In silico–based combinatorial pharmacophore modelling and docking studies of GSK-3β and GK inhibitors of Hippophae.

Type 2 diabetes is an inevitably progressive disease, with irreversible β cell failure. Glycogen synthase kinase and Glukokinase, two important enzymes with diverse biological actions in carbohydrate metabolism, are promising targets for developing novel antidiabetic drugs. A combinatorial structure-based molecular docking and pharmacophore modelling study was performed with the compounds of Hippophae salicifolia and H. rhamnoides as inhibitors. Docking with Discovery Studio 3.5 revealed that two compounds from H. salicifolia, viz Lutein D and an analogue of Zeaxanthin, and two compounds from H. rhamnoides, viz Isorhamnetin-3-rhamnoside and Isorhamnetin-7-glucoside, bind significantly to the GSK-3 β receptor and play a role in its inhibition; whereas in the case of Glucokinase, only one compound from both the plants, i.e. vitamin C, had good binding characteristics capable of activation. The results help to understand the type of interactions that occur between the ligands and the receptors. Toxicity predictions revealed that none of the compounds had hepatotoxic effects and had good absorption as well as solubility characteristics. The compounds did not possess plasma protein-binding, crossing blood–brain barrier ability. Further, in vivo and in vitro studies need to be performed to prove that these compounds can be used effectively as antidiabetic drugs.

Evaluation of phytochemical constituents and antioxidant activity of selected actinorhizal fruits growing in the forests of Northeast India.

Hippophae salicifolia, Elaeagnus pyriformis, Myrica esculenta and M. nagi are actinorhizal plants growing in the sacred forests of Northeast India with multipurpose uses. The present investigation was undertaken to determine the phenol, flavonoid and flavonol contents of the fresh fruit juice of these plant species including the antioxidant potential by means of DPPH, H2O2 and NO scavenging activity and FRP. The total phenolic, flavonoid and flavonol contents of fruit juice ranged from 321.68±0.06 to 76.67±0.01 mg/g GAE, 272.92±0.07 to 20.12±0.02 mg/g QE and 258.92±0.08 to 18.72±0.02 mg/g QE, respectively. At 2.0 mg/mL concentration, DPPH scavenging activity was found to be the highest in M. esculenta (89.62%) and the lowest in E. pyriformis (17.58%). The reducing power activity was found significantly higher in H. salicifolia juice, which increased with increase in concentration. The H2O2 scavenging activity of H. salicifolia juice was found to be as high as 98.78%, while Elaeagnus juice was found to be less effective with just 48.90%. Juice of H. salicifolia showed the greatest NO scavenging effect of 75.24% as compared to juice of E. pyriformis, where only 37.54% scavenging was observed at the same concentration. Taking into account all the experimental data, it can be said that the fruits of H. salicifolia and both M. nagi and M. esculenta have good antioxidant activity compared to fruits of E. pyriformis.

Growth and N2 fixation in an Alnus hirsuta (Turcz.) var. sibirica stand in Japan.

To estimate the N2 fixation ability of the alder (Alnus hirsuta (Turcz.) var. sibirica), we examined the seasonal variation in nitrogenase activity of nodules using the acetylene reduction method in an 18-year-old stand naturally regenerated after disturbance by road construction in Japan. To evaluate the contribution of N2 fixation to the nitrogen (N) economy in this alder stand, we also measured the phenology of the alder, the litterfall, the decomposition rate of the leaf litter, and N accumulation in the soil. The acetylene reduction activity per unit nodule mass (ARA) under field conditions appeared after bud break, peaked the maximum in midsummer after full expansion of the leaves, and disappeared after all leaves had fallen. There was no consistent correlation between ARA and tree size (dbh). The amount of N2 fixed in this alder stand was estimated at 56.4 kg ha−1 year−1 when a theoretical molar ratio of 3 was used to convert the amount of reduced acetylene to the amount of fixed N2. This amount of N2 fixation corresponded to the 66.4% of N in the leaf litter produced in a year. These results suggested that N2 fixation still contributed to the large portion of N economy in this alder stand.

Caracterização morfológica, fisiológica e infectividade em planta de estirpes de Frankia isoladas de nódulos de Casuarina / Morphological, physiological and plant infectivity characterization of Frankia strains isolated from Casuarina’s nodules

Frankia são microrganismos capazes de fixar N2 quando em simbiose com espécies arbóreas, denominadas plantas actinorrízicas. Este estudo foi conduzido para caracterizar morfologicamente, fisiologicamente e avaliar a nodulação de quatro estirpes referência de Frankia (HFPCcI3, JCT287, KB5 e F59) e 12 estirpes(IPRF) isoladas de nódulos de Casuarina. Todas as estirpes (Referência e IPRF) foram Gram-positivas e 50% foram “acid-fast”. As estirpes de Frankia alcalinizaram o meio de cultura, exceto IPRF006, IPRF008e IPRF010. As colônias das estirpes F59, IPRF002, IPRF004, IPRF005 e IPRF011, produziram melanina. Entre as estirpes referência, apenas a JCT287 cresceu no meio de cultura com pH 5,5, enquanto no meio com pH 6,0 as duas, JCT287 e KB5, apresentaram crescimento. A análise de regressão mostrou uma relação linear (Y = 67,56+ 3,88X e R2=0,5862, p<0,05) e coeficiente de correlação de Pearson (r=0,766,p<0,05) entre número de esporos e hifas (120 a 480 UFC mL-1) e proteína total (18 a 145 µg mL-1). Foi observado que a estirpe F59 apresentou uma maior proporção de proteína total (50%) do que a JCT287(7,0%) e, que as estirpes IPRF mostraram valores entre 17,5 e 29,3%. Todas as estirpes produziram compostos indólicos com valores variando de 5,9 a 98,8 µM.

Frankia are soil microorganisms that form symbiosis with roots of tree species called actinorhizal plants and are capable of fixing atmospheric N2. This study was carried out to characterize morphologically, physiologically and to assess the nodulation of four Frankia reference strains (HFPCcI3, JCT287, KB5and F59) and 12 (IPRF) isolated from root nodules of Casuarina plants. All strains (Reference and IPRF)were characterized as Gram-positive and 50% as acid-fast. The Frankia strains produced alkali in the culture medium, except the IPRF006, IPRF008 and IPRF010. The colonies of strains F59, IPRF002, IPRF004,IPRF005, and IPRF011 produced melanin. Among reference strains, only JCT287 grew in culture mediawith pH 5.5, while with pH 6.0 both strains JCT287 and KB5 presented growth. The regression analysis showed a linear relationship (Y = 67.56+ 3.88X and R2=0.5862, p<0.05) and Pearson’s correlation coefficient(r=0.766, p<0.05) between number of spores and hyphae (120 to 480 UFC mL-1) and total protein (18 to 145µg mL-1). It was observed that the strains F59 had a higher proportion of total protein 50.0% than JCT287with 7.0% and that the IPRF strains showed values between 17.5 and 29.3%. All strains presented ability to produce indolic compounds in growth media with values ranging from 5.9 to 98.8 µM.