Antimicrobial and Phytochemical Investigation of the Leaves of Carica papaya L . , Cynodon dactylon ( L . ) Pers . , Euphorbia hirta L . , Melia azedarach L . and Psidium guajava

Carica papaya L. , Cynodon dactylon (L.) Pers, Euphorbia hirta L. , Melia azedarach L. , Psidium guajava L. belong to 5 different families, viz., Caricaceae, Gramineae (Poaceae), Euphorbiaceae, Meliaceae and Myrtaceae. The plant leaves contain a number of medicinally important compounds. In the present study, we evaluated the phytochemical analysis for the quantity of amino acids, a amylase, ßamylase, carbohydrate, glutamine, protein, proline, phenolic compounds and the presence of various secondary metabolites such as alkaloids, anthroquinone, catachol, flavonoids, phenols, saponins, steriods, triterpenoids, tannins. The antibacterial activity of the leaf extracts of Carica papaya, Cynodon dactylon, Euphorbia hirta, Melia azedarach and Psidium guajava against pathogenic bacteria like gram positive (Bacillus subtilis, Pseudomonas aeruginosa and Staphylococcus aureus) and gram negative (Escherichia coli and Klebsiella pneumoniae) bacteria by invitro agar well diffusion method. The plants aqueous leaf extracts showed pronounced inhibition than chloroform leaf extracts. Leaf extracts showed more inhibitory action on Bacillus subtilis, Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli and Klebsiella pneumoniae. Introduction In recent years, the growing demand for herbal product has led to a quantum jump in volume of plant materials traded within and across the countries. In recent years, Secondary plant metabolites (Phytochemicals), previously with unknown pharmacological activities, has been extensively investigated as a source of medicinal agents (Krishnaraju et al., 2005). Thus it is anticipated that phytochemicals with adequate antibacterial efficacy will be used for the treatment of the bacterial infections (Balandrin et al., 1985). Such a fact is cause for concern, because of the number of patients in hospitals who have suppressed immunity, and due to new bacterial strains, which are multi-resistant. Consequently, new infections can occur in hospitals resulting in high mortality. Nature has been a source of medicinal agents since times immemorial. The importance of herbs in the management of human ailments cannot be over emphasized. It is clear that the plant kingdom harbors an inexhaustible source of active ingredients invaluable in the management of many intractable diseases. Furthermore, the active components of herbal remedies have the advantage of being combined with many other substances that appear to be inactive. However, these complementary components give the plant as a whole a safety and efficiency much superior to that of its isolated and pure active components (Shariff, 2001). The screening of plant extracts and plant products for antimicrobial activity has shown that higher plants represent a potential source of novel antibiotic prototypes (Afolayan, 2003). DESCRIPTION OF PLANTS USED IN THE PRESENT STUDY Botanical Name : Carica papaya L. Family : Caricaceae Description : Erect, fast growing, usually unbranched tree or shrub, 7-8 m tall, with copious latex, trunk about 20 cm in diameter. Distribution : Throughout Asia, Papaya has been carried throughout the tropics. Parts used Leaves, fruit, root, seed, latex. Uses : Cancer, tumors, corns, nervous pains, piles and yaws. elephantoid growths. Botancial Name : Cynodon dactylon (L.) Pers Family : Gramineae (Poaceae) Description : Perennial grass, very variable, with long rapid – growing, creeping runner or stolons. Distribution : Throughout Asia. Parts used : Aerial parts. Uses : antiseptic, aperient, astringent, cyanogenetic, demulcent, depurative. Botanical Name : Euphorbia hirta L. Family : Euphorbiaceae Description : Small, annual herb, that grows 30-40 cm in hight, the stem is slender and often reddish in colour. Distribution : It is widely distributed in all over the world. Parts used : Aerial parts. Uses : Anodyne, Antiasthmatic, antipruritic, carminative, depurative. Botanical Name : Melia azedarach L. Family : Meliaceae Description : Deciduous tree, leaves alternate, 2-pinnately divided with toothed. Distribution : Throughout Asia. Parts used : Leaves, bark, fruit, seed. Uses : To cure stomach irritation, vomiting, bloody diarrhoea. Botanical Name : Psidium guajava L. Family : Myrtaceae Description : Evergreen shrub or small tree to 9m tall, with scaly greenish – brown bark and young branches 4-angled. Distribution : Throughout Asia. Parts used : the whole guava plant is used. Uses : To cure diarrhoea, dysentery, stomach upsets and regulate menstrual periods. MATERIAL AND METHODS Preparation of leaf extracts Apparently healthy plant leaves were collected, washed thoroughly in tap water and dried in room temperature for 15 days. The dried 20 g leaves were powdered and soaked separately in 100 ml water and chloroform by keeping it in a shaker for 3 days. The extracts were filtered through cheesecloth and the extracts were reduced to 10% of its original volume. The organic solvent filtrates were concentrated in vacuum using a rotary evaporator, while aqueous extract was dried using water bath. Phytochemical Screening of Leaf Extracts The phytochemical components of the Carica papaya, Cynodon dactylon, Euphorbia hirta, Melia azedarach and Psidium guajava leaves were screened by using the methods of Brindha et al., (1977). The components quantitatevely analysed were amino acids, aamylase, ßamylase, carbohydrate, glutamine, protein, proline and phenolic compounds. The components qualitatively analysed were alkaloids, anthroquinone, catachol, flavonoids, phenols, saponins, steriods, triterpenoids and tannins.