There are many plants in Kashmir valley which have been shown to possess medicinal properties. Among them is Euphorbia helioscopia which is known for its medicinal values. At present drug resistance is a worldwide problem and much emphasis is being laid on the natural plant sources to act as antibiotics which can overcome this problem. Euphorbia helioscopia which is known for its medicinal values has febrifuge and vermifuge activities in its roots and stem respectively. The root is anti helminthic. The milky sap is applied externally to skin eruptions. The seeds, mixed with roasted pepper, have been used in the treatment of cholera and the oil from the seeds has purgative properties. However, isolation of any antibacterial protein has not been reported till date. The essence of the work was to check the antibacterial activity of the plant following its purification and characterization from leaves using conventional protein purification techniques. The lectin is a homodimer (Mr 65000Da), thermostable between 0 C- 40 C but exhibits a narrow range of pH stability being optimally active at pH 7. The lectin shows antimicrobial activity against P. aeruginosa, K.pneumoniae and E. coli.

Lectins are carbohydrate-binding proteins of non-immune origin that agglutinate cells or precipitate glycoconjugates.Based on evolutionary and structural relatedness, seven lectin families have been distinguished, of which legume lectins are the best characterized. Lectins typically constitute a large fraction of the total protein in most leguminous seeds and plant storage tissues where they play an important role in several defense mechanisms. A lectin from the seeds of Indigofera heterantha, member of family leguminosae was isolated, purified, partially characterized and its antimicrobial activity evaluated. The lectin is a homotetramer with a molecular weight of about 70 KDa. The lectin shows a reasonable temperature stability and is stable in the pH range of 2-9. It demonstrates a remarkable antibacterial activity against E.coli, K.pneumonia, S.aureus, and B.subtilis and also inhibits the growth of phytopathogens Aspergillis niger, Aspergillis oryzie and Fusarium oxysporum. These results point out that future findings on applications of lectins isolated from leguminous plants can be of great importance for clinical microbiology and possible therapeutic applications.

Lectins are sugar-binding proteins that are highly specific for their sugar moieties. They play a role in biological recognition phenomena involving cells and proteins. For example, some viruses use lectins to attach themselves to the cells of the host organism during infection. Lectins may be disabled by specific mono- and oligosaccharides, which bind to them and prevent their attachment to cell membranes.Lectins serve many different biological functions in animals, from the regulation of cell adhesion to glycoprotein synthesis and the control of protein levels in the blood. They may also bind soluble extracellular and intercellular glycoproteins.The large concentration of lectins in plant seeds decreases with growth, and suggests a role in plant germination and perhaps in the seed's survival itself.Since lectins specifically recognize cell surface sugars, they have the potential of being used as antimicrobials as well as anticancer agents.Foods with high concentrations of lectins, may be harmful if consumed in excess in uncooked or improperly cooked form. Adverse effects may include nutritional deficiencies, and immune (allergic) reactions due to gastrointestinal distress.

Medicinal plants are being used in traditional treatments to cure variety of diseases from thousands of years. Screening of antimicrobial and antioxidant activities performed on Elsholtzia densa crude extracts which is traditionally used as herb shows that they are endowed with potentially utilizable antimicrobial and free radical scavenging activity. Accordingly, this implies the inhibition of microbial pathogenesis and cellular oxidation that is linked to pathological incidents such as heart disease, aging and cancer. It was seen that the ethylacetate extract showed the maximum inhibitory effects against both bacterial and fungal growth. This may be due to the presence of such ingredients in the said extracts like flavonoids, terpenes, tannins, polyphenolic compounds, alkaloids, etc. The crude extracts of the plant possess radical scavenging activity as estimated by in vitro antioxidant assays like DNA damage assay, lipid peroxidation assay, DPPH assay, FTC assay, etc. Hence, Elsholtzia densa extracts could be used as an easy accessible source of natural antioxidants and antimicrobial agent.

Lectins are proteins or glycoproteins of non immune origin which have a wide distribution in animals, plants, and microorganisms. Their medicinal role extends from simple antimicrobial action to anti- tumour properties.In view of the advancement in understanding the potential medicinal role of the plant lectins, a lectin from the leaves of Prunella vulgaris was isolated, purified, partially characterized and its antimicrobial activity evaluated. The lectin is specific for galactose and N-acetyl-galactosamine The molecular weight of the lectin as determined by SDS-PAGE was 32500 Da and that estimated from Sephadex G-100 gel filtration column was 65000 Da indicating that the purified lectin is a homodimer. The purified lectin also shows a significant antimicrobial activity against the infectious agents of some common diseases such as Salmonella typhi, Klebseilla pnuemonea and Escherhia coli.

Plant lectins are a heterogeneous group of proteins or glycoproteins that share in common their ability to recognize and bind specific sugar residues. At present hundreds of plant lectins have been isolated and characterized with respect to their molecular structures and carbohydrate-binding specificities. Since the unique biological properties of lectins can be exploited in the investigation of numerous biochemical and cellular phenomena, intense efforts are being made in many labs to isolate lectins with unique and unusual sugar-binding specificities. The study deals with the purification and partial characterization of a lectin from Crotalaria pallida belonging to Leguminoseae. Conformational changes and changes in biological properties by chemical modification of the lectin are also a part of the study. The lectin is a monomeric galactose and blood group A specific glycoprotein with about 4% carbohydrate and a molecular weight of 43 kDa. The activity yield of the lectin was about 4.6% with nearly three fold purification. Conformational changes were investigated by gel filtration, viscometery and UV absorption spectroscopy.