Elsevier

Food Chemistry

Volume 126, Issue 3, 1 June 2011, Pages 1025-1032
Food Chemistry

Antifungal and antibacterial activities of lectin from the seeds of Archidendron jiringa Nielsen

https://doi.org/10.1016/j.foodchem.2010.11.114Get rights and content

Abstract

A Archidendron jiringa Nielsen lectin was purified by aqueous extraction, 90% ammonium sulphate precipitation and concanavalinA-Sepharose 4B affinity chromatography. Its specific activity was of 88.3 × 102 hemagglutination unit/mg protein for a yield of 51.6% total protein. The molecular weight is of 35.7 kDa. It has hemagglutinating activity against human blood group, rabbit, mouse, rat, guinea pig, geese and sheep erythrocytes. The hemagglutination activity of lectin was relatively insensitive to acidic pH above 2, had an optimal activity at pH 8, and stable below 45 °C for 30 min. The activity was stimulated by Ca2+, Mg2+ and Mn2+. The internal sequence indicated similarity with legume lectin family. Moreover, even at low concentrations antifungal activity was observed against Exserohilum turcicum, Fusarium oxysporum and Colletotrichum cassiicola. The minimal inhibitory concentrations were 0.227, 0.0567 and 0.0567 mg/ml for Bacillus subtilis, Staphylococcus aureus, and Candida albicans, respectively.

Research highlights

► Many plants contain proteins that are usually referred to as lectins on the basis of their specific carbohydrate-binding properties. ► They were originally only isolated from plant extracts and were used for the agglutination of blood cells. ► Some of the lectins isolated from plants were found to exhibit different biological activities. ► This paper reports on the inhibitory effect of purified A. jiringa seed lectin against growth of plant-pathogenic bacteria and fungi.

Introduction

Lectins are proteins or glycoproteins of a ubiquitous distribution in nature, which have at least one carbohydrate or derivative binding site without catalytic function or immunological characteristics. They have the unique ability to recognise and bind reversibly to specific carbohydrate ligands without any chemical modification; this distinguishes lectins from other carbohydrate binding proteins and enzymes, and makes them invaluable tools in biomedical and glycoconjugate research (Peumans & Van Damme, 1995). Plants were the first discovered source of lectins and, although lectins have since been found to be universally distributed, plants remain the most frequently used source of lectin studies due to both the ease of their extraction and the relatively high yields that can be obtained. Moreover, different families of plants, as well as different tissues within the same plant, can contain different lectins with different bioactivities, including different carbohydrate-binding specificities. It has been suggested that plant lectins may have important roles according to their abundance, including in the immune defence, and also that lectins have been co-opted adapted for several functions during evolution (Sharon & Lis, 2001).

The role of lectins in the defense mechanism of plants may have evolved from the ability to lectins to agglutinate and immobilise microorganisms. The supporting evidence for this proposed role in defense against pathogens falls into two main observed categories, namely (a) the presence of lectins at potential sites of invasion by infectious agents, and (b) the binding of lectins to various fungi and their ability to inhibit fungal growth and germination. A number of studies with respect to the potential defense role of plant lectins have been reported. For example, during the imbibition of dry soybean seeds, lectin is released into the water and the presence of this lectin in the vicinity of germinating seeds hints at possible interactions of lectins with potential pathogens. The developmental pattern of the initial accumulation and final disappearance of lectin can be observed during the seed dormancy, germination and maturation, which may implicate the role of lectins in a defense mechanism necessary for plants in the initial stages of growth. Moreover, some lectins may provide some protection to plants against generalist herbivores (Howard et al., 1972, Peumans and Van Damme, 1995).

Archidendron jiringa Nielsen (Fabaceae: Mimosoideae), the Jenkol bean or Luk Nieng tree, is a leguminous tree that is found in Indonesia, Malaysia and Thailand, and is economically important with diverse uses, including as a vegetable (young shoots) and pulse or food flavouring agent (seeds), medicine (leaves), source of dye for silk (pods) and timber for craft work and firewood (Ong & Norzalina, 1999). Given the abundance of this commercial species, and especially the abundant seed production (1000–4000 seeds per tree per year).

An overwhelming number of plant lectins have been isolated and characterised from various diverse plant families. The majority of the well characterised plant lectins have been isolated from the seeds of plants, such as Leguminoseae. However, plant lectins of seeds from other plant species outside of legumes (mimosaceous plants) are also emerging as promising tools, chiefly because they can contain novel sugar binding sites and can provide valuable information regarding the biological roles of plant lectins, which to a large extent still remains elusive. The objective of this research was to evaluate an appropriate isolation and purification technique for lectin(s) from the abundantly produced A. jiringa seeds and to biochemically characterise the lectin obtained for future novel applications.

Section snippets

Biological material

Seeds of A. jiringa were purchased from a local market (Bangkok, Thailand). A voucher specimen (BKF. No. 8261) is deposited at The Forest Herbarium (BKF), Royal Forest Department, Bangkok, Thailand. The human blood was obtained from the blood donation office of the Thai Red Cross Society, Bangkok, Thailand. All other animal blood was supplied from the Division of Production and Supply, National Laboratory Animal Center, Mahidol University, Nakhon Pathom, Thailand. The five bacterial strains

Purification of lectin from the seeds of A. jiringa

The present report represents the first investigation on the purification of a lectin from A. jiringa seeds. A. jiringa seeds were homogenated and defated to form a crude soluble extract and, after 90% saturation ammonium sulphate precipitation and dialysis, the lectin was purified in a single step by affinity chromatography column using ConA Sepharose, yielding a single apparent lectin at ∼3.3% (w/w) of the total starting seed weight. The yield and specific agglutination activity, as a marker

Conclusions

A lectin was purified from the seeds of A. jiringa by ConA Sepharose based affinity chromatography with elution by competitive displacement using methyl-α-d-glucopyranoside. The hemagglutination activity of lectin was optimal at pH 8 and relatively stabile, although suboptimal, at acidic pH values down to pH 2, but was markedly reduced by more basic pH values above 8. The lectin was heat stable below 45 °C for 30 min, with 50% of its maximum activity being retained after 120 min of incubation at 40

Acknowledgements

The authors wish to thank the Chulalongkorn University graduate school thesis grant, the National Research University Project of CHE, the Ratchadaphiseksomphot Endowment Fund (AM007I), and the Thai Government Stimulus Package 2 (TKK2555), for financial support of this research, as well as the Institute of Biotechnology and Genetic Engineering and Biotechnology program, the Faculty of Science, Chulalongkorn University for support and facilities. We also wish to thank Dr. Robert Butcher

References (31)

  • N. Vega et al.

    Isolation and characterisation of a Salvia bogotensis seed lectin specific for the Tn antigen

    Phytochemistry

    (2006)
  • P. Verheyden et al.

    1H-NMR Study of the interaction of N, N′, N′′-triacetyl chitotriose with Ac-Amp2, a sugar binding antimicrobial protein isolated from Amaranthus caudatus

    FEBS Letters

    (1995)
  • D.A. Wah et al.

    Crystal structure of native and Cd/Cd-substituted Dioclea guianensis seed lectin. A novel manganese-binding site and structural basis of dimer-tetramer association

    Journal of Molecular Biology

    (2001)
  • J.H. Wong et al.

    A mannose/glucose-specific lectin from Chinese evergreen chinkapin (Castanopsis chinensis)

    Biochimica et Biophysica Acta (BBA)-General Subjects

    (2008)
  • N. Absar et al.

    Single step purification, characterization and N-terminal sequences of a mannose specific lectin from mulberry seeds

    Protein Journal

    (2005)
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