Department of Zoology, Netaji Mahavidyalaya, Arambagh-712601, West Bengal, India

Corresponding author email: avimukh77@gmail.com

Article Publishing History

INTRODUCTION

During ancient times, plants are the important source of natural products for maintaining normal human life; they are used as natural therapies. According to World Health Organization (Santos et al.1995) all medicinal plants around the world are of good source to obtain a variety of important drugs. Acacia auriculiformis is one of the important therapeutic plant from which many valuable compounds have been isolated. The active principle, which was isolated from the funicles of A. auriculiformis contains two triterpenoid saponins, acaciaside A and acaciaside B which have antifilarial activity against Setaria cervi. Its native origin is in Australia but came in India in 1946 in West Bengal (Kushalapa 1991). It is also important for making paper, furniture’s etc. and has medicinal and forestry importance (Singh et al.2007). The growth of A. auriculiformis is very fast generally first year of its development, its growth rate is also high 2-3 m per year even in low fertility soil (Pinyopusarerk 1990) By adding nitrogen to soil and mixed with other species A. auriculiformis provides enhanced productivity in early thinning operations (CABI 2013).

Acacia auriculiformis is also known as ear leaf Acacia which is an important medicinal plant and widely distributed group of fabaceae (Gijasahnkar 2010). This plant acts as safe and effective substitutes for chemical control against several types of pathogens (Ouassat et al.2020). Many parts of the plant used in traditional medicine such as bark is used as a remedy from rheumatism in Australia, its seeds and roots are used in the treatment of skin diseases and sore eyes respectively (Singh et al. 2007). The plant is also useful as antimalarial drug in many parts of the world as in Nigeria (Okokon et al. 2010). It acts as an antifilarial (Ghosh et al. 1993, Mahato 1996), antioxidant (okokon et al. 2010), antidiabetic (Sathya et al. 2013), antimutagenic (Kaur et al. 2002) compound. Ethylacatate fraction of A. auriculiformis was found to be most potent extract which have protein kinase inhibitory activity and another ethylacetate fraction, 3, 4’, 7, 8-tetrahydroxyflavone was isolated and it is also a potent inhibitor of DYRK1A and CDK9 which proves the plants anticancer and intiflammatory property (Ahmadu et al. 2019).

Acaciaside generally grows in humid areas and also rich in glucuronic acid, methylglucuronic acid, arabinose, rhamnose and galactose (Anderson 1978).Their antibacterial and antifungal activity was proved in several bacterial and fungal strains. In Aspergillus ochraceous and Curvularia lunata complete inhibition of conidial germination was recorded at 300 μg/ml or less but in case of Salmonella typhimurium, Pseudomonas aeruginosa and Bacillus megaterium 700 μg/ml or higher concentrations of the mixture was required for inhibition of their growth (Mandal et al. 2005). E.coli the gram negative bacteria which normally resides as intestinal flora in humans, and also acts as an indicator species of fecal contamination to assess the safety and quality of water (US EPA 1986).

Although E. coli maintains a friendly environment for its anaerobic neighbors by consuming oxygen that enters the gut (Chang et al. 2004), most of them are harmless to humans but certain strains are pathogenic and causes several types of fatal diseases such as bloody diarrhea, watery diarrhea, meningitis, urinary tract infection, and sepsis, which can lead to human death (Nataro et al. 1998, Gyles et al. 2007). E.coli also causes worldwide infections neonatal meningitis, bacteremia and also traveler’s diarrhea (Peleg et al. 2010).Urinary tract infections is the most common in many countries causing community and hospital acquired urinary tract infections (gajdacs et al. 2019). A recent WHO report mentioned that medicinal plants around the world are one of the good sources of new important drugs (Efferth 2017). There are several examples of these compounds isolated from many plants that have been proved to be effective as antimicrobial agents.

In this research, antibacterial activity of acaciaside A and acaciaside B or their mixture were performed to investigate the inhibitory effect of the samples obtained from Acacia plant on the activity of drug-resistant E.coli. This research plays a foundation for the further development of antibacterial agents and also identify the least MIC (minimum inhibitory concentration) value for E.coli in comparison to other bacteria for sustainable normal human life.

MATERIALS AND METHODS

Plant material: Acacia auriculiformis A.Cunn (Mimosaceae) funicles collected from Santiniketan was authenticated by Department of Botany, Visva-Bharati University. The dried and powered leaf extracts of Acacia auriculiformis mixing up with 70% ethanol for 72 hours. Then it is vaccum at 38⁰C and the extract was stored in a refrigerator at 4⁰C for future use.

Use as traditional medicine: Different extracts of the plant material are used against filaridis and helminthes (Ghosh et al. 1993, Ghosh et al. 1996). It has also been examined for its spermicidal activity (Pakrashi et al. 1991) and also for fungicidal activities against Aspergillus ochraceous and Curvularia lunata (Mandal et al. 2005).

Experimental material: Acaciaside A, Acaciaside B and mixture of acaciaside A and acaciaside B obtained from Acacia auriculiformis was used in this experiment (Ghosh et al.1993)

Studied activity: Experiment was conducted to study antibacterial activity after treating with sublithal concentration of acaciaside A, acaciaside B and the mixture of acaciaside A and acaciaside B (Mandal et al. 2005)

Used microorganisms in the experiment: Four bacterial strains belonging to both Gram positive and Gram negative categories (Table 1) were procured from Microbial type Culture Collection, Institute of Microbial Technology, Chandigarh, India.

RESULTS AND DISCUSSION

Antimicrobial activity of acaciaside A and acaciaside B and the mixture of acaciaside A and acaciaside B against four bacteria are reported in (Table 1)

Table 1. MIC (minimum inhibitory concentration) value of acaciaside A and acaciaside B against different bacterial strains

Test Compound (µg/ml)	E.coli MTCC 68 Gram Negative	P.aeruginosa MTCC 741 Gram Negative	S.typhimurium MTCC 98 Gram Negative	B.megaterium MTCC 1684 Gram Positive
Acaciaside A	200	More than 1000	400	600
Acaciaside B	600	600	600	1000
Acaciaside A+B	200	600	400	600

Acaciaside A and acaciaside B singly or in mixture produced inhibitory effect on the growth of bacteria tested. However, the minimum inhibitory concentration of the two saponins when tested against bacterial strains appears to differ. Acaciaside A completely inhibited E.coli at 200 µg/ml as did the mixture of two saponins, whereas acaciaside B inhibited completely at 600 µg/ml. Similar results were obtained in S.typhimurium and B.megaterium where acaciaside A singly or in combination of acaciaside B contributed as the major inhibitory substance. It appears from the results that bacteriostatic activity of saponins may be mediated by acaciaside A. Acaciaside B completely inhibited P. aeruginosa at 600 µg/ml as did the mixture of two saponins, which indicate that the bacterioststic effect of saponins on P.aeruginosa may rest with acaciaside B. Previuosly it was reported that the mixture of two saponins inhibited the growth of P.aeruginosa and S.typhimurium at 700 µg/ml (Mandal et al. 2005).

Here it is suggested that saponins-induced bacteriostatic activity may be strain specific i.e. either Gram +ve or Gram –ve bacteria. In case of E.coli it was noticed that their minimum inhibitory treatment dose either by acaciaside A or their combinationis is only 200.When acaciaside A and B applied in combination or acaciaside A singly to the growing culture, they produced almost similar kind of effects on the inhibition of B.megaterium cells. Major deviation occurs due to stress induced by the compounds at early phases of sporogenesis process. Change of morphology of different Gram positive and Gram negative bacteria were reported due to change in nutritional conditions or stress in the growth environment an even in the growth phase dependent process (Rasanen 2002, Sawer et al. 2005).

Kumar et al, showed that the ethanolic, ethyl acetate, and water extracts with Acaciaside were found be active against certain bacteria such as E.coli and fungi. Many evidences till date shows that the extracts obtained from medicinal plants are effective as antimicrobial agents. But no reports have claimed to observe that bacteria developing resistance to plant-based antimicrobials (PBAs) (Cheesman et al. 2017). In the present investigation inhibitory effect produced by acaciaside A, or in combination with acaciaside B in some bacterial cells was clearly established. As inhibition of P.aeruginosa is not affected very much by saponins probably a different mechanism is operating in the process of inhibition. But in case of E.coli minimum inhibitory concentration was noticeable perfectly.

CONCLUSION

E.coli has a variety of strains that ranging from commensal residents of the gastrointestinal tract to mixed pathogens that are able to create several illnesses. The present investigation aims to discuss the least minimum inhibitory concentration Acacia auriculiformis on bacterial population particularly E.coli. This plant has many medicinally important phytoconstituents which prove their pharmacological activities. Inhibition of E.coli growth by acaciaside A or their combination insights a significant outcome and better understanding in medicinal purposes for future human life.

ACKNOWLEDGEMENT

The Author is thankful to The Institute of Microbial Technology, Chandigarh, India for supplying bacterial strains. Author is also thankful to Prof.S.P.SinhaBabu and Prof. N.C.Mandal Visva-Bharati University for their guidance and valuable suggestions.

REFERENCES

Ahmadu, AA., Lawal, BA., Haruna, A., Mustapha, L. (2019). Tetrahydroxy Flavone from Acacia auriculiformis A. Cunn Ex Benth. (Fabaceae) with Novel Kinase Activity. Journal of Pharmacognosy and Phytochemistry,11(3),559-63.

Anderson, DMW. (1978). Chemotaxonomic aspects of the chemistry of Acacia gum exudates. Kew Bulletin, 32(3),529-536.

CABI, (2013). Acacia auriculiformis. Forestry Compendium,www.cabi.org/fc.

Chang, DE., Smalley, DJ., Tucker, DL., Leatham, MP., Norris, WE., Stevenson, SJ., Anderson, AB., Grissom, JE., Laux, DC., Cohen, PS. (2004). Carbon nutrition of Escherichia coli in the mouse intestine. Proceedings of the National Academy of Sciences of USA, 101(19),7427–7432.

Cheesman, MJ., Ilanko, A., Blonk, B., Cock, IE. (2017). Pharmacognosy reviews developing new antimicrobial therapies: are synergistic combinations of plant extracts/compounds with conventional antibiotics the solution? Pharmacognosy Reviews, 11(22),57–72.

Das, SK., Sarkar, K. (2005). A new method for isolation of leukocytes from the peripheral blood of amphibians [Bufo himalayanus, (Gunther)] and study of their surface morphology by scanning electron microscopy. Indian Journal of Experimental Biology, 43(6),488‐492.

Efferth, T. (2017). From ancient herb to modern drug: Artemisia annua and artemisinin for cancer therapy. Seminars in Cancer Biology, 46:65-83.

Gajd´acs, M., Abr´ok, M., L´az´ar, A., Buri´an, K. (2019). “Comparative ´ epidemiology and resistance trends of common urinary pathogens in a tertiary-care hospital: a 10-year surveillance study,” Medicina, 55 (7), 356.

Ghosh, M., SinhaBabu, SP., Sukul, NC., Mahato, SB.(1993). Antifilarial effect of two triterpenoid saponins isolated from Acacia auriculiformis. Indian Journal of Experimental Biology, 31(7), 604-606.

Gijasahnkar, V. (2010). Micropropagation of multipurpose medicinal tree: Acacia auriculiformis. Journal of Medicinal Plant Research, 5(3),482-6.

Gosh, NK., SinhaBabu, SP., Sukul, NC., Ito, A. (1996). Cestocidal activity of Acacia auriculiformis. Journal of Helminthology,70(2),171 172.

Gyles, CL. (2007). Shiga toxin-producing Escherichia coli: an overview. Journal of Animal Science. 85 (13 Suppl), E45– E62. PMID: 17085726.

Kaur, K., Arora, S., Hawthorne, ME., Kaur, S., Kumar, S., Mehta, R. (2002).A correlative study on antimutagenic and chemopreventive activity of Acacia auriculiformis A. Cunn. and Acacia nilotica (L) Willd ex Del. Drug and Chemical Toxicology,25(1), 39-64.

Kushalapa, KA. (1991) In: Advances in tropical Acacia research. ACIAR Proceedings of an International Workshop held at Bangkok, Thailand, 35, 189-193.

Kumar, SD., Srinivasan, P., Rajalakshmi, M., Raj, RG., Sathiyamurthy, K. (2017). Ecofriendly larvicide source from Acacia auriculiformis and its antimicrobial activity against clinical pathogens. International Journal of Phytomedicine, 9(1), 60-71.

Mahato, SB. (1996). Saponins with antifilarial activity from Acacia auriculiformis Advances in  Experimental Medicine and  Biology,404, 173-184.

Mandal, P., SinhaBabu, SP., Mandal, NC. (2005). Antimicrobial activity of saponins from Acacia auriculiformis. Fitoterapia, 76(5),462‐465.

Nataro, JP., Kaper, JB. (1998). Diarrheagenic Escherichia coli. Clinical Microbiology Review. 11(1), 142–201. Erratum in: Clinical Microbiology Review, 11(2), 403. PMID: 9457432

Okokon, JE., Jackson, O., Opara, KN., Emmanuel, E. (2010).In vivo antimalarial activity of ethanolic leaf extract of Acacia auriculiformis. International Journal of Drug Development and Research, 2(3),482-487.

Ouassat, S., Allam, L. (2020). Toxicity of Three Pesticides to The European red mite Panonychusulmi and its predator, Typhlodromus (T.) setubali (Acari: Phytoseiidae, Tetranychidae). Advances in Agriculture, Horticulture and Entomology, 1-6. AAHE-106.

Pakrashi, A., Ray, H., Pal, BC., Mahato, SB. (1991). Sperm immobilizing effect on triterpene saponins from Acacia auriculiformis. Contraception, 43(5),475-483.

Peleg, A., Hooper, D. (2010). Hospital-Acquired Infections Due to Gram-Negative Bacteria The New England Journal of Medicine, 362(19), 1804–13.

Pinyopusarerk, K (Khongsak). (1990). Winrock International Institute for Agricultural Development and Australian Centre for International Agricultural Research Acacia auriculiformis: an annotated bibliography. Winrock International Institute for Agricultural Development; Canberra: Australian Centre for International Agricultural Research, Morrilton, Ark.

Rasanen, L. (2002).Academic Dissertation Submitted to the University of Helsinki, Helsinki,

Santos, PRV., Oliveira, ACX., Tomassini, TCB. (1995). Controle microbiogico de produtos fitoterapicos. Review Farmacia Bioquímica, 31(1), 35-38.

Sathya, A., Siddhuraju, P. (2013). Protective effect of bark and empty pod extracts from Acacia auriculiformis against paracetamol intoxicated liver injury and alloxan induced type II diabetes. Food and Chemical Toxicology, 56,162‐170.

Sawer, IK., Berry, MI., Ford, JL. (2005). The killing effect of cryptolepine on Staphylococcus aureus. Letters in applied microbiology, 40(1):24‐29.

Singh, R., Singh, S., Kumar, S., Arora, S. (2007). Evaluation of antioxidant potential of ethyl acetate extract/fractions of Acacia auriculiformis A. Cunn. Food and Chemical Toxicology, 45(7),1216‐1223.

U.S. Environmental Protection Agency (EPA). (1986).Ambient water quality criteria for bacteria- 1986. Washington, D.C.: U.S. EPA, Office of Water Regulations and Standards Division, EPA-A440/5-84002.