Introduction Infectious diseases remain one of the leading causes of death due to antibiotic resistant microorganisms. The frequency of resistance in microbial pathogens continues to grow at an alarming rate throughout the world (Schmitz et al., 1999). Decreased efficacy and resistance of pathogens to antibiotics has necessitated development of new alternatives (Ravikumar et al., 2010). To overcome these problems, the development of effective newer drugs without any side effects is an urgent need. In general, marine plants such as mangroves, seaweeds, sea grasses and marines sponges are extensively studied for antiviral, antiplasmodial, antibacterial, antifungal, hepatoprotective, anti-ulcer properties (Ravikumar et al., 2009&2011). Medicinal plant is plant containing substance which can be used for the medication or become precursor of drug synthesis (Sofowora, 1982). Medicinal plant has been source of human health since ancient time, whereas about 60-75% of world populations require plant for carrying health (Farnsworth, 1994; Joy et al., 1998 and Harvey, 2000). Plants and microbes are the main source of natural products (Hayashi et al., 1997; Armaka et al., 1999; Lin et al., 1999a &b and Basso et al., 2005), and consistently become main source of the newest drugs (Harvey, 2000). The drug development from natural sources are based on the bioassay-guided isolation of natural products, due to the traditional uses of local plants (ethnobotanical and ethanopharmacological applications) (Atta-ur-Rahman and Choudhary, 1999). Seagrasses are submerged marine angiosperms growing abundantly in tidal and sub tidal areas of all seas except in the Polar Regions. Sea grass biomass is used as human food especially by coastal populations (Hemminga and Duarte, 2000). In folk medicine, seagrasses have been used for a variety of remedial purposes, like, fever, skin diseases, muscle pains, wounds and stomach problems etc. (de la Torre-Castro and Rönnbäck, 2004). In India, seagrasses were used as medicine (treatment of heart conditions, seasickness), food (nutritious seeds), fertilizer (nutrient rich biomass) and livestock feed (goats and sheep) (Newmaster et al., 2011). Seeds of Enhalus acoroides are thought to have aphrodisiac and contraceptive properties (Aliño et al., 1990). (12) Numerous seagrasses have been shown to have antibacterial activities. Halophila stipulacea,Cymodocea serrulata and Halodule pinifolia (Kannan et al., 2010a), Enhalus acoroides (Qi et al., 2008) and Enhalus acoroides, Thalassiahemprichii, Halodule pinifolia, Syringodium isoetifolium, and Cymodocea rotundata have been reported to exhibit antibacterial activity (Kannan et al., 2013). Moreover, preliminary data suggest that seagrasesses could represent an interesting source of antilarvacidal (Ali et al., 2013) and antioxidant (Ramah et al., 2014) Discussion In recent years, development of multidrug resistance in the pathogenic bacteria and parasites has created major clinical problem.

1. Introduction
Infectious diseases remain one of the leading causes of death
due to antibiotic resistant microorganisms. The frequency of
resistance in microbial pathogens continues to grow at an
alarming rate throughout the world (Schmitz et al., 1999).
Decreased efficacy and resistance of pathogens to antibiotics
has necessitated development of new alternatives (Ravikumar et
al., 2010). To overcome these problems, the development of
effective newer drugs without any side effects is an urgent need.
In general, marine plants such as mangroves, seaweeds, sea
grasses and marines sponges are extensively studied for
antiviral, antiplasmodial, antibacterial, antifungal,
hepatoprotective, anti-ulcer properties (Ravikumar et al.,
2009&2011).
Medicinal plant is plant containing substance which can be used
for the medication or become precursor of drug synthesis
(Sofowora, 1982). Medicinal plant has been source of human
health since ancient time, whereas about 60-75% of world
populations require plant for carrying health (Farnsworth, 1994;
Joy et al., 1998 and Harvey, 2000). Plants and microbes are the
main source of natural products (Hayashi et al., 1997; Armaka
et al., 1999; Lin et al., 1999a &b and Basso et al., 2005), and
consistently become main source of the newest drugs (Harvey,
2000). The drug development from natural sources are based on
the bioassay-guided isolation of natural products, due to the
traditional uses of local plants (ethnobotanical and
ethanopharmacological applications) (Atta-ur-Rahman and
Choudhary, 1999).
Seagrasses are submerged marine angiosperms growing
abundantly in tidal and sub tidal areas of all seas except in the
Polar Regions. Sea grass biomass is used as human food
especially by coastal populations (Hemminga and Duarte,
2000). In folk medicine, seagrasses have been used for a variety
of remedial purposes, like, fever, skin diseases, muscle pains,

2. wounds and stomach problems etc. (de la Torre-Castro and
Rönnbäck, 2004). In India, seagrasses were used as medicine
(treatment of heart conditions, seasickness), food (nutritious
seeds), fertilizer (nutrient rich biomass) and livestock feed
(goats and sheep) (Newmaster et al., 2011). Seeds of Enhalus
acoroides are thought to have aphrodisiac and contraceptive
properties (Aliño et al., 1990). (12)
Numerous seagrasses have been shown to have antibacterial
activities. Halophila stipulacea,Cymodocea serrulata and
Halodule pinifolia (Kannan et al., 2010a), Enhalus acoroides
(Qi et al., 2008) and Enhalus acoroides, Thalassiahemprichii,
Halodule pinifolia, Syringodium isoetifolium, and Cymodocea
rotundata have been reported to exhibit antibacterial activity
(Kannan et al., 2013). Moreover, preliminary data suggest that
seagrasesses could represent an interesting source of
antilarvacidal (Ali et al., 2013) and antioxidant (Ramah et al.,
2014)
Discussion
In recent years, development of multidrug resistance in the
pathogenic bacteria and parasites has created major clinical
problems in the treatment of infectious diseases (Ravikumar et
al., 2010a). There have been a number of reports that
demonstrating the antimicrobial activity of seaweeds,
mangroves and other marine forms and only limited information
were available from the seagrasses of the corners of the world
and even very mere information available from India. The aim
of this study is to evaluate and compare the ability of seagrass
extracts to produce bioactive compounds of potential
therapeutic interest. Antimicrobial activities found in seagrass
was considered to be an indication of synthesis of bioactive
secondary metabolites (Kannan et al., 2010a).
The antibacterial activity of five different leaves extracts of H.
uninervis against seven bacterial pathogens strains were
effective. Among them, ethanol extract was the more effective
against P. aeruginosa than other extracts, this showed that
ethanol is suitable for extracting active compounds from

3. seagrass. This investigation were supported the earlier reports
thus, the methanolic extract of Enhalus acoroides were effective
against P. aeruginosa, K. pneumoniaeand S. aureus than hexane
extract (Alam et al., 1994). The ethanolic extract in this study
showed the best activity against pathogenic bacteria and this
present findings is consistent with some earlier reports
(Umamaheshwari et al., 2009) and it showed that ethanol and
methanol extractions of the seagrasses Halophila ovalis and
Halodule pinafolia showed better zone of inhibition against
bacterial pathogens that other tested extracts.
In our present finding Gram-negative bacteria was more
sensitive than Gram-positive bacteria. This results in agreement
with the finding that the antifouling of some marine organisms
against Bacillus and Pseudomonas sp. was reported (Bhosale et
al., 2002), regarding the acetone extract our results coincide
with the report of acetone extract of Halophila ovalis and
Zostera capensis which showed less activity compared to the
other solvents (Sreenath Kumar et al., 2008). The variation of
antibacterial activity of the extracts might be due to distribution
of antimicrobial substances, which varied from species to
species (Lustigman and Brown, 1991).
The difference further observed in the antimicrobial effect of
the sea grass extracts studied against both gram positive and
gram negative bacteria in the present studymay be due to
differences in permeability barriers. In gram negative species
outer membrane is fairly effect barrier for the extract and also
active compounds persist in the sea grass (Ravikumar et al.,
2009). The more susceptibility of gram positive bacteria to the
sea grass extract was due to the differences in their cell wall
structure and their composition (Tortora et al., 2001). In gram
negative bacteria the outer membrane act as barrier to many
environmental substances including antibiotics (Kandhasamy
and Arunachalam, 2008).
The ethyl acetate extract of H. uninervis had lowest activity and
this can be correlated with the results of (Sreenath Kumar et al.,
2008) who reported that the ethyl acetate extracts of H. ovalis

4. was active against the tested pathogens namely Staphylococcus
aureus, Bacillus cereus, Bacillus subtilis, Salmonella
typhimurium and Micrococcus luteus.
The results indicated that the aqueous extracts have lightly
activity only against P. aeruginosa than other tested bacterial
pathogens. This results in agreement with the finding that the
water extract showed no activity against any of the tested
organisms. Aqueous and ethanol extract of Heracleum
Sphondylium showed antimicrobial activities against Gram-
positive and Gram-negative bacteria, (Ergene et al., 2006).
Also because of the reported study of phytochemical analysis of
Hexane, Chloroform, Ethyl acetate, Ethanol and Aqueous
extracts of three glycosides have saponins, and tannins. Sugars
and quinine were absent in all the three seagrasses (Cymodocea
serrulata, Halophila ovalis and Halodule pinifolia) (Sangeetha
and Asokan, 2016). The earlier reports like Ergene et al., 2006
who revealed the presence of tannins, saponins, proteins, resins,
reducing sugar, acidic compounds, alkaloids, cardiac glycosides
and terpenoids in the phytochemical analysis of C. rotundata.
The phytochemical compounds viz., glycoside, saponins,
tannins, flavonoids, terpenoides and alkaloids have
antimicrobial activity (Okeke et al., 2001).
2