Rhododendron arboreum

National flower of Nepal having wide range of medicinal value. B.pharma course

1. Rhododendron arboreum

2. Introduction The word rhododendron comes from the Greek words " rhodon ", or rose, and " dendron ", or tree. Rhododendron arboreum is the national flower of Nepal. The Rhododendron arboreum also known as burans or gurans, belonging to ericaceae . It is an evergreen shrub or small tree with a showy display of bright red flowers. Lali Gurans are found at altitudes as low as 1200 meters and as high as 3,600 meters. Its trees reach a height of up to 15 meters, the tallest in Nepal among other species.

3. History The first of many  Rhododendron   which were to come from southeastern Asia was the tree species,  R. arboreum , with blood-red flowers, which was discovered by Captain Hardwicke in 1799 and arrived from India in  1811 . In  1821  Don introduced  R. anthopogen  and  R. setosum   from Asia. In  1823,   R. molle , destined to become famous as one of the parents of the Mollis hybrids, was introduced from China. In  1832,   R. zeylanicum   (a subspecies of  R. arboreum )  came into England from Ceylon. From the Himalayan regions of Nepal and sikkim R. campanulatum  was introduced 1825. The native place are Bhutan, China, India, Nepal and Pakistan.

4. Nomenclature Kingdom: Plantae Divison : Angiosperms Order: Ericales Family: Ericaceae Genus: Rhododendron Species: R.arboreum

5. Common names English :rose tree, rhododendron Nepali : lali gurans Tamil: billu Punjabi: adrawal Trade name: chalan

6. Habit and habitat Altitude: 1200 - 3600 m Mean annual temperature: 12 - 17ºC Mean annual rainfall: 200 - 1800 mm Soil type: The plant prefers light (sandy) and medium (loamy) soils and requires well-drained soil. The plant prefers acid soils and can grow in very acid soil. It can grow in semi-shade (light woodland) or no shade. It requires moist soil.

7. Macroscopic identification Leaves: Leaves glossy green, oblong- lanceolate , 10-20 cm long and 3.6 cm wide. Crowded towards the ends of branches, petiole covered with white scales when young.

8. Flower The flowers of R. arboreum range in color from a deep scarlet, to red with white markings, to pink to white. Bearing up to twenty blossoms in a single truss this rhododendron is a spectacular sight when in full bloom. Bright red forms of this rhododendron are generally found at the lower elevations. Calyx- fine cleft, Corolla-tube spotted funnel shaped, Stamens hypozygnous declining, Filaments- filiform , Anthers-ovate, Style- capitate .

9. Seeds Seeds-minute, dark brown, compressed, thin linear having an obvolute membrane

10. Fruit Fruit a capsule, oblong, curved, longitudinally ribbed, up to 3.8 cm long and 1.25 cm wide.

11. Stem Stem often much branched, crooked or gnarled. Bark reddish brown, soft and rough, exfoliating in thin flakes.  Stem smooth or rough, sometimes warted ; bark.

12. Microscopic identification Chromosome number (2n)= 26

13. T.S of leaf

14. ORGANOLEPTIC PROPERTIES Appearance: liquid  Color:  Pale yellow  Aroma:  Sweet herbal, faintly balsamic

15. PHYTO-CHEMISTRY Bark: The petroleum ether extract of the bark indicated the presence of a single triterpenoid substance taraxerol (C30H50O) & ursolic acid acetate (C32H50O4). The ether extract of the bark following petroleum ether extract showed the identity of betulinic acid (C30H48O3). The acetone extract of the bark gave the substance leuco - pelargonidin (C15H14O6).

16. Structure taraxerol Betulinic acid

17. leaves Green leaves contain glucoside , ericolin ( arbutin ) (C12H16O7), ursolic acid (C30H48O4), α- amyrin (C30H50O), epifriedelinol (C30H52O), quercetin & hyperoside (C21H20O12)

18. Structure ursolic acid α- Amyrin epifriedelinol quercetin

19. Flowers Quercetin-3-rhamnoside a crystalline chemical compound is found the flowers of this species. Three biologically active phenolic compounds i.e. quercetin (C15H10O7), rutin (C27H30O16) and coumaric acid (C9H8O3) are found in flowers of R.arboreum using high-performance thin-layer chromatography.

20. Pharmacology Anti-inflammatory and Anti- nociceptive activity Hepatoprotective activity Anti- diarrhoeal activity Anti-diabetic activity Antioxidant or Adaptogenic activity .

21. Medicinal uses Rhododendron arboreum’s nectar is brewed to make wine and is effective in diarrhoea and dysentery. Its Corolla is administered in case of fishbone stuck in the gullet. Snuff made from the bark of the tree is excellent cold reliever. The bark juice is used to treat jaundice, diabetes, liver disorders, and intestinal worms. Young leaves can be processed into paste and applied on the forehead to alleviate headaches.

22. Cont… The juice of the flowers is used in the treatment of menstrual disorders Rhododendron is also used in making of aromatic oil, perfumery and cosmetics.

23. Intoxicating properties Rhododendron flower are sweet, sour and are packed with Vitamin C. However, when too many flowers are consumed the flower can become intoxicating. Bees that harvest pollen exclusively from these plants will often produce honey that is a natural laxative and hallucinogenic.

24. REFERENCES Medicinal plants of india A Review- Debjyoti Bhattacharyya Nepal's Magnificent Rhododendron Agroforestry Database 4.0 ( Orwa et al.2009) Asian Pacific Journal of Tropical Biomedicine A Journal of the Bangladesh Pharmacological Society (BDPS)

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