Optimized extraction of polyphenolic antioxidants from the leaves of Himalayan Oak species.

In this study heat-assisted extraction conditions were optimized to enhance extraction yield of antioxidant polyphenols from leaves of Himalayan Quercus species. In initial experiments, a five-factor Plackett-Burman design including 12 experimental runs was tested against the total polyphenolic content (TP). Amongst, XA: extraction temperature, XC: solvent concentration and XE: sample-to-solvent ratio had shown significant influence on yield. These influential factors were further subject to a three-factor-three-level Box-Wilson Central Composite Design; including 20 experimental runs and 3D response surface methodology plots were used to determine optimum conditions [i.e. XA: (80°C), XC:(87%), XE: (1g/40ml)].This optimized condition was further used in other Quercus species of western Himalaya, India. The High-Performance Liquid Chromatography (HPLC) revealed occurrence of 12 polyphenols in six screened Quercus species with the highest concentration of catechin followed by gallic acid. Amongest, Q. franchetii and Q. serrata shared maximum numbers of polyphenolic antioxidants (8 in each). This optimized extraction condition of Quercus species can be utilized for precise quantification of polyphenols and their use in pharmaceutical industries as a potential substitute of synthetic polyphenols.

Molecular dynamics simulation for screening phytochemicals as α-amylase inhibitors from medicinal plants.

Diabetes mellitus (DM) is a complicated metabolic disorder with several enzymes, including α-amylase and α-glycosidase. The α-amylase is responsible for postprandial glucose levels; therefore, inhibiting its activity is helpful in diabetes management. Hence, to find natural inhibitors of α-amylase, we have prepared a 257 phytochemical library from selected medicinal plants with antidiabetic activity and conducted a virtual screening and molecular dynamics study. Seventy-nine phytochemicals were screened out of 257 phytochemicals based on binding energy, ranged from -10.1 kcal mol-1 to -7.6 kcal mol-1. The binding energies of screened compounds were lower or equal to the reference molecule (-7.6 kcal mol-1). The binding affinity of six screened phytochemicals was re-scored by X-SCORE. These phytochemicals were subjected to ADMET and Drug-likeness analysis. After screening docking and drug-likeness analysis, six phytochemicals viz., Shahidine, Epicatechin, Quercetin, Isocolumbin, Ellagic acid, Luteolin and a reference molecule (Acarbose) were subjected to Molecular dynamics (MD) simulation to analyze the stability of the docked protein-ligand complex. The values of root mean square deviation, RMSF, RG, SASA, H-Bond, the interaction energy of all protein-ligand complexes were calculated after 30 ns of MD simulation. The results of screened complexes revealed good stability as compared to reference Acarbose. Pharmacophore features of the screened phytochemicals and α-amylase inhibitors showed many common pharmacophore features. Based on finding the screened phytochemicals, e.g. Shahidine, Epicatechin, Quercetin, Isocolumbin, Ellagic acid, and Luteolin, may be used as a potential inhibitors against α-amylase. These phytochemicals could be optimized and synthesized to develop potential drugs to manage and treat diabetes, targeting α-amylase.Communicated by Ramaswamy H. Sarma.

Using Chou's 5-steps rule to study pharmacophore-based virtual screening of SARS-CoV-2 Mpro inhibitors.

Recently emerged SARS-CoV-2 is the cause of the ongoing outbreak of COVID-19. It is responsible for the deaths of millions of people and has caused global economic and social disruption. The numbers of COVID-19 cases are increasing exponentially across the world. Control of this pandemic disease is challenging because there is no effective drug or vaccine available against this virus and this situation demands an urgent need for the development of anti-SARS-CoV-2 potential medicines. In this regard, the main protease (Mpro) has emerged as an essential drug target as it plays a vital role in virus replication and transcription. In this research, we have identified two novel potent inhibitors of the Mpro (PubChem3408741 and PubChem4167619) from PubChem database by pharmacophore-based high-throughput virtual screening. The molecular docking, toxicity, and pharmacophore analysis indicate that these compounds may act as potential anti-viral candidates. The molecular dynamic simulation along with the binding free energy calculation by MMPBSA showed that these compounds bind to Mpro enzyme with high stability over 50 ns. Our results showed that two compounds: PubChem3408741 and PubChem4167619 had the binding free energy of - 94.02 kJ mol-1 and - 122.75 kJ mol-1, respectively, as compared to reference X77 (- 76.48 kJ mol-1). Based on our work's findings, we propose that these compounds can be considered as lead molecules for targeting Mpro enzyme and they can be potential SARS-CoV-2 inhibitors. These inhibitors could be tested in vitro and explored for effective drug development against COVID-19.

In silico screening of potential antidiabetic phytochemicals from Phyllanthus emblica against therapeutic targets of type 2 diabetes.

ETHNOPHARMACOLOGICAL RELEVANCE: Phyllanthus emblica Linn. (Syn. Emblica officinalis Gaertn.), has been used to cure many ailments of human beings. Literature survey demonstrates that it has many pharmacological activities i.e. antidiabetic, antioxidant, anti-microbial, antifungal, antiallergic, antiviral, and anticancer properties. AIM OF THE STUDY: The present study aimed to identify the novel plant-derived antidiabetic compounds from P. emblica to understand the molecular basis of antidiabetic activities. MATERIAL AND METHODS: Text mining analysis of P. emblica and its disease association was carried out using server DLAD4U. Due to the highest score of P. emblica with diabetes, the virtual screening of a phytochemical library of P. emblica against three targets of diabetes was carried out. After that FAF-Drug4, admetSAR and DruLiTo servers were used for drug-likeness prediction. Additionally, pharmacophore modeling was also carried out to understand the antidiabetic activity of screened compounds. RESULTS: The docking scores, drug-likeness and pharmacophore studies found that Ellagic acid, Estradiol, Sesamine, Kaempferol, Zeatin, Quercetin, and Leucodelphinidin are potential antidiabetic compounds. CONCLUSIONS: Our study shows that phytochemicals of P. emblica are very potential antidiabetic candidates. Using the modern techniques these molecules could be used to develop an effective antidiabetic drugs from a natural resource.

Phenolic compounds, antioxidant capacity and antimutagenic activity in different growth stages of in vitro raised plants of Origanum vulgare L.

Efficient micropropagation procedure was developed for Origanum vulgare, a high-value culinary herb, and the phytochemicals, phenolic content, antioxidant and antimutagenic activity of leaf and stem, derived from different growing stages were analyzed. The agar solidified Murashige and Skoog (MS) medium supplemented with a combination of 6-benzylaminopurine and α-naphthaleneacetic acid was optimized as best shoot-multiplication-medium. Shoots were rooted best on 1/2 strength MS medium supplemented with 50 µM indole-3-butyric acid (IBA). The plantlets were successfully acclimatized ex vitro in a soil, sand and farmyard manure mixture (2:1:1 v/v/v) with 100% survival rate in greenhouse. The total anthocyanin and total phenolic content were observed significantly higher in leaves of in vitro-raised plants. However, total tannin, flavonoid and antioxidant activity remained higher in leaves of mother plant maintained under ployhouse condition. All the plant extracts have shown significant antimutagenic activity except in vitro-growing plants. A total of 13 polyphenolic compounds were detected in different extracts using high performance liquid chromatography. Among these, catechin was detected maximum in in vitro-growing cultures and chlorogenic acid in leaves of mother plant. These findings will help the farmers, medicinal plant growers, and industries for mass multiplication and effective extraction of phytochemicals from O. vulgare.

Optimisation and characterisation of the orange pigment produced by a cold adapted strain of Penicillium sp. (GBPI_P155) isolated from mountain ecosystem.

With globalisation and growing health risks of synthetic colourants, search for pigments from natural sources has increased owing to their non-toxic nature. The present study highlights the bioprospection of natural pigment from a cold adapted fungal strain of Penicillium sp. (GBPI_P155), isolated from soil of Indian Himalayan region. The fungus produced insoluble and orange-coloured pigment in liquid medium with maximum production recorded in potato dextrose (PD) broth at 15°C and 3 pH, while maximum biomass was produced at 25°C and pH 3. While examining the effect of different mineral salts, and carbon and nitrogen sources on pigment production, maximum accumulation of pigment was recorded in PD broth supplemented with 2% maltose. Following production, extraction of pigment was performed using chloroform and characterised partially by UV/vis (λmax at 495 nm and a shoulder peak at 530 nm) and Fourier Transform Infrared (FT-IR) spectroscopy. Thin layer chromatography of chloroform extract resulted in separation of pigment in three fractions with Rf values 0.911, 0.852 and 0.808, which were further analysed using Liquid Chromatography Mass Spectrometry (LC/MS). The overall approach resulted in identification of pigment as a mixture of different derivatives of carotenoids. The extracted pigment also possessed antimicrobial activity against Gram-positive and Gram-negative bacteria and actinobacteria.

Prolonged Laccase Production by a Cold and pH Tolerant Strain of Penicillium pinophilum (MCC 1049) Isolated from a Low Temperature Environment.

Production of laccase by a cold and pH tolerant strain of Penicillium pinophilum has been investigated under different cultural conditions for up to 35 days of incubation. The fungus was originally isolated from a low temperature environment under mountain ecosystem of Indian Himalaya. The estimations were conducted at 3 temperatures (15, 25, and 35°C), a range of pH (3.5-11.5), and in presence of supplements including carbon and nitrogen sources, vitamins, and antibiotics. Optimum production of laccase was recorded at 25°C (optimum temperature for fungal growth) and 7.5 pH. The production of enzyme was recorded maximum on day 28 (11.6 ± 0.52 U/L) following a slow decline at day 35 of incubation (10.6 ± 0.80 U/L). Fructose and potassium nitrate (0.2%) among nutritional supplements, chloramphenicol (0.1%) among antibiotics, and folic acid (0.1%) among vitamins were found to be the best enhancers for production of laccase. Relatively lower but consistent production of laccase for a longer period is likely to be an ecologically important phenomenon under low temperature environment. Further, enhancement in production of enzyme using various supplements will be useful for its use in specific biotechnological applications.