. Microscopy of the powdered stem bark displayed calcium oxalate crystals, pitted vessels and lignified fibres. Tannins, flavonoids, coumarins, saponins, triterpenes and alkaloids were identified in the bark. This is the first report on the wound healing potential and safety profile of X. evansii, giving scientific credence to its use in traditional medicine.

Treatment Management of Diabetic Wounds Utilizing Herbalism: An Overview

BACKGROUND AND OBJECTIVES

Diabetes Mellitus, commonly known as DM, is a metabolic disorder which is characterized by high blood glucose level, i.e., chronic hyperglycemia. If it is not managed properly, DM can lead to many severe complexities with time and can cause significant damage to the kidneys, heart, eyes, nerves and blood vessels. Diabetic foot ulcers (DFU) are one of those major complexities which affect around 15-25% of the population diagnosed with diabetes. Due to diabetic conditions, the body's natural healing process slows down leading to longer duration for healing of wounds only when taken care of properly. Herbal therapies are one of the approaches for the management and care of diabetic foot ulcer, which utilizes the concept of synergism for better treatment options. With the recent advancement in the field of nanotechnology and natural drug therapy, a lot of opportunities can be seen in combining both technologies and moving towards a more advanced drug delivery system to overcome the limitations of polyherbal formulations.

METHODS

During the writing of this document, the data was derived from existing original research papers gathered from a variety of sources such as PubMed, ScienceDirect, Google Scholar.

CONCLUSION

Hence, this review includes evidence about the current practices and future possibilities of nano-herbal formulation in treatment and management of diabetic wounds.

Natural Flavonoids as Potential Therapeutics in the Management of Diabetic Wound: A Review

Flavonoids are important bioactive phenolic compounds abundant in plants and exhibit different therapeutic potentials. A wound is a significant problem in diabetic individuals. A hyperglycaemic environment alters the normal wound-healing process and increases the risk of microbial infection, leading to hospitalization, morbidity, and amputation. Flavonoids are an important class of phytochemicals with excellent antioxidant, anti-inflammatory, antimicrobial, antidiabetic, antitumor, and wound healing property. Quercetin, hesperidin, curcumin, kaempferol, apigenin, luteolin, morin, etc. have shown their wound healing potential. Flavonoids effectively exhibit antimicrobial activity, scavenge reactive oxygen species, augment endogenous antioxidants, reduce the expression and synthesis of inflammatory cytokines (i.e. IL-1β, IL-6, TNF-α, NF-κB), inhibit inflammatory enzymes, enhance anti-inflammatory cytokine (IL-10), enhance insulin section, reduce insulin resistance, and control blood glucose level. Several flavonoids like hesperidin, curcumin, quercetin, rutin, naringin, and luteolin have shown their potential in managing diabetic wounds. Natural products that maintain glucose haemostatic, exert anti-inflammatory activity, suppress/inhibit microbial growth, modulate cytokines, inhibit matrix metalloproteinase (MMP), stimulate angiogenesis and extracellular matrix, and modulate growth factor can be considered as a potential therapeutic lead to treat diabetic wound. Flavonoids were found to play a positive role in management of diabetic wounds by regulating MMP-2, MMP-8, MMP-9, MMP-13, Ras/Raf/ MEK/ERK, PI3K/Akt, and nitric oxide pathways. Therefore, it can be assumed that flavonoids could be potential therapeutics to prevent devastating effects of diabetic wounds. This paper focused on the potential role of flavonoids in managing diabetic wounds and discussed their possible mechanism of action.

Assessment of Toxicity and Wound Healing Activity of Selaginella Bryopteris Extract

AIM

The aim of the study was to assess the toxicity profile of Selaginella bryopteris extract and evaluate its wound healing activity.

METHODS

In vitro wound healing activity of S. bryopteris extract (5% and 10%) was performed using Clonogenic and Scratch assays. The toxicity profile of S. bryopteris extract ointment was evaluated on animals using acute toxicity and dermal toxicity tests. In vivo wound healing activity of S. bryopteris extract ointment (5% and 10%) was used to determine tensile strength in the incision wound healing model.

RESULTS

Results exhibited that the extract was safe up to 2000 mg/kg per oral dose and non-reactive while applied topically. In vitro results showed that S. bryopteris extract closed the wound gap created by 97.13% in 48 h. The clonogenic assay revealed that the surviving factor for HaCaT cells and MEF cells was 0.78 and 0.85 after treated with 10% concentrations of S. bryopteris. The tensile strength exhibited by S. bryopteris 5% and 10% groups was 395.4 g and 558.5 g in comparison to the control group.

CONCLUSION

Thus, S. bryopteris extract can be used as an alternative safe drug therapy against topical wounds.

Antibacterial Activity of Medicinal Plants and Their Constituents in the Context of Skin and Wound Infections, Considering European Legislation and Folk Medicine-A Review

Bacterial infections of skin and wounds may seriously decrease the quality of life and even cause death in some patients. One of the largest concerns in their treatment is the growing antimicrobial resistance of bacterial infectious agents and the spread of resistant strains not only in the hospitals but also in the community. This trend encourages researchers to seek for new effective and safe therapeutical agents. The pharmaceutical industry, focusing mainly on libraries of synthetic compounds as a drug discovery source, is often failing in the battle with bacteria. In contrast, many of the natural compounds, and/or the whole and complex plants extracts, are effective in this field, inactivating the resistant bacterial strains or decreasing their virulence. Natural products act comprehensively; many of them have not only antibacterial, but also anti-inflammatory effects and may support tissue regeneration and wound healing. The European legislative is in the field of natural products medicinal use formed by European Medicines Agency (EMA), based on the scientific work of its Committee on Herbal Medicinal Products (HMPC). HMPC establishes EU monographs covering the therapeutic uses and safe conditions for herbal substances and preparations, mostly based on folk medicine, but including data from scientific research. In this review, the medicinal plants and their active constituents recommended by EMA for skin disorders are discussed in terms of their antibacterial effect. The source of information about these plant products in the review is represented by research articles listed in scientific databases (Science Direct, PubMed, Scopus, Web of Science, etc.) published in recent years.

Incorporation of grape seed extract towards wound care product development

Naturally derived ingredients are becoming more prevalent in therapeutic drug formulations due to consumers' concerns about chemical side effects. In the context of wound care, despite the impressive progress in therapeutic product development, drugs dispensed to treat impaired healing challenged by biofilms; excessive inflammation and oxidation are not yet really effective. Thus, the hunts for improved drug formulations preferably using natural ingredients that are cost-effective in accelerating the wound-healing process are of constant demand. The grape seed extract is extensively studied and is reported to be rich in phenolic compounds, unsaturated fatty acids and vitamins which exhibit numerous therapeutic benefits owing to their anti-inflammatory, anti-microbial, and anti-oxidative properties that support its potential use in the development of wound-healing products. We conducted a literature study using Scopus, PubMed, and Google Scholar including the keywords "grape seed extract" and "wound healing". We also scanned all the references cited by the retrieved articles. Accordingly, this review is aimed to (i) explore the various phytochemical constituents found in grape seed extracts along with their mechanism of action that instigate wound healing, (ii) to highlight the latest pre-clinical and clinical assessments of grape seed extract in wound models, and (iii) to encourage innovation scientists in the field to address current limitations and to effectively develop grape seed extract-based wound care product formulations for commercialization.

Hitting the sweet spot: A systematic review of the bioactivity and health benefits of phenolic glycosides from medicinally used plants

Phenolic acid and flavonoid glycosides form a varied class of naturally occurring compounds, characterised by high polarity-resulting from the glycone moiety-and the presence of multiple phenol functionalities, which often leads to strong antioxidant activity. Phenolic glycosides, and in particular flavonoid glycosides, may possess strong bioactive properties with broad spectrum activity. This systematic literature review provides a detailed overview of 28 studies examining the biological activity of phenolic and flavonoid glycosides from plant sources, highlighting the potential of these compounds as therapeutic agents. The activity of glycosides depends upon the biological activity type, identity of the aglycone and the identity and specific location of the glycone moiety. From studies reporting the activity of both glycosides and their respective aglycones, phenolic glycosides appear to generally be a storage/reserve pool of precursors of more bioactive compounds. The glycosylated compounds are likely to be more bioavailable compared to their aglycone forms, due to the presence of the sugar moieties. Hydrolysis of the glycoside in the in vivo environment would release the free aglycone, potentiating their biological activity. However, further high-quality studies are needed to firmly establish the clinical efficacy of glycosides from many of the plant species studied.

Phytochemical profile, acute dermal toxicity and wound healing activity of Guettarda calyptrata A. Rich

Introduction: The leaves and barks of Guettarda calyptrata have been attributed to the property of healing wounds on the skin and mucous membranes. However, the scientific information about the phytochemical composition and biological properties is scarce. This research evaluates the chemical composition, dermal safety, and wound healing properties of a hydroalcoholic extract of G. calyptrata. Methods: Hydroalcoholic extract of G. calyptrata was obtained from leaves. The phytochemical profile was analyzed by phytochemical screening, thin layer chromatography, high performance liquid chromatography (HPLC), and quantification of phenols and flavonoids by Folin-Ciocalteu and aluminum chloride methods, respectively. An acute dermal toxicity test was performed in rats, and the healing activity was evaluated using the excision wound model at 100 mg/kg of the extracts. Statistical significance (P < 0.05) was determined by an analysis of variance followed by the Student-Newman-Keuls test. Results: The presence of alkaloids, saponins, terpenoids, phenolic compounds, rutin, and quercetin flavonoids, among others, was suggested. The extract did not cause toxicity at the dose of 2000 mg/kg and was able to reduce the size of the wounds during the seven days of the test, with a healing effect comparable to the silver sulfadiazine cream used as a positive control, favoring collagen deposition and re-epithelialization. Conclusion: This work makes an important contribution to the chemical composition and provides the first findings on the efficacy in the healing of topical wounds, which justify the use of G. calyptrata in traditional Cuban medicine.

The therapeutic effects of Agrimonia eupatoria L

Agrimonia eupatoria L. is an herb of the Rosaceae family, widely used in traditional (folk) medicine for its beneficial effects. Its water extracts (infusions and decoctions) are used in the treatment of airway and urinary system diseases, digestive tract diseases, and chronic wounds. Phytochemical analyses of Agrimonia eupatoria L. identified a variety of bioactive compounds including tannins, flavonoids, phenolic acids, triterpenoids and volatile oils possessing antioxidant, immunomodulatory and antimicrobial activities. The authors review the available literature sources examining and discussing the therapeutic and pharmacological effects of Agrimonia eupatoria L. at the molecular level in vitro and in vivo.

Prunus spinosa Extract Loaded in Biomimetic Nanoparticles Evokes In Vitro Anti-Inflammatory and Wound Healing Activities

Prunus spinosa fruits (PSF) contain different phenolic compounds showing antioxidant and anti-inflammatory activities. Innovative drug delivery systems such as biomimetic nanoparticles could improve the activity of PSF extract by promoting (i) the protection of payload into the lipidic bilayer, (ii) increased accumulation to the diseased tissue due to specific targeting properties, (iii) improved biocompatibility, (iv) low toxicity and increased bioavailability. Using membrane proteins extracted from human monocyte cell line THP-1 cells and a mixture of phospholipids, we formulated two types of PSF-extract-loaded biomimetic vesicles differing from each other for the presence of either 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) or 1,2-dioleoyl-sn-glycero-3-phospho-(1'-rac-glycerol) (DOPG). The biological activity of free extract (PSF), compared to both types of extract-loaded vesicles (PSF-DOPCs and PSF-DOPGs) and empty vesicles (DOPCs and DOPGs), was evaluated in vitro on HUVEC cells. PSF-DOPCs showed preferential incorporation of the extract. When enriched into the nanovesicles, the extract showed a significantly increased anti-inflammatory activity, and a pronounced wound-healing effect (with PSF-DOPCs more efficient than PSF-DOPG) compared to free PSF. This innovative drug delivery system, combining nutraceutical active ingredients into a biomimetic formulation, represents a possible adjuvant therapy for the treatment of wound healing. This nanoplatform could be useful for the encapsulation/enrichment of other nutraceutical products with short stability and low bioavailability.