research article fabrication and antibacterial effects of...

Research ArticleFabrication and Antibacterial Effects of PolycarbonateLeafExtract Based Thin Films

R Mahendran1 D Sridharan1 C Arunmozhidevan1 T A Selvakumar2 and P Rajasekar2

1Department of Chemistry Anjalai Ammal Mahalingam Engineering College Anna University Kovilvenni 614 403 India2Department of Biotechnology Rajalakshmi Engineering College Anna University Thandalam Chennai 602105 India

Correspondence should be addressed to R Mahendran anishmahendran10gmailcom

Received 22 April 2016 Revised 23 August 2016 Accepted 1 September 2016

Academic Editor Huan-Tsung Chang

Copyright copy 2016 R Mahendran et al This is an open access article distributed under the Creative Commons Attribution Licensewhich permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

We have reported the preparation and antibacterial activities of leaf extract incorporated polycarbonate thin films to improve theantibacterial characteristics of host polycarbonates (PCs) Crude extracts of Azadirachta indica Psidium guajava Acalypha indicaAndrographis paniculata andOcimum sanctumwere prepared bymaceration usingDimethylformamide as solventThe leaf extracts(LE) were incorporated into the PC matrix by solution blending method and the thin films were fabricated byThermally InducedPhase Separation (TIPS) technique The antibacterial activities of the as-prepared films were evaluated against E coli and S aureusby disk diffusion method The inhibitory effects of the PCLE films are higher for S aureus than the E coli but pristine PC filmdid not exhibit any remarkable antibacterial characteristics Further the model fruit (Prunus) studies revealed that the PCLE filmsretained the freshness of the fruits for more than 11 days This study demonstrates that the PCLE films have excellent antibacterialactivities thus the films could be promising candidate for active antibacterial packaging applications

1 Introduction

Bacterial growth on food surface is the main cause ofspoilage of the foods In order to control undesirable bacterialactivities on foods antibacterial packaging films are beingutilized to keep the food safe The antibacterial materialsinhibitreduce the ability of bacterial colonies to grow onthe surface of the food Generally the antibacterial materialsare blendedimmobilizedcoated on the packaging materialsto prolong shelf-life sensory properties and freshness ofthe food [1] Furthermore antibacterial materials protect thefood from pathogens oxygen moisture and dust Generallyantibacterial materials have been fabricated by incorporatingbiologically active compounds such as antioxidants and fla-voring agents into matrixcoating of the packaging material[2 3] which reduce the growth of bacteria

Conventionally the metal nanoparticles are being im-pregnated into the polymer matrix for enhancing theirantibacterial activities however they have certain drawbackssuch as high cost toxicity harmfulness and problems indisposal of the wastes [4 5] In order to overcome these

difficulties ecofriendly antibacterial materials such asmedic-inal leaf extract are used for destroying Gram-positive andGram-negative bacteria [6] The leaf extracts are in liquidform which protect their commercial applications in activepackagingmaterialsThismajor drawback could be overcomeby incorporating the leaf extract into the polymer matrixfor the fabrication of films which can protect the food andbeverages from the bacterial attackGenerallymost of the leafextracts have rich content of tannins terpenoids alkaloidsflavonoids glycosides and polyphenols which was clearlyidentified as their in vitro antibacterial activities

The biodegradable polymers like cellulosic polymers havebeen utilized for the fabrication of antibacterial packagingfilms however their water sensitivity poor interfacial adhe-sion and low melting point reduce their potential applica-tions In order to overcome these drawbacks polycarbonate(PC) based thin films have been used for food packaging dueto their hydrophobic nature durability dimensional stabilitylight weight excellent mechanical and thermal stabilitiesand moisture barrier properties which are the essentialcharacteristics for active antibacterial packaging films The

Hindawi Publishing CorporationJournal of MaterialsVolume 2016 Article ID 3194154 7 pageshttpdxdoiorg10115520163194154

2 Journal of Materials

PCs have been studied in a number of applications by directcontact with foods and beverages however they have verypoor antibacterial activities which reduce their efficiency inantibacterial packaging system effectively The antibacterialactivities of the PC have been enhanced by functionalizingreactive groupsblending with antibacterial agents [7ndash9]

In this research we have reported leaf extract incorpo-rated PC films whichwere fabricated using solution blendingfollowed by Thermally Induced Phase Separation techniqueHere the maceration was employed for preparing the leafextract in which the solvents diffuse into the solid plantmaterial and solubilize their compounds The as-preparedleaf extracts are safe and effective for long term use since theypossess antibacterial molecules as well as antioxidants Thefollowing medicinal leaves crude extracts were used in thisstudy Firstly the extract that was collected from the leaf ofAzadirachta indica (neem) has flavonoids dihydrochalconesarabinogalactans isoprenoids polyphenolics coumarin andtannins which are the important constituents for its antibac-terial activities [10] Then Psidium guajava (Guava) leafextract consists of effective phytochemical constituents suchas acalypus tannins saponins and acalyphine for its antibac-terial nature [11] Acalypha indica commonly known asIndian Acalypha has potential antibacterial molecules suchas acalyphine cyanogenic glucosides alkaloids and triace-tone amine Furthermore the leaf extract of Andrographispaniculata (Green Chiretta) contains flavonoids alkaloidssteroids phenols tannins and particularly andrographolidefor its antibacterial efficacy [12] Finally the fresh leaf of Oci-mum sanctum (Holy Basil) possesses steroid flavonoid phe-nols tannin alkaloid saponin and carotenoid compoundsand it could be also used as insecticide antibiotics andfungicide [13] All the leaf extracts possess the vital propertieslike antifungal antiviral antioxidant anti-inflammatory andantipyretic Based on the above merits the mentioned leafextract was prepared by maceration for blending with the PCsolution to obtain active antibacterial thin films

Here we report a facile low-cost and scalable techniquefor the fabrication of PCLE films In addition the antibac-terial activities of the PC and PCLE films were assessedagainst S aureus and E coli which are identified as foodspoilage bacteria To the best of our knowledge in an openliterature the antibacterial studies of mentioned crude leafextract incorporated PC thin films have not yet been reportedfor active antibacterial packaging applications

2 Materials and Methods

21 Materials Bisphenol A polycarbonate (PC 119872119908sim

150000 gmol molecular weight of repeating unit 2543 gmol polydispersity index 18) was supplied by GE PlasticLtd India and dried at 100∘C in an oven for 6 hrs priorto use Azadirachta indica Psidium guajava Acalyphaindica Andrographis paniculata and Ocimum sanctum werecollected at various regions whichwerementioned in Table 1Prunus (plum) fruit model were cleaned with distilled waterseveral times to remove the adhering impurities on thesurface NN-Dimethylformamide (DMF) was purchased

from Sigma-Aldrich India and used as received The list ofabbreviations of the chemicals and leaves used in this studyis listed in Abbreviations

22 Processing of the Leaf Firstly the leaves (Azadirachtaindica Psidium guajava Acalypha indica Andrographis pan-iculata and Ocimum sanctum) were washed with runningtap water for 15min followed by distilled water several timesto remove the impurities on the leavesrsquo surface The sampleswere dried at room temperature under shade for 10 days toevaporate the residual water The leaves were finely groundby stainless steel grinder to turn them to powdery form andstored in airtight containers [14 15]

23 Preparation of Leaf Extract Powdered leaf (10 g) waspoured in an Erlenmeyer flask containing 100mL of DMFThe flask was put on a hot plate for 10min and kept asidefor 24 h at room temperature for complete macerationThenthe macerate was filtered through nylon mesh followed byWhatman number 1 filter paper The similar procedure wasfollowed by preparing all the leaf crude extracts In additionfor the preparation of PC-AI 2 and PC-AI 3 samples 20 g and30 g of dried neem powder weremacerated inDMF (100mL)respectively [16]

24 Fabrication of PC and PCLE Films The PC and PCLEthin films were fabricated by solution blending followed byTIPS [17 18] Figure 1 shows the schematic representationof the fabrication of PCLE thin films The figure reveals theprocessing of neem leaves maceration of the neem powderand the appearance of as-prepared film with inhibitionzones respectively Briefly the PC (15wt) was dissolved inDMF and stirred for 5 hrs by magnetic stirring to obtain ahomogeneous solution Consequently the as-prepared leafextract (10mL) was added to the PC solution with stirringfor 5 hrs at room temperature The PCLE solution waspoured on a glass plate and cast by a doctor blade (thickness50 120583m) at room temperature The nascent film was beingkept on a hot plate (80∘C) to evaporate the solvent Thenthe film was peeled off and placed in a stainless steel plateat 100∘C for 2 hr to remove the residual solvent completelyThe thickness of the as-prepared films was measured usinga digital micrometer (Mitutoyo Tokyo Japan) at differentlocations and an average value of sixmeasurements was takenfor each film

25 Fruit Model Studies The antibacterial efficacy of the PCand PCLE films was assessed using genus Prunus as a modelfruit Fresh Prunus of almost equal size were washed withdistilled water and then dried at room temperature for 3 hrsPrunus was wrapped with the as-prepared films individuallyand placed in an open atmosphere and the unwrappedPrunus was served as control [19]

26 Evaluation of Antibacterial Activity The antibacterialactivities of the PC and PCLE films were assessed usingE coli (Gram-negative ATCC 25922) and S aureus (Gram-positive ATCC29213) by Disc Diffusion method (Kirby

Journal of Materials 3

Table 1 Descriptive features of the leaf used for the antibacterial assay

S number Botanical species Family name Location(DMS latitude) Studied organ

1 Acalypha indica Myrtaceae N 10∘4710158401310158401015840 Leaves2 Psidium guajava Euphorbiaceae N 10∘4610158401910158401015840 Leaves3 Andrographis paniculata Acanthaceae N 10∘3910158403610158401015840 Leaves4 Ocimum sanctum Lamiaceae N 10∘4610158401910158401015840 Leaves5 Azadirachta indica Meliaceae N 10∘3910158403610158401015840 Leaves

Figure 1 Schematic representation of fabrication of PCLE thin films

Bauer test) [20 21] Briefly the sterilizedMueller-Hinton agarwas poured in Petri plates after solidification the inoculumswere spread on the plate using L-rod Later the as-preparedfilms were cut into pieces and placed on the bacterial strainThe plates were incubated for 24 h in an aerobic incubationchamberThe inhibition zones around the films were visuallyidentified and the diameter of the inhibition zone was alsomeasured

3 Results and Discussion

Table 2 shows the PCLE weight ratio and thickness of theas-prepared thin films The thickness of the PC-AI 1 PC-AI2 and PC-AI 3 thin films minutely increased with respectto the concentration of neem leaf extract in the PC matrixand the thickness of the remaining films did not changesignificantly Figure 2 shows the PC PC-AC PC-PG PC-OS PC-AI 1 PC-AI 2 and PC-AI 3 transparent thin filmson the flower image the color of the films shifted from dullto dark greenish with respect to the chlorophyll and otherconstituents in content of the leaf extract [22] The pristinePC film appears transparent and colorless which is shownin Figure 2 However the PC-AC PC-PG and PC-OS filmshave light greenish color due to low content of chlorophyllin their leaf Since the content of neem leaf extract increasedfrom 10 to 30wt the color of the resulting films changedfrom light green (PC-AI 1) to dark green (PC-AI 3) At higherquantity (40mL) of Azadirachta indica leaf extract in thepolymermatrix the film lost its transparency slightly and theleaf extract did not homogeneously mix within the matrix

Figure 3 shows photographic images of the model fruitsample of Prunus unwrapped control and wrapped withpristine PCandPCLEfilmsThepreservation study had beencarried out for 11 days until the control and PC wrapped

Table 2 Composition and thickness of as-prepared PC and PCLEthin films

S number Thin filmcode

PC(wt)

Leaves extract(mL)

Thickness(120583m)

1 PC 30 10 172 PC-AC 30 10 253 PC-PG 30 10 244 PC-AP 30 10 235 PC-OS 30 10 266 PC-AI 1 30 10 277 PC-AI 2 30 20 298 PC-AI 3 30 30 30

Prunus spoiledAfter 11 daysPrunuswrappedwith the PCLEfilms retained higher shelf-life and freshness compared withthe control and PCwrapped one In these fruit model studiesthe control sample started to deteriorate after 3 days andthe PC wrapped sample deteriorated after 5 days From theimages (Figure 3) it can be concluded that Prunus (control)and Prunus covered with pristine PC film started to damageand deteriorate due to the attack of bacterial pathogenswhereas Prunus wrapped with the PCLE films maintainedfreshness and the shape of the fruit even after 11 days ofstorage time due to their antibacterial characteristics [23]

Figure 4 shows photographic images of PC and PCLEfilms on the bacterial lawnThepristine PCfilms did not showany significant inhibition zone for both bacteria whereasthe PCLE films were more effective and exhibited inhibitionzones for E coli and S aureus This is due to the presence ofantibacterial agents in the leaf extracts which did effectivelyfunction in the PCmatrix In this research all the PCLEfilmspossessed significant inhibitory activities against E coli and S


PCA indica 1 PCA indica 2 PCA indica 3

Pristine PC PCAcalypha indica PCPsidium guajava PCAndrographis paniculata

Figure 2 Photographic images of PC and PCLE thin films

(a) (b) (c) (d) (e) (f)

(g) (h) (i) (j) (k) (l)

Figure 3 Photographic images of Prunus (a) pristine PC (b) PC-AC (c) PC-PG (d) PC-OS (e) and PC-AI 1 (f) After 11 days Prunus (g)pristine PC (h) PC-AC (i) PC-PG (j) PC-OS (k) and PC-AI 1 (l)

aureus which concluded that the leaf extracts also retain theirantibacterial property in the polymer matrix

In Figure 5 the PC-OS sample showed the highestinhibition zones of 821 and 782mm for E coli and S aureusrespectively due to the presence of effective antibacterialagents such as saponins alkaloids flavonoids cardiac glyco-sides steroids phenols and tannin [24] In the PC-AI 1ndash3

films since the leaf extract concentration was increased from10mL to 30mL the antibacterial activity of the films also wassignificantly enhanced meaning that the bacteria have beenkilled faster at higher concentration of antibacterial agentsin the PC films [25] The antibacterial studies revealed thatthe efficacy of the antibacterial agents against S aureus washigher for all the films compared with E coli This might be


1

2

3

4

5

E coli

(a)

6

7

8

E coli

(b)

1

2

3

4

5

S aureus

(c)

6

7

8

S aureus

(d)

Figure 4 Inhibition zones of films against E coli (a and b) and S aureus (c and d) PC (1) PC-AC (2) PC-PG (3) PC-AP (4) PC-OS (5)PC-AI 1 (6) PC-AI 2 (7) and PC-AI 3 (8)

due to the fact that the damage of cell wall structure of the Saureus is easier than the E coli by bactericidal molecules inthe leaf extract For E coli the PC-AC PC-PG PC-AP PC-OS PC-AI 1 and PC-AI 2 exhibited the inhibition zones of324 213 332 812 132 and 451mm respectively In caseof S aureus the inhibition zones were observed around 343330 543 764 116 421 and 648mm for the PC-AC PC-PG PC-AP PC-OS PC-AI 1 and PC-AI 2 respectively Theresults concluded that the antibacterial agents present in theleaf effectively destroyed the S aureusmore than the E coli

4 Conclusion

A simple and reliable route has been proposed to fabri-cate bactericidal films by incorporating leaf extract intothe polymer matrix The as-prepared films showed signif-icant antibacterial activities against E coli and S aureusSpecifically P guajava based PC thin films exhibited thehighest antibacterial activities against both bacteria even at

low loading (10wt) of leaf extract in the polymer matrixMost of the films showed excellent inhibitory effects againstS aureus compared to the E coli More importantly themodel fruit studies revealed that the as-prepared PCLE filmscould be the promising materials in antibacterial packagingapplications due to their significant antibacterial efficacy

Abbreviations

PC PolycarbonateLE Leaf extractS aureus Staphylococcus aureusE coli Escherichia coliDMF NN-DimethylformamideAC Acalypha indicaPG Psidium guajavaAP Andrographis paniculataOS Ocimum sanctumAI Azadirachta indica


0

1

2

3

4

5

6

7

8

9

E coliS aureus

Inhi

bitio

n zo

ne d

iam

eter

(mm

)

Sample code

PC

PC-A

C

PC-P

G

PC-A

P

PC-O

S

PC-A

I 1

PC-A

I2

PC-A

I3

Figure 5 Comparison of antibacterial activities of PC and PCLEfilms against E coli and S aureus

Competing Interests

The authors declare that there are no competing interestsregarding the publication of this paper

References

[1] R Shemesh M Krepker D Goldman et al ldquoAntibacterialand antifungal LDPE films for active packagingrdquo Polymers forAdvanced Technologies vol 26 no 1 pp 110ndash116 2014

[2] L H Chong M M Lim and N Sultana ldquoFabrication andevaluation of polycaprolactonegelatin-based electrospunnanofibers with antibacterial propertiesrdquo Journal of Nano-materials vol 2015 Article ID 970542 8 pages 2015

[3] L Vermeiren F Devlieghere M Van Beest N De Kruijf andJ Debevere ldquoDevelopments in the active packaging of foodsrdquoTrends in Food Science and Technology vol 10 no 3 pp 77ndash861999

[4] G M Raghavendra J Jung D kim and J Seo ldquoMicrowaveassisted antibacterial chitosan-silver nanocomposite filmsrdquoInternational Journal of Biological Macromolecules vol 84 pp281ndash288 2016

[5] M A Awad W K Mekhamer N M Merghani et al ldquoGreensynthesis characterization and antibacterial activity of sil-verpolystyrene nanocompositerdquo Journal of Nanomaterials vol2015 Article ID 943821 6 pages 2015

[6] S-A Riyajan and J Nuim ldquoInteraction of green polymer blendof modified sodium alginate and carboxylmethyl celluloseencapsulation of turmeric extractrdquo International Journal ofPolymer Science vol 2013 Article ID 364253 10 pages 2013

[7] J Xu E Feng and J Song ldquoRenaissance of aliphatic polycar-bonates new techniques and biomedical applicationsrdquo Journalof Applied Polymer Science vol 131 no 5 Article ID 39822 2014

[8] L Kessler G Legeay A Coudreuse et al ldquoSurface treatment ofpolycarbonate films aimed at biomedical applicationrdquo Journal ofBiomaterials Science Polymer Edition vol 14 no 10 pp 1135ndash1153 2003

[9] S H Lee K Sung T-M Chung et al ldquoPreparation of silvernanoparticles and antibiotic test of its polycarbonate filmscompositerdquo Journal of Nanoscience and Nanotechnology vol 8no 9 pp 4734ndash4737 2008

[10] S Siddiqui S Faizi and B S Siddiqui ldquoConstituents ofAzadirachta indica Isolation and structure elucidation of anew antibacterial tetranortriterpenoid mahmoodin and a newprotolimonoid naheedinrdquo Journal of Natural Products vol 55no 3 pp 303ndash310 1992

[11] P Jaiarj P Khoohaswan Y Wongkrajang et al ldquoAnticough andantimicrobial activities of Psidium guajava Linn leaf extractrdquoJournal of Ethnopharmacology vol 67 no 2 pp 203ndash212 1999

[12] U S Mishra A Mishra R Kumari P N Murthy and B SNaik ldquoAntibacterial activity of ethanol extract of Andrographispaniculatardquo Indian Journal of Pharmaceutical Sciences vol 71no 4 pp 436ndash438 2009

[13] AKumar R Shukla P Singh andNKDubey ldquoChemical com-position antifungal and antiaflatoxigenic activities of Ocimumsanctum L essential oil and its safety assessment as plant basedantimicrobialrdquo Food and Chemical Toxicology vol 48 no 2 pp539ndash543 2010

[14] B Lapornik M Prosek and A G Wondra ldquoComparisonof extracts prepared from plant by-products using differentsolvents and extraction timerdquo Journal of Food Engineering vol71 no 2 pp 214ndash222 2005

[15] J Azmir I S M Zaidul M M Rahman et al ldquoTechniquesfor extraction of bioactive compounds from plant materials areviewrdquo Journal of Food Engineering vol 117 no 4 pp 426ndash4362013

[16] P Bergweiler and C Lutz ldquoDetermination of leaf pigmentsby HPLC after extraction with NN-dimethylformamide eco-physiological applicationsrdquo Environmental and ExperimentalBotany vol 26 no 3 pp 207ndash210 1986

[17] M Joshi S W Ali and S Rajendran ldquoAntibacterial finishing ofpolyestercotton blend fabrics using neem (Azadirachta indica)a natural bioactive agentrdquo Journal of Applied Polymer Sciencevol 106 no 2 pp 793ndash800 2007

[18] S Sodha K Wall S Redenti H Klassen M J Young and SL Tao ldquoMicrofabrication of a three-dimensional polycaprolac-tone thin-film scaffold for retinal progenitor cell encapsulationrdquoJournal of Biomaterials Science Polymer Edition vol 22 no 4ndash6pp 443ndash456 2011

[19] D Shanmugapriya R Suriyaprabha R Yuvak kumar andV Rajendran ldquoChitosan-incorporated different nanocompositeHPMCfilms for antibacterial preservationrdquo Journal of Nanopar-ticle Research vol 16 article 2248 2014

[20] I Bhattacharjee S K Chatterjee A Ghosh and G ChandraldquoAntibacterial activities of some plant extracts used in Indiantraditional folk medicinerdquo Asian Pacific Journal of TropicalBiomedicine vol 1 no 2 pp S165ndashS169 2011

[21] A Rawani S Pal and G Chandra ldquoEvaluation of antimicrobialproperties of four plant extracts against human pathogensrdquoAsian Pacific Journal of Tropical Biomedicine vol 1 no 1 ppS71ndashS75 2011

[22] KHayakawa andG E Timbers ldquoInfluence of heat treatment onthe quality of vegetables changes in visual green colorrdquo Journalof Food Science vol 42 no 3 pp 778ndash781 1977

[23] P Lopez C Sanchez R Batlle and C Nerın ldquoDevelopment offlexible antimicrobial films using essential oils as active agentsrdquoJournal of Agricultural and Food Chemistry vol 55 no 21 pp8814ndash8824 2007


[24] S S Deo F Inam andR PMahashabde ldquoAntimicrobial activityand HPLC fingerprinting of crude ocimum extractsrdquo E-Journalof Chemistry vol 8 no 3 pp 1430ndash1437 2011

[25] K G Purushotham P Arun J J Jayarani R VasnthakumariL Sankar and B R Reddy ldquoSynergistic in vitro antibacterialactivity ofTectonagrandis leaveswith tetracyclinerdquo InternationalJournal of PharmTech Research vol 2 no 1 pp 519ndash523 2010

Submit your manuscripts athttpwwwhindawicom

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NanoparticlesJournal of



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Biomaterials


NanoscienceJournal of

TextilesHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Journal of

NanotechnologyHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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CrystallographyJournal of


The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014


CoatingsJournal of

Advances in

Materials Science and EngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Smart Materials Research



MetallurgyJournal of


BioMed Research International

MaterialsJournal of


Nano

materials


Journal ofNanomaterials


PCs have been studied in a number of applications by directcontact with foods and beverages however they have verypoor antibacterial activities which reduce their efficiency inantibacterial packaging system effectively The antibacterialactivities of the PC have been enhanced by functionalizingreactive groupsblending with antibacterial agents [7ndash9]

In this research we have reported leaf extract incorpo-rated PC films whichwere fabricated using solution blendingfollowed by Thermally Induced Phase Separation techniqueHere the maceration was employed for preparing the leafextract in which the solvents diffuse into the solid plantmaterial and solubilize their compounds The as-preparedleaf extracts are safe and effective for long term use since theypossess antibacterial molecules as well as antioxidants Thefollowing medicinal leaves crude extracts were used in thisstudy Firstly the extract that was collected from the leaf ofAzadirachta indica (neem) has flavonoids dihydrochalconesarabinogalactans isoprenoids polyphenolics coumarin andtannins which are the important constituents for its antibac-terial activities [10] Then Psidium guajava (Guava) leafextract consists of effective phytochemical constituents suchas acalypus tannins saponins and acalyphine for its antibac-terial nature [11] Acalypha indica commonly known asIndian Acalypha has potential antibacterial molecules suchas acalyphine cyanogenic glucosides alkaloids and triace-tone amine Furthermore the leaf extract of Andrographispaniculata (Green Chiretta) contains flavonoids alkaloidssteroids phenols tannins and particularly andrographolidefor its antibacterial efficacy [12] Finally the fresh leaf of Oci-mum sanctum (Holy Basil) possesses steroid flavonoid phe-nols tannin alkaloid saponin and carotenoid compoundsand it could be also used as insecticide antibiotics andfungicide [13] All the leaf extracts possess the vital propertieslike antifungal antiviral antioxidant anti-inflammatory andantipyretic Based on the above merits the mentioned leafextract was prepared by maceration for blending with the PCsolution to obtain active antibacterial thin films

Here we report a facile low-cost and scalable techniquefor the fabrication of PCLE films In addition the antibac-terial activities of the PC and PCLE films were assessedagainst S aureus and E coli which are identified as foodspoilage bacteria To the best of our knowledge in an openliterature the antibacterial studies of mentioned crude leafextract incorporated PC thin films have not yet been reportedfor active antibacterial packaging applications

2 Materials and Methods

21 Materials Bisphenol A polycarbonate (PC 119872119908sim

150000 gmol molecular weight of repeating unit 2543 gmol polydispersity index 18) was supplied by GE PlasticLtd India and dried at 100∘C in an oven for 6 hrs priorto use Azadirachta indica Psidium guajava Acalyphaindica Andrographis paniculata and Ocimum sanctum werecollected at various regions whichwerementioned in Table 1Prunus (plum) fruit model were cleaned with distilled waterseveral times to remove the adhering impurities on thesurface NN-Dimethylformamide (DMF) was purchased

from Sigma-Aldrich India and used as received The list ofabbreviations of the chemicals and leaves used in this studyis listed in Abbreviations

22 Processing of the Leaf Firstly the leaves (Azadirachtaindica Psidium guajava Acalypha indica Andrographis pan-iculata and Ocimum sanctum) were washed with runningtap water for 15min followed by distilled water several timesto remove the impurities on the leavesrsquo surface The sampleswere dried at room temperature under shade for 10 days toevaporate the residual water The leaves were finely groundby stainless steel grinder to turn them to powdery form andstored in airtight containers [14 15]

23 Preparation of Leaf Extract Powdered leaf (10 g) waspoured in an Erlenmeyer flask containing 100mL of DMFThe flask was put on a hot plate for 10min and kept asidefor 24 h at room temperature for complete macerationThenthe macerate was filtered through nylon mesh followed byWhatman number 1 filter paper The similar procedure wasfollowed by preparing all the leaf crude extracts In additionfor the preparation of PC-AI 2 and PC-AI 3 samples 20 g and30 g of dried neem powder weremacerated inDMF (100mL)respectively [16]

24 Fabrication of PC and PCLE Films The PC and PCLEthin films were fabricated by solution blending followed byTIPS [17 18] Figure 1 shows the schematic representationof the fabrication of PCLE thin films The figure reveals theprocessing of neem leaves maceration of the neem powderand the appearance of as-prepared film with inhibitionzones respectively Briefly the PC (15wt) was dissolved inDMF and stirred for 5 hrs by magnetic stirring to obtain ahomogeneous solution Consequently the as-prepared leafextract (10mL) was added to the PC solution with stirringfor 5 hrs at room temperature The PCLE solution waspoured on a glass plate and cast by a doctor blade (thickness50 120583m) at room temperature The nascent film was beingkept on a hot plate (80∘C) to evaporate the solvent Thenthe film was peeled off and placed in a stainless steel plateat 100∘C for 2 hr to remove the residual solvent completelyThe thickness of the as-prepared films was measured usinga digital micrometer (Mitutoyo Tokyo Japan) at differentlocations and an average value of sixmeasurements was takenfor each film

25 Fruit Model Studies The antibacterial efficacy of the PCand PCLE films was assessed using genus Prunus as a modelfruit Fresh Prunus of almost equal size were washed withdistilled water and then dried at room temperature for 3 hrsPrunus was wrapped with the as-prepared films individuallyand placed in an open atmosphere and the unwrappedPrunus was served as control [19]

26 Evaluation of Antibacterial Activity The antibacterialactivities of the PC and PCLE films were assessed usingE coli (Gram-negative ATCC 25922) and S aureus (Gram-positive ATCC29213) by Disc Diffusion method (Kirby












PC(wt)

Leaves extract(mL)

Thickness(120583m)








(a) (b) (c) (d) (e) (f)

(g) (h) (i) (j) (k) (l)






1

2

3

4

5

E coli

(a)

6

7

8

E coli

(b)

1

2

3

4

5

S aureus

(c)

6

7

8

S aureus

(d)



4 Conclusion



Abbreviations



0

1

2

3

4

5

6

7

8

9

E coliS aureus

Inhi

bitio

n zo

ne d

iam

eter

(mm

)

Sample code

PC

PC-A

C

PC-P

G

PC-A

P

PC-O

S

PC-A

I 1

PC-A

I2

PC-A

I3


Competing Interests


References


































CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials














PC(wt)

Leaves extract(mL)

Thickness(120583m)








(a) (b) (c) (d) (e) (f)

(g) (h) (i) (j) (k) (l)






1

2

3

4

5

E coli

(a)

6

7

8

E coli

(b)

1

2

3

4

5

S aureus

(c)

6

7

8

S aureus

(d)



4 Conclusion



Abbreviations



0

1

2

3

4

5

6

7

8

9

E coliS aureus

Inhi

bitio

n zo

ne d

iam

eter

(mm

)

Sample code

PC

PC-A

C

PC-P

G

PC-A

P

PC-O

S

PC-A

I 1

PC-A

I2

PC-A

I3


Competing Interests


References


































CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials







(a) (b) (c) (d) (e) (f)

(g) (h) (i) (j) (k) (l)






1

2

3

4

5

E coli

(a)

6

7

8

E coli

(b)

1

2

3

4

5

S aureus

(c)

6

7

8

S aureus

(d)



4 Conclusion



Abbreviations



0

1

2

3

4

5

6

7

8

9

E coliS aureus

Inhi

bitio

n zo

ne d

iam

eter

(mm

)

Sample code

PC

PC-A

C

PC-P

G

PC-A

P

PC-O

S

PC-A

I 1

PC-A

I2

PC-A

I3


Competing Interests


References


































CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials




1

2

3

4

5

E coli

(a)

6

7

8

E coli

(b)

1

2

3

4

5

S aureus

(c)

6

7

8

S aureus

(d)



4 Conclusion



Abbreviations



0

1

2

3

4

5

6

7

8

9

E coliS aureus

Inhi

bitio

n zo

ne d

iam

eter

(mm

)

Sample code

PC

PC-A

C

PC-P

G

PC-A

P

PC-O

S

PC-A

I 1

PC-A

I2

PC-A

I3


Competing Interests


References


































CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials




0

1

2

3

4

5

6

7

8

9

E coliS aureus

Inhi

bitio

n zo

ne d

iam

eter

(mm

)

Sample code

PC

PC-A

C

PC-P

G

PC-A

P

PC-O

S

PC-A

I 1

PC-A

I2

PC-A

I3


Competing Interests


References


































CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials













CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials



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