Evaluation of phytoconstituents and assessment of adaptogenic activity in vivo in various extracts of Rhododendron arboreum (leaves).

Natural products particularly of plant origin with antistress property and nutraceutical value have become the focus of scores of scientific investigation in recent times. Against this background the present study was carried out to analyse the phytochemical components and adaptogenic activity of Rhododendron arboreum which grow in high altitudes. Adaptogenic activity of the plant extract was evaluated in vivo in rat and mice animal models. Methanol, hydroethanol and aqueous extract of the leaves were prepared and preliminary screening of the phytochemical constiteunts was carried out. The important phytoconstituents viz. flavonoids and phenolics were estimated and amount of gallic acid and quercetin were evaluated by HPTLC. Adaptogenic activity of the extract was studied in vivo using rat and mice as test animals. The criteria taken were forced swimming test in rat and mice and tail suspension test in mice. Methanol extract showed the presence of diterpenes, triterpenes, flavonoids, steroids, tannin, phenolics. Hydroethanol extract showed the presence of diterpenes, triterpenes, saponin, glycosides, alkaloids, tannin and aqueous extract showed the presence of tannin, glycosides, triterpenes, flavonoids, diterpenes. Quantitative analysis exhibited that the methanol extract have the highest amount of flavonoid and phenolics. The HPTLC profile of methanol extract showed the presence of highest amount of quercetin. Gallic acid was detected only in methanol extract. In vivo study in test animals revealed that the methanol extract of R. arboreum exhibited potent anti stress activity. Hence, presence of these compounds which are known to have strong anti-oxidant activity in high quantity might be responsible for adaptogenic activity.

Pharmacological evaluation of hyperin for antihyperglycemic activity and effect on lipid profile in diabetic rats.

Antihyperglycemic potential of hyperin at 25 and 50 mg/kg doses for 30 days to streptozotocin induced diabetic rats has been reported. In oral glucose tolerance test, hyperin treated rats showed a significant reduction in blood glucose level after 120 min. It was found that hyperin exhibited dose dependent and significant antihyperglycemic activity in streptozotocin induced diabetic rats which were nearly similar with standard drug glybenclamide. Activities of glucose-6-phosphatase, fructose-1,6-bisphosphatase, glycogen phosphorylase, glycosylated haemoglobin and level of serum urea and creatinine were significantly decreased in hyperin supplemented diabetic rats, dose dependently. Activities of hexokinase and glycogen synthase were increased with augmentation in liver glycogen, insulin and haemoglobin content in hyperin treated diabetic rats. General hematological parameters did not show any significant change in hyperin treated diabetic rats hence it is safe at these doses. Histopathological studies showed significant morphological changes in pancreatic β-cells of streptozotocin induced diabetic rats. A decreased number of secretory granules of β- cells were observed in diabetic rats and these pathological abnormalities were normalized after treatment with hyperin and standard drug glybenclamide. Further, hyperin decreases significant in serum total cholesterol, triglyceride, low density lipoprotein, very low density lipoprotein levels coupled with elevation of high density lipoprotein in diabetic rats. These results suggest that hyperin has a pivotal role in blood glucose level in streptozotocin induced hyperglycemia by improving the function of pancreatic islets and increasing glycolysis and decreasing gluconeogenesis.

Rhododendron arboreum: An overview.

Rhododendron arboreum is an evergreen shrub or small tree with a showy display of bright red flowers. The name ‘RHODODENDRON’ is derived from the Greek word ‘RHODO’ means rose & ‘DENDRON’ means tree. Rhododendron is the national flower of Nepal & is known as (Laligurans) & the state tree of Uttarakhand. It is called ‘Burans, Bras, Buras or Barahke- phool’ in local dialect. It is widely popular for the processed juice of its flowers which have gained market popularity as rhodojuice / sharbat. The plant is found in the Himalayas from Kashmir eastwards to Nagaland. Various parts of the plant exhibited medicinal properties & is used for the treatment of various ailments. The present review is an effort to give the detailed survey of literature on its pharmacognosy, phytochemistry & pharmacological uses of the plant under study.

Preliminary phytochemical studies of the leaf extracts of Rhododendron arboreum Sm. ssp. nilagiricum (Zenker) Tagg

Objective: To examine the secondary metabolites present in the leaf extracts of Rhododendron arboreum Sm. ssp. nilagiricum (Zenker) Tagg. Methods: Phytochemical screening of the leaf extract was done to determine the phytochemical constituents in the various solvents studied.Results:nilagiricum (Zenker) Tagg. confirm the existence of secondary metabolites such as phenols, saponins and tannins. Conclusions: The study suggests that the leaf extracts of R. arboreum Sm. ssp. nilagiricum (Zenker) Tagg. can be best utilized in developing bioactive compounds against pathogenic infection. The phytochemical study carried out on the leaf extracts of R. arboreum Sm. ssp.

Antihyperglycemic and antihyperlipidemic activity of ethyl acetate fraction of Rhododendron arboreum Smith flowers in streptozotocin induced diabetic rats and its role in regulating carbohydrate metabolism

<p><b>OBJECTIVE</b>To explore and identify the most potent antihyperglycemic fraction from the ethanol extract of Rhododendron arboreum (R. arboreum) flowers.</p><p><b>METHODS</b>Normal and streptozotocin induced diabetic rats were treated with all four fractions of R. arboreum flowers for short term and with fraction 3 for long term study. On completion of the treatment, a range of indicators were tested including fasting blood glucose, plasma protein, haemoglobin A1C, insulin secretion, body weight, blood lipid profile and carbohydrate metabolism regulating enzymes of liver.</p><p><b>RESULTS</b>In short term study, the fraction 3 (Active fraction) produced a significant (P<0.000 1) reduction (73.6%) in blood glucose level at a dose of 200 mg/kg after the treatment in the diabetic rats. Administration of active fraction (200 and 400 mg/kg) once daily for 30 d in streptozotocin diabetic rats resulted in a significant (P<0.001 to P<0.000 1) fall in blood glucose level, hemoglobin A1C, serum urea and creatinine with significant but a increase in insulin level similar to standard drug glybenclamide. Further, the active fraction showed antihyperlipidemic activity as evidenced by significant (P<0.001 to P<0.000 1) decreases in serum serum total cholesterol, triglycerides, low density lipoprotein cholesterol and very low density cholesterol levels coupled together with elevation of high density lipoprotein cholesterol in the diabetic rats.</p><p><b>CONCLUSIONS</b>The active fraction of R. arboreum flowers decreases streptozotocin induced hyperglycemia by promoting insulin secretion and glycolysis and by decreasing gluconeogenesis.</p>