Antibacterial Activity of Kaempferia rotunda Rhizome Lectin and Its Induction of Apoptosis in Ehrlich Ascites Carcinoma Cells

Plant lectins: A new antimicrobial frontier

Pathogenic bacteria, viruses, fungi, parasites, and other microbes constantly change to ensure survival. Several pathogens have adopted strict and intricate strategies to fight medical treatments. Many drugs, frequently prescribed to treat these pathogens, are becoming obsolete and ineffective. Because pathogens have gained the capacity to tolerate or resist medications targeted at them, hence the term antimicrobial resistance (AMR), in that regard, many natural compounds have been routinely used as new antimicrobial agents to treat infections. Thus, plant lectins, the carbohydrate-binding proteins, have been targeted as promising drug candidates. This article reviewed more than 150 published papers on plant lectins with promising antibacterial and antifungal properties. We have also demonstrated how some plant lectins could express a synergistic action as adjuvants to boost the efficacy of obsolete or abandoned antimicrobial drugs. Emphasis has also been given to their plausible mechanism of action. The study further reports on the immunomodulatory effect of plant lectins and how they boost the immune system to curb or prevent infection.

Phytogenic silver nanoparticles from tissue-cultured Kaempferia angustifolia - an underutilized medicinal herb: a comparative antibacterial study on urinary pathogens

Background

Ethnomedicinally important Kaempferia angustifolia is a rhizomatous aromatic herb belonging to the family Zingiberaceae. The present manuscript deals with the green synthesis of silver nanoparticles through a rapid reduction process mediated by the rhizome extract of tissue culture-raised plants. The present study was conducted to evaluate the antimicrobial activity of the bio-nanoparticles, and the plant extracts themselves against seven multidrug-resistant urinary tract infecting (MDR-UTI) pathogens.

Result

The ethanolic extracts of the rhizomes of the plant executed a very rapid synthesis of silver bio-nanoparticles, and the generation of the nanoparticles was confirmed through UV-vis spectrophotometry, dynamic light scattering (DLS), and electron dispersion spectroscopic (EDS) analysis. Finally, the precise shapes and dimensions of these nanoparticles were confirmed under the transmission electron microscope (TEM). The shapes of the nanoparticles obtained were diverse in nature and varied from rod, triangular, spherical, to oval shaped, with the size, ranging from 10–60 nm. Silver nanoparticles exhibited a maximum zone of inhibition (ZI) of 16.93 ± 0.04 mm against isolate no. 42332. The ex vitro and in vivo extracts exhibited ZI 14.03 ± 0.04 mm and 11.56 ± 0.04 mm, respectively, against the same strain, which are comparatively lower than the nanoparticles but unignorable.

Conclusion

Although the pathogens used in the present study are resistant to at least three or more types of pharmacologically important antibiotics, nanoparticles, as well as the plant extracts, exhibited significant inhibition to all the seven MDR-UTI pathogens, which confirms that they are highly antimicrobic. Hence, this underutilized medicinal plant extracts of K. angustifolia and the bio-nanoparticles synthesized from these can be explored in pharmaceutical industries to treat multidrug-resistant human pathogenic bacteria. Furthermore, their broad-spectrum activity leads to the opportunity for the synthesis of future generation drugs.

Supplementary Information

The online version contains supplementary material available at 10.1186/s43141-022-00414-4.

Antioxidant, cytotoxic and apoptotic activities of the rhizome of Zingiber zerumbet Linn. in Ehrlich ascites carcinoma bearing Swiss albino mice

Due to having a long history of traditional uses as a functional food, Zingiber zerumbet was selected here to explore the inherent antioxidant and antineoplastic activities of methanolic extract of its rhizome (MEZZR) against Ehrlich ascites carcinoma (EAC) cells. The rich polyphenol containing MEZZR showed a marked DPPH, ABTS, nitric oxide radicals and lipid peroxidation inhibition activity with an IC₅₀ of 3.43 ± 1.25, 11.38 ± 1.39, 23.12 ± 3.39 and 16.47 ± 1.47 µg/ml, respectively, when compared to the standard catechin. In vivo, MEZZR significantly inhibited EAC cell growth, decreased body weight gain, increased life span and restored the altered hematological characteristics of EAC-bearing mice. Moreover, MEZZR induced nuclear condensation and fragmentation, which are notable features of apoptosis as observed by fluorescence microscopy after staining EAC cells of MEZZR-treated mice with Hoechst 33342. Additionally, in vitro, the cell growth inhibition caused by the MEZZR in MTT assay, was remarkably decreased in the presence of caspase-3, -8 and -9 inhibitors. This study thus suggests that MEZZR may possess promising antiproliferative efficacy against EAC cells by inducing cell apoptosis.

A review on the antimicrobial properties of lectins

Lectins are biologically versatile biomolecules with remarkable antimicrobial effects, notably against bacteria, fungi and protozoa, in addition to modulating host immunity. For this, the lectins bind to carbohydrates on the surface of the pathogen, which can cause damage to the cell wall and prevent the attachment of microorganisms to host cells. Thus, this study intends to review the biological activities of lectins, with an emphasis on antimicrobial activity. Lectins of plant stood out for its antimicrobial effects, demonstrating that they act against a variety of strains, where in vitro were able to inhibit their development and affect their morphology. In vivo, they modulated host immunity, signaling and activating defense cells. Some of these lectins were capable to modulate the action of antibiotics, indicating their potential to minimize the antibiotic resistance. The results suggest that lectins have antimicrobial activity with potential to be used in drug development.

A N-acetyl-D-galactosamine-binding lectin from Amaranthus gangeticus seeds inhibits biofilm formation and Ehrlich ascites carcinoma cell growth in vivo in mice

AGL, a 15-kDa lectin from Amaranthus gangeticus seeds was isolated using ion-exchange and gel filtration chromatography. AGL contained 8.55% of neutral sugar and became specifically inhibited by N-acetyl-D-galactosamine. Hemagglutination activity of the lectin was maximum over the pH range of 4.0-6.0 and temperatures of 30-60 °C though it lost the activity when treated with urea and EDTA. With an LC₅₀ value of 250 μg/ml, AGL showed mild toxicity against Artemia nauplii. It inhibited the growth of pathogenic bacteria like Shigella boydii, Shigella dysenteriae and Staphylococcus aureus when treated for 8 and 16 h, respectively, but lost the antibacterial activity during a 24 h treatment. AGL could not inhibit the growth of Escherichia coli and mitogenic growth (7.0-9.0%) was observed instead. AGL inhibited 37.14%, 65.71% and 82.85% of biofilm formation of Escherichia coli at the concentrations of 250, 500 and 1000 μg/ml, respectively. Marked inhibition of the proliferation of Ehrlich ascites carcinoma cells was determined when treated with various doses of AGL. AGL inhibited 65.89% and 81.25% of the in vivo growth of EAC cells in mice at the doses of 2.0 and 4.0 mg/kg/day, respectively. Significant alteration of the expression of apoptosis related genes Fas, NF-kB and MAPK were observed.

Trichosanthes dioica seed lectin inhibits Ehrlich ascites carcinoma cells growth in vivo in mice by inducing G0 /G1 cell cycle arrest

Trichosanthes dioica seed lectin (TDSL), having a molecular mass of 57 ± 2 kDa was purified in an alternative way. For the purification process, the galactose-sepharose-4B affinity column was used. The purified TDSL agglutinated human and mouse erythrocytes at the minimum concentration of 8  μg/ml. d-lactose and d-galactose were the most potent inhibitory sugars as observed. The purified lectin was a glycoprotein having 3.0% of a neutral sugar. The lectin exhibited maximum activity up to 60°C and pH range from 7.0 to 10.0 and stable up to 4.0 M urea as tested. The lectin demonstrated mild toxicity when administered against brine shrimp nauplii, and the LC₅₀ value was calculated to be 84.0 µg/ml. Minimum agglutination of Ehrlich ascites carcinoma (EAC) cells caused by the lectin was found at the protein concentration of 1.56 µg/ml. TDSL inhibited 7, 50.2%, and 60.3% of the EAC cells growth in vivo in mice when administered with 0.75, 1.5, and 3.0 mg kg^-1  day^-1 (i.p.), respectively, for five consecutive days. After lectin treatment, red blood cell (RBC) and hemoglobin levels were increased significantly toward the normal compared with EAC cells-bearing control and normal mice. The tumor burden reduced to 29.5% and 67% after treatment with 1.5 and 3.0 mg kg^-1  day^-1 of the lectin. TDSL triggered the cell cycle arrest at the G₀ /G₁ phase, which was observed using flow cytometry. In conclusion, TDSL can be a candidate for the potent anticancer agents that exerts low toxicity toward brine shrimp nauplii. PRACTICAL APPLICATIONS: A 57 ± 2 kDa lectin (designated TDSL) was purified from Trichosanthes dioica seeds using a galactose-sepharose-4B affinity column. The lectin demonstrated mild toxicity and agglutinated Ehrlich ascites carcinoma (EAC) cells. The lectin inhibited 50.2% and 60.3% of the EAC cell growth in vivo in mice when administered with 1.5 and 3.0 mg kg^-1  day^-1 (i.p.), respectively, for five consecutive days. The lectin increased RBC and hemoglobin level toward the normal compared with lectin-treated EAC cells-bearing, EAC cells-bearing control and normal mice. The tumor burden reduced to 29.5% and 67% after treatment with 1.5 and 3.0 mg kg^-1  day^-1 lectin. TDSL triggered the cell cycle arrest at the G₀ /G₁ phase. The lectin can be a candidate for potent anticancer agents.

Animal Galectins and Plant Lectins as Tools for Studies in Neurosciences

Lectins are proteins or glycoproteins of non-immunological origin capable of reversibly and specifically binding to glycoconjugates. They exist in free form or associated with cells and are widely distributed in nature, being found in plants, microorganisms, and animals. Due to their characteristics and mainly due to the possibility of reversible binding to glycoconjugates, lectins have stood out as important tools in research involving Neurobiology. These proteins have the ability to modulate molecular targets in the central nervous system (CNS) which may be involved with neuroplasticity, neurobehavioral effects, and neuroprotection. The present report integrates existing information on the activity of animal and plant lectins in different areas of Neuroscience, presenting perspectives to direct new research on lectin function in the CNS, providing alternatives for understanding neurological diseases such as mental disorders, neurodegenerative, and neuro-oncological diseases, and for the development of new drugs, diagnoses and therapies in the field of Neuroscience.

MytiLec-1 Shows Glycan-Dependent Toxicity against Brine Shrimp Artemia and Induces Apoptotic Death of Ehrlich Ascites Carcinoma Cells In Vivo

MytiLec-1, a 17 kDa lectin with β-trefoil folding that was isolated from the Mediterranean mussel (Mytilus galloprovincialis) bound to the disaccharide melibiose, Galα(1,6) Glc, and the trisaccharide globotriose, Galα(1,4) Galβ(1,4) Glc. Toxicity of the lectin was found to be low with an LC₅₀ value of 384.53 μg/mL, determined using the Artemia nauplii lethality assay. A fluorescence assay was carried out to evaluate the glycan-dependent binding of MytiLec-1 to Artemia nauplii. The lectin strongly agglutinated Ehrlich ascites carcinoma (EAC) cells cultured in vivo in Swiss albino mice. When injected intraperitoneally to the mice at doses of 1.0 mg/kg/day and 2.0 mg/kg/day for five consecutive days, MytiLec-1 inhibited 27.62% and 48.57% of cancer cell growth, respectively. Antiproliferative activity of the lectin against U937 and HeLa cells was studied by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay in vitro in RPMI-1640 medium. MytiLec-1 internalized into U937 cells and 50 μg/mL of the lectin inhibited their growth of to 62.70% whereas 53.59% cell growth inhibition was observed against EAC cells when incubated for 24 h. Cell morphological study and expression of apoptosis-related genes (p53, Bax, Bcl-X, and NF-κB) showed that the lectin possibly triggered apoptosis in these cells.

Plant lectins in cancer therapeutics: Targeting apoptosis and autophagy-dependent cell death

Plant lectins are non-immunoglobin in nature and bind to the carbohydrate moiety of the glycoconjugates without altering any of the recognized glycosyl ligands. Plant lectins have found applications as cancer biomarkers for recognizing the malignant tumor cells for the diagnosis and prognosis of cancer. Interestingly, plant lectins contribute to inducing cell death through autophagy and apoptosis, indicating their potential implication in cancer inhibitory mechanism. In the present review, anticancer activities of major plant lectins have been documented, with a detailed focus on the signaling circuit for the possible molecular targeted cancer therapy. In this context, several lectins have exhibited preclinical and clinical significance, driving toward therapeutic potential in cancer treatment. Moreover, several plant lectins induce immunomodulatory activities, and therefore, novel strategies have been established from preclinical and clinical investigations for the development of combinatorial treatment consisting of immunotherapy along with other anticancer therapies. Although the application of plant lectins in cancer is still in very preliminary stage, advanced high-throughput technology could pave the way for the development of lectin-based complimentary medicine for cancer treatment.

Integrins Were Involved in Soybean Agglutinin Induced Cell Apoptosis in IPEC-J2

Soybean agglutinin (SBA), is a non-fiber carbohydrate related protein and a major anti-nutritional factor. Integrins, transmembrane glycoproteins, are involved in many biological processes. Although recent work suggested that integrins are involved in SBA-induced cell-cycle alterations, no comprehensive study has reported whether integrins are involved in SBA-induced cell apoptosis (SCA) in IPEC-J2. The relationship between SBA and integrins are still unclear. We aimed to elucidate the effects of SBA on IPEC-J2 cell proliferation and cell apoptosis; to study the roles of integrins in IPEC-J2 normal cell apoptosis (NCA) and SCA; and to illustrate the relationship and connection type between SBA and integrins. Thus, IPEC-J2 cells were treated with SBA at the levels of 0, 0.125, 0.25, 0.5, 1.0 or 2.0 mg/mL to determine cell proliferation and cell apoptosis. The cells were divided into control, SBA treated groups, integrin inhibitor groups, and SBA + integrin inhibitor groups to determine the integrin function in SCA. The results showed that SBA significantly (p < 0.05) lowered cell proliferation and induced cell apoptosis in IPEC-J2 (p < 0.05). Inhibition of any integrin type induced the cell apoptosis (p < 0.05) and these integrins were involved in SCA (p < 0.05). Even SBA had no physical connection with integrins, an association was detected between SBA and α-actinin-2 ACTN2 (integrin-binding protein). Additionally, SBA reduced the mRNA expression of integrins by down regulating the gene expression level of ACTN2. We concluded an evidence for the anti-nutritional mechanism of SBA by ACTN2 with integrins. Further trials are needed to prove whether ACTN2 is the only protein for connecting SBA with integrin.

Cytotoxic and antiproliferative effect of tepary bean lectins on C33-A, MCF-7, SKNSH, and SW480 cell lines

For many years, several studies have been employing lectin from vegetables in order to prove its toxic effect on various cell lines. In this work, we analyzed the cytotoxic, antiproliferative, and post-incubatory effect of pure tepary bean lectins on four lines of malignant cells: C33-A; MCF-7; SKNSH, and SW480. The tests were carried out employing MTT and 3[H]-thymidine assays. The results showed that after 24 h of lectin exposure, the cells lines showed a dose-dependent cytotoxic effect, the effect being higher on MCF-7, while C33-A showed the highest resistance. Cell proliferation studies showed that the toxic effect induced by lectins is higher even when lectins are removed, and in fact, the inhibition of proliferation continues after 48 h. Due to the use of two techniques to analyze the cytotoxic and antiproliferative effect, differences were observed in the results, which can be explained by the fact that one technique is based on metabolic reactions, while the other is based on the 3[H]-thymidine incorporated in DNA by cells under division. These results allow concluding that lectins exert a cytotoxic effect after 24 h of exposure, exhibiting a dose-dependent effect. In some cases, the cytotoxic effect is higher even when the lectins are eliminated, however, in other cases, the cells showed a proliferative effect.