Reetika Singh

Couroupita guianensis Aubl. is an important medicinal tree. This tree is rich in various phytochemicals, and is therefore used as a potent antioxidant and antibacterial agent. This plant is also used for the treatment of various diseases. Here, we have improved its medicinal usage with the biosynthesis of silver nanoparticles (AgNPs) using Couroupita guianensis Aubl. flower extract as a reducing and capping agent. The biosynthesis of the AgNPs reaction was carried out using 1 mM of silver nitrate and flower extract. The effect of the temperature on the biosynthesis of AgNPs was premeditated by room temperature (25 °C) and 60 °C. The continuous stirring of the reaction mixture at room temperature for approximately one hour resulted in the successful formation of AgNPs. A development of a yellowish brown color confirmed the formation of AgNPs. The efficacious development of AgNPs was confirmed by the characteristic peaks of UV–Vis, X-ray diffraction (XRD) and Fourier transform infrared (FT-IR) spectroscopy spectra. The biosynthesized AgNPs exhibited significant free radical scavenging activity through a DPPH antioxidant assay. These AgNPs also showed potent antibacterial activity against many pathogenic bacterial species. The results of molecular dynamics simulations also proved the average size of NPs and antibacterial potential of the flower extract. The observations clearly recommended that the green biosynthesized AgNPs can serve as effective antioxidants and antibacterial agents over the plant extract.

Carissa carandas L. is traditionally used as antibacterial medicine and accumulates many antioxidant phytochemicals. Here, we expand this traditional usage with the green biosynthesis of silver nanoparticles (AgNPs) achieved using a Carissa carandas L. leaf extract as a reducing and capping agent. The green synthesis of AgNPs reaction was carried out using 1mM silver nitrate and leaf extract. The effect of temperature on the synthesis of AgNPs was examined using room temperature (25 °C) and 60 °C. The silver nanoparticles were formed in one hour by stirring at room temperature. In this case, a yellowish brown colour was developed. The successful formation of silver nanoparticles was confirmed by UV–Vis, Fourier transform infrared (FT-IR) and X-ray diffraction (XRD) analysis. The characteristic peaks of the UV-vis spectrum and XRD confirmed the synthesis of AgNPs. The biosynthesised AgNPs showed potential antioxidant activity through DPPH assay. These AgNPs also exhibited potential antibacterial activity against human pathogenic bacteria. The results were compared with the antioxidant and antibacterial activities of the plant extract, and clearly suggest that the green biosynthesized AgNPs can constitute an effective antioxidant and antibacterial agent.

Background Carissa carandas L. is a well-known wild fruit plant distributed through-out the India and also present in other countries. The fruits are rich in nutrients and minerals. A number of medicinally important phytochemicals such as carrisone, carindone, carandinol, lupeol, scopoletin, stigmasterol, β-sitosterol, myo-inositol, β-amyrin, Des-n-methylnoracronycine etc. have been reported from the extract of this plant. Being safe and cost effective molecules, the activity of phytochemicals against HIV-1 enzymes needs to be screened. Objective The aim of this study was to screen the potent phytocompound of C. carandas against human immunodeficiency virus-1 using docking method. Methods Total nine compounds viz. carandinol, caridone, carrisone, lupeol, p-coumaric acid, gallic acid, rutin, scopoletin and ursolic acid were used for in-silico study towards drug development against human immunodeficiency virus-1 reverse transcriptase (HIV-1RT; PDB ID: 1REV) and human immunodeficiency virus-1 protease (PDB ID:1EBY) using Autodock software. Results The qualitative characterization of the extracts showed the presence of a number of phytochemicals such as phenolics, flavonoids, alkaloids, terepnoids, terpenes, steroids, glycosides etc. Carandinol was observed as most effective anti-HIV-1 molecule having lowest binding energy and small inhibition coefficient. Another compound, p-coumaric acid, showed least effectiveness against human immunodeficiency virus- 1 reverse transcriptase or human immunodeficiency virus-1 protease showing highest binding energy and inhibition coefficients among all the evaluated phytocompounds. Conclusion The in-silico study demonstrated that some phytoconstituents of C. carandas exhibit potential anti-human immunodeficiency virus -1 activity and hence can be optimized to develop as a drug candidate in future.

Somatic embryogenic system was developed in Sapindus mukorossi Gaertn. using rachis as explants from a mature tree. Explants showed callus initiation on Murashige and Skoog medium supplemented with TDZ (1-Phenyl-3-(1, 2, 3-thiadiazol-5-yl) urea), zeatin or 6-benzylaminopurine. Induction of somatic embryogenesis was achieved on both MS basal medium and MS medium supplemented with 8.88 µM 6-benzylaminopurine. Hundred percent embryogenesis was observed on MS medium supplemented with 8.88 µM 6-benzylaminopurine with maximum intensity of embryogenesis (51.92 ± 0.40 a). Maximum maturation of somatic embryos (92.86 ± 0.34 a) was observed on induction medium supplemented with 0.0378 µM abscisic and treated for 21 days. Germination of somatic embryos was maximum (77.33 ± 0.58 a) on MS medium supplemented with 8.88 µM 6-benzylaminopurine. In vitro raised plantlets were hardened, acclimatized and transferred to the field. Survival frequency of plantlets was 80 % in field conditions. The genetic fidelity of in vitro regenerated plants was also evaluated and compared with mother plant using random amplified polymorphic DNA and inter simple sequence repeat. Both markers showed similarity in molecular profile of mother plant and in vitro regenerated plants.

A somatic embryogenesis system was developed for Sapindus mukorossi Gaertn. from leaf explants obtained from fresh flushes of a mature tree. Callus was induced from the midrib region of leaf explants on Murashige and Skoog (MS) medium containing different concentrations of 2,4-dichlorophenoxyacetic acid or 6-benzylaminopurine. Callus induction and somatic embryogenesis was significantly influenced by the size, physiological age, and orientation of leaf explants on the culture medium and plant growth regulators. Adaxial-side-up orientation of leaf explants significantly promoted embryogenesis in comparison with abaxial-side-up orientation. Maximum number of somatic embryos was induced on MS medium supplemented with 8.88 μM 6-benzylaminopurine. Scanning electron microscopy of embryogenic callus revealed somatic embryo origin and the development of globular-, heart-, and cotyledonary-stage somatic embryos. The frequency of maturation as well as germination of somatic embryos was higher on MS medium containing 8.88 μM 6-benzylaminopurine than on medium without 6-benzylaminopurine. Plantlets which developed from somatic embryos were acclimatized successfully with 90 % survival.