The effect of lichen secondary metabolites on Aspergillus fungi

A systematic review of literature data on the antifungal potential of extracted lichen compounds and individual secondary metabolites against mold species of the genus Aspergillus is provided. Crude extracts from 49 epiphytic, 16 epigeic and 22 epilithic species of lichens and 44 secondary metabolites against 10 species, Aspergillus candidus, A. flavus, A. fumigatus, A. nidulans, A. niger, A. ochraceus, A. parasiticus, A. restrictus, A. stellatus and A. ustus, were analysed. Several measuring techniques were employed for such analyses. Lichen substances were extracted with alcoholic and other organic solvents mainly using the Soxhlet apparatus. Among the three most-studied mold species, the results showed that the crude extracts from the thalli of the lichens Cladonia foliacea, Hypotrachyna cirrhata, Leucodermia leucomelos, Platismatia glauca and Pseudevernia furfuracea against Aspergillus flavus, from C. foliacea, Nephroma arcticum and Parmelia sulcata against A. fumigatus and from Evernia prunastri, Hypogymnia physodes, Umbilicaria cylindrica and Variospora dolomiticola against A. niger have the greatest antifungal potential. The lichen secondary metabolites showed a higher inhibitory potential, e.g. protolichesterinic acid against A. flavus, lecanoric acid against A. fumigatus and orsellinic acid against A. niger; the other seven species of Aspergillus have been poorly studied and require further investigation. A comparison of the inhibitory potential of the tested mixtures of lichen substances and their secondary metabolites shows that they can compete with commonly used antifungal substances, such as ketoconazole and clotrimazole against A. flavus, A. nidulans, A. niger and A. parasiticus and fluconazole in the case of A. fumigatus.

Phytochemical and Biological Investigation of Bridelia tomentosa Blume Growing in Bangladesh

Bridelia tomentosa Blume is a small evergreen tree which has enormous folklore applications in the treatment of colic, traumatic injury, epidemic influenza and neurasthenia. The main purpose of this study was to isolate bioactive compounds from the stem bark of B. tomentosa growing in Bangladesh. Extensive chromatographic separation and purification of the methanolic extract of stem bark of B. tomentosa led to the isolation of four compounds. The purified constituents were identified as friedoolean-5(6),14(15)-dien-3-one (1), β-taraxerol (2), D4- stigmasterone (3) and lupeol (4) by extensive analysis of NMR spectroscopic data. While compound 1 is appeared to be new, the other compounds (2-4) have been isolated for the first time from this plant. β-taraxerol (2) demonstrated significant cytotoxic activity against the brine shrimp Artemia salina and moderate to strong antimicrobial efficacy with the highest inhibitory potential against Salmonella Typhi (zone of inhibition = 21.3 mm) and Sarcina lutea (zone of inhibition =20.8 mm). In conclusion, B. tomentosa has been found to be a rich source of secondary metabolites and thus it may be studied further in order to isolate of more bioactive constituents. Dhaka Univ. J. Pharm. Sci. 20(2): 213-218, 2021 (December)

Multi-Targeted Approaches and Drug Repurposing Reveal Possible SARS-CoV-2 Inhibitors

The COVID-19 pandemic caused by SARS-CoV-2 is unprecedented in recent memory owing to the non-stop escalation in number of infections and deaths in almost every country of the world. The lack of treatment options further worsens the scenario, thereby necessitating the exploration of already existing US FDA-approved drugs for their effectiveness against COVID-19. In the present study, we have performed virtual screening of nutraceuticals available from DrugBank against 14 SARS-CoV-2 proteins. Molecular docking identified several inhibitors, two of which, rutin and NADH, displayed strong binding affinities and inhibitory potential against SARS-CoV-2 proteins. Further normal model-based simulations were performed to gain insights into the conformational transitions in proteins induced by the drugs. The computational analysis in the present study paves the way for experimental validation and development of multi-target guided inhibitors to fight COVID-19.

HPLC-DAD Based Polyphenolic Profiling and Evaluation of Pharmacological Attributes of Putranjiva roxburghii Wall.

The current study was intended to explore the phytochemical profiling and therapeutic activities of Putranjiva roxburghii Wall. Crude extracts of different plant parts were subjected to the determination of antioxidant, antimicrobial, antidiabetic, cytotoxic, and protein kinase inhibitory potential by using solvents of varying polarity ranges. Maximum phenolic content was notified in distilled water extracts of the stem (DW-S) and leaf (DW-L) while the highest flavonoid content was obtained in ethyl acetate leaf (EA-L) extract. HPLC-DAD analysis confirmed the presence of various polyphenols, quantified in the range of 0.02 ± 0.36 to 2.05 ± 0.18 μg/mg extract. Maximum DPPH scavenging activity was expressed by methanolic extract of the stem (MeOH-S). The highest antioxidant capacity and reducing power was shown by MeOH-S and leaf methanolic extract (MeOH-L), respectively. Proficient antibacterial activity was shown by EA-L extract against Bacillus subtilis and Escherichia coli. Remarkable α-amylase and α-glucosidase inhibition potential was expressed by ethyl acetate fruit (EA-F) and n-Hexane leaf (nH-L) extracts, respectively. In case of brine shrimp lethality assay, 41.67% of the extracts (LC50 < 50 µg/mL) were considered as extremely cytotoxic. The test extracts also showed mild antifungal and protein kinase inhibition activities. The present study explores the therapeutic potential of P. roxburghii and calls for subsequent studies to isolate new bioactive leads through bioactivity-guided isolation.

Phytochemical Screening and In vitro Albumin Denaturation Inhibitory Potential of Methanolic Root Extract of Acorus calamus

Introduction: Medicinal plants are chief antidotes for numerous diseases and have been used since time immemorial. Sweet flag’s (Acorus calamus) presence is in Ayurveda and belongs to the genus Acorus L. of the family Acoraceae and is widely distributed in temperate to sub temperate regions. It is commonly used to treat appetite loss, diarrhoea, digestive disorders in traditional medicinal systems of Asian and European countries. The aim of this study is to explore the phytoconstituents, antioxidant and anti-inflammatory potential of methanolic root extract of Acorus calamus. Materials and Methods: Methanolic root extract of Acorus calamus was done by the Hot Percolation method. Later it was dried and used to analyse the antioxidant and anti-inflammatory potentials. Phytochemical screening was done to analyse the presence of various phytochemicals. Antioxidant effect of Acorus calamus was tested by 2, 2-Diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging activity and Albumin denaturation inhibitory potential test was organised for testing it’s anti-inflammatory Activity. The data were analysed statistically by a one-way analysis of Variance (ANOVA) followed by Duncan’s multiple range test was used to see the statistical significance among the groups. The results with the p<0.05 level were considered to be statistically significant. Results: Methanolic root extract of Acorus calamus was found to be rich in Alkaloids, Flavonoids, Terpenoids, Sapanoids, Steroids and Phlobatannin. The presence of phytochemicals like alkaloids, saponins, Flavonoids indicates that the extract has potential for further in vitro analysis like antioxidant and anti-inflammatory potentials. It was observed that Acorus calamus has both antioxidant (IC50 of = 295 µg/ml) as well as anti inflammatory potentials (IC50 =310 µg/ml) and the activity increased in a dose dependent manner as compared to that of standard (Vitamin C and Diclofenac respectively). Conclusion: The study proves the antioxidant and anti-inflammatory efficacy of Acorus calamus and throws light on the prospects of drug formulation against oxidant activity and inflammation.

Evaluation of Antioxidant and Xanthine Oxidase Inhibitory Potential of Methanolic Leaf Extract of Stevia rebaudiana

Background: Stevia rebaudiana is a shrub-like plant that belongs to the sunflower family and is commonly referred as stevia.It is 1000 times sweeter than sugar even at a very low concentration. Xanthine oxidase is an enzyme that generates oxygen species and catalyzes the production of uric acid from purine metabolism.Overproduction of uric acid results in a clinical condition called gout. The aim of this study is to explore the phytochemicals, antioxidant and xanthine oxidase inhibitory potential of methanolic leaf extract of stevia rebaudiana. Methods: Methanolic leaf extract of Stevia rebaudiana was prepared by the Hot Percolation method. Phytochemical screening was done to analyse the presence of various phytochemicals. The leaf extract was tested for its antioxidant and xanthine oxidase inhibitory potentials. The data were analyzed statistically by a one-way analysis of variance (ANOVA) followed by Duncan’s multiple range test was used to see the statistical significance among the groups. The results with the p<0.05 level were considered to be statistically significant. Results: It was observed that the methanolic leaf extract of Stevia rebaudiana has significant antioxidant potential (Ic50 of = 310 μg/ml) as well as xanthine oxidase inhibitory potentials(Ic50 of = 270 μg/ml) and the activity increased in a dose dependent manner as compared to that of standard (Vitamin C and Allopurinol respectively). Conclusion: The study proves the antioxidant and xanthine oxidase inhibitory efficacy of Stevia rebaudiana and throws light on the prospects of drug formation against oxidant activity and gout formation.

Computational Study of the Therapeutic Potential of Novel Heterocyclic Derivatives against SARS-CoV-2

Severe Acute Respiratory Syndrome Coronavirus- 2 (SARS-CoV-2), including the recently reported severe variant B.1.617.2, has been reported to attack the respiratory tract with symptoms that may ultimately lead to death. While studies have been conducted to evaluate therapeutic interventions against the virus, this study evaluated the inhibitory potential of virtually screened novel derivatives and structurally similar compounds towards SARS-CoV-2 via a computational approach. A molecular docking simulation of the inhibitory potentials of the compounds against the SARS-CoV-2 drug targets—main protease (Mpro), spike protein (Spro), and RNA-dependent RNA polymerase (RdRp)—were evaluated and achieved utilizing AutoDock Vina in PyRx workspace. The absorption, distribution, metabolism, excretion, and toxicity (ADMET) properties of these compounds were assessed using SwissADME and ADMETLab servers. All the compounds displayed high binding affinities for the SARS-CoV-2 drug targets. However, the C13 exhibited the highest binding affinity for the drug targets, Spro and RdRp, while C15 exhibited the highest binding affinity for Mpro. The compounds interacted with the LEU A:271, LEU A:287, ASP A:289, and LEU A:272 of Mpro and the HIS A:540, PRO A:415, PHE A:486, and LEU A:370 of the Spro receptor binding motif and some active site amino acids of RdRp. The compounds also possess a favourable ADMET profile and showed no tendency towards hERG inhibition, hepatotoxicity, carcinogenicity, mutagenicity, or drug-liver injury. These novel compounds could offer therapeutic benefits against SARS-CoV-2, and wet laboratory experiments are necessary to further validate the results of this computational study.

Evaluation of Antioxidant and Protease-inhibitory Potential of Ethanolic Extract of Myristica fragrans (Nutmeg)

Introduction: Myristica fragrans is an important commercial plant used for spices. The plant has been traditionally used as an anticancer, anti inflammatory, antioxidant, sedative hypnotics and antimicrobial agent. Plants have played an important role in maintaining human health & improving the quality of human life for thousands of years and have served humans well as valuable components of medicines. Methods: Ethanolic extract of myristica fragrans was obtained by hot percolation method. Preliminary Phytochemical screening of the extract was done .Antioxidant and anti inflammatory potential of ethanolic extract of myristica fragrans was analysed. The data were analysed statistically using two – way analysis of variance (ANOVA) and Tukey’s multiple range test to assess the significance of individual variations between the groups. In Tukey’s test, significance was considered at the level of p<0.05. Results: Ethanolic extract of Myristica fragrans (Nutmeg) was rich in the phytoconstituents such as alkaloids, flavonoids, terpenoids and saponins. IC50 of antioxidant activity of ethanolic extract of Myristica fragrans was found to be 300 µg/ml. IC50 of anti-inflammatory potential of the ethanolic extract of Myristica fragrans was found to be 360 µg/ml. Conclusion: From the study, it was evident that the ethanolic extract of myristica fragrans has significant antioxidant and anti-inflammatory potential. In future, the extract can be validated as a drug formulation.