1 Introduction
Emergence of multi-drug resistance among various microbial pathogens has been a cause of serious concern to the medical world limiting the choice of antibiotics. Considering the fact that it may take decades to synthesize a viable antimicrobial drug, today we are searching for alternatives to antimicrobial agents (Kandi V, 2015). Emergence and spread of microbes resistant to multiple antibiotics (super-bugs) due to various resistance mechanisms should be considered as a cause of deep concern. Methicillin-resistant Staphylococcus aureus (MRSA), Vancomycin- resistant Enterococci, Staphylococcus spp and Streptococcus spp, bacteria possessing New Delhi metallo-betalactamase (NDM) genes coding for resistance, carbapenem resistance in many bacteria colonizing intestinal tract and those existing in the environment (Pseudomonas spp and Acinetobacter spp) are some of the bacteria which cause infections that are hard to treat (Kalaskar and Venkataramana, 2012; Ramana et al., 2008; Ramana et al., 2009; Ramana et al., 2013; Ramana et al., 2013a; Sharada et al., 2014). Aerva lanata is a medicinal plant belonging to the family Amaranthaceae, which grows all along the plains of India. Aerva lanata is a perennial herbaceous weed growing up to 2 meters (30 cm to 2 m) tall which is present trough the warmer geographical plains of India including the states of Telangana, Andhrapradesh, Tamilnadu and Karnataka. Other countries where this plant grows include srilanka, Arabian regions, Egypt, African regions, Java and Philippines (Baladrin and Kloeke, 1988; Kareru et al., 2008).

2 The Phyto-chemical characteristics of Aerva lanata
The Aerva lanata stem branches from the bottom and leaves are oppositely whorled, woolly, sessile, sublunate, linear, abaxially, white lanose, adaxially glabrous, bracts and bracteoles lanceolate and tomentose throughout and appear smaller at the flowering branches Figure 1. Flowers are very small, sessile, bisexual, appear green to dull white in colour and appear clustered in spikes. The roots of Aerva lanata produce camphor like aroma and are believed to possess medicinal values. The plant extracts of Aerva lanata plant produces many phytochemicals that include Flavonoids, saponins, alkaloids, steroids, catachins, coumarins, steroids, terpenoids, xanthoproteins, minerals, anthra quinones, tannins and phenolic compounds. Tiliroside, coumaryl tiliroside, isorhamentin glycoside, O-acyl glycosides, β-sitosterol, daucosterol, syringic acid, vanillic acid, feruloyl tyramine, feruloyl homovanillylamine, narcissi and aervitrine are some of the phytochemicals synthesized from the stem, leaves, flowers and roots of Aerva lanata plant. Other metabolites of Aerva lanata plant having medicinal values include sitostreol palmitate, hentriacontane, D-glucoside, α-amyrin, betulin, kaempferol 3-rhamn-ogalactoside and kaempferol 3- (6” p-coumaryl) O-glucoside, saponins, sugars like fructose, galactose, rhamnose, mannose, xylose, arabinose and sucrose, canthine 6-one and 3- β-carboline 1-yl propionic acid, 10-methoxy canthin 6-one (methyl aervine), 10-hydr-oxy-canthin 6-one (Aervine), 10-O- β-D-glucopyranosyl oxycanthin 6-one (Aervoside) and 6-methoxy- β-carboline l propionic acid (Aervolanine) (Cushnie and Lamb, 2005) Table 1 .

Figure 1 The whole plant and the flowering branches of Aerva lanata

Table 1 Phytochemical composition and medicinal properties of various extracts of Aerva lanata

3 Current research on the Medicinal properties of Aerva lanata plant Extracts
The various plants extracts of Aerva lanata plant was evaluated for its anti-oxidant properties, nephroprotective values, hepatoprotective properties, anti lithiatic activities (increased urinary excretion of calcium, oxalate and uric acid crystals), anti-diabetic/hypoglycaemic activities (Agrawal, 2013), anti-hyperlipidemicactivities and anti-cancer properties. Other pharmacol-ogical activities of Aerva lanata plant extracts investigated include its diuretic properties, anti-infla-mmatory activities, cytotoxic nature, anti-HIV (Gujjeti and Mamidala, 2014) and antimicrobial properties (Vetrichelvan et al., 2000; Appia Krishnan et al., 2009; Tushar et al., 2008; Nevin, 2003; Vetrichelvan and Jegadeesan, 2002; Manoharan et al., 2008; Soundararajan, 2006; Chouwdhury, 2002).

Traditionally the plant extracts of Aerva lanata are used to treat head ache, jaundice, cholera, reduce bleeding during normal deliveries, treating burns wounds and skin conditions, urinary and gall stones, nasal bleeding, cough and bronchitis, diarrhoea and dysentery, rheumatoid arthritis, fractures, and scorpion stings and snake bites (Kakrani and Sulja,1994, Vedavathy and Rao, 1990; Gupta and Neeraj, 2004; Sankaran and Alagesaboopathi, 1995; Yoga Narasimhan et al., 1979; Upadhyay, 1998; Singh and Pandey, 1980; Mukerjee et al., 1984; Sikarwar and Kaushik, 1993; Girach et al., 1994; Shah and Gopal, 1985; Mohanty et al., 1996; Deepak et al., 2009 )

Only few studies are available in literature, which have evaluated the antimicrobial properties of various extracts of this medicinal plant (Muthukumaran et al., 2001; Srujana et al., 2012; Kalirajan et al., 2013; Duraipandiyan et al., 2006; Rajesh et al., 2010; Malar et al., 2011).

4 Discussion
Aerva lanata is also called as Aerva elegans, Illecebrum lanatum and Achyranthes lanata and is commonly known as mountain knot grass. There are about 28 identified species of Aerva genus (Chawla et al., 2012). This medicinal plant is locally named as Pindidonda in Telugu, Chaya, Gorakh buti, Gorakh ganja, kapurijad, Khari and Khali in Hindi, Ciru-pulai and Ulinai in Tamil, Kapurmadhuri in Marathi, Bili Himdi Soppu in Kannada, Cherula in Malayalam, Bhuyi in Rajasthan, Chaya in Bengali, Bhui and Jari in Sindhi, Polpala in Sinhalese, Kinongo in Swahili and Bhadra, Ashmahabhedah, Gorakshaganja, Pashanabheda and Shatakabhedi in Sanskrit. Aerva lanata has been traditionally used as a medicine for treating various ailments. Increased antibacterial activities of the Aerva lanata plant extracts were observed against few potential bacterial pathogens as compared to the standard drug tested highlighting their use in treating the infections in human. Antifungal properties of Aerva lanata plant extracts were compared with the control drug and were found to possess either similar or increased activities. A previous research study has reported the antibacterial activity of whole plant extract of Aerva lanata against both multi-drug resistant (Escherechia coli and Pseudomonas aeruginosa which are extended spectrum beta lactamase (ESBL) producers) and common human pathogens (Salmonella typhi, Salmonella paratyphi A, Salmonella paratyphi B, Proteus spp, Streptococcus spp, Klebsiella spp, Serretia marcescens, Escherechia coli and Pseudomonas aeruginosa). The study revealed that ethanolic extract showed maximum zone of inhibition against Klebsiella pneumoniae, Proteus mirabilis and Pseudomonas aeruginosa (ESBL). It was also observed that ethanolic extract was ineffective against Salmonella paratyphi A. The study results also indicated that petroleum ether and benzene plant extract was ineffective against many bacterial species (Murugan et al., 2014).

5 Conclusion
Very limited studies are available in literatures which have evaluated the in-vitro and the potential in-vivo antimicrobial properties of various plants extracts of Aerva lanata. In view of emerging multi-drug resistance among various microbes isolated from human infections, extensive research on the potential antimicrobial activities of Aerva lanata plant extracts is warranted. Future studies should include evaluating the various plant extracts of A lanata for their antimicrobial activities against proven multi-drug resistant microorganisms responsible for serious infections and other potential medicinal properties both in-vitro and in-vivo.

References
Agrawal R., Sethiya N.K., and Mishra S.H., 2013, Antidiabetic activity of alkaloids of Aerva lanata roots on streptozotocin-nicotinamide induced type-II diabetes in rats, Pharmaceutical Biology, 51(5): 635-642
http://dx.doi.org/10.3109/13880209.2012.761244

Appia K.G., Ravi V.K., Nandy B.C., and et al., 2009, Hypoglycemic and antihyperlipidemic effect of ethanolic extract of aerial parts of A. lanata Linn. In normal and alloxan induced diabetic rats, International Journal of Phamaceutical Sciences and Drug Research, 1(3):191-194.

Baladrin M.J., and Kloeke J.A., 1988, Medicinal, aromatic and industrial materials from plants, Berlin: Springer, Verlag, pp.1-36

Cushnie T.P.T., and Lamb A.J., 2005, Antimicrobial activity of flavonoids, International Journal Antimicrobial Agents, 26: 343-356
http://dx.doi.org/10.1016/j.ijantimicag.2005.09.002

Deepak K, Prasad D.N, Jyoti Prakash and et al., 2009, Anti asthmatic activity of ethanolic extract of A. lanata Linn. Pharmacologyonline, 2:1075-1081

Dulaly C., 2002, Antimicrobial activity and cytotoxicity of Aerva lanata, Fitoterapia, 73(1): 92-94
http://dx.doi.org/10.1016/S0367-326X(01)00369-0

Duraipandiyan V., Ayyanar M., and Ignacimuthu S., 2006, Antimicrobial activity of some ethnomedical plants used by Paliyar tribe from Tamilnadu, India, BMC Complem Altern Med., 6: 35
http://dx.doi.org/10.1186/1472-6882-6-35

Girach R.D., Aminuddin S.P.A., and Khan S.A., 1994, Traditional plant remedies among the Kondh of district Dhenkal (Orissa), Int. J. Pharmacogn, 32: 274-283
http://dx.doi.org/10.3109/13880209409083005

Guha B.D.N., 1984, Flora of Murshidabad district, West Bengal, India, Scientific Publishers, Jodhpur, pp.262

Guha B.D.N., Sena S.P., and Pal D.C., 1999, A lexicon of medicinal plants in Ind, Vol 1, Naya Prokash, Calcutta, pp.61-62

Gujjeti R.P., and Mamidala E., 2014, Anti-HIV activity and cytotoxic effects of Aerva lanata root extracts; American Journal of Phytomedicine and Clinical Therapeutics, 2(7): 894-900

Gupta A.K., and Neeraj T., 2004, Reviews on Indian Madicinal plants, Vol 1, ICMR, New Delhi, pp.338-340

Kakrani H.K.N., and Sulja A.K., 1994, Traditional treatment through herbs in Kutch district, Gujarat state, India, part II, Analgesic, anti-inflammatory, anti rheumatic, antiarthritic plants, Fitoterapia, 65: 427-430

Kalaskar A., and Venkataramana K., 2012, Determination of antimicrobial resistance pattern and production of extended-spectrum β-lactamases amongst Escherichia coli and Klebsiella pneumoniae from clinical isolates, J. Med. Bacteriol, 1(2): 17-24

Kalirajan A., Narayanan K.R., Ranjitsingh A.J.A., Ramalakshmi C., and Parvathiraj P., 2013, Bioprospecting medicinal plant Aerva lanata Juss. Ex Schult, flowers for potential antimicrobial activity against clinical and fish-borne pathogens, Indian Journal of Natural Products and resources, 4(3): 306-311

Kandi V., 2015, Antimicrobial properties of nanomolecules: potential candidates as antibiotics in the era of multi-drug resistance, Epidemiol Health, 37: e2015008
http://dx.doi.org/10.4178/epih/e2015008

Kareru P.G., Keriko J.M., Gachanja A.N., and Kenji G.M., 2008, Direct detection of triterpenoid saponins, in medicinal plants, African Journal of Traditional, Complementary and Alternative medicines, 5: 56-60
http://dx.doi.org/10.4314/ajtcam.v5i1.31257

Malar R.J.J., Johnson M., Mary U.M., and Arthy A., 2011, Antibacterial activity of ethanol extracts of selected medicinal plants against human pathogens, Asian Pacific J. Trop Biomed., 2011: S76-S78

Manoharan S., Jaswanth A., Sengottuvelu S., Nandhakumar J., Duraisamy R., Karthikeyan D., and Mallegaswari R., 2008, Hepatoprotective activity of Aerva lanata Linn. against paracetamol induced hepatotoxicity in rats, Res. J. Pharm. Tech., 1(4): 398-400

Mohanty R.B., Padhy S.N., and Dash S.K., 1996, Traditional phytotherapy for diarrhoeal diseases in Ganjan and Phulbani districts of south Orissa, India, Ethnobotany, 8: 60-65

Mukerjee T., Bhalla N., Singh A.G., and Jain H.C., 1984, Herbal drugs for urinary stones, Indian Drugs, 21: 224-228

Murugan M., and Mohan V.R., 2014, Phytochemical, FT-IR and antibacterial activity of whole plant extract of Aerva lanata (L.) Juss. Ex. Schult, Journal of Medicinal Plants Studies, 4(3): 51-57

Muthukumaran P., Shanmuganathan P., and Malathi C., 2001, Antoxidative and Antimicrobial study of Aerva lanata, Asian Journal of Biochemical and Pharmaceutical Research, 2(1): 265-271

Nevin K.G., 2003, Effect of Aerva lanata on solid tumor induced by Dla cells in mice, Fitoterapia, 74(6): 578-582
http://dx.doi.org/10.1016/S0367-326X(03)00148-5

Payal C., Amit C., Neeru V., and Sharma S.K., 2012, A review of chemistry and biological activities of the genus Aerva in a desert plant, Pharmaceutica Drug Research, 69(2): 171-177

Rajesh R., Chitra K., and Paarakh P.M., 2010, In vitro antihelminthic activity of aerial parts of Aerva lana (L.) Juss. Ex Schult., Int. J. Pharm. Sci. Drug Res., 2(4): 269-271

Ramana K.V., and Rao R., 2009, Significance of screening for colonization and vancomycin resistance in Staphylococcus aureus isolated from anterior nares of school going children, Online J. Health Allied Scs., 8(3): 20

Ramana K.V., Kalaskar A., Rao M., and Rao S.D., 2013,  Aetiology and Antimicrobial Susceptibility Patterns of Lower Respiratory Tract Infections (LRTI’s) in a Rural Tertiary Care Teaching Hospital in Karimnagar, South India, American Journal of Infectious Diseases and Microbiology, 1(5): 101-105
http://dx.doi.org/10.12691/ajidm-1-5-5

Ramana K.V., Mohanty S.K., and Kumar A., 2008, In-vitro activities of current antimicrobial agents against isolates of pyoderma, Indian J. Dermatol. Venereol. Leprol, 74: 430
http://dx.doi.org/10.4103/0378-6323.42886

Ramana K.V., Rao R., Sharada C., Kareem M.A., Reddy L.R., and Ratna M.M.S., 2013a, Modified hodge test: a useful and the low cost phenotypic method for detection of carbapenemase producers in Enterobacteriaceae members, J. Nat. Sci. Biol. Med., 4: 346-348
http://dx.doi.org/10.4103/0976-9668.117009

Sankaran S., and Alagesaboopathi C., 1995, Some medicinal plants used by tribals of shervaroy hills, Tamilnadu, Flora Fauna, 1: 137-138

Shah G.L., and Gopal G.V., 1985, Ethomedical notes from the tribal inhabitants of north Gujarat (India), J. Econ. Taxon Bot., 6: 193-201

Sharada C.V., and Ramana K.V., 2014, Colistin, polymyxin B and tigecycline suspectibility to metallo betalactamase producing Acinetobacter baumannii isolated from tertiary health care hospital, American Journal of Microbiological Research, 2(2) : 60-62
http://dx.doi.org/10.12691/ajmr-2-2-3

Sikarwar R.L.S., and Kaushik J.P., 1993, Folk medicines of Morena district of Madhya pradesh, India, Int. J. Pharmacogn, 31: 283-287
http://dx.doi.org/10.3109/13880209309082954

Singh V., and Pandey R.P., 1980, Medicinal plantore of tribals of east-Rajasthan (India), J. Econ. Taxon Bot., 1: 137-147

Soundararajan P., 2006, Effect of Aerva lanata on calcium oxalate urolithiasis in rats, Indian Journal of Experimental Biology, 44: 981-986

Srujana M., Hariprasad P., Hindu M.J., Sravani P., Raju V., et al.,, 2012,  In vitro antibacterial activity of stem extracts of Aerva lanata Linn., Int. J. Pharm. Sci. Rev. Res., 14 (1): 21-23

Tushar A., Mukh D., Bapuso V.Y., and et al., 2008, Anti hyperglycemic activity of alcoholic extract of A. lanata (L.) A.L. Juss Ex J.A., Schultes leaves in alloxan induced diabetic mice, J. Appl. Biomed, 6: 81-87

Upadhay O.P., Kumar K., and Tieari R.K., 1998, Ethno-botanical study of skin treatment uses of medicinal plants of Bihar, Pharmaceut. Biol, 36: 167-172
http://dx.doi.org/10.1076/phbi.36.3.167.6339

Vedavathy S., and Rao K.N., 1990, Nephro protectors folk medicine of rayalaseema, Andhrapradesh, Ancient Sci. Life, 9: 164-167

Vetrichelvan T., and Jegadeesan M., 2002, Anti-diabetic activity of alcoholic extract of Aerva lanata (L.) Juss. Ex Schultes in rats, J. Ethnopharmacol, 80: 103-107
http://dx.doi.org/10.1016/S0378-8741(01)00412-3

Vetrichelvan T., Jegadeesan M., Palaniappan M.S., Murali N.P., and Sasikumar K., 2000, Diuretic and anti-inflammatory activities of Aerva lanata in rats, Ind. J. Pharam. Sci, 60(4): 300-302

Yoga N.S.N., Bhat A.V., and Togunashi V.S., 1979, Medicinal plants from Mysore district, Karnataka, Indian Drug Pharmaceut. Ind., 14: 7-22

Yuldashev A.A., Yuldashev M.P., and Abdullabekova V.N., 2002, Components of Aerva lanata, Chem. Nat. Comp, 38(3): 293-294
http://dx.doi.org/10.1023/A:1020448531522
http://dx.doi.org/10.1023/A:1020400615593