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.