Purification of a Chitin-Binding Protein from Moringa oleifera Seeds with Potential to Relieve Pain and Inflammation

In-vitro antimicrobial activity of AF-DP protein and in-silico approach of cell membrane disruption

Microbial resistance against common antibiotics has become one of the most serious threats to human health. The increasing statistics on this problem show the necessity of finding a way to deal with it. In recent years, antimicrobial peptides with unique properties and the capability of targeting a wide range of pathogens, have been considered as a potential for replacing common antibiotics. A small chitin-binding protein with anticandidal activity was isolated from Moringa oleifera seeds by Neto and colleagues in 2017, which very much resembled antimicrobial peptides. In this study, the antimicrobial protein 'AF-DP' was identified and characterized. AF-DP was heterologously expressed, purified, and characterized, and its 3D structure was predicted. Six molecular dynamic simulations were performed to investigate how the protein interacts with Gram-negative inner and outer, Gram-positive, fungal, cancerous, and normal mammalian membranes. Also, its antimicrobial and anticancer activity was assessed in vitro via minimum inhibition concentration (MIC) and MTT assays, respectively. This protein with 111 amino acids and a total net charge (of 10.5) has been predicted to be mainly composed of alpha helix and random coils. Its MIC affecting the growth of Escherichia coli, Staphylococcus aureus, and Candida albicans was 30 µg/ml, 100 µg/ml, and 100 µg/ml, respectively; AF-DP showed anticancer activity against MCF-7 breast cancer cell line. Scanning electron microscopic analysis confirmed the creation of pores and scratches on the surface of the bacterial membrane. The results of this research show that AF-DP can be a candidate for the production of new drugs as an AMP with antimicrobial activity.Communicated by Ramaswamy H. Sarma.

Mo-HLPs: New flocculating agents identified from Moringa oleifera seeds belong to the hevein-like peptide family

Cationic peptides found in Moringa oleifera seeds belong to different protein families and are described as the main flocculating agents of the species. In this study we report the identification and isolation of four new flocculant peptides, called Mo-HLPs 1-4, belonging to the family of hevein-like peptides, previously only known for their members' antimicrobial activity. Purification of the peptides followed two sequential membrane ultrafiltration steps and separation by reverse-phase liquid chromatography. Proteomic analyses showed that Mo-HLPs are extremely basic (pI >10) cysteine-rich molecules with molecular masses between 4.5 and 4.8 kDa and with a highly conserved chitin-binding domain. Searches in BLAST revealed high similarity of Mo-HLPs with hevein and other hevein-like peptides and 90% identity with morintides, which are members of the 8C-hevein-like subfamily found in M. oleifera leaves. Mo-HLPs microflocculation assays showed distinct coagulation/flocculation efficiencies, promoting turbidity reduction levels between 67 and 89% in synthetic turbid water. Activity variations were attributed to the substitution of some amino acids among the isoforms, which may have altered the final net charge of the molecules. The identification of Mo-HLPs represents the discovery of a new group of cationic peptides involved in the flocculation properties of M. oleifera seeds. SIGNIFICANCE: The study reveals the presence of hevein-like peptides in Moringa oleifera seeds. It is reported for the first time that members of this family have properties to act as flocculating agents of importance for water treatment processes. The identification of these peptides as well as new functional assignment broadens the horizon for speculation on new species which could act as sources of green coagulants for sustainable water treatment, and contributes to the knowledge about occurrence, distribution, molecular and active diversity of peptides belonging to the hevein-like family.

Mo-CBP4, a purified chitin-binding protein from Moringa oleifera seeds, is a potent antidermatophytic protein: In vitro mechanisms of action, in vivo effect against infection, and clinical application as a hydrogel for skin infection

Dermatophytes belonging to Trichophyton ssp. are important anthropophilic and zoophilic pathogens, which developed resistance to griseofulvin, the common antifungal drug used to treat dermatophytosis. In this context, Moringa oleifera seed proteins have been described as antifungal agents with potential applications. Thus, this work aimed to evaluate the antidermatophytic in vitro, focusing on mechanisms, and in vivo potential of Mo-CBP₄, purified from M. oleifera seeds. Mo-CBP₄was purified after protein extraction with 50 mM Tris-HCl buffer, pH 8.0, and chromatography on chitin and CM Sepharose™ columns and antidermatophytic potential of Mo-CBP₄ evaluated in vitro and in vivo. In vitro, Mo-CBP₄ reduced in 50% the germination of microconidia of Trichophyton mentagrophytes at 45 μM; but did not show inhibition of mycelial growth. Mo-CBP₄ (45 μM) presents the inhibitory activity even when incubated with N-acetyl-d-glucosamine (NAG). Analysis of the mechanisms of Mo-CBP₄ revealed an increase in membrane permeability, ROS overproduction and damage to cell wall leading to microconidia death. Furthermore, using in vivo models, Mo-CBP₄ (5, 10 and 20 mg g^-1) reduced the severity and time of dermatophytosis. Altogether, these findings indicate that Mo-CBP₄ has great potential for the development of novel antifungal drugs for the clinical treatment of dermatophytosis.

Role of membrane sterol and redox system in the anti-candida activity reported for Mo-CBP2, a protein from Moringa oleifera seeds

Plant proteins are emerging as an alternative to conventional treatments against candidiasis. The aim of this study was to better understand the mechanism of action of Mo-CBP₂ against Candida spp, evaluating redox system activity, lipid peroxidation, DNA degradation, cytochrome c release, medium acidification, and membrane interaction. Anti-candida activity of Mo-CBP₂ decreased in the presence of ergosterol, which was not observed with antioxidant agents. C. albicans treated with Mo-CBP₂ also had catalase and peroxidase activities inhibited, while superoxide dismutase was increased. Mo-CBP₂ increased the lipid peroxidation, but it did not alter the ergosterol profile in live cells. External medium acidification was strongly inhibited, and cytochrome c release and DNA degradation were detected. Mo-CBP₂ interacts with cell membrane constituents, changes redox system enzymes in C. albicans and causes lipid peroxidation by ROS overproduction. DNA degradation and cytochrome c release suggest apoptotic or DNAse activity. Lipid peroxidation and H⁺-ATPases inhibition may induce the process of apoptosis. Finally, Mo-CBP₂ did not have a cytotoxic effect in mammalian Vero cells. This study highlights the biotechnological potential of Mo-CBP₂ as a promising molecule with low toxicity and potent activity. Further studies should be performed to better understand its mode of action and toxicity.

Biological, nutritional, and therapeutic significance of Moringa oleifera Lam

The genus Moringa Adans. comprises 13 species, of which Moringa oleifera Lam. native to India and cultivated across the world owing to its drought and frost resistance habit is widely used in traditional phytomedicine and as rich source of essential nutrients. Wide spectrum of phytochemical ingredients among leaf, flower, fruit, seed, seed oil, bark, and root depend on cultivar, season, and locality. The scientific studies provide insights on the use of M. oleifera with different aqueous, hydroalcoholic, alcoholic, and other organic solvent preparations of different parts for therapeutic activities, that is, antibiocidal, antitumor, antioxidant, anti-inflammatory, cardio-protective, hepato-protective, neuro-protective, tissue-protective, and other biological activities with a high degree of safety. A wide variety of alkaloid and sterol, polyphenols and phenolic acids, fatty acids, flavanoids and flavanol glycosides, glucosinolate and isothiocyanate, terpene, anthocyanins etc. are believed to be responsible for the pragmatic effects. Seeds are used with a view of low-cost biosorbent and coagulant agent for the removal of metals and microbial contamination from waste water. Thus, the present review explores the use of M. oleifera across disciplines for its prominent bioactive ingredients, nutraceutical, therapeutic uses and deals with agricultural, veterinarian, biosorbent, coagulation, biodiesel, and other industrial properties of this "Miracle Tree."

Nutritional compositions of Indian Moringa oleifera seed and antioxidant activity of its polypeptides

To study the nutritional composition of Indian Moringa oleifera seed and the antioxidant activity of M. oleifera seed polypeptide, Indian M. oleifera seed was used as raw material for composition analysis and content determination. After extraction of the seed protein, enzymatic hydrolysis with flavourzyme, dispase, papain, pepsin, and alcalase was conducted for different time, and the optimal enzymatic hydrolysis conditions was determined with DPPH scavenging capacity as an indicator. The seed polypeptides obtained by enzymatic hydrolysis were ultrafiltered, and the active peptide fragments were tracked with DPPH, HO (•OH), ABTS and superoxide anion (O2•-) free radical scavenging ability and lipid oxidation inhibition rate as indicators. The results showed that the protein content in Indian M. oleifera seed was high to 40.34%, containing seven essential amino acids. The content of macroelements such as potassium, sodium, and magnesium is high, with the potassium content as high as 2,357.71 mg/kg, among the microelements, the iron content as high as 36.2 mg/kg. The optimum enzymatic hydrolysis conditions were as follows: enzymatic hydrolysis with flavourzyme (50°C, pH 6.7) for 300 min, and DPPH scavenging capacity was 84.76%. Activity tracing found that the polypeptide fragment with molecular weight <3.5 kDa had the strongest antioxidant capacity, and the EC50 values of DPPH, •OH, ABTS, and O2•- free radical scavenging rates were 4.0, 4.2, 5.3, and 4.3 mg/ml, respectively. The above results show that Indian M. oleifera seed not only has high nutritional value, but its protease enzymatic hydrolyzate also has significant antioxidant activity, which can be further developed into nutrition products, healthcare products, functional foods, beauty and skin care products, liver protection drugs, etc.

Gene expression and spatiotemporal localization of antifungal chitin-binding proteins during Moringa oleifera seed development and germination

Chitin-binding proteins behave as storage and antifungal proteins in the seeds of Moringa oleifera. Moringa oleifera is a tropical multipurpose tree. Its seed constituents possess coagulant, bactericidal, fungicidal, and insecticidal properties. Some of these properties are attributed to a group of polypeptides denominated M. oleifera chitin-binding proteins (in short, Mo-CBPs). Within this group, Mo-CBP₂, Mo-CBP₃, and Mo-CBP₄ were previously purified to homogeneity. They showed high amino acid similarity with the 2S albumin storage proteins. These proteins also presented antimicrobial activity against human pathogenic yeast and phytopathogenic fungi. In the present study, the localization and expression of genes that encode Mo-CBPs and the biosynthesis and degradation of the corresponding proteins during morphogenesis and maturation of M. oleifera seeds at 15, 30, 60, and 90 days after anthesis (DAA) and germination, respectively, were assessed. The Mo-CBP transcripts and corresponding proteins were not detected at 15 and 30 days after anthesis (DAA). However, they accumulated at the latter stages of seed maturation (60 and 90 DAA), reaching the maximum level at 60 DAA. The degradation kinetics of Mo-CBPs during seed germination by in situ immunolocalization revealed a reduction in the protein content 48 h after sowing (HAS). Moreover, Mo-CBPs isolated from seeds at 60 and 90 DAA prevented the spore germination of Fusarium spp. Taken together, these results suggest that Mo-CBPs play a dual role as storage and defense proteins in the seeds of M. oleifera.

Thiocarbamates from Moringa oleifera Seeds Bioactive against Virulent and Multidrug-Resistant Vibrio Species

Prospect of antibacterial agents may provide an alternative therapy for diseases caused by multidrug-resistant bacteria. This study aimed to evaluate the in vitro bioactivity of Moringa oleifera seed extracts against 100 vibrios isolated from the marine shrimp Litopenaeus vannamei. Ethanol extracts at low (MOS-E) and hot (MOS-ES) temperature are shown to be bioactive against 92% and 90% of the strains, respectively. The most efficient Minimum Inhibitory Concentration (MIC) levels of MOS-E and MOS-ES against a high percentage of strains were 32 µg mL^-1. Bioguided screening of bioactive compounds showed that the ethyl acetate fraction from both extracts was the only one that showed antibacterial activity. Vibriocidal substances, niazirine and niazimicine, were isolated from the aforementioned fraction through chromatographic fractionation.

A Chitin-binding Protein Purified from Moringa oleifera Seeds Presents Anticandidal Activity by Increasing Cell Membrane Permeability and Reactive Oxygen Species Production

Candida species are opportunistic pathogens that infect immunocompromised and/or immunosuppressed patients, particularly in hospital facilities, that besides representing a significant threat to health increase the risk of mortality. Apart from echinocandins and triazoles, which are well tolerated, most of the antifungal drugs used for candidiasis treatment can cause side effects and lead to the development of resistant strains. A promising alternative to the conventional treatments is the use of plant proteins. M. oleifera Lam. is a plant with valuable medicinal properties, including antimicrobial activity. This work aimed to purify a chitin-binding protein from M. oleifera seeds and to evaluate its antifungal properties against Candida species. The purified protein, named Mo-CBP₂, represented about 0.2% of the total seed protein and appeared as a single band on native PAGE. By mass spectrometry, Mo-CBP₂ presented 13,309 Da. However, by SDS-PAGE, Mo-CBP₂ migrated as a single band with an apparent molecular mass of 23,400 Da. Tricine-SDS-PAGE of Mo-CBP₂ under reduced conditions revealed two protein bands with apparent molecular masses of 7,900 and 4,600 Da. Altogether, these results suggest that Mo-CBP₂ exists in different oligomeric forms. Moreover, Mo-CBP₂ is a basic glycoprotein (pI 10.9) with 4.1% (m/m) sugar and it did not display hemagglutinating and hemolytic activities upon rabbit and human erythrocytes. A comparative analysis of the sequence of triptic peptides from Mo-CBP₂ in solution, after LC-ESI-MS/MS, revealed similarity with other M. oleifera proteins, as the 2S albumin Mo-CBP₃ and flocculating proteins, and 2S albumins from different species. Mo-CBP₂ possesses in vitro antifungal activity against Candida albicans, C. parapsilosis, C. krusei, and C. tropicalis, with MIC₅₀ and MIC₉₀ values ranging between 9.45–37.90 and 155.84–260.29 μM, respectively. In addition, Mo-CBP₂ (18.90 μM) increased the cell membrane permeabilization and reactive oxygen species production in C. albicans and promoted degradation of circular plasmid DNA (pUC18) from Escherichia coli. The data presented in this study highlight the potential use of Mo-CBP₂ as an anticandidal agent, based on its ability to inhibit Candida spp. growth with apparently low toxicity on mammalian cells.

Proteomic Profiles Reveal the Function of Different Vegetative Tissues of Moringa oleifera

Moringa oleifera is a rich source of bioactive compounds and is widely used in traditional medicine and food for its nutritional value; however, the protein and peptide components of different tissues are rarely discussed. Here, we describe the first investigation of M. oleifera proteomes using mass spectrometry and bioinformatics methods. We aimed to elucidate the protein profiles of M. oleifera leaves, stem, bark, and root. Totally 202 proteins were identified from four vegetative organs. We identified 101 proteins from leaves, 51 from stem, 94 from bark and 67 from root, finding that only five proteins existed in both four vegetative parts. The calculated pI of most of the proteins is distributed in 5-10 and the molecular weight distributed below 100 kDa. Functional classification analysis revealed that proteins which are involved in catalytic activities are the most abundant both in leaves, stem, bark and root. Identification of several heat shock proteins in four vegetative tissues might be adaptive for resistance to high temperature environmental stresses of tropical or subtropical areas. Some enzymes involved in antioxidant processes were also identified in M. oleifera leaves, stem, bark and root. Among the four tissues studies here, leaves protein content and molecular diversity were the highest. The identification of the flocculating protein MO2.1 and MO2.2 in the bark and root provides clue to clarify the antimicrobial molecular mechanisms of root and bark. This study provides information on the protein compositions of M. oleifera vegetative tissues that will be beneficial for potential drug and food supplement development and plant physiology research.

A Protein Isolate from Moringa oleifera Leaves Has Hypoglycemic and Antioxidant Effects in Alloxan-Induced Diabetic Mice

Moringa oleifera has been used in traditional medicine to treat diabetes. However, few studies have been conducted to relate its antidiabetic properties to proteins. In this study, a leaf protein isolate was obtained from M. oleifera leaves, named Mo-LPI, and the hypoglycemic and antioxidant effects on alloxan-induced diabetic mice were assessed. Mo-LPI was obtained by aqueous extraction, ammonium sulphate precipitation and dialysis. The electrophoresis profile and proteolytic hydrolysis confirmed its protein nature. Mo-LPI showed hemagglutinating activity, cross-reaction with anti-insulin antibodies and precipitation after zinc addition. Single-dose intraperitoneal (i.p.) administration of Mo-LPI (500 mg/kg·bw) reduced the blood glucose level (reductions of 34.3%, 60.9% and 66.4% after 1, 3 and 5 h, respectively). The effect of Mo-LPI was also evidenced in the repeated dose test with a 56.2% reduction in the blood glucose level on the 7th day after i.p. administration. Mo-LPI did not stimulate insulin secretion in diabetic mice. Mo-LPI was also effective in reducing the oxidative stress in diabetic mice by a decrease in malondialdehyde level and increase in catalase activity. Mo-LPI (2500 mg/kg·bw) did not cause acute toxicity to mice. Mo-LPI is a promising alternative or complementary agent to treat diabetes.

Chitin and chitinase: Role in pathogenicity, allergenicity and health

Chitin, a polysaccharide with particular abundance in fungi, nematodes and arthropods is immunogenic. It acts as a threat to other organisms, to tackle which they have been endowed with chitinase enzyme. Even if this enzyme is not present in all organisms, they possess proteins having chitin-binding domain(s) (ChtBD). Many lethal viruses like Ebola, and HCV (Hepatitis C virus) have these domains to manipulate their carriers and target organisms. In keeping with the basic rule of survival, the self-origin (own body component) chitins and chitinases are protective, but that of non-self origin (from other organisms) are detrimental to health. The exogenous chitins and chitinases provoke human innate immunity to generate a deluge of inflammatory cytokines, which injure organs (leading to asthma, atopic dermatitis etc.), and in persistent situations lead to death (multiple sclerosis, systemic lupus erythromatosus (SLE), cancer, etc.). Unfortunately, chitin-chitinase-stimulated hypersensitivity is a common cause of occupational allergy. On the other hand, chitin, and its deacetylated derivative chitosan are increasingly proving useful in pharmaceutical, agriculture, and biocontrol applications. This critical review discusses the complex nexus of chitin and chitinase and assesses both their pathogenic as well as utilitarian aspects.