Evaluation of the Antiviral Potential of Halogenated Dihydrorugosaflavonoids and Molecular Modeling with nsP3 Protein of Chikungunya Virus (CHIKV).

Antiviral therapy is crucial for the circumvention of viral epidemics. The unavailability of a specific antiviral drug against the chikungunya virus (CHIKV) disease has created an alarming situation to identify or develop potent chemical molecules for remedial management of CHIKV. In the present investigation, in silico studies of dihydrorugosaflavonoid derivatives (5a-f) with non-structural protein-3 (nsP3) were carried out. nsP3 replication protein has recently been considered as a possible antiviral target in which crucial inhibitors fit into the adenosine-binding pocket of the macrodomain. The 4'-halogenated dihydrorugosaflavonoids displayed intrinsic binding with the nsp3 macrodomain (PDB ID: 3GPO) of CHIKV. Compounds 5c and 5d showed docking scores of -7.54 and -6.86 kcal mol-1, respectively. Various in vitro assays were performed to confirm their (5a-f) antiviral potential against CHIKV. The non-cytotoxic dose was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and was found to be <100 µM. The compounds 5c and 5d showed their inhibitory potential for CHIKV, which was determined through cytopathic effect assay and plaque reduction assay, which show inhibition up to 95 and 92% for 70 µM concentration of the compounds, respectively. The quantitative real-time polymerase chain reaction assay result confirmed the ability of 5c and 5d to reduce the viral RNA level at 70 µM concentration of compounds to nearly 95 and 93% concentration, respectively, in cells with CHIKV infection. Further, the CHIKV-inhibitory capacity of these compounds was corroborated by execution of immunofluorescence assay. The executed work will be meaningful for the future research of studied dihydrorugosaflavonoids against prime antiviral entrants, leading to remedial management to preclude CHIKV infection.

Stability studies of crude plant material of Bacopa monnieri and quantitative determination of bacopaside I and bacoside A by HPLC.

INTRODUCTION: Bacopa monnieri (BM) contains several dammarane-type triterpenoid saponins including bacopaside I and bacoside A. These bioactive compounds may be used as chemical markers for the quality control of different BM products used for promoting mental health and intellect. OBJECTIVE: Quantification of bacopaside I and bacoside A in crude plant material of BM stored under the stability study conditions by HPLC. METHODOLOGY: Crude BM samples were stored at long-term (LS; 30°C and 65% RH), accelerated (AS; 40°C and 75% RH) and real-time (RT) study conditions. HPLC of BM extracts was carried out using a LiChroCART Purospher® STAR RP-18 endcapped column along with a guard column, Purospher STAR RP 18e 4.0 4.0 mm 5 µm using a gradient of acetonitrile (A) and water containing 0.05% (v/v) orthophosphoric acid (B) at a flow rate 1.5 mL/min with UV detection at 205 nm. RESULTS: The linear range of bacopaside I and bacoside A was 0.2 to 1 mg/mL. With the help of a regression equation the coefficient of determination (r²) values for bacopaside I and bacoside A were found to be > 0.999 and > 0.994 respectively. Relative standard deviation (RSD) values were < 4.0 for all the concentrations injected (n = 3). The HPLC study indicated that BM samples kept under LS condition are rich in saponin contents as compared with the samples stored under AS and RT study conditions. CONCLUSION: The study indicated that BM plant material should be used fresh to obtain maximum concentration of active saponins or it should be stored under LS conditions up to 3 months.

Essential oil of Terminalia chebula fruits as a repellent for the indian honeybee Apis florea.

Plant-based repellent formulations for honeybees play an important role in the bee management. For this purpose, the essential oil of an Indian medicinal plant, Terminalia chebula, commonly known as Myrobalan, was isolated for the first time. Hitherto unknown chemical constituents of the essential oil were determined by GC/MS. The repellent activity of formulations of the essential oil, tested towards the Indian honeybee Apis florea, was found to be dose dependent. The repellency (DeltaR) increased with the concentration of essential oil in the formulations, reaching a maximum for the formulation containing 50 mg/ml of oil. A further increase in the oil concentration was found to reduce the DeltaR. The screening of formulations of the major essential-oil components identified indicated that formulations of furfural, 5-methylfurfural, tetradecanoic acid, palmitic acid, and oleic acid elicited no response in honeybees. In contrast, the formulations of phenylacetaldehyde were repellent, while those of ethyl cinnamate were attractant. These findings might be an asset for beekeepers to improve the bee management. Attractant formulations are effective to attract bees to the desired areas, thus improving the efficiency of pollination. Repellent formulations are used to repel honeybees, especially when toxic insecticides are sprayed on the fields.