Lonchin Suguna

Curcumin improves wound healing by modulating collagen and decreasing reactive oxygen species

Wound healing consists of an orderly progression of events that re-establish the integrity of the damaged tissue. Several natural products have been shown to accelerate the healing process. The present investigation was undertaken to determine the role of curcumin on changes in collagen characteristics and antioxidant property during cutaneous wound healing in rats. Full-thickness excision wounds were made on the back of rat and curcumin was administered topically. The wound tissues removed on 4th, 8th and 12th day (post-wound) were used to analyse biochemical and pathological changes. Curcumin increased cellular proliferation and collagen synthesis at the wound site, as evidenced by increase in DNA, total protein and type III collagen content of wound tissues. Curcumin treated wounds were found to heal much faster as indicated by improved rates of epithelialisation, wound contraction and increased tensile strength which were also confirmed by histopathological examinations. Curcumin treatment was shown to decrease the levels of lipid peroxides (LPs), while the levels of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), activities were significantly increased exhibiting the antioxidant properties of curcumin in accelerating wound healing. Better maturation and cross linking of collagen were observed in the curcumin treated rats, by increased stability of acid-soluble collagen, aldehyde content, shrinkage temperature and tensile strength. The results clearly substantiate the beneficial effects of the topical application of curcumin in the acceleration of wound healing and its antioxidant effect.

Spontaneous ultra fast synthesis of gold nanoparticles using Punica granatum for cancer targeted drug delivery

Rapid synthesis of mono-dispersed gold nanoparticles through economically feasible green chemistry approach is highly desirable. In this study, we have developed a method to synthesize mono-dispersed gold nanoparticles (PAuNPs) by mixing gold solution with fruit peel extract of Punica granutum without using any surfactant or external energy. In this method, physiologically stable, biocompatible PAuNPs were formed within 60s. Casein, being a biocompatible polymer, is used to couple the prepared PAuNPs for functionalization of folic acid, which is highly expressed in cancer cells. These functionalized PAuNPs could be used for targeted drug delivery for cancer with enhanced therapeutic efficacy and minimal side effects. PAuNPs were characterized by UV, IR, TEM, Particle size analyzer and zeta potential measurement. In vitro stability of the PAuNPs was also analyzed. Hemocompatibility of PAuNPs was evaluated in human blood samples and found that the particles were hemocompatible. The toxicity of the PAuNPs, 5-Fu and 5Fu@PAuNPs was analyzed in zebrafish embryos. The in vitro cytotoxicity of free 5-Fu, 5Fu@PAuNPs-Fa was investigated against MCF-7 cells (breast cancer) and observed that the amount of 5-Fu required to achieve 50% of growth of inhibition (Ic50) was much lower when compared to free 5-Fu.

The effect of nerve growth factor on the early responses during the process of wound healing.

In this study, we investigated the role of nerve growth factor (NGF)-incorporated collagen on wound healing in rats. Full-thickness excision wounds were made on the back of female rats weighing about 150-160 g. Topical application of NGF-incorporated collagen, at a concentration of 1 microg/1.2 mg collagen/cm(2), once a day, for 10 days resulted in complete healing of wounds on the 15th day. The concentrations of collagen, hexosamine and uronic acid in the granulation tissue were determined. The NGF-incorporated collagen-treated rats required shorter duration for the healing with an increased rate of wound contraction. Histological and electron microscopical evaluations were also performed, which reveal the activation of fibroblasts and endoplasmic reticulum and therefore increased level of collagen synthesis due to NGF application. These results clearly indicate that the topical application of NGF-incorporated collagen enhanced the rate of healing of excision wounds.

Emblica officinalis exerts wound healing action through up-regulation of collagen and extracellular signal-regulated kinases (ERK1/2).

During wound healing, the wound site is rich in oxidants, such as hydrogen peroxide, mostly contributed by neutrophils and macrophages. Ascorbic acid and tannins of low molecular weight, namely emblicanin A (2,3‐di‐O‐galloyl‐4,6‐(S)‐hexahydroxydiphenoyl‐2‐keto‐glucono‐δ‐lactone) and emblicanin B (2,3,4,6‐bis‐(S)‐hexahydroxydiphenoyl‐2‐keto‐glucono‐δ‐lactone) present in Emblica officinalis (emblica), have been shown to exhibit a very strong antioxidant action. We proposed that addition of these antioxidants to the wound microenvironment would support the repair process. The present investigation was undertaken to determine the efficacy of emblica on dermal wound healing in vivo. Full‐thickness excision wounds were made on the back of the rat and topical application of emblica accelerated wound contraction and closure. Emblica increased cellular proliferation and cross‐linking of collagen at the wound site, as evidenced by an increase in the activity of extracellular signal‐regulated kinase 1/2, along with an increase in DNA, type III collagen, acid‐soluble collagen, aldehyde content, shrinkage temperature and tensile strength. Higher levels of tissue ascorbic acid, α‐tocopherol, reduced glutathione, superoxide dismutase, catalase, and glutathione peroxidase support the fact that emblica application promotes antioxidant activity at the wound site. In summary, this study provides firm evidence to support that topical application of emblica represents a feasible and productive approach to support dermal wound healing.

Green synthesis of pullulan stabilized gold nanoparticles for cancer targeted drug delivery

The aim of this study was to synthesize green chemistry based gold nanoparticles using liver specific biopolymer and to develop a liver cancer targeted drug delivery system with enhanced efficacy and minimal side effects. Pullulan stabilized gold nanoparticles (PAuNPs) were coupled with 5-Fluorouracil (5-Fu) and folic acid (Fa) which could be used as a tool for targeted drug delivery and imaging of cancer. The toxicity of 5-Fu, 5-Fu adsorbed gold nanoparticles (5-Fu@AuNPs), Fa-coupled 5-Fu adsorbed gold nanoparticles (5-Fu@AuNPs-Fa), was studied using zebrafish embryo as an in vivo model. The in vitro cytotoxicity of free 5-Fu, 5-Fu@AuNPs, 5-Fu@AuNPs-Fa against HepG2 cells was studied and found that the amount of 5-Fu required to achieve 50% of growth of inhibition (Ic50) was much lower in 5-Fu@AuNP-Fa than in free 5-Fu, 5-Fu@AuNPs. The in vivo biodistribution of PAuNPs showed that higher amount of gold had been accumulated in liver (54.42±5.96 μg) than in other organs.

Topical application of Acalypha indica accelerates rat cutaneous wound healing by up-regulating the expression of Type I and III collagen

ETHNOPHARMACOLOGICAL RELEVANCE Acalypha indica Linn. (Acalypha indica) vernacularly called Kuppaimeni in Tamil, has been used as a folklore medicine since ages for the treatment of wounds by tribal people of Tamil Nadu, Southern India. The present study investigates the biochemical and molecular rationale behind the healing potential of Acalypha indica on dermal wounds in rats. MATERIAL AND METHODS Acalypha indica extract (40 mg/kg body weight) was applied topically once a day on full-thickness excision wounds created on rats. The wound tissue was removed and used for estimation of various biochemical and biophysical analyses and to observe histopathological changes with and with-out extract treatment. The serum levels of pro-inflammatory cytokine tumor necrosis factor (TNF-α) was measured at 12 h, 24 h, 48 h and 72 h post-wounding using ELISA. Reverse transcription-polymerase chain reaction (RT-PCR) analysis was performed to study the expression pattern of transforming growth factor [TGF-β1], collagen 1 α (I) [Col 1 α (I)] and collagen 3 α (I) [Col 3 α (I)]. Likewise, linear incision wounds were created and treated with the extract and used for tensile strength measurements. RESULTS Wound healing in control rats was characterized by less inflammatory cell infiltration, lack of granulation tissue formation, deficit of collagen and significant decrease in biomechanical strength of wounds. Acalypha indica treatment mitigated the oxidative stress and decreased lipid peroxidation with concomitant increase in ascorbic acid levels. It also improved cellular proliferation, increased TNF-α levels during early stages of wound healing, up-regulated TGF-β1 and elevated collagen synthesis by markedly increasing the expression of Col 1 α (I) and Col 3 α (I). Increased rates of wound contraction, epithelialization, enhanced shrinkage temperature and high tensile strength were observed in the extract treated rats. CONCLUSION Acalypha indica extract was shown to augment the process of dermal wound healing by its ability to increase collagen synthesis through up-regulation of key players in different phases of wound healing and by its antioxidative potential.

Efficacy of Annona squamosa on wound healing in streptozotocin-induced diabetic rats

Annona squamosa L. (Annonaceae), commonly known as custard apple, mainly used for its edible fruit, is also recognised with numerous medicinal properties. As there is no report on the efficacy of this plant for wound healing, we examined the efficacy of ethanolic extract of A. squamosa leaves on wound repair in streptozotocin–nicotinamide‐induced diabetic rats. Open excision wounds were made on the back of rats. The drug at a dosage of 100 mg/kg body wt was reconstituted in 200 µl of phosphate buffered saline and applied topically once daily for the treated wounds. The control wounds were left untreated. Wound tissues formed on days 4, 8, 12 and 16 (post‐wound) were used to estimate DNA, total protein, total collagen, hexosamine and uronic acid. Levels of lipid peroxides were also evaluated along with tensile strength and period of epithelialisation. A. squamosa L. increased cellular proliferation and collagen synthesis at the wound site as evidenced by increase in DNA, protein and total collagen. The treated wounds were observed to heal much faster as proved by enhanced rates of epithelialisation and wound contraction, which was also confirmed by histopathological examinations. The results strongly substantiate the beneficial effects of the topical application of A. squamosa L. in the acceleration of normal and diabetic wound healing.

Molecular species of collagen in the intramuscular connective tissues of the marine crab, Scylla serrata

Type V like collagens are widely distributed in marine invertebrates, particularly crustaceans and molluscs. We have been investigating the nature of collagens in the muscular tissues of crustaceans. The presence of type V like homotrimeric collagen in prawn muscle was noted before. We report here a comparative analysis of collagens purified from the pepsin digest of abdominal and pereiopod muscle tissues of the crab, Scylla serrata. The major collagen in either muscle precipitated at 1.2 M NaCl at acid pH, suggestive of a type V like property. The homotrimeric collagen was then purified to near homogeneity by precipitation with 20% ammonium sulphate. Solubility characteristics and biochemical studies indicated the leg muscle collagens to be highly crosslinked and stabilised by more bound carbohydrates, as compared to the abdominal muscle collagen. Analysis of amino acid composition revealed a close similarity to known type V collagens and the leg muscle collagen was characterised by more lysine hydroxylation and slightly reduced glycine content. The leg muscle collagen had a higher denaturation temperature and intrinsic viscosity than the abdominal muscle collagen. Our results confirm the similarity of major crustacean muscle collagens to vertebrate type V collagen. Further, the relative complexity of leg muscle collagen, unlike the abdominal muscle collagen, correlates to the specific functional requirements, where the former is involved in locomotion and preying and the latter in normal growth and development.

Wound healing activity of a collagen-derived cryptic peptide

Wound healing involves a well-controlled series of interactions among cells and several mediators leading to the restoration of damaged tissue. Degradation of the extracellular matrix (ECM) protein collagen during remodelling of wound tissue leads to the release of bioactive peptides that can possibly influence the healing process. The RGD-containing, antioxidative collagen peptide E1 isolated in an earlier work was screened in this study for its ability to influence multiple steps of the wound healing process. E1 was assayed for and found to be chemotactic. Excision and incision wounds were created on separate groups of rats and E1 was administered topically. The wound tissues were isolated on the 4th and 8th days post-wound and subjected to biochemical and biophysical analysis. A significant decrease in lipid peroxides in the treatment group confirmed the in vivo antioxidant capacity of E1. The treatment group also displayed significant increase in total protein, collagen and amino sugar synthesis indicating faster ECM formation. The significantly increased rate of wound contraction and reepithelialisation along with higher tensile strength of the wound tissue corroborated the results of biochemical analysis. The results confirm the significant role played by collagen peptides in accelerating the healing process and justify their possible use as a pharmaceutical agent.

Modulatory effect of Coccinia indica on aortic collagen in streptozotocin‐induced diabetic rats

1. The effects of Coccinia indica, an indigenous plant used in Ayurvedic medicine in India, on aortic collagen content and its characteristics were assessed in streptozotocin (STZ) diabetic rats.