Background: Himalayan honey, a natural product of wild honey bees found in the Himalayan mountains of Nepal, has been used in medicine for many years. The successful development of nanotechnology and beneficial effects of honey would bring a new opportunity to synthesize hybrid nanomaterials for biomedical applications. Thus, the purpose of this study was to load Himalayan honey onto iron oxide nanoparticles (IO-NPs) and study their antioxidant and antimicrobial activities. Methods: Himalayan honey loaded iron oxide nanoparticles (HHLIO-NPs) were synthesized and X-ray diffraction (XRD) and scanning electron microscope (SEM) analyses were performed for characterization. UV-VIS spectra confirmed the loading of honey onto nanoparticles. The antioxidant activity of these nanoparticles was studied against 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radical system. We also tested antimicrobial activity of HHLIO-NPs using well diffusion method towards both Gram-positive and Gram-negative bacterial strains of Staphylococus aureus & Escherichia coli . Results: From XRD analysis, the average particle size was found to be 33–40 nm. The SEM images show needle shape porous structures of HHLIO-NPs compared to free IO-NPs indicating the surfactant-like behaviour of honey. In DPPH radical system, the scavenging activities of Himalayan honey (HH), free IO-NPs and HHLIO-NPs ranged 7.93-35.99%, 11.02-52.02% and 16.10-80.52% respectively, with corresponding IC50 values of 1.36 mg/mL, 1.09 mg/mL and 0.52 mg/mL. The antimicrobial property of all test samples showed a noteworthy inhibition on both bacterial strains. However, the HH and HHLIO-NPs exhibited strong antibacterial activity against E. coli . Conclusion: This work reveals that the biological activity of HH is enhanced significantly after loading into IO-NPs. Thus, the HHLIO-NPs would be a promising alternative for antioxidant and antimicrobial agents.

Objective: The objectives of the study are to screen out various phytochemicals and to evaluate the antioxidant and antidiabetic potential of the stem bark of Holarrhena pubescens Wall (Holarrhena antidysenterica). Materials and Methods:The antioxidant activity was determined by the DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging activity where ascorbic acid was taken as positive control. The antioxidant property was later exploited and the methanolic extract of plant was tested for antihyperglycemic activity in glucose overloaded hyperglycemic mice. The extract was tested for its hypoglycemic activity at two-dose levels, 250 and 500 mg/kg respectively where Glipizide 5 mg/kg was taken as standard reference drug. All results are presented as mean ± SD (Standard Deviation). Significant differences between experimental groups were determined by Student's t-test. Results:The methanolic and water extract showed strong antioxidant activity with inhibition of more than 90% DPPH free radicals at the concentration of 100µg/mL. The hypoglycemic activity of methanolic extract on glucose tolerance test were significant (p <0.05) for the effects of 500 mg/kg after 120 min of treatment and (p <0.01) for 250 mg/kg of extract after half hour of treatment compared to control.

Usnic acid contents in acetone extracts of 31 samples of lichen Parmelia flexilis collected from different altitudes were identified using thin layer chromatography (TLC) and determined by high performance liquid chromatography (HPLC). The usnic acid content varied in between highest 5.13% to lowest 1.66% in oven dried (80 • C) lichen samples. The species collected from lower altitudes all show high levels of usnic acid. The negative relationship between usnic acid and altitude was obtained. Statistically, it is revealed that there is a significant difference between average percentages of usnic acid in lichen samples with varying altitudes (p < 0.05). Beside these, the precipitation averages of the regions where the species have been collected were linked with the content of usnic acid. It is clear that lichens from the regions receiving the highest precipitation produced lower amounts of usnic acid. The results suggest that the production of secondary metabolite in lichens is altered due to the climatic variables like temperature and precipitation at different altitude gradients.

Free radicals are molecules with reactive unpaired electrons which are produced during cell metabolism and create the oxidative stress inside tissue resulting in tissue damage. The aim of the present study was qualitative and quantitative phytochemical screening, determination of total phenolic and total flavonoid content, and free radical scavenging activity of different parts of ethnomedicinally used Rubus ellipticus Sm. plant. Root, stem, and leaves of Rubus ellipticus Sm. were collected from Annapurna Rural Municipality, Kaski, Western Nepal. Ethyl acetate and ethanol extracts of the plant parts were obtained by subsequent maceration process. The phytochemical screening of most of the extract showed the presence of phenols, carbohydrates, flavonoids, and glycosides. The ethanolic extract of stem showed the higher phenolic content with the value of 343.75 ± 2.21 µg GAE/mg. Ethanolic extract of stem had the highest amount of flavonoid content (1563.17 ± 10.79 µg QE/mg of extract), whereas all the ethyl acetate extracts of root, leaves and stem showed comparable flavonoid content. Ethanolic extracts of leaves showed potent DPPH free radical scavenging activity with IC50 value of 5.03µg/ml while ethyl acetate extract of stem showed the maximum free radical scavenging properties. The result depicted that the ethanolic extract of Rubus ellipticus Sm. showed the potent antioxidant activity by scavenging free radicals.

Diabetes mellitus, a physiological disorder is characterized by low secretion of insulin due to the attack in insulin producing beta cell (Type I) or the body cell become insulin resistance (Type II). This study was designed to evaluate the DPPH lowering effect, in-vitro alpha amylase and glucose diffusion inhibition of the selected medicinal plants. Five different plant sample Amomum subulatum, Choerospondias axillaris, Musa sp, Myrica esculenta and Nephrolepis cordifolia were taken for the study. From the result it was revealed that the methanol extracts of Myrica esculenta stem bark and small branches showed potent DPPH free radical scavenging activity with the IC50 value of 4.23 µg/ml and 3.14 µg/ml respectively which is almost comparable to standard Ascorbic acid taken. Meanwhile, alpha-amylase inhibitory study showed that Myrica esculenta stem bark showed potent subsidiary effect on methanol extracts with IC50 value of 0.96 mg/ml which is comparable to standard volgibose taken. Lastly, membrane diffusion study with glucose and plant sample showed that Amomum subulatum seed and Choerospondias axillaris fruit have potent glucose diffusion inhibition with highest GDRI %. From the result, it could be correlated that the free radical scavenging activity and glucose lowering effect of these plant extracts is due to the presence of phytoconstituents like phenolics, flavonoids, alkaloids, terpenoids, glycosides saponins etc. as well as several other uncompetitive modes of inhibition.