Isolation of alliumin, a novel protein with antimicrobial and antiproliferative activities from multiple-cloved garlic bulbs

Dual Antifungal and Antiproliferative Activities of a Novel Protein Fraction from a Medicinally Important Herb Trillium govanianum Wall. ex. D. Don

Antimicrobial resistance of microorganisms and the unwanted side effects of chemoradiation therapy in cancer are major issues in healthcare. In recent times, protein-based drugs have emerged as promising candidates due to their high specificity, less side effects, etc. In this context, the rhizome of Trillium govanianum was first explored for biologically active proteins/peptides. For this, three protein fractions namely Aqueous protein fraction (APF), Hexane-Methanol-treated aqueous protein fraction (HMAPF), and Methanol-treated aqueous protein fraction (MAPF) were prepared and evaluated for antimicrobial and antiproliferative activities. In antifungal activity, HMAPF showed the lowest MIC90 values of 1.56 µg/ml against Candida parapsilosis and Candida glabrata and 3.12 µg/ml against Candida albicans and Candida auris. The antifungal activity was further confirmed by a chitinase assay, a growth kinetics and a proteinase inhibitory assay. Surprisingly, none of the three protein fractions exhibited antibacterial activity against Escherichia coli and Staphylococcus aureus. Moreover, APF exhibited potent antiproliferative and antioxidant activities with IC50 values of 18 µg/ml and 227 µg /ml, respectively. For HMAPF, an IC50 value of 70 µg/ml against the MDA-MB-231 cell line was observed. The present results demonstrate that the protein fractions, particularly HMAPF and APF, might serve as potential sources of a dual antifungal and antiproliferative protein-based drug.

Health-promoting properties of bioactive proteins and peptides of garlic (Allium sativum)

Garlic is a popular food spice with diverse and well-established medicinal properties. Many research interests have been directed toward the biological activities of the phytochemical constituents of garlic. However, prospects of its bioactive proteins and peptides have been understudied to date. With the advances in food proteomics/peptide research, a review of studies on garlic bioactive proteins and peptides, especially on their nature, extraction, and biological activities, is timely. Garlic has been reported to express several proteins, endogenous and protein-derived peptides with interesting bioactivities, including antioxidant, anti-inflammatory, antibacterial, antifungal, anti-proliferative, antiviral, anti-hypertensive and immunomodulatory activities, suggesting their therapeutic and pharmacological potentials. Compared to legumes, the low protein contents of garlic bulbs and their low stability are possible limitations that would hinder future applications. We suggest adopting heterologous expression systems for peptide overproduction and stability enhancement. Therefore, we recommend increased scientific interest in the bioactive peptides of garlic and other spice plants.

Venkatesh, Nagaraj Parisara, B. T. Prabhakar, Pramod.S.N.. Characterization of antioxidant, anti-cancer, and immunomodulatory functions of partially purified garlic (Allium sativum L.) lectin

Introduction and Aim: The metabolic and oxidative stress induces highly reactive free radicals that are known to harm normal physiology and play a role in the development of cancer. Elevated levels of these free radicals contribute to excessive neovascularization leading to angiogenesis mediated cancer progression. Targeting these free radicals through dietary source is important strategy in regulation of cancer. Allium sativum L. (AsL) garlic has important multi pharmacological properties. On the other hand, dietary lectins are proven to be the best anti-cancer molecules. The study presents investigation that focus to assess the antioxidant, immunomodulatory and anticancer activities of partially purified garlic lectin (PPAsL).  Materials and Methods: Fresh garlic bulbs were processed and evaluated for lectin induced HA activity. Further the garlic lectins (AsL) were partially purified by ammonium sulphate precipitation and dialysis and analyzed through SDS-PAGE. Further lectins were characterized by producing Anti-AsL polyclonal antibodies and purification by affinity chromatography. Pharmacological evaluations of the lectins were assessed through antioxidant, anti-proliferative and antiangiogenic mediated anti-cancer activity. Results: Lectin positive activity was confirmed by HA activity and partial purification lectin identified ?12kDa protein having Glc/Man glycan specificity. The polyclonal antibodies raised against PPAsL, confirmed that it has potent immunogen. Pharmacological evaluation confirmed that PPAsL has potent antioxidant, antiangiogenic and antiproliferative effect both in-vitro and in-vivo.  Conclusion: PPAsL is potent antioxidant, anti-proliferative and anti-cancer molecule. The dietary recommendation of the garlic lectin is an important therapeutic strategy against the cancer.

The Updated Review on Plant Peptides and Their Applications in Human Health

Biologically active plant peptides, consisting of secondary metabolites, are compounds (amino acids) utilized by plants in their defense arsenal. Enzymatic processes and metabolic pathways secrete these plant peptides. They are also known for their medicinal value and have been incorporated in therapeutics of major human diseases. Nevertheless, its limitations (low bioavailability, high cytotoxicity, poor absorption, low abundance, improper metabolism, etc.) have demanded a need to explore further and discover other new plant compounds that overcome these limitations. Keeping this in mind, therapeutic plant proteins can be excellent remedial substitutes for bodily affliction. A multitude of these peptides demonstrates anti-carcinogenic, anti-microbial, anti-HIV, and neuro-regulating properties. This article's main aim is to list out and report the status of various therapeutic plant peptides and their prospective status as peptide-based drugs for multiple diseases (infectious and non-infectious). The feasibility of these compounds in the imminent future has also been discussed.

Therapeutic Potential of Medicinal Plant Proteins: Present Status and Future Perspectives

Biologically active molecules obtained from plant sources, mostly including secondary metabolites, have been considered to be of immense value with respect to the treatment of various human diseases. However, some inevitable limitations associated with these secondary metabolites like high cytotoxicity, low bioavailability, poor absorption, low abundance, improper metabolism, etc., have forced the scientific community to explore medicinal plants for alternate biologically active molecules. In this context, therapeutically active proteins/peptides from medicinal plants have been promoted as a promising therapeutic intervention for various human diseases. A large number of proteins isolated from the medicinal plants have been shown to exhibit anti-microbial, anti-oxidant, anti-HIV, anticancerous, ribosome-inactivating and neuro-modulatory activities. Moreover, with advanced technological developments in the medicinal plant research, medicinal plant proteins such as Bowman-Birk protease inhibitor and Mistletoe Lectin-I are presently under clinical trials against prostate cancer, oral carcinomas and malignant melanoma. Despite these developments and proteins being potential drug candidates, to date, not a single systematic review article has documented the therapeutical potential of the available biologically active medicinal plant proteome. The present article was therefore designed to describe the current status of the therapeutically active medicinal plant proteins/peptides vis-à-vis their potential as future protein-based drugs for various human diseases. Future insights in this direction have also been highlighted.

Biological Properties and Characterization of ASL50 Protein from Aged Allium sativum Bulbs

Allium sativum is well known for its medicinal properties. The A. sativum lectin 50 (ASL50, 50 kDa) was isolated from aged A. sativum bulbs and purified by gel filtration chromatography on Sephacryl S-200 column. Agar well diffusion assay were used to evaluate the antimicrobial activity of ASL50 against Candida species and bacteria then minimal inhibitory concentration (MIC) was determined. The lipid A binding to ASL50 was determined by surface plasmon resonance (SPR) technology with varying concentrations. Electron microscopic studies were done to see the mode of action of ASL50 on microbes. It exerted antimicrobial activity against clinical Candida isolates with a MIC of 10-40 μg/ml and clinical Pseudomonas aeruginosa isolates with a MIC of 10-80 μg/ml. The electron microscopic study illustrates that it disrupts the cell membrane of the bacteria and cell wall of fungi. It exhibited antiproliferative activity on oral carcinoma KB cells with an IC50 of 36 μg/ml after treatment for 48 h and induces the apoptosis of cancer cells by inducing 2.5-fold higher caspase enzyme activity than untreated cells. However, it has no cytotoxic effects towards HEK 293 cells as well as human erythrocytes even at higher concentration of ASL50. Biological properties of ASL50 may have its therapeutic significance in aiding infection and cancer treatments.

Medicinal plants, human health and biodiversity: a broad review

Biodiversity contributes significantly towards human livelihood and development and thus plays a predominant role in the well being of the global population. According to WHO reports, around 80 % of the global population still relies on botanical drugs; today several medicines owe their origin to medicinal plants. Natural substances have long served as sources of therapeutic drugs, where drugs including digitalis (from foxglove), ergotamine (from contaminated rye), quinine (from cinchona), and salicylates (willow bark) can be cited as some classical examples.Drug discovery from natural sources involve a multifaceted approach combining botanical, phytochemical, biological, and molecular techniques. Accordingly, medicinal-plant-based drug discovery still remains an important area, hitherto unexplored, where a systematic search may definitely provide important leads against various pharmacological targets.Ironically, the potential benefits of plant-based medicines have led to unscientific exploitation of the natural resources, a phenomenon that is being observed globally. This decline in biodiversity is largely the result of the rise in the global population, rapid and sometimes unplanned industrialization, indiscriminate deforestation, overexploitation of natural resources, pollution, and finally global climate change.Therefore, it is of utmost importance that plant biodiversity be preserved, to provide future structural diversity and lead compounds for the sustainable development of human civilization at large. This becomes even more important for developing nations, where well-planned bioprospecting coupled with nondestructive commercialization could help in the conservation of biodiversity, ultimately benefiting mankind in the long run.Based on these findings, the present review is an attempt to update our knowledge about the diverse therapeutic application of different plant products against various pharmacological targets including cancer, human brain, cardiovascular function, microbial infection, inflammation, pain, and many more.

A review on the role of nutraceuticals as simple as se(2+) to complex organic molecules such as glycyrrhizin that prevent as well as cure diseases

Nutraceuticals are nutritional medicines which are present in edible food items. Most of them are antioxidants with various other biological properties viz, anti inflammatory, anti atherogenic, anticancer, anti viral, anti aging properties etc. They are as simple as minerals like Se(2+) to complex organic molecules such as glycyrrhizin (Ca(2+), K(+) salts of glycyrrhizic acid). They can prevent as well as cure various diseases. Most of the medical people are not aware of the importance of the nutraceuticals as such matters are not part of their text books. Many still think that vitamins are the major nutritional medicines. Actually other dietary principles like terpenes, carotenes, phytosterols, polyphenols, flavanoids, di and poly sulphides, their sulfoxides and their precursor amino acids are necessary to scavenge free radicals in the body which are reactive oxygen species to protect and maintain the vitamin levels in the body. They down regulate the activities of those enzymes which are increased in diseases and they increase those that remove oxidants and detoxify carcinogens. They are immune boosters too. Recently glucosinolates, non toxic alkaloids, certain proteins and even fiber are included in the list of nutraceuticals.

A novel antifungal peptide from foxtail millet seeds

BACKGROUND

Antifungal proteins (AFP) help plants to combat phytopathogenic fungi and thus protect plants from the devastating damage caused by fungal infections and prevent massive economic losses. To date, several proteins with antibacterial and/or antifungal properties have been isolated and characterized from different plant species and tissues; however, there are no reports concerning the antifungal peptide from foxtail millet seeds.

RESULTS

An antifungal peptide with a molecular mass of 26.9 kDa was isolated from dry seeds of the foxtail millet (Setaria italica (L.) Beauv.), using a procedure that involved four chromatographic steps. The antifungal peptide was adsorbed on CM-Sepharose, Affi-gel blue gel and Superdex 75. It was further purified by C(18) reverse-phase high-performance liquid chromatography and submitted for analysis of peptide mass fingerprint. The Mascot peptide mass fingerprint of the isolated protein hit no existing protein (score >60), and it was proved to be a novel antifungal peptide. It inhibited mycelial growth in Alternaria alternate with an IC(50) of 1.3 µmol L(-1) , and it also exhibited antifungal activity against Trichoderma viride, Botrytis cinerea and Fusarium oxysporum. Transmission electron microscopy of mold forms of Alternaria alternate after incubation with 20 µg mL(-1) of the antifungal protein for 48 h revealed marked ultrastructural changes in the fungus.

CONCLUSION

A novel antifungal peptide with high potency was isolated from foxtail millet seeds.

Identity of the immunomodulatory proteins from garlic (Allium sativum) with the major garlic lectins or agglutinins

Garlic (Allium sativum), an important medicinal spice, displays a plethora of biological effects including immunomodulation. Although some immunomodulatory proteins from garlic have been described, their identities are still unknown. The present study was envisaged to isolate immunomodulatory proteins from raw garlic, and examine their effects on certain cells of the immune system (lymphocytes, mast cells, and basophils) in relation to mitogenicity and hypersensitivity. Three protein components of approximately 13 kD (QR-1, QR-2, and QR-3 in the ratio 7:28:1) were separated by Q-Sepharose chromatography of 30 kD ultrafiltrate of raw garlic extract. All the 3 proteins exhibited mitogenic activity towards human peripheral blood lymphocytes, murine splenocytes and thymocytes. The mitogenicity of QR-2 was the highest among the three immunomodulatory proteins. QR-1 and QR-2 displayed hemagglutination and mannose-binding activities; QR-3 showed only mannose-binding activity. Immunoreactivity of rabbit anti-QR-1 and anti-QR-2 polyclonal antisera showed specificity for their respective antigens as well as mutual cross-reactivity; QR-3 was better recognized by anti-QR-2 (82%) than by anti-QR-1 (55%). QR-2 induced a 2-fold higher histamine release in vitro from leukocytes of atopic subjects compared to that of non-atopic subjects. In all functional studies, QR-2 was more potent compared to QR-1. Taken together, all these results indicate that the two major proteins QR-2 and QR-1 present in a ratio of 4:1 in raw garlic contribute to garlic's immunomodulatory activity, and their characteristics are markedly similar to the abundant Allium sativum agglutinins (ASA) I and II, respectively.

Cytotoxic effect of potato aspartic proteases (StAPs) on Jurkat T cells

StAPs are potato aspartic proteases with cytotoxic activity against plant pathogens and spermatozoa. StAPs cytotoxic activity is selective, since these proteins do not exert toxic effect on plant cells and erythrocytes. In this work, we investigated the capacity of StAPs to exert cytotoxicity on human leukaemia cells. Obtained results show that StAPs induce apoptosis on Jurkat T cells after a short time of incubation in a dose-dependent manner. However, no significative effect on the T lymphocytes viability was observed at all StAPs incubation times and concentrations tested. These results suggest that StAPs can be conceptually promising leads for cancer therapy.

Proteinaceous cytotoxic component of Allium sativum induces apoptosis of INT-407 intestinal cells

Garlic has long been known for its wide array of therapeutic effects, including hypolipidemic, antihypertensive, antimicrobial, and possibly anticancer effects; conversely, some adverse effects of garlic, such as acute pain and neurogenic inflammation, have also been reported. However, information detailing the toxicological significance of garlic is scarce. In this study, the cytotoxicities of fresh garlic extract (FGE) and boiled garlic extract (BGE) and their underlying toxic mechanisms were investigated using INT-407 intestinal epithelial cells. A brief exposure (20 minutes) to FGE induced a concentration-dependent increase in cell death (37 +/- 2% at 300 microg/mL), but no cytotoxic effects were induced after exposure to BGE. For FGE, only the high-molecular-mass (>10-kDa) proteins were associated with cytotoxic effects. FGE-treated cells showed morphological changes such as increased cell rounding and fragmentation, suggesting programmed cell death (apoptosis). Apoptosis of FGE-treated cells was evaluated by observing the fragmented multinuclei stained with Hoechst 33342. From the cell cycle analysis, the increase in hypodiploidic cells and in the G2/M phase cell population suggested not only apoptosis but also cell cycle arrest of FGE-treated cells. Pretreatment with N-acetyl-l-cysteine almost completely prevented FGE-induced cell death, suggesting that reactive oxygen species (ROS) may play a key role in FGE-associated cytotoxicity. Consumption of fresh garlic may be linked to potential cytotoxicity of intestinal cells when ROS scavengers are not present.

An antifungal peptide from red lentil seeds

An antifungal peptide, with a molecular mass of 11 kDa, was isolated from dry seeds of the red lentil (Lens culinaris) using a procedure that involved four chromatographic steps. The antifungal peptide was unadsorbed on DEAE-cellulose, and adsorbed on Affi-gel blue gel and S-Sepharose. The final chromatographic step involved gel filtration by fast protein liquid chromatography on Superdex 75. The antifungal peptide inhibited mycelial growth in Mycosphaerella arachidicola with an IC50 of 36 microM. It also exhibited antifungal activity against Fusarium oxysporum, but there was no inhibitory activity toward tumor cell lines and human immunodeficiency virus type 1 reverse transcriptase (RT).

An antifungal protein from the pea Pisum sativum var. arvense Poir

An antifungal protein with a molecular mass of 11 kDa and a lysine-rich N-terminal sequence was isolated from the seeds of the pea Pisum sativum var. arvense Poir. The antifungal protein was unadsorbed on DEAE-cellulose but adsorbed on Affi-gel blue gel and CM-cellulose. It exerted antifungal activity against Physalospora piricola with an IC50 of 0.62 microM, and also antifungal activity against Fusarium oxysporum and Mycosphaerella arachidicola. It inhibited human immunodeficiency virus type 1 reverse transcriptase with an IC50 of 4.7 microM.

Smilaxin, a novel protein with immunostimulatory, antiproliferative, and HIV-1-reverse transcriptase inhibitory activities from fresh Smilax glabra rhizomes

A protein, with a novel N-terminal amino acid sequence and a molecular mass of 30 kDa, was purified from fresh Smilax glabra rhizomes by adsorption on DEAE-cellulose, CM-cellulose, Con A-Sepharose, and Mono S, and by fast protein liquid chromatography-gel filtration on Superdex 75. The protein, designated as smilaxin, stimulated uptake of [methyl-3H]thymidine by murine splenocytes, peritoneal macrophages, and bone marrow cells, and production of nitric oxide by peritoneal macrophages. It inhibited uptake of [methyl-3H]thymidine by MBL2 and PU5 tumor cells but not uptake by S180 and L1210 cells. Smilaxin augmented glucose uptake into rat adipose tissue. It attenuated the activity of HIV-1-reverse transcriptase with an IC50 of 5.6 microM. However, it did not display hemagglutinating, antifungal or translation-inhibitory activities, indicating that it is not a lectin, an antifungal protein, or a ribosome-inactivating protein.

Raw and boiled garlic enhances plasma antioxidant activity and improves plasma lipid metabolism in cholesterol-fed rats

In the present study the effect of garlic, in a form more similar to how most people eat garlic, on lipid and antioxidant metabolism in rats was investigated. The antioxidant activity was determined by the efficacy to scavenge 2, 2'-azino-bis (3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) derived radicals in garlic samples. The highest results were estimated in aqueous fraction in comparison with other extracts divided on the basis of polarity. Wistar male rats were randomly divided into 10 diet groups, each with seven animals. The groups were named: Control, RG (raw garlic), BG (boiled garlic for 20 min), AERG (aqueous extract of raw garlic), AEBG (aqueous extract of boiled garlic), Ch (Cholesterol), Ch/RG, Ch/BG, Ch/AERG and Ch/AEBG. All experimental diets were supplemented with 25 mg of lyophilized garlic/kg body weight obtained from raw, boiled and their aqueous extracts over a period of 30 days. Serum lipid (total cholesterol, LDL-cholesterol and triglycerides) concentrations were higher in all groups fed cholesterol (Ch); however, the increase was significant only in Ch group, without garlic supplementation. In groups of rats fed diets with cholesterol, garlic samples significantly hindered the rise of TC and LDL-C (P < 0.05). A significant increase (P < 0.05) in the plasma antioxidant activity was registered in experimental groups of rats fed cholesterol-free diets supplemented with garlic; oppositely, a significant decrease was only in group of rats given food containing cholesterol without garlic. The protein spectra has shown that during short boiling some proteins change their functional properties such as solubility and mobility, resulting in a number of protein bands in SDS-electrophoresis.

CONCLUSIONS

Raw and boiled garlic improved plasma lipid metabolism and plasma antioxidant activity in an experiment on rats. Thus, dietary hypolipidemic garlic was effective in reducing the oxidant stress, which was indicated by an increase of antioxidant activity and a decrease of lipids in the rats' blood. It was found that garlic boiled for 20 min has the same bioactivity as raw garlic in its antioxidant and protein spectra. Therefore it should be added at this time to foods. The selenium and copper content of raw garlic is not altered by boiling. The protein electrophoretic pattern of raw garlic is altered by boiling.