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Corrosion and Fungal Growth Inhibiting Effects of Piper guineense Extracts

Imo E.O.*, Orji J.C., Nweke C.O.

Department of Microbiology, Federal University of Technology, Owerri, Nigeria

Abstract: Seed extracts of Piper guineense were assessed for anticorrosion and antifungal activities. The study was performed on aluminum (Al) coupon with weight percentage composition of Al>95% and 3x1.5x0.1cm in size. Anticorrosion effects of the extracts was studied using gravimetric and potentiodynamic polarization techniques, while the antifungal potency of ethanol, methanol, cold water and hot water extracts respectively against the corrosion-associated Aspergellius fumigatus was assessed by agar disc diffusion methods. Results revealed that the corrosion of the aluminum was inhibited by adsorption of the extract organic matter on the surface of the metal. Proximate phytochemical analysis of the P.guineense reveals the presence of alkaloids (1.67±0.29%), flavonoids (0.64±0.05%), tannins (0.67±0.01%), saponin (39.24±1.2%) and Phenols (1.92±0.04%). Fungal growth inhibition of P. guineense can be attributed to the actions of the phytochemical constituents of the extract.

Keywords: biocides, corrosion, fungi, inhibition, plant extract, polarization, metals

Citation: Imo E.O., Orji J.C., Nweke C.O., Corrosion and Fungal Growth Inhibiting Effects of Piper guineense Extracts. Journal of Applied & Environmental Microbiology, 6 (2). 37-41. January 2018. doi:10.12691/jaem-6-2-2

1. Introduction

Fungi are considered the primary colonizers of surfaces in both natural and man- made environments [1]. In aqueous environments, metals are corroded not only by purely chemical or electrochemical reactions but also by metabolic activities of microorganisms [2]. Many fungi adhere to metals and form mat of hyphae or biofilms on material surfaces, with interactions governed strongly by the material surface properties and adhesion mechanisms [3,4]. Microbial growth on the surface of metals exposed to soil, oil fields and environmental contaminants can influence its corrosion in most adverse ways [5]. The possibilities of some fungal species to grow on metal surfaces are determined by their secreted metabolites which enable them to adapt to new environmental and nourishment conditions. Chemicals that control microbial activities are called biocides. Biocides are chemical substance intended to destroy, deter, render harmless, or exert a controlling effect on any harmful organism by chemical or biological means. Biocides can be either oxidizing or non-oxidizing agents [6]. Oxidizing agents such as chlorine, chlorinating compounds, choramines and bromine are commonly used in freshwater systems [7]. Non-oxidizing biocides are more stable than oxidizing biocides [7] and can be used in a variety of different environments. They have been shown to be effective against a broad range of microorganisms such as bacteria, fungi and algae as well as a greater persistence in the environment [6]. The choice of the biocide or inhibitor to use in the control of biocorrion is very important. A study by Rajaskar et al., [8] shows that the widespread use of ester based or toxic biocides in the petroleum industry has led to the growth and dominance of Bacillus species, due to their ability to form resistance spores. Therefore the effectiveness of a biocide depends on the nature of the target microorganisms and the service environment.

The known hazardous effects of most synthetic inhibitors and the need to develop cheap, nontoxic and eco-friendly process have made researchers to focus on the use of natural products [9]. Most biocides in use today are inherently toxic and are very difficult to degrade as they persist in the environment. The environmental toxicity of inorganic corrosion inhibitors has promoted the search for green corrosion inhibitors as they are biodegradable, do not contain heavy metals or other toxic compounds. Stringent environmental regulation have restricted the use of toxic inorganic corrosion inhibitors such as chromates, nitrates and oxides leading to their replacement by organic compounds [5], mostly plant extracts. In addition to being environmentally friendly and ecologically acceptable, plant products are inexpensive, readily available and renewable [4,10,11]. Environmental concern has lead to the promulgation of legislations that encourages the replacement of environmentally toxic inorganic biocides with more readily degradable corrosion inhibitors that are environmentally less toxic. The interest in the use of plant extracts in the control and inhibition of biocorrosion can be attributed to the phytochemical constituents of the extract which often bear similar molecular, electronic structure with organic corrosion inhibitors as well as antimicrobial properties [12]. Tannin, organic acids, alkaloids, pigments and proteins from plants are known to inhibit metal corrosion [13,14]. Extracts of Zenthoxylum alatum were active on the corrosion of carbon steel in phosphoric acid [10]. Li et al., [4] investigated the inhibitory effect of berberine extracted from Coptis chinensis in soft steel which was active against corrosion in 1M sulfuric acid. Molecules present in aqueous extract of Fenugreek leaves were spontaneously adsorbed on mild steel surface and were capable of inhibiting corrosion on steel in a dose-dependent manner in the presence of HCl and H₂SO₄. Aqueous extract of Rosmarinus officinalis [15], Lawsonia inermis leaves [11], Allium sativum [16] and Phaseolus vulgaris [17] inhibited metal corrosion.

The adhesive protein from the marine mussel Mytilus edulis and the bovine serum albumin (BSA) were both absorbed on carbon steel and were able to inhibit corrosion [18]. Plant products have also shown antimicrobial activity and studies in the use of extracts or isolated compounds to combat human-pathogens and phytopathogenic bacteria and microorganisms involved in corrosion are well documented [15,19,20]. The activity of an aqueous extract of Brassica nigra on planktonic and sessile Pseudomonas sp., the fungus Aspergillus fumigatus and a mixture of sulfate-reducing bacteria (SRB) revealed a promissory biocidal action against microorganisms frequently found in industrial biofilms [21].

In this study, the inhibiting effect of cold water (CW) extracts of Piper guineense on the fungal influenced corrosion of aluminum including evaluation of the phytochemical constituents of the extract was investigated. Anticorrosion effects of the extract on the corrosion associated Aspergillius fumigatus was assessed using gravimetric and electrochemical techniques. Antifungal screening to determine the growth inhibition of the extract and the minimum inhibitory concentration were assessed using agar disc diffusion method.

2. Materials and Methods

2.1. Material Preparation

Metal coupons: Corrosion experiments were performed on aluminum metal with weight percentage composition of Al>95%.

2.2. Plant Extracts

The dried plant seeds were washed with sterile distilled water. The seeds were then pulverized with a blender. The stock solution was prepared using standard procedure outlined by [22]. Hundred grams (100g) of each powdered seed was soaked in 500mL of 95% ethanol (ET), methanol (MT), cold water (CW) and hot water (HW) for 48 hrs to allow for maximum extraction of components. The filtrates were then evaporated to eliminate the solvents using a rotary evaporator. The residue (crude extracts) were then stored in sterile reagent bottles at 21°C until analysis. The amount of plant material extracted was quantified by comparing the weight of the dried residue with the initial weight of the dried plant material before extraction. From the individual stock inhibitor test solutions were prepared in the desired concentration range by diluting with distilled water. Quantitative and qualitative phytochemical screening of the extract was done using standard laboratory procedures [5].

The test fungus was isolated from aluminum roofing sheet. The biofilm covered area of the aluminum sheet was aseptically scrapped. One gram (1g) of corroded metal samples was serially diluted into 9mL of sterile distilled water in sterile 20mL test tube. About 0.1mL of dilutions 10⁻⁵ to 10⁻⁷ was plated in triplicate on potato dextrose agar PDA (Oxoid) plates supplemented with antibiotics streptomycin (5μg/mL). Each morphological discrete fungal colony was then sub-cultured and purified by repeated streaking on PDA plates. Pure cultures were then preserved on PDA slants in Bijou bottles and stored at 4°C in a refrigerator for further studies. Each fungal isolate was characterized and identified based on their morphological characteristics and microscopic analysis using taxonomic guides and standard procedures as outlined by [22].

2.3. Gravimetric Experiments

Gravimetric experiments were conducted on test coupon of dimension 3x1.5x0.1cm. The coupons were wet- polished with abrasive paper (from grad no. 400-1000), rinsed with distilled water, dried weighed and stored in moisture free desiccators prior to use. The metal coupons were placed in Petri dishes filled with malt extract poor in nutritive materials and supplied with streptomycin (5μg/mL). The medium with the metal coupons treated with the P.guineense extract (25mg/mL conc.) was then inoculated with fungi isolated from corroded aluminum metal. For the control C1, metal was exposed to common conditions (room temperature and humidity) and not contaminated with fungi. Medium with metals was incubated at 27°C. The entire experiments were uniformly prepared in triplicates, labeled accordingly and inserted on the same day. The experiment was observed for a period of 60days. To determine weight loss with respect to time, the coupons were retrieved after 10 days intervals progressively, scrubbed with bristle brush, washed with distilled water, dried and weighed. The weight loss was taken to be the difference between the weight of coupons at a given time (day) and its initial weight. All tests were in triplicate and the data showed good reproducibility.

2.4. Antifungal Screening

The plant extracts were assayed for antifungal activity by the disc diffusion method. About 100g of the dried and powered seed was extracted with 500mL each of methanol, ethanol, hot water (90°C), and cold water (20°C) respectively to yield four distinct extracts. The Petri dishes were filled with malt extract poor in nutritive materials and supplied with streptomycin (5μg/mL). The medium was then inoculated with fungi and filter discs impregnated with the extracts (100mg/L and 50mg/L concentrations) subsequently placed aseptically on the seeded plates which were incubated at 27ºC for 7 days. The radius of the zone of inhibition was measured from the edge of the disc to the edge of the zone. To determine the minimum inhibitory concentrations of the extract, the stock was diluted to yield four different concentrations (12.5, 25, 50 and 100mg/mL). The medium was prepared as above but at this time the filter discs were impregnated with the different concentrations of the extract. The lowest concentration of the extracts that showed clear visible growth inhibition was recorded as the minimum inhibitory concentration.

2.5. Electrochemical Measurement

The potentiodynamic polarization test was carried out in a standard three-electrode glass cell of 500 ml capacity using Electrochemical System workstation (PAR 263). A graphite rod served as counter electrode and, a saturated calomel electrode (SCE) was used as reference electrodes. A mild steel and aluminum specimen of 1 cm2 dimension were used as working electrode. Electrochemical measurements were carried out at 30±1°C, using standard procedures as outlined by [5], in aerated solutions at the end of 1800s of immersion, which allowed the open circuit potential (OCP) values to attain steady state. The potentiodynamic polarization (PDP) experiments were then conducted at a scan rate of 0.333 mV/s. The potential range employed was -250 mV to + 300 mV versus corrosion potential. Powersuite software was used in analyzing the polarization data.

3. Results

3.1. Phytochemical Analysis

Table 1 shows the results of the phytochemical screening and the percentage amounts of key phytochemical constituents present in P.guineense seed extract. They include saponins, alkaloids, tannins, flavonoids and phenol. According to [12], the alkaloids present in P.guineense extract are essentially piperidyl amide alkaloids, including piperine which is responsible for the pungency. They also observed that tannin moieties present in the extract with their protein –binding abilities could interact with basic constituents of protein present in cell membranes thereby inhibiting some key metabolic functions of the cells [12].

Table 1. Qualitative and Quantitative phytochemical constituents of P. guineense

3.2. Antifungal Activity of the Extract

The results of the fungicidal activity of the extract of P. guineense against A.fumigatus are shown in Table 2. The highest growth inhibitory activity was obtained from the stock solution of the cold water extract. Table 3 shows the summary of the minimum inhibitory concentration (MIC) of the extracts. The MIC closely followed the same trend as the growth inhibition effect of the extracts [12] with only the cold water extract exhibiting significant inhibition of the mycelia growth of A.fumigatus at the 25mg/mL concentration.

Table 2. Antifungal activity of the seed extract of P. guineense against A. fumigatus

Table 3. Minimum inhibitory concentration (MIC) of different extracts of Piper guineense against A.fumigatus

3.3. Corrosion Inhibition Results

3.3.1. Gravimetric Data

The inhibitive effects of cold water CW extract of P.guineense on the corrosion behavior of aluminum in the presence of A. fumigatus was studied using gravimetric technique. Figure 1 and Figure 2 shows the weight loss and corrosion rates of aluminum in the presence and absence of the inhibitor respectively. The plots show that P.guineense extract effectively retarded aluminum corrosion at the concentration studied. Furthermore, the corrosion rate was found to increase with exposure time.

Figure 1. Weight loss of A. fumigatus influenced corrosion of aluminium in the presence and absence of inhibitor Piper guineense

Figure 2. Corrosion rate of A. fumigatus influenced corrosion of aluminium in the presence and absence of inhibitor Piper guineense

3.3.2. Electrochemical Data

Potentiodynamic polarization studies were carried to ascertain the effects of the fungi on the corrosion behavior of the metals, the influence of the fungi on the anodic and cathodic reactions processes and the influence of the extract on the kinetics of anodic and cathodic partial reactions of the corrosion processes. The electrochemical parameters including the corrosion current density (Icorr) and corrosion potential (Ecorr) in the presence of the inhibitor can be observed from Tafel plot (Figure 3).

Table 4. Polarization data for aluminium in the presence and absence of fungi and Piper guineense

Figure 3. Potentiodynamic polarization curve for aluminium in the presence of A. fumigatus and inhibitor P.guineense

4. Discussion

The results of the phytochemical screening and percentage amount of key phytochemical constituents of P. guineense seed extract is in line with the findings of [23] and [12]. They isolated alkaloids, flavonoids, saponins and tannin from the seeds extracts of P. guineense. Also the phytochemical screening of P.guineense and A. melegueta conducted by [24] showed that the seeds of these plants contained alkaloids, flavonoids, tannin, saponin, steroids, terpenes, phenols and cardiac glycosides. Oguzie et al., [5] reported that the alkaloidal constituents responsible for the pungency and peppery flavour are collectively called capsaicinoids. For instance, components with phenolic structures such as phenylpropenes are known to be very active against microorganisms. The high concentration of saponin present in the extracts act on the microbial cells as detergents, just as reported for quaternary ammonium salts [5], dissolving lipids and thus causing the loss of cellular contents. The tannin moieties, with their protein-binding abilities, could interact with bacic constituents of proteins present in cell walls, cell membranes and cytoplasm with resultant inhibition of key metabolic functions of the cells. The above effects could have contributed to the observed fungal growth inhibition. Echo et al., [24] observed that these phytochemicals exhibit a wide range of biological effects as a consequence of their antioxidant properties. Okoye and Ebeledike [23] also observed that flavoids possess antioxidant activity and equally anti-inflammatory. Kubmarawa et al., [25] reported the importance of alkaloids, saponins and tannins in various antibiotics used in treating common pathogenic strains. Nwaiwu and Imo [29] also reported the antifungal properties of the essential oil of P.guineense on food-borne fungi. It is therefore possible that the antimicrobial properties of these extracts might have played some roles in inhibiting the growth of the fungi and subsequent inhibition of the corrosion processes.

Figure 1 and Figure 2 shows gravimetric results of the effects of P.guineense on the influence of fungi on Aluminium. Oguzie et al., [5] studied the anticorrosion effects of the ethanol extract of Capsicum frutescens on the low carbon in acidic media using gravimetric, impedence and polarization techniques. They observed that C.frutescens effectively inhibited both corrosion and growth of SRB due to the action of the phytochemical constituents present therein which included alkaloids, tannins and saponins (which are also present in P.guineense). It is therefore possible that the inhibition of the corrosion and fungal growth observed might have been as a result of the presence of these phytochemicals in the seed extracts. The authors also stated that saponin possesses fungicidal activities against A. fumigatus species. Although the detailed mechanism of the fungicidal actions of P. guineense were not extensively investigated, actions of the observed growth inhibition abilities could be attributed to lipids dissolving ability of saponin moieties [5] which results in loss of cellular content as well as the protein binding abilities of tannins which facilitates interference with key metabolic functions of the cells. Oguzie et al., [12] also studied the anticorrosion effect of P.guineense leave extract on corrosion associated sulfate –reducing bacteria (SRB), Desulfotomaculum species. P.guineense was found to be excellent inhibitor for both corrosion and SRB growth. They also attributed both effects to phytochemical constituents present in the extract.

From the polarization curve it can be observed that the cathodic reaction was inhibited by P.guineese. This was observed in the shift of Ecorr towards the more negative potential. Similar observations have been reported by [30] in their study of corrosion and microbial (SRB) growth inhibiting effects of P. guineense extract. Ahamed et al., [19] stated that if displacement in Ecorr is > 85mV, the inhibitor can be seen as a cathodic or anodic type inhibitor and if the displacement is < 85mV the inhibitor can be seen as mixed type. In this study, the Ecorr value is less than 85mV, which indicates that the inhibitor is a mixed type inhibitor showing more inhibition at the cathodic than at the anodic sites.

5. Conclusions

This study has established that the seed extract of P.guineense can inhibit the fungal corrosion of aluminum as well as the growth of A.fumigatus. The antifungal effect of the cold water extract is attributed to the absorption of the phytochemical constituents of the extract which disrupt the growth and essential metabolic functions of the fungus. For example the high concentration of saponin in the extract acts on the microbial cells as detergents. Secondly components with phenolic structures such as phenylpropene are known to be very active against microorganism. The polarization measurements show that the corrosion inhibition followed a mixed-type mechanism. The results obtained in this study are consistent with our hypothesis that the phytochemical constituents of P. guineense seed extract can be exploited for fungal –influenced corrosion of metals and inhibition of fungal growth.

Conflict of Interest

The authors declare that there is no conflict of interest.

References

[1]   | Beech IB and Sunner J. Biocorrosion: towards understanding Interaction biofilms and metals.Current Opinion in Biotech, 15: 181-186, 2004.
[2]   | Koch GH, Brongers MPH, Thomas NG, Virman YP and Payer JH. Corrosion cost and preventive strategies in United States Supplement to Material Performance, 1-12, 2002.
[3]   | Lichter JA, Van Vliet, KJ and Rubner, MF. Design of antibacterial surfaces and interfaces: polyeletrolyte multilayers as a multifunctional platform. Macromolecules, 42: 8573, 2009.
[4]   | Li Y, Zhao P, Liang Q, and Hou B. Beberine as a natural source inhibitor for mild steel in 1M H₂SO₄. Applied Surface Sci, 252: 1245-1253. 2005.
[5]   | Oguzie EE, Oguzie, KL, Akalezi, CO, Udeze, IO, Ogbulie, JN and Njoku, VO. Natural Products for materials protection: Corrosion and Microbial growth inhibition using Capsicum frutescens biomass extraction. Chemical Eng, 1: 214-225. 2013.
[6]   | Videla HA, and Herrera LK. Microbiologically influenced corrosion: looking to the future. International Microbiol, 8: 169-180. 2005.
[7]   | Lin J, and Ballim R. Biocorrosion control: current strategies and promising alternatives. African Journal of Biotechnol, 11(91) 15736-15747. 2012.
[8]   | Rajasekar A, Anandkumar B, Maruthamuthu S, Ting YP, and Rahman PKSM. Characterization of corrosive bacteria consortia isolated from petroleum product-transporting pipelines. Applied Microbiology and Biotechnol, 85: 1175-1188. 2010.
[9]   | Amitha Rani BE, and Bharathi Bai JB. Green inhibitors for corrosion protection of metals and alloys: An overview. International Journal of Corr; 10: 70-80. 2012.
[10]   | Gunasekaran G, and Chuhan LR, Eco-friendly for corrosion inhibition of mild steel in phosphoric acid medium. Electrochimica. Acta, 49: 4387-4395. 2005.
[11]   | El-Etre AY, Abdallah M, and El-Tantawy, ZE. Corrosion inhibition of some metals using Lawsonia extract. Corrosion Sci, 47: 385-395. 2006.
[12]   | Oguzie EE, Ogukwe, CE, Ogubulie, JN, Nwanebo FC, Adindu CB, Udeze IO, Oguzie KL Eze FC. Broad Spectrum corrosion inhibition: Corrosion and Microbial (SRB) growth inhibiting effects of Piper guinenese extracts. Journal Material Sci; 47: 3592-3601. 2012.
[13]   | Singh A, Ebenso EE, Quraishi MA. Corrosion inhibition of carbon steel in HCl solution by some plant extracts. International Jorunal of Corr; Article ID 897430. 2012.
[14]   | Merritt K, and Brown SA. Effect of proteins and pH on fretting corrosion and metal ion release. Journal of Biomedical Materials Research, 22: 111-120. 2004.
[15]   | Lambert RJW, Sjandamis PN, Coote PJ, and Nychas GJE. A study of minimum inhibitory concentration and mode of action of oregano essential oil, thmol and carvacrol. Journal of Applied Microbiol, 91: 453-462. 2001.
[16]   | O’toole GA, Kaplan B and Kolter R. Biofilm formation as microbial development. Annual Review of Microbiol, 54: 49-79. 2000.
[17]   | Abdel-Gaber AM, Abd-El-Nabey B.A, Sidahmed IM, El- Zayady MA and Saadaway M. Inhibitive action of some plant extracts on the corrosion of steel in acid media. Corrosion Sci, 48: 2765-2779. 2006.
[18]   | Zhang F, Pan J and Claesson PM. Electrochemical and AFM studies of mussel adhesive protein (Mefp-1) as corrosion inhibitor for carbon steel. Electrochemical Acta, 56:1636-1645. 2011.
[19]   | Ahamad J Prasad R and Quraishi MA Adsorption and inhibitive properties of some new mannich bases of Isatin derivatives on corrosion of mild steel in acidic media. Corrosion Sci., 52, 1474-1475. 2010.
[20]   | Costa RMPB, Vaz AFM, Oliva MLV and Correia, MTS. A new Phthirusa pyrifolia leaf lectin with antimicrobial properties. Process Biochem; 45: 526-533. 2010.
[21]   | Videla HA. Biocorrosion and biofouling of metals and alloys of industrial usage: Present state of art at the beginning of new millennium. Revista de Metalurgia, Madrid, 1:256-264. 2003.
[22]   | Hussian HA, Charles W, Spear JR, Brajendra M and David, LO. Identification of microorganisms and their effects on corrosion of carbon steel pipeline. NACE International conference and expo. Paper No. 11231, 2011.
[23]   | Okoye, E.I. and Ebeledike, A.O. Phytochemical constituents of Piper guineense and their health implications on some microorganisms. Global research Journal of Science, 2(2): 42-46. 2013.
[24]   | Echo I A, Osuagwu AN, Agbor RB, Okpako EC, Ekanem BE. Phytochemical Composition of Aframomum melegueta and Piper guineense seeds. World Journal of Applied Environmental Chem, 2: 17-2. 2012.
[25]   | Kubmarawa, D., Ajoku, G.A., Enworem, N.M. and Okorie, D.A. (2007) Afri. J. Biotechnol, 6: 1690-1696. 2007.
[26]   | Doss, A., Dhanabalan, R., Palaniswamy, S.M., Geeltha, V. and Ayyapa Das, M.P. Screening for antibacterial activity of twelve medicinal plants used in South India for folklonic medicine. Pharmacologyonline, 1: 83-89. 2009.
[27]   | Kredy, M.H. Antibacterial activity of Saponins extracts from Sider. Zizphus Journal of Thi Qar University, 1(6). 2010.
[28]   | Cushine T.P.T. and Lamb, A.J. Antimicrobial activity of flavoids. International Journal of Antimicrobial Agents, 26: 343-356. 2005.
[29]   | Nwaiwu, M.Y., Imo, E.O. (1999) Control of food-borne fungi by essential oils from local spices in Nigeria. Acta Phytopoathologica Hungarica, 34(1-2) 91-97. 1999.
[30]   | Kliskic M Radosevic J Gudic S and Katalinic V. Aqueous extract of Rosemarinus officinalis L. as inhibitor of Al-Mg alloy corrosion in chloride solution. Journal of Applied Electrochem, 30: 823-830. 2000.