Identification of sustainable trypsin active-site inhibitors from Nigrospora sphaerica strain AVA-1.

Trypsin is a protein-digesting enzyme that is essential for the growth and regeneration of bone, muscle, cartilage, skin, and blood. The trypsin inhibitors have various role in diseases such as inflammation, Alzheimer's disease, pancreatitis, rheumatoid arthritis, cancer prognosis, metastasis and so forth. From 10 endophytic fungi isolated, we were able to screen only one strain with the required activity. The fungus with activity was obtained as an endophyte from Dendrophthoe falcata and was later identified as Nigrospora sphaerica. The activity was checked by enzyme assays using trypsin. The fungus was fermented and the metabolites were extracted and further purified by bioassay-guided chromatographic methods and the compound isolated was identified using gas chromatography-mass spectrometry. The compound was identified as quercetin. Docking studies were employed to study the interaction. The absorption, distribution, metabolism, and excretion analysis showed satisfactory results and the compound has no AMES and hepatotoxicity. This study reveals the ability of N. sphaerica to produce bioactive compound quercetin has been identified as a potential candidate for trypsin inhibition. The present communication describes the first report claiming that N. sphaerica strain AVA-1 can produce quercetin and it can be considered as a sustainable source of trypsin active-site inhibitors.

Extraction and optimization of Penicillium sclerotiorum strain AK-1 pigment for fabric dyeing.

Recently, the demand for fungal pigments has increased due to their several benefits over synthetic dyes. Many species of fungi are known to produce pigments and a large number of fungal strains for pigment production are yet to be extensively investigated. The natural pigment from sustainable natural sources has good economic and industrial value. Many synthetic colorants used in textile and various industries have many harmful effects on the human population and environment. Pigments and coloring agents may be extracted from a wide range of fungal species. These compounds are among the natural compounds having the most significant promise for medicinal, culinary, cosmetics, and textile applications. This study attempts to isolate and optimize the fermentation conditions of Penicillium sclerotiorum strain AK-1 for pigment production. A dark yellow-colored pigment was isolated from the strain with significant extractive value and antioxidant capacity. This study also identifies that the pigment does not have any cytotoxic effect and is multicomponent. The pigment production was optimized for the parameters such as pH, temperature, carbon and nitrogen source. Fabric dyeing experiments showed significant dyeing capacity of the pigment on cotton fabrics. Accordingly, the natural dye isolated from P. sclerotiorum strain AK-1 has a high potential for industrial-scale dyeing of cotton materials.

Repurposing simeprevir, calpain inhibitor IV and a cathepsin F inhibitor against SARS-CoV-2 and insights into their interactions with Mpro.

The world has come to a sudden halt due to the incessant spread of a viral pneumonia dubbed COVID-19 caused by the beta-coronavirus, SARS-CoV-2. The main protease of SARS-CoV-2 plays a key role in the replication and propagation of the virus in the host cells. Inhibiting the protease blocks the replication of the virus; therefore it is considered as an attractive therapeutic target. Here we describe the screening of the DrugBank database, a public repository for small molecule therapeutics, to identify approved or experimental phase drugs that can be repurposed against the main protease of SARS-CoV-2. The initial screening was performed on more than 13,000 drug entries in the target database using an energy optimised pharmacophore hypothesis AARRR. A sub-set of the molecules selected based on the fitness score was further screened using molecular docking by sequentially filtering the molecules through the high throughput virtual screening, extra precision and standard precision docking modalities. The best hits were subjected to binding free energy estimation using the MM-GBSA method. Approved drugs viz, Cobicistat, Larotrectinib and Simeprevir were identified as potential candidates for repurposing. Drugs in the discovery phase identified as inhibitors include the known cysteine protease inhibitors, Calpain inhibitor IV and an experimental cathepsin F inhibitor. In order to analyse the stability of the binding interactions, the known cysteine protease inhibitors viz, Simeprevir, calpain inhibitor IV and the cathepsin F inhibitor in complex Mpro were subjected to molecular dynamics simulations at 100 ns. Based on the results Simeprevir was found to be a strong inhibitor of SARS-CoV-2 Mpro.Communicated by Ramaswamy H. Sarma.

Role of taraxerone isolated from Leucas lavandulifolia, as an immunomodulator.

ETHNOPHARMACOLOGICAL RELEVANCE: The Indian tradition system of medicine enlists a large number of plants for basic health care. Leucas lavandulifolia is mentioned in the ayurvedic medicinal system and also used among the folklores. The plant is used for the treatment of fever, asthma, psoriasis, dermatitis and healing snake bites. The scientific validation of the plant for their traditional use in different immune related disorders are yet to be explored. AIM OF THE STUDY: The study aims to isolate immunomodulatory active compound from Leucas lavandulifolia and evaluating its efficiency in immune related disorders. MATERIALS AND METHODS: The immunomodulatory activity of the phytocompound is evaluated through in vitro and in vivo studies. The compound purification and identification were done by chromatography and LC/Q-TOF respectively. Its immunomodulatory activity was evaluated in cells like PBMC, neutrophils and macrophages by MTT assay and cell cycle analysis. Animal studies were performed on Swiss albino mice. The levels of IL-4 and IL-6 cytokines were also evaluated in both in vitro and in vivo models. RESULTS: Leucas lavandulifolia stem portion was found to have good modulatory property. An active immunomodulator was isolated from the methanol extract of the plant. LC/Q-TOF data revealed the isolated compound to be taraxerone. In PBMC, the compound was capable of suppressing the proliferation rate of the compound indicated by a decrease in cell numbers. The activated IL-4 and IL-6 production was also suppressed actively at 25 µg/ml of taraxerone. Similar inhibitory effects were seen in RAW 264.7 and THP-1 macrophage cell lines. An IC50 value of 17.5 µg/ml was obtained for taraxerone in LPS stimulated RAW 264.7 macrophage cell lines. The NO level, IL-4, IL-6 and phagocytosis in the LPS stimulated macrophage was effectively lowered by 25 µg/ml of taraxerone. In PMA stimulated THP-1 Macrophage Cell Lines, taraxerone was capable of suppressing the cell number and IL-6. The compound didn't show any effect on IL-4 levels. The compound exhibited an immunosuppressive activity in PHA induced PMN cells by suppressing the respiratory burst and interleukins IL-4 and IL-6. TX could also suppress the proliferation of DNCB induced monocyte cells and IL-4. The haematological parameters exhibited a significant suppression for the high dose group of taraxerone. The antibody titre and phagocytic index was suppressed by the high dose group, whereas the low dose group did not have any effect. So taraxerone at 50 mg/kg body weight is capable of modulating the B-lymphocytes and macrophages. But the compound has exhibited insignificant effect on the DTH hypersensitivity response and organ index. CONCLUSION: Taraxerone at high concentration was capable of suppressing stimulated PBMC, macrophage and PMN. The activated nitric oxide, IL-4, IL-6 production and phagocytosis was also suppressed. The haematological parameters, antibody titre and phagocytic index was also lowered in antigenically challenged mice. The terpenoid taraxerone exhibits a good modulatory effect on the immune system and proves to be a potent drug for the treatment of many allergic disorders.

Chemical similarity assisted search for acetylcholinesterase inhibitors: Molecular modeling and evaluation of their neuroprotective properties.

Alzheimer's disease (AD) is an obstinate and progressive neurodegenerative disorder, mainly characterized by cognitive decline. Increasing number of AD patients and the lack of promising treatment strategies demands novel therapeutic agents to combat various disease pathologies in AD. Recent progresses in understanding molecular mechanisms in AD helped researchers to streamline the various therapeutic approaches. Inhibiting acetylcholinesterase (AChE) activity has emerged as one of the potential treatment strategies. The present study discusses the identification of two potent AChE inhibitors (ZINC11709541 and ZINC11996936) from ZINC database through conventional in silico approaches and their in vitro validations. These inhibitors have strong preferences towards AChE than butyrylcholinesterase (BChE) and didn't evoke any significant reduction in the cell viability of HEK-293 cells and primary cortical neurons. Furthermore, promising neuroprotective properties has also been displayed against glutamate induced excitotoxicity in primary cortical neurons. The present study proposes two potential drug lead compounds for the treatment of AD, that can be used for further studies and preclinical evaluation.

Structural characterization of a novel derivative of myricetin from Mimosa pudica as an anti-proliferative agent for the treatment of cancer.

The study was initiated to determine the anticancer activity of a novel compound isolated from the plant Mimosa pudica. The structure of the compound was identified as a derivative of myricetin having alkyl, hydroxy alkyl and methyl substitutions on the basis of spectral evidences (UV-vis, FT-IR, 1H NMR and Mass spectra). The isolated compound was interpreted as 2-(2',6'-dimethyl-3',4',5'-alkyl or hydroxy alkyl substituted phenyl)-3-oxy-(alkyl or hydoxy alkyl)- 5,7-dihydroxy-chromen-4-one. In vitro evaluation of anticancer activity against human lung adenocarcinoma cell line (A549) and human erythroleukemic cell line (K562) were conducted using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. In vivo anticancer activity was determined against Dalton's Ascites Lymphoma (DAL) in Swiss albino mice. The mice were treated with intraperitoneal administration of the compound at 25mg/kg and 100mg/kg body weight and were compared with the normal, DAL control and standard drug cyclophosphamide treated groups. The histology revealed that the compound could protect the cellular architecture of liver and kidney. The results from the in vitro, in vivo and histological examinations confirmed the ethnopharmacological significance of the isolated compound and could be considered further for the development of an effective drug against cancer.