Rationalisation of Antifungal Properties of α-Helical Pore-Forming Peptide, Mastoparan B.

The high mortality associated with invasive fungal infections, narrow spectrum of available antifungals, and increasing evolution of antifungal resistance necessitate the development of alternative therapies. Host defense peptides are regarded as the first line of defense against microbial invasion in both vertebrates and invertebrates. In this work, we investigated the effectiveness of four naturally occurring pore-forming antimicrobial peptides (melittin, magainin 2, cecropin A, and mastoparan B) against a panel of clinically relevant pathogens, including Candida albicans, Candida parapsilosis, Candida tropicalis, and Candida glabrata. We present data on the antifungal activities of the four pore-forming peptides, assessed with descriptive statistics, and their cytocompatibility with cultured human cells. Among the four peptides, mastoparan B (MB) displayed potent antifungal activity, whereas cecropin A was the least potent. We show that MB susceptibility of phylogenetically distant non-candida albicans can vary and be described by different intrinsic physicochemical parameters of pore-forming α-helical peptides. These findings have potential therapeutic implications for the design and development of safe antifungal peptide-based drugs.

Cell-free stem cell-derived extract formulation for treatment of knee osteoarthritis: study protocol for a preliminary non-randomized, open-label, multi-center feasibility and safety study.

BACKGROUND: Musculoskeletal conditions are highly prevalent, and knee OA is most common. Current treatment modalities have limitations and either fail to solve the underlying pathophysiology or are highly invasive. To address these limitations, attention has focused on the use of biologics. The efficacy of these devices is attributed to presence of growth factors (GFs), cytokines (CKs), and extracellular vesicles (EVs). With this in mind, we formulated a novel cell-free stem cell-derived extract (CCM) from human progenitor endothelial stem cells (hPESCs). A preliminary study demonstrated the presence of essential components of regenerative medicine, namely GFs, CKs, and EVs, including exosomes, in CCM. The proposed study aims to evaluate the safety and efficacy of intraarticular injection of the novel cell-free stem cell-derived extract (CCM) for the treatment of knee OA. METHODS AND ANALYSIS: This is a non-randomized, open-label, multi-center, prospective study in which the safety and efficacy of intraarticular CCM in patients suffering from grade II/III knee OA will be evaluated. Up to 20 patients with grade II/III OA who meet the inclusion and exclusion criteria will be consented and screened to recruit 12 patients to receive treatment. The study will be conducted at up to 2 sites within the USA, and the 12 participants will be followed for 24 months. The study participants will be monitored for adverse reactions and assessed using Numeric Pain Rating Scale (NPRS), Patient-Reported Outcomes Measurement Information System (PROMIS) Score, Knee Injury and Osteoarthritis Outcome Score Jr. (KOOS Jr.), 36-ietm short form survey (SF-36), Single Assessment Numeric Evaluation (SANE), physical exams, plain radiography, and magnetic resonance imaging (MRI) with Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) score for improvements in pain, function, satisfaction, and cartilage regeneration. DISCUSSION: This prospective study will provide valuable information into the safety and efficacy of intraarticular administration of cell-free stem cell-derived extract (CCM) in patients suffering with grade II/III knee OA. The outcomes from this initial study of novel CCM will lay the foundation for a larger randomized, placebo-controlled, multi-center clinical trial of intraarticular CCM for symptomatic knee OA. TRIAL REGISTRATION: Registered on July 21, 2021. ClinicalTrials.gov NCT04971798.

Milk Proteins-Their Biological Activities and Use in Cosmetics and Dermatology.

Milk and colostrum have high biological potential, and due to their natural origin and non-toxicity, they have many uses in cosmetics and dermatology. Research is ongoing on their potential application in other fields of medicine, but there are still few results; most of the published ones are included in this review. These natural products are especially rich in proteins, such as casein, ß-lactoglobulin, α-lactalbumin, lactoferrin, immunoglobulins, lactoperoxidase, lysozyme, and growth factors, and possess various antibacterial, antifungal, antiviral, anticancer, antioxidant, immunomodulatory properties, etc. This review describes the physico-chemical properties of milk and colostrum proteins and the natural functions they perform in the body and compares their composition between animal species (cows, goats, and sheep). The milk- and colostrum-based products can be used in dietary supplementation and for performing immunomodulatory functions; they can enhance the effects of certain drugs and can have a lethal effect on pathogenic microorganisms. Milk products are widely used in the treatment of dermatological diseases for promoting the healing of chronic wounds, hastening tissue regeneration, and the treatment of acne vulgaris or plaque psoriasis. They are also increasingly regarded as active ingredients that can improve the condition of the skin by reducing the number of acne lesions and blackheads, regulating sebum secretion, ameliorating inflammatory changes as well as bestowing a range of moisturizing, protective, toning, smoothing, anti-irritation, whitening, soothing, and antiaging effects.

Andrographis overcomes 5-fluorouracil-associated chemoresistance through inhibition of DKK1 in colorectal cancer.

Colorectal cancer (CRC) ranks as the third leading cause of cancer-related deaths in the USA. 5-Fluorouracil (5FU)-based chemotherapeutic drug remains a mainstay of CRC treatment. Unfortunately, ~50-60% of patients eventually develop resistance to 5FU, leading to poor survival outcomes. Our previous work revealed that andrographis enhanced 5FU-induced anti-cancer activity, but the underlying mechanistic understanding largely remains unclear. In this study, we first established 5FU-resistant (5FUR) CRC cells and observed that combined treatment with andrographis-5FU in 5FUR cells exhibited superior effect on cell viability, proliferation, and colony formation capacity compared with individual treatments (P < 0.001). To identify key genes and pathways responsible for 5FU resistance, we analyzed genome-wide transcriptomic profiling data from CRC patients who either responded or did not respond to 5FU. Among a panel of differentially expressed genes, Dickkopf-1 (DKK1) overexpression was a critical event for 5FU resistance. Moreover, andrographis significantly downregulated 5FU-induced DKK1 overexpression, accompanied with enhanced anti-tumor effects by abrogating downstream Akt-phosphorylation. In line with in vitro findings, andrographis enhanced 5FU-induced anti-cancer activity in mice xenografts and patient-derived tumoroids (P < 0.01). In conclusion, our data provide novel evidence for andrographis-mediated reversal of 5FU resistance, highlighting its potential role as an adjunct to conventional chemotherapy in CRC.

Tumour-derived Dilp8/INSL3 induces cancer anorexia by regulating feeding neuropeptides via Lgr3/8 in the brain.

In patients with advanced-stage cancer, cancer-associated anorexia affects treatment success and patient survival. However, the underlying mechanism is poorly understood. Here, we show that Dilp8, a Drosophila homologue of mammalian insulin-like 3 peptide (INSL3), is secreted from tumour tissues and induces anorexia through the Lgr3 receptor in the brain. Activated Dilp8-Lgr3 signalling upregulated anorexigenic nucleobinding 1 (NUCB1) and downregulated orexigenic short neuropeptide F (sNPF) and NPF expression in the brain. In the cancer condition, the protein expression of Lgr3 and NUCB1 was significantly upregulated in neurons expressing sNPF and NPF. INSL3 levels were increased in tumour-implanted mice and INSL3-treated mouse hypothalamic cells showed Nucb2 upregulation and Npy downregulation. Food consumption was significantly reduced in intracerebrospinal INSL3-injected mice. In patients with pancreatic cancer, higher serum INSL3 levels increased anorexia. These results indicate that tumour-derived Dilp8/INSL3 induces cancer anorexia by regulating feeding hormones through the Lgr3/Lgr8 receptor in Drosophila and mammals.

Sweet as honey, bitter as bile: Mitochondriotoxic peptides and other therapeutic proteins isolated from animal tissues, for dealing with mitochondrial apoptosis.

Mitochondria are subcellular organelles involved in cell metabolism and cell life-cycle. Their role in apoptosis regulation makes them an interesting target of new drugs for dealing with cancer or rare diseases. Several peptides and proteins isolated from animal and plant sources are known for their therapeutic properties and have been tested on cancer cell-lines and xenograft murine models, highlighting their ability in inducing cell-death by triggering mitochondrial apoptosis. Some of those molecules have been even approved as drugs. Conversely, many other bioactive compounds are still under investigation for their proapoptotic properties. In this review we report about a group of peptides, isolated from animal venoms, with potential therapeutic properties related to their ability in triggering mitochondrial apoptosis. This class of compounds is known with different names, such as mitochondriotoxins or mitocans.

Discovery of novel integrase-LEDGF/p75 allosteric inhibitors based on a benzene scaffold.

We report herein the discovery of novel integrase-LEDGF/p75 allosteric inhibitors (INLAIs) based on a benzene scaffold 3. This scaffold can extend substituents from the C1 position unlike the common pyridine scaffolds 2. Structure-activity relationship studies showed that the sulfonamide linker at the C1 position was important for the antiviral activity. Interaction between sulfonamide and Q95 was observed by X-ray crystallography. Compound 31h showed more potent antiviral activity (EC50 (NL432) = 3.9 nM) than BI-224436 (EC50 (NL432) = 56 nM), suggesting the potential of the newly designed scaffold 3.

Antimicrobial peptides as a promising treatment option against Acinetobacter baumannii infections.

BACKGROUND: With the increasing rate of antibiotic resistance in Acinetobacter, the World Health Organization introduced the carbapenem-resistant isolates in the priority pathogens list for which innovative new treatments are urgently needed. Antimicrobial peptides (AMPs) are one of the antimicrobial agents with high potential to produce new anti-Acinetobacter drugs. This review aims to summarize recent advances and compare AMPs with anti-Acinetobacter baumannii activity. METHODS: Active AMPs against Acinetobacter were considered, and essential features, including structure, mechanism of action, anti-A. baumannii potent, and other prominent characteristics, were investigated and compared to each other. In this regard, the Google Scholar search engine and databases of PubMed, Scopus, and Web of Science were used. RESULTS: Forty-six anti-Acinetobacter peptides were identified and classified into ten groups: Cathelicidins, Defensins, Frog AMPs, Melittin, Cecropins, Mastoparan, Histatins, Dermcidins, Tachyplesins, and computationally designed AMPs. According to the Minimum Inhibitory Concentration (MIC) reports, six peptides of Melittin, Histatin-8, Omega76, AM-CATH36, Hymenochirin, and Mastoparan have the highest anti-A. baumannii power against sensitive and antibiotic-resistant isolates. All anti-Acinetobacter peptides except Dermcidin have a net positive charge. Most of these peptides have alpha-helical structure; however, ß-sheet and other structures have been observed among them. The mechanism of action of these antimicrobial agents is divided into two categories of membrane-based and intracellular target-based attack. CONCLUSION: Evidence from this review indicates that AMPs would be likely among the main anti-A. baumannii drugs in the post-antibiotic era. Also, the application of computer science to increase anti-A. baumannii activity and reduce toxicity could be helpful.

The Natural Flavonoid Naringenin Elicits Analgesia through Inhibition of NaV1.8 Voltage-Gated Sodium Channels.

Naringenin (2S)-5,7-dihydroxy-2-(4-hydroxyphenyl)-3,4-dihydro-2H-1-benzopyran-4-one is a natural flavonoid found in fruits from the citrus family. Because (2S)-naringenin is known to racemize, its bioactivity might be related to one or both enantiomers. Computational studies predicted that (2R)-naringenin may act on voltage-gated ion channels, particularly the N-type calcium channel (CaV2.2) and the NaV1.7 sodium channel-both of which are key for pain signaling. Here we set out to identify the possible mechanism of action of naringenin. Naringenin inhibited depolarization-evoked Ca2+ influx in acetylcholine-, ATP-, and capsaicin-responding rat dorsal root ganglion (DRG) neurons. This was corroborated in electrophysiological recordings from DRG neurons. Pharmacological dissection of each of the voltage-gated Ca2+ channels subtypes could not pinpoint any selectivity of naringenin. Instead, naringenin inhibited NaV1.8-dependent and tetrodotoxin (TTX)-resistant while sparing tetrodotoxin sensitive (TTX-S) voltage-gated Na+ channels as evidenced by the lack of further inhibition by the NaV1.8 blocker A-803467. The effects of the natural flavonoid were validated ex vivo in spinal cord slices where naringenin decreased both the frequency and amplitude of sEPSC recorded in neurons within the substantia gelatinosa. The antinociceptive potential of naringenin was evaluated in male and female mice. Naringenin had no effect on the nociceptive thresholds evoked by heat. Naringenin's reversed allodynia was in mouse models of postsurgical and neuropathic pain. Here, driven by a call by the National Center for Complementary and Integrative Health's strategic plan to advance fundamental research into basic biological mechanisms of the action of natural products, we advance the antinociceptive potential of the flavonoid naringenin.

Chitosan based hydrogels and their applications for drug delivery in wound dressings: A review.

Advanced development of chitosan hydrogels has led to new drug delivery systems that can release their active ingredients in response to environmental stimuli. This review considers more recent investigation of chitosan hydrogel preparations and the application of these preparations for drug delivery in wound dressings. Applications and structural characteristics of different types of active ingredients, such as growth factors, nanoparticles, nanostructures, and drug loaded chitosan hydrogels are summarized.

Discovery of a Novel HIV-1 Integrase/p75 Interacting Inhibitor by Docking Screening, Biochemical Assay, and in Vitro Studies.

Protein-protein interaction between lens epithelium-derived growth factor (LEDGF/p75) and HIV-1 integrase becomes an attractive target for anti-HIV drug development. The blockade of this interaction by small molecules could potentially inhibit HIV-1 replication. These small molecules are termed as LEDGINs; and several newly identified LEDGINs have been reported to significantly reduce HIV-1 replication. Through this project, we have finished the docking screening of the Maybridge database against the p75 binding site of HIV-1 integrase using both DOCK and Autodock Vina software. Finally, we have successfully identified a novel scaffold LEDGINs inhibitor DW-D-5. Its antiviral activities and anticatalytic activity of HIV-1 integrase are similar to other LEDGINs under development. We demonstrated that the combination of DW-D-5 and FDA approved anti-HIV drugs resulted in additive inhibitory effects on HIV-1 replication, indicating that DW-D-5 could be an important component of combination pills for clinic use in HIV treatment.

Preparation and in vivo evaluation of cationic elastic liposomes comprising highly skin-permeable growth factors combined with hyaluronic acid for enhanced diabetic wound-healing therapy.

To enhance the therapeutic effects of exogenous administration of growth factors (GFs) in the treatment of chronic wounds, we constructed GF combinations of highly skin-permeable epidermal growth factor (EGF), insulin-like growth factor-I (IGF-I), and platelet-derived growth factor-A (PDGF-A). We genetically conjugated a low-molecular-weight protamine (LMWP) to the N-termini of these GFs to form LMWP-EGF, LMWP-IGF-I, and LMWP-PDGF-A. Subsequently, these molecules were complexed with hyaluronic acid (HA). Combinations of native or LMWP-fused GFs significantly promoted fibroblast proliferation and the synthesis of procollagen, with a magnification of these results observed after the GFs were complexed with HA. The optimal proportions of LMWP-EGF, LMWP-IGF-I, LMWP-PDGF-A, and HA were 1, 1, 0.02, and 200, respectively. After confirming the presence of a synergistic effect, we incorporated the LMWP-fused GFs-HA complex into cationic elastic liposomes (ELs) of 107±0.757nm in diameter and a zeta potential of 56.5±1.13mV. The LMWP-fused GFs had significantly improved skin permeation compared with native GFs. The in vitro wound recovery rate of the LMWP-fused GFs-HA complex was 23% higher than that of cationic ELs composed of LMWP-fused GFs alone. Moreover, the cationic ELs containing the LMWP-fused GFs-HA complex significantly accelerated the wound closure rate in a diabetic mouse model and the wound size was maximally decreased by 65% and 58% compared to cationic ELs loaded with vehicle or native GFs-HA complex, respectively. Thus, topical treatment with cationic ELs loaded with the LMWP-fused GFs-HA complex synergistically enhanced the healing of chronic wounds, exerting both rapid and prolonged effects. STATEMENT OF SIGNIFICANCE: We believe that our study makes a significant contribution to the literature, because it demonstrated the potential application of cationic elastic liposomes as topical delivery systems for growth factors (GFs) that have certain limitations in their therapeutic effects (e.g., low percutaneous absorption of GFs at the lesion site and the requirement for various GFs at different healing stages). Topical treatment with cationic elastic liposomes loaded with highly skin-permeable low-molecular-weight protamine (LMWP)-fused GFs-hyaluronic acid (HA) complex synergistically enhanced the healing of diabetic wounds, exerting both rapid and prolonged effects.

A Novel Assay for Screening Inhibitors Targeting HIV Integrase LEDGF/p75 Interaction Based on Ni(2+) Coated Magnetic Agarose Beads.

HIV-1 integrase (IN) plays an essential role in viral replication and thus serves as an important target for chemotherapeutic intervention against HIV-1 infection. However, the current three clinical IN inhibitors, raltegravir, elvitegravir and dolutegravir share the same inhibitory mechanism, resulting in a common clinical resistance profile which have emerged in infected patients receiving treatment. Therefore, it is important to develop small molecule inhibitors that impair IN function with distinct mechanisms of action. In this work, a magnetic-beads based biochemical assay targeting the protein-protein interaction (PPI) between HIV IN and the cellular cofactor LEDGF/p75 was developed for identification of HIV-1 IN inhibitors. Furthermore, a library containing 1000 US. Food and Drug Administration (FDA)-approved drugs currently used for human medication was screened to identify inhibitors targeting the PPI. The assay was proved to be quite robust and with the novel assay we successfully identified dexlansoprazole (IC50 of 4.8 µM), a FDA-approved proton pump inhibitor, as a potential inhibitor for the PPI between IN and LEDGF/p75, which bound to the LEDGF/p75 partner with a kinetic dissociation (Kd) constant of 330 nM ± 2.6 nM.

A monoclonal antibody against the Wnt signaling inhibitor dickkopf-1 inhibits osteosarcoma metastasis in a preclinical model.

The outcome of patients with metastatic osteosarcoma has not improved since the introduction of chemotherapy in the 1970s. Development of therapies targeting the metastatic cascade is a tremendous unmet medical need. The Wnt signaling pathway has been the focus of intense investigation in osteosarcoma because of its role in normal bone development. Although the role of Wnt signaling in the pathogenesis of osteosarcoma is controversial, there are several reports of dickkopf-1 (DKK-1), a Wnt signaling antagonist, possibly playing a pro-tumorigenic role. In this work we investigated the effect of anti-DKK-1 antibodies on the growth and metastasis of patient-derived osteosarcoma xenografts. We were able to detect human DKK-1 in the blood of tumor-bearing mice and found a correlation between DKK-1 level and tumor proliferation. Treatment with the anti-DKK-1 antibody, BHQ880, slowed the growth of orthotopically implanted patient-derived osteosarcoma xenografts and inhibited metastasis. This effect was correlated with increased nuclear beta-catenin staining and increased expression of the bone differentiation marker osteopontin. These findings suggest that Wnt signaling is anti-tumorigenic in osteosarcoma, and support the targeting of DKK-1 as an anti-metastatic strategy for patients with osteosarcoma.

The evaluation of statins as potential inhibitors of the LEDGF/p75-HIV-1 integrase interaction.

Lovastatin was identified through virtual screening as a potential inhibitor of the LEDGF/p75-HIV-1 integrase interaction. In an AlphaScreen assay, lovastatin inhibited the purified recombinant protein-protein interaction (IC50 = 1.97 ± 0.45 µm) more effectively than seven other tested statins. None of the eight statins, however, yielded antiviral activity in vitro, while only pravastatin lactone yielded detectable inhibition of HIV-1 integrase strand transfer activity (31.65% at 100 µm). A correlation between lipophilicity and increased cellular toxicity of the statins was observed.

New scaffolds of natural origin as Integrase-LEDGF/p75 interaction inhibitors: virtual screening and activity assays.

The disruption of crucial interactions between HIV-1 Integrase and cellular cofactor LEDGF/p75 represents an emerging approach for the design and development of new antiretroviral agents. In this study we report the successful application of a structure-based virtual screening strategy for the discovery of natural hit structures able to inhibit Integrase-LEDGF/p75 interaction. The application of sequential filters (drug-likeness, 3D-pharmacophore mapping, docking, molecular dynamics simulations) yielded a hit list of compounds, out of which 9 were tested in the in vitro AlphaScreen assays and 8 exhibited a detectable inhibition of the interaction between the two proteins. The best inhibitors belong to different chemical classes and could be represent a good starting point for further optimization and structure-activity relationship studies.

Influence of phenolic compounds of Kangra tea [Camellia sinensis (L) O Kuntze] on bacterial pathogens and indigenous bacterial probiotics of Western Himalayas

Phenolic compounds of nutraceutical importance viz., catechins (C), (-)-epicatechin (EC), (-)-epigallocatechin (EGC), (-)-epigallocatechin-3-gallate (EGCG) and (-)-epicatechin-3-gallate (ECG) were estimated in fresh green tea shoots of Camellia sinensis (L) O Kuntze cultivar. The total polyphenols and total catechins were in the range of 219.90 to 317.81 and 140.83 to 271.39 g/kg, respectively in monthly samples of tea. The values of C, EC, EGC, EGCG and ECG in tea powders as analyzed through high performance liquid chromatography (HPLC) were in the range of 1.560 to 3.661, 13.338 to 27.766, 26.515 to 39.597, 62.903 to 102.168 and 18.969 to 39.469 mg/g, respectively. Effect of tea extracts and standard flavanols against five pathogenic bacteria viz., Listeria monocytogenes (MTCC-839), Pseudomonas aeruginosa (MTCC-741), Bacillus cereus (MTCC-1272), Staphylococcus aureus (MTCC-96) and Escherichia coli (MTCC-443), and eleven indigenous potential bacterial probiotics belonging to genera Enterococcus, Bacillus and Lactobacillus spp. obtained from fermented foods of Western Himalayas, was investigated. EGCG, ECG and EGC exhibited antibacterial activity but, C and EC did not show this activity. Tea extracts having high concentrations of EGCG and ECG were more potent in antibacterial action against bacterial pathogens. Tea extracts and standard flavan-3-ols augmented viability of potential probiotics in an order of EGCG > EGC > ECG > EC > C. Tea extracts and standard flavanols had no antibacterial activity against Escherichia coli (MTCC-443) but, in combination with probiotic culture supernatants, this activity was seen. The Kangra tea thus, exerts antibacterial effect on bacterial pathogens through EGCG, ECG and EGC constituents while stimulatory effect on growth of indigenous potential probiotics.

Discovery of novel inhibitors of LEDGF/p75-IN protein-protein interactions.

Human lens epithelium-derived growth factor (LEDGF)/p75 plays an important role in the HIV life cycle by stimulating integrase (IN)-led viral DNA integration into cellular chromosomes. Mechanistic studies show the majority of IN inhibitors chelate magnesium ions in the catalytic active site, a region topologically distant from the LEDGF/p75 binding site. Compounds disrupting the formation of LEDGF/p75 and IN complexes serve as a novel mechanistic approach different from current antiretroviral therapies. We previously built pharmacophore models mimicking LEDGF/p75 residues and identified four classes of LEDGF/p75-IN inhibitors. Substructure and similarity searches yielded additional LEDGF/p75-IN inhibitors containing an acylhydrazone moiety. The most potent of the acylhydrazones inhibited LEDGF/p75-IN interaction with an IC(50) value of 400nM. We explored structure-activity relationships (SAR) and identified new acylhydrazones, hydrazines, and diazenes as lead molecules for further optimization. Two lead LEDGF/p75-IN inhibitors showed antiviral activity.

Expression, high-pressure refolding and purification of human leukocyte cell-derived chemotaxin 2 (LECT2).

Human leukocyte cell-derived chemotaxin 2 (LECT2) is a chemotactic factor for neutrophils and a 16-kDa secreted protein consisting of 133 amino acids with three intramolecular disulfide bonds. Here, we propose an efficient method for the preparation of human LECT2 using a high hydrostatic pressure (HHP, 200 MPa) refolding technique. When LECT2 was over-expressed in Escherichia coli cells, most of LECT2 molecules became insoluble inclusion bodies (IBs). HHP was applied to the refolding of LECT2 from insoluble IBs, which dramatically improved the yield of the active LECT2. CD and NMR measurements demonstrated that the refolded LECT2 had a tertiary structure indistinguishable from the solubly expressed LECT2. In addition, both the refolded and solubly expressed LECT2 showed the same level of chemotactic activity.

Influence of phenolic compounds of Kangra tea [Camellia sinensis (L) O Kuntze] on bacterial pathogens and indigenous bacterial probiotics of Western Himalayas.

Phenolic compounds of nutraceutical importance viz., catechins (C), (-)-epicatechin (EC), (-)-epigallocatechin (EGC), (-)-epigallocatechin-3-gallate (EGCG) and (-)-epicatechin-3-gallate (ECG) were estimated in fresh green tea shoots of Camellia sinensis (L) O Kuntze cultivar. The total polyphenols and total catechins were in the range of 219.90 to 317.81 and 140.83 to 271.39 g/kg, respectively in monthly samples of tea. The values of C, EC, EGC, EGCG and ECG in tea powders as analyzed through high performance liquid chromatography (HPLC) were in the range of 1.560 to 3.661, 13.338 to 27.766, 26.515 to 39.597, 62.903 to 102.168 and 18.969 to 39.469 mg/g, respectively. Effect of tea extracts and standard flavanols against five pathogenic bacteria viz., Listeria monocytogenes (MTCC-839), Pseudomonas aeruginosa (MTCC-741), Bacillus cereus (MTCC-1272), Staphylococcus aureus (MTCC-96) and Escherichia coli (MTCC-443), and eleven indigenous potential bacterial probiotics belonging to genera Enterococcus, Bacillus and Lactobacillus spp. obtained from fermented foods of Western Himalayas, was investigated. EGCG, ECG and EGC exhibited antibacterial activity but, C and EC did not show this activity. Tea extracts having high concentrations of EGCG and ECG were more potent in antibacterial action against bacterial pathogens. Tea extracts and standard flavan-3-ols augmented viability of potential probiotics in an order of EGCG > EGC > ECG > EC > C. Tea extracts and standard flavanols had no antibacterial activity against Escherichia coli (MTCC-443) but, in combination with probiotic culture supernatants, this activity was seen. The Kangra tea thus, exerts antibacterial effect on bacterial pathogens through EGCG, ECG and EGC constituents while stimulatory effect on growth of indigenous potential probiotics.