Plant-based Natural Products for Wound Healing: A Critical Review

Wound healing and anti-inflammatory effects of LAA, the N-acetyl-D-galactosamine-binding lectin from seeds of Luetzelburgia auriculata (Allemão) ducke

Cutaneous wounds represent a significant health concern, and effective treatment strategies are crucial for optimal healing. This study investigates the therapeutic potential of Luetzelburgia auriculata lectin (LAA), a plant-derived protein, in accelerating wound closure. Excisional wounds were created on the backs of mice, which were subsequently treated topically with LAA solutions at two concentrations (100 µg/mL and 200 µg/mL) or saline control. Wound healing was assessed through clinical observations, including wound area measurement and inflammatory score, as well as histopathological analysis and measurement of inflammatory cytokines. LAA significantly accelerated wound closure, reduced inflammation, and promoted tissue regeneration. Histological analysis revealed enhanced re-epithelialization, increased fibroblast proliferation, and improved collagen deposition in LAA-treated wounds compared with the control group. Furthermore, LAA treatment significantly reduced the levels of proinflammatory cytokines in wound tissues (interleukin-6, tumor necrosis factor-alpha, and monocyte chemoattractant protein-1). These findings suggest that LAA exerts its beneficial effects through a multifaceted mechanism, likely involving anti-inflammatory properties and stimulation of cellular processes crucial for tissue repair. This study provides preliminary evidence for the therapeutic potential of LAA in wound healing and warrants further investigation into its underlying mechanisms and clinical applications.

Co-assembled supramolecular hydrogel of asiaticoside and Panax notoginseng saponins for enhanced wound healing

Self-assembling natural drug hydrogels have emerged as promising biomaterials for scalable and customizable drug delivery systems attributed to their inherent biocompatibility and biodegradability. Asiaticoside (AS), a bioactive compound derived from Centella asiatica (L.) Urb., is known for its antioxidant, antifibrotic, and anti-inflammatory properties, primarily accelerating wound healing through the promotion of collagen synthesis. However, its low water solubility leads to poor transdermal absorption and reduced bioavailability when applied topically. Panax notoginseng saponins (PNS), active compounds derived from the stems of Panax notoginseng (Burk.) F.H. Chen, exhibit amphiphilic and surfactant properties, rendering them effective stabilizers. Our research has demonstrated that the co-assembly of AS and PNS forms a hydrogel, termed AS&PNS hydrogel, which significantly enhances wound healing by reducing interleukin-6 (IL-6) levels and promoting the production of vascular endothelial growth factor (VEGF). Treatment with AS&PNS hydrogel also tended to normalize epidermal thickness and improve collagen fiber organization at the wound site. This novel hydrogel material presents a straightforward and effective approach to managing skin wounds.

A critical overview of challenging roles of medicinal plants in improvement of wound healing technology

PURPOSE

Chronic diseases often hinder the natural healing process, making wound infections a prevalent clinical concern. In severe cases, complications can arise, potentially leading to fatal outcomes. While allopathic treatments offer numerous options for wound repair and management, the enduring popularity of herbal medications may be attributed to their perceived minimal side effects. Hence, this review aims to investigate the potential of herbal remedies in efficiently treating wounds, presenting a promising alternative for consideration.

METHODS

A literature search was done including research, reviews, systematic literature review, meta-analysis, and clinical trials considered. Search engines such as Pubmed, Google Scholar, and Scopus were used while retrieving data. Keywords like Wound healing 'Wound healing and herbal combinations', 'Herbal wound dressing', Nanotechnology and Wound dressing were used.

RESULT

This review provides valuable insights into the role of natural products and technology-based formulations in the treatment of wound infections. It evaluates the use of herbal remedies as an effective approach. Various active principles from herbs, categorized as flavonoids, glycosides, saponins, and phenolic compounds, have shown effectiveness in promoting wound closure. A multitude of herbal remedies have demonstrated significant efficacy in wound management, offering an additional avenue for care. The review encompasses a total of 72 studies, involving 127 distinct herbs (excluding any common herbs shared between studies), primarily belonging to the families Asteraceae, Fabaceae, and Apiaceae. In research, rat models were predominantly utilized to assess wound healing activities. Furthermore, advancements in herbal-based formulations using nanotechnology-based wound dressing materials, such as nanofibers, nanoemulsions, nanofiber mats, polymeric fibers, and hydrogel-based microneedles, are underway. These innovations aim to enhance targeted drug delivery and expedite recovery. Several clinical-based experimental studies have already been documented, evaluating the efficacy of various natural products for wound care and management. This signifies a promising direction in the field of wound treatment.

CONCLUSION

In recent years, scientists have increasingly utilized evidence-based medicine and advanced scientific techniques to validate the efficacy of herbal medicines and delve into the underlying mechanisms of their actions. However, there remains a critical need for further research to thoroughly understand how isolated chemicals extracted from herbs contribute to the healing process of intricate wounds, which may have life-threatening consequences. This ongoing research endeavor holds great promise in not only advancing our understanding but also in the development of innovative formulations that expedite the recovery process.

Next generation sequencing-aided screening, isolation, molecular identification, and antimicrobial potential for bacterial endophytes from the medicinal plant, Elephantorrhiza elephantina

Elephantorrhiza elephantina, a wild plant in southern Africa, is utilized in traditional medicine for various ailments, leading to its endangerment and listing on the Red List of South African Plants. To date, there have been no reports on bacterial endophytes from this plant, their classes of secondary metabolites, and potential medicinal properties. This study presents (i) taxonomic characterization of bacterial endophytes in leaf and root tissues using 16S rRNA, (ii) bacterial isolation, morphological, and phylogenetic characterization, (iii) bacterial growth, metabolite extraction, and LC-MS-based metabolite fingerprinting, and (iv) antimicrobial testing of bacterial crude extracts. Next-generation sequencing yielded 693 and 2,459 DNA read counts for the rhizomes and leaves, respectively, detecting phyla including Proteobacteria, Bacteroidota, Gemmatimonadota, Actinobacteriota, Verrucomicrobiota, Dependentiae, Firmicutes, and Armatimonodata. At the genus level, Novosphingobium, Mesorhizobium, Methylobacterium, and Ralstonia were the most dominant in both leaves and rhizomes. From root tissues, four bacterial isolates were selected, and 16S rRNA-based phylogenetic characterization identified two closely related Pseudomonas sp. (strain BNWU4 and 5), Microbacterium oxydans BNWU2, and Stenotrophomonas maltophilia BNWU1. The ethyl acetate:chloroform (1:1 v/v) organic extract from each isolate exhibited antimicrobial activity against all selected bacterial pathogens. Strain BNWU5 displayed the highest activity, with minimum inhibitory concentrations ranging from 62.5 μg/mL to 250 μg/mL against diarrhoeagenic Escherichia coli, Escherichia coli O157:H7, Salmonella enterica, antibiotic-resistant Vibrio cholerae, Staphylococcus aureus, Bacillus cereus, and Enterococcus durans. LC-MS analysis of the crude extract revealed common antimicrobial metabolites produced by all isolates, including Phenoxomethylpenicilloyl (penicilloyl V), cis-11-Eicosenamide, 3-Hydroxy-3-phenacyloxindole, and 9-Octadecenamide.

In Vivo Evaluation of Wound Healing Efficacy of Gel-Based Dressings Loaded with Pycnogenol™ and Ceratothoa oestroides Extracts

Ceratothoa oestroides and French maritime pine bark (Pycnogenol™) extracts are considered promising therapeutic agents in wound healing. This study explores the healing efficacy of composite dressings containing these extracts, aiming to enhance their stability and effectiveness, utilizing a low-temperature vacuum method for producing Sodium Alginate-Maltodextrin gel dressings. Surgical wounds were inflicted on SKH-hr2 hairless mice. Dressings were loaded with Pycnogenol™ and/or C. oestroides extracts and assessed for their efficacy. Wound healing was primarily evaluated by clinical and histopathological evaluation and secondarily by Antera 3D camera and biophysical measurements. Dressings were stable and did not compromise the therapeutic properties of C. oestroides extract. All interventions were compared to the C. oestroides ointment as a reference product. Most of the wounds treated with the reference formulation and the C. oestrodes dressing had already closed by the 15th day, with histological scores of 7 and 6.5, respectively. In contrast, wounds treated with Pycnogenol™, either alone or in combination with C. oestroides, did not close by the end of the experiment (16th day), with histological scores reaching 15 in both cases. Furthermore, treatment with 5% Pycnogenol™ dressing appeared to induce skin thickening and increase body temperature. The study underscores the wound healing potential of C. oestroides extracts and highlights the need for further research to optimize Pycnogenol™ dosing in topical applications.

Quercetin and its derivatives for wound healing in rats/mice: Evidence from animal studies and insight into molecular mechanisms

Aimed to clarify the effect of quercetin and its derivatives on wound healing in animal experiments. PubMed, Embase, Science Direct, Web of Science, SinoMed, Vip Journal Integration Platform, China National Knowledge Infrastructure and WanFang databases were searched for animal experiments investigating the effect of quercetin and its derivatives on wound healing to April 2023. The Review Manager 5.4 software was used to conduct meta-analysis. Eighteen studies were enrolled in this article. According to the SYRCLE's RoB tool assessment, these studies exposed relatively low methodological quality. It was shown that animals with cutaneous wound receiving quercetin had faster wound healing in wound closure (%) than the control group. Moreover, the difference in efficacy gradually emerged after third day (WMD = 7.13 [5.52, 8.74]), with a peak reached on the tenth day after wounding (WMD = 19.78 [17.82, 21.74]). Subgroup analysis revealed that quercetin for wound closure (%) was independent of the types of rats and mice, wound area and with or without diabetes. Clear conclusion was also shown regarding the external application of quercetin for wound healing (WMD = 17.77 [11.11, 24.43]). A significant reduction in the distribution of inflammatory cells occurred in the quercetin group. Quercetin could increase blood vessel density (WMD = 1.85 [0.68, -3.02]), fibroblast distribution and collagen fraction. Biochemical indicators, including IL-1β, IL-10, TNF-α, TGF-β, vascular endothelial growth factor (VEGF), hydroxyproline and alpha-smooth muscle actin (α-SMA), had the consistent results. Quercetin and its derivatives could promote the recovery of cutaneous wound in animals, through inhibiting inflammatory response and accelerating angiogenesis, proliferation of fibroblast and collagen deposition.

1-Tetracosanol isolated from the leaves of Eupatorium glandulosum, accelerates wound healing by expressing inflammatory cytokines and matrix metalloproteinase

ETHNOPHARMACOLOGICAL RELEVANCE

The leave paste of the plant, Eupatorium glandulosum H. B & K, has been traditionally used to treat cuts and wounds by the tribal community of the Nilgiris district of Tamilnadu, India.

AIM OF THE STUDY

The present study was carried out to investigate the wound healing potential of this plant extract and the compound, 1-Tetracosanol, isolated from the ethyl acetate fraction.

MATERIALS AND METHODS

An in vitro study was designed to compare the viability, migration and apoptosis of the fresh methanolic extract fractions and 1-Tetracosanol using mouse fibroblast NIH3T3 cell lines and human keratinocytes HaCaT cell lines, respectively. 1-Tetracosanol was evaluated for its viability, migration, qPCR analysis, in silico, in vitro and in vivo.

RESULTS

1-Tetracosanol at the concentration of 800, 1600, 3200 μM has significant wound closure of 99% at 24 h. The compound when screened in silico against various wound healing markers, TNF-α, IL-12, IL-18, GM-CSF and MMP-9, revealed high binding energy of -5, 4.9 and -6.4 kcal/mol for TNF-α, IL-18 and MMP-9, respectively. Gene expression and the release of cytokines increased at an early stage of the wound repair. 1-Tetracosanol, at 2% gel showed 97.35 ± 2.06% wound closure at 21st day.

CONCLUSION

1-Tetracosanol is a good lead for drug development targeted towards wound healing activity and work in this direction is in progress.

Cedrus deodara: In Vivo Investigation of Burn Wound Healing Properties

Objective

Cedrus deodara (Roxb. Ex Lamb.) G. Don possesses various biological activities, which have been documented in modern and traditional medicine. In this study, burn wound healing activity of the methanol extract of C. deodara wood was evaluated via a burn wound model in Wistar rats.

Methods

The methanol extract of C. deodara was evaluated for the contents of phenolic compounds, flavonoids, and tannins. Also, its antioxidant activity was determined using the DPPH assay. Then, a topical ointment containing the methanol extract of C. deodara (10%) was used to evaluate the healing effects on a model of second-degree thermal burn in 4 groups of 7 rats within 21 days. In this respect, average wound surface area, wound closure, and various histological features were examined.

Results

Our findings revealed that the wounds treated with the methanol extract of C. deodara showed higher wound contraction (33.6, 87.1, and 93.4% on days 7, 14, and 21, respectively) compared with the positive control (27.6, 80.7, and 88.3% on days 7, 14, and 21, respectively) and the negative control (20.1, 77.9, and 80.2% on days 7, 14, and 21, respectively). According to the results from epitheliogenesis score, the number of inflammatory cells, neovascularization, and collagen density, good burn wound healing activity of the methanol extract of C. deodarawas demonstrated.

Conclusion

Using the methanol extract of C. deodara in an ointment formulation can be developed to prevent or reduce burn injury progression.

Effect of Hydrogel Containing Achyrocline satureioides (Asteraceae) Extract-Loaded Nanoemulsions on Wound Healing Activity

Achyrocline satureioides (Lam.) DC extract-loaded nanoemulsions have demonstrated potential for wound healing, with promising effects on keratinocyte proliferation. We carried out the first in vivo investigation of the wound healing activity of a hydrogel containing A. satureioides extract-loaded nanoemulsions. We prepared hydrogels by adding the gelling agent (Carbopol^® Ultrez) to extract-loaded nanoemulsions (~250 nm in diameter) obtained by spontaneous emulsification. The final flavonoid content in formulation was close to 1 mg/mL, as estimated by ultra-fast liquid chromatography. Permeation/retention studies using porcine ear skin showed that flavonoids reached deeper layers of pig ear skin when it was damaged (up to 3.2 µg/cm² in the dermis), but did not reach the Franz-type diffusion cell receptor fluid. For healing activity, we performed a dorsal wound model using Wistar rats, evaluating the lesion size, anti-inflammatory markers, oxidative damage, and histology. We found that extract-loaded formulations promoted wound healing by increasing angiogenesis by ~20%, reducing inflammation (tumor necrosis factor α) by ~35%, decreasing lipid damage, and improving the re-epithelialization process in lesions. In addition, there was an increase in the number of blood vessels and hair follicles for wounds treated with the formulation compared with the controls. Our findings indicate that the proposed formulation could be promising in the search for better quality healing and tissue reconstruction.

Schinus terebinthifolius Leaf Lectin (SteLL) Reduces the Bacterial and Inflammatory Burden of Wounds Infected by Staphylococcus aureus Promoting Skin Repair

Staphylococcus aureus is commonly found in wound infections where this pathogen impairs skin repair. The lectin isolated from leaves of Schinus terebinthifolius (named SteLL) has antimicrobial and antivirulence action against S. aureus. This study evaluated the effects of topical administration of SteLL on mice wounds infected by S. aureus. Seventy-two C57/BL6 mice (6−8 weeks old) were allocated into four groups: (i) uninfected wounds; (ii) infected wounds, (iii) infected wounds treated with 32 µg/mL SteLL solution; (iv) infected wounds treated with 64 µg/mL SteLL solution. The excisional wounds (64 mm2) were induced on the dorsum and infected by S. aureus 432170 (4.0 × 106 CFU/wound). The daily treatment started 1-day post-infection (dpi). The topical application of both SteLL concentrations significantly accelerated the healing of S. aureus-infected wounds until the 7th dpi, when compared to untreated infected lesions (reductions of 1.95−4.55-fold and 1.79−2.90-fold for SteLL at 32 µg/mL and 64 µg/mL, respectively). The SteLL-based treatment also amended the severity of wound infection and reduced the bacterial load (12-fold to 72-fold for 32 µg/mL, and 14-fold to 282-fold for 64 µg/mL). SteLL-treated wounds show higher collagen deposition and restoration of skin structure than other groups. The bacterial load and the levels of inflammatory markers (IL-6, MCP-1, TNF-α, and VEGF) were also reduced by both SteLL concentrations. These results corroborate the reported anti-infective properties of SteLL, making this lectin a lead candidate for developing alternative agents for the treatment of S. aureus-infected skin lesions.