Therapeutic application of natural inhibitors against snake venom phospholipase A(2).

Natural inhibitors occupy an important place in the potential to neutralize the toxic effects caused by snake venom proteins and enzymes. It has been well recognized for several years that animal sera, some of the plant and marine extracts are the most potent in neutralizing snake venom phospholipase A(2) (svPLA(2)). The implication of this review to update the latest research work which has been accomplished with svPLA(2) inhibitors from various natural sources like animal, marine organisms presents a compilation of research in this field over the past decade and revisiting the previous research report including those found in plants. In addition to that the bioactive compounds/inhibitor molecules from diverse sources like aristolochic alkaloid, flavonoids and neoflavonoids from plants, hydrocarbones -2, 4 dimethyl hexane, 2 methylnonane, and 2, 6 dimethyl heptane obtained from traditional medicinal plants Tragia involucrata (Euphorbiaceae) member of natural products involved for the inhibitory potential of phospholipase A(2) (PLA(2)) enzymes in vitro and also decrease both oedema induced by snake venom as well as human synovial fluid PLA(2). Besides marine natural products that inhibit PLA(2) are manoalide and its derivatives such as scalaradial and related compounds, pseudopterosins and vidalols, tetracylne from synthetic chemicals etc. There is an overview of the role of PLA(2) in inflammation that provides a rationale for seeking inhibitors of PLA(2) as anti-inflammatory agents. However, more studies should be considered to evaluate antivenom efficiency of sera and other agents against a variety of snake venoms found in various parts of the world. The implications of these new groups of svPLA(2) toxin inhibitors in the context of our current understanding of snake biology as well as in the development of new novel antivenoms therapeutics agents in the efficient treatment of snake envenomations are discussed.

Evaluation of antibacterial activity of proteins and peptides using a specific animal model for wound healing.

Wound healing is a complex process involving the integrated actions of numerous cell types, soluble mediators, and extracellular matrix (ECM). In this study, phospholipase A(2) (PLA(2)) purified from crotalid snake venom was found to express in vitro bactericidal activity against a group of clinical human pathogens. Based on the sequence homology of PLA(2), a series of peptides were derived from the C-terminal region of crotalid PLA(2). These short synthetic peptides were found to reproduce the bactericidal activity of its parent molecule. In vitro assays for bactericidal and cytolytic activities of these peptides showed very high microbicidal potency against Gram-negative and Gram-positive (Staphylococcus aureus) bacteria. Variants of the peptides showed reduced toxicity toward normal human cells, while retaining high bactericidal potency. Here we describe the protocol for evaluating the wound healing process by antibacterial peptides. We evaluated the biological roles of the candidate peptides in skin wound healing, using a specific BALB/c mice model. Peptide-treated animals showed accelerated healing of full-thickness skin wounds, with increased reepithelialization, collagen synthesis, and angiogenesis observed during the healing process. Healing wounds in protein/peptide-treated mice had higher densities of neutrophils, macrophages, and fibrocytes. Along with increased leukocyte infiltration, levels of macrophage-derived chemokine expression were also upregulated. These results demonstrate that the protein/peptide derived from snake venoms promotes healing of skin wounds. The primary mechanism seems to be an increase in leukocyte infiltration, leading to locally elevated synthesis and release of collagen and growth factors.

Venom neutralization by purified bioactive molecules: Synthetic peptide derivatives of the endogenous PLA(2) inhibitory protein PIP (a mini-review).

Envenomation due to snakebite constitutes a significant public health problem in tropical and subtropical countries. Antivenom therapy is still the mainstay of treatment for snake envenomation, and yet despite recent research focused on the prospects of using antivenom adjuncts to aid in serotherapy, no new products have emerged so far for therapeutic use. Various methodologies including molecular biology, crystallography, functional and morphological approaches, etc., are employed in the search for such inhibitors with a view to generate molecules that can stop partially or completely the activities of toxic phospholipase A(2) (PLA(2)) and snake venom metalloproteinase (SvMPs) enzymes at the molecular level. Herein, both natural and synthetic inhibitors derived from a variety of sources including medicinal plants, mammals, marine animals, fungi, bacteria, and from the venom and blood of snakes have been briefly reviewed. Attention has been focused on the snake serum-based phospholipase A(2) inhibitors (PLIs), particularly on the PLI derived from python snake serum (PIP), highlighting the potential of the natural product, PIP, or possible derivatives of it, as a complementary treatment to serotherapy against the inflammation and/or muscle-damaging activity of snake venoms. The data indicate a more efficient pathway for inhibition and blocking the activity of PLA(2)s and matrix metalloproteinases (MMPs), thus representing a feasible complementary treatment for snakebites. Such information may be helpful for interfering on the biological processes that these molecules are involved in human inflammatory-related diseases, and also for the development of new drugs for treatment of snake envenomation.

Therapeutic Potential of Plants as Anti-microbials for Drug Discovery.

The uses of traditional medicinal plants for primary health care have steadily increased worldwide in recent years. Scientists are in search of new phytochemicals that could be developed as useful anti-microbials for treatment of infectious diseases. Currently, out of 80% of pharmaceuticals derived from plants, very few are now being used as anti-microbials. Plants are rich in a wide variety of secondary metabolites that have found anti-microbial properties. This review highlights the current status of traditional medicine, its contribution to modern medicine, recent trends in the evaluation of anti-microbials with a special emphasis upon some tribal medicine, in vitro and in vivo experimental design for screening, and therapeutic efficacy in safety and human clinical trails for commercial outlet. Many of these commercially available compounds are crude preparations administered without performing human clinical trials. Recent methods are useful to standardize the extraction for scientific investigation of new phytochemicals and anti-microbials of traditionally used plants. It is concluded that once the local ethnomedical preparations of traditional sources are scientifically evaluated before dispensing they should replace existing drugs commonly used for the therapeutic treatment of infection. This method should be put into practice for future investigations in the field of ethnopharmacology, phytochemistry, ethnobotany and other biological fields for drug discovery.

Ethnobotanical survey of folk plants for the treatment of snakebites in Southern part of Tamilnadu, India.

Ethnobotanical surveys were conducted in four different indigenous groups in Southern parts of Tamilnadu, India, using a questionnaire. The herbal practitioners in the study area were interviewed, and information on medicinal plants was collected from the traditional healers called "Vaidyars". This survey covers 72 medicinal plants belonging to 53 families that are used for the treatment of snakebite in a traditional way. Traditional approach was evaluated scientifically with some selected plant extracts (7.2 mg/kg bw) and partially purified fractions (2.4 mg/kg bw) were orally administered to mice experimentally envenomed with rattlesnake venom s.c. injection (2.5-15 microg/kg bw). Tested fractions (Aristolochia indica, Hemidesmus indicus, Gloriosa superba, Strychnos nux-vomica, Eclipta prostrata, and Andrographis paniculata) showed potent neutralizing effect against the venom. Compared to the extracts, administration of purified fractions was more effective in increasing the body weight. Control mice injected with the venom alone showed weight loss and severe toxicity at 15 microg/kg bw. The purified fractions (2.4 mg/kg bw) produced significant protection against venom induced changes in serum SOD and LPx levels. The isolated fractions effectively inhibited the toxic effect of snake venoms in vitro than in vivo. The above observations confirmed the protective activity of plants-Aristolochia indica, Hemidesmus indicus, Gloriosa superba, Strychnos nux-vomica, Eclipta prostrata, and Andrographis paniculata against the lethal action of snake venom and need further investigation.

A compilation of bioactive compounds from Ayurveda.

This review deals with the key bioactive compounds and the role of medicinal plants in Ayurvedic systems of medicine in India and their earlier investigation. There has been an increase in demand for the Phytopharmaceutical products of Ayurveda in Western countries, because of the fact that the allopathic drugs have more side effects. Many pharmaceutical companies are now concentrating on manufacturing of Ayurvedic Phytopharmaceutical products. Ayurveda is the Indian traditional system of medicine, which also deals about pharmaceutical science. Different type of plant parts used for the Ayurvedic formulation; overall out line of those herbal scenario and its future prospects for the scientific evaluation of medicinal plants used by traditional healers are also discussed. In India most of them, where Ayurvedic treatment is frequently used, for their ailments and provides instructions to local people how to prepare medicine from the herbs. As much as possible importance is also given for the taxonomic literature.

Purification of antibacterial agents from Tragia involucrata--a popular tribal medicine for wound healing.

Tragia involucrata has been widely used in traditional systems of medicine for a variety of diseases. In the present study, in vitro antibacterial properties of nine different compounds including vinyl hexylether, shellsol, 2,4-dimethyl hexane, 2-methylnonane and 2,6-dimethyl heptane were isolated from the leaf of Tragia involucrata studied against Escherichia coli, Proteus vulgaris and Staphylococcus aureus using the disc-diffusion method at 50 microg/ml concentrations. The compound vinyl hexylether showed a broad spectrum of activity. The highest activity was found in shellsol (50 microg/ml) against Proteusvulgaris and Staphylococcus aureus. Minimum inhibitory concentrations were determined for the effective compounds (MICs 2.5-40 microg/ml), shellsol and vinyl hexylether showed inhibitory action at the lowest dilution (10 microg/ml) than 2-methylnanone. Shellsol inhibited the growth of Staphylococcus aureus very effectively than the other compounds. These compounds showed bactericidal effects against all the tested bacteria (MBC, 12.25 microg/ml). However, the compound shellsol showed effective killing of wound causing bacteria (Staphylococcus aureus). So, the study was focused on the constituent to evaluate wound healing in rat model. Rats that received 50 microg/kg, b.w. of shellsol showed complete healing after 24 days. Histological examination revealed an increase in the fibroblast, neovascularization, granulation and thickness of scar tissue after the treatment of shellsol as compared to control. The topical application of shellsol did not cause any toxic response on rat skin. Thus, the antibacterial properties of the constituents give some scientific basis to its usage in traditional medicine.

Effect of aqueous extract of Tragia involucrata Linn. on acute and subacute inflammation.

Antiinflammatory activity of aqueous extract of Tragia involucrata was tested on carrageenan-induced hind paw oedema and cotton pellet granuloma models in albino rats. In the subacute model, cotton pellet granuloma was produced by implantation of 10 mg sterile cotton in the axilla under ether anaesthesia. The animals were administered an aqueous extract at various concentrations of 50, 100, 200, 300 and 400 mg/kg. Phenyl butazone (80 mg/kg) was used as a standard drug. The paw diameter was measured at different time intervals and the dry granuloma weight was taken after the treatment. The aqueous leaf extract (400 mg/kg) showed the maximum inhibition (84.23%) of oedema at the end of 3 h following carrageenin-induced rat paw oedema. In subacute inflammation, the extract showed 76.25% reduction in granuloma weight. The results prove that the aqueous leaf extract showed highest antiinflammatory activity in acute and subacute inflammation and also support the usage of traditional claims.