Rhododendron Arboreum Sm Research Articles

Characterization, quantitation, and natural variability of phenolics in Rhododendron arboreum leaves of western Himalayan origin using UPLC-PDA and UHPLC-ESI-Q/TOF-MS/MS

Rhododendron arboreum Sm. is very popular in the Indian Himalayan region due to its significant ethnomedicinal importance and potential commercial applications. Apart from the ornamental value derived from its vibrant red flowers, fresh flowers are used to prepare medicinal juices, and dried are utilized as spices. Despite being a rich source of phenolics, these lack identified marker chemicals and validated methods. The present work encompasses the chemical investigation of R. arboreum leaves using UHPLC-ESI-Q/TOF-MS/MS. The chemotypic variability was assessed through a reverse phase ultra-performance liquid chromatography method coupled with a photodiode array detector (RP-UPLC-PDA) chemical signatures of R. arboreum leaves from different altitudes combined with chemometric analysis. The chromatographic method was developed and validated for the quantitative analysis of three vital secondary metabolites, i.e., Isoquercetin or Quercetin-3-O-glucoside (Qg), Reynoutrin or Quercetin-3-O-xyloside (Qx), and Quercitrin or Quercetin-3-O-rhamnoside (Qr)The hyphenation of the method with ESI-Q/TOF-MS/MS has confirmed the distribution of 11 chemicals (nine known and two unknown) in R. arboreum leaves belonging to the phenolic and hydrolyzable tannins class. Samples from higher altitudes >3000 m (above mean sea level) were exceptionally rich in Quercitrin. The chemometric investigation, comprising hierarchical cluster analysis (HCA), principal component analysis (PCA), and partial least square method-discriminant analysis (PLS-DA), successfully categorized thirty-three samples from diverse geographic regions into two distinct categories. This current study provides a validated method for the chemotypic discrimination and quality assessment of the R. arboreum leaves from Uttarakhand, Western Himalayan region of India, and laid the foundation for the comprehensive utilization of these renewable and sustainable resources.

Phytochemical Profiling and Antioxidant Evaluation of Rhododendron arboreum Sm leaf and flower: Integrative Analysis using Advanced Analytical Techniques

ABSTRACT Objective This study investigates the biological activities of Rhododendron arboreum Sm from the eastern Himalayas, addressing a literature gap on its properties. It explores the plant's phytochemical, antioxidant, and medicinal characteristics. Significance: Evaluating methanolic extracts of R. arboreum offers valuable insights into its bioactive potential. Comprehensive GC-MS analysis identified a diverse array of compounds, highlighting the plant's chemical composition. Methods: Methanolic leaf and flower extracts underwent sequential extraction and phytochemical profiling using column chromatography, TLC, and GC-MS analysis. Spectral studies aided compound identification, and antioxidant activity was assessed via spectrophotometric assays. Results: Column chromatography separated methanol leaf and flower extracts into 17 and 24 distinct fractions, respectively. TLC analysis showed specific Rf values for leaf (0.58, 0.65, 0.75, 0.8, 0.86, 0.9) and flower samples (0.91, 0.38, 0.48, 0.51, 0.56, 0.6, 0.65, 0.75, 0.85, 0.96). GC-MS analysis revealed a variety of organic functional groups, including aliphatic hydrocarbons, aromatic compounds, heterocyclic molecules, phenolic compounds, steroids, terpenoids, alcohols, esters, and other bioactive compounds. FTIR spectra identified functional groups such as hydroxyls, primary amines, alkanes, and alkynes. NMR data indicated a complex molecular composition with diverse proton environments. Leaf extracts demonstrated superior antioxidant activity compared to flower extracts in DPPH, ABTS, hydrogen peroxide scavenging, lipid peroxidation inhibition, and FRAP assays. Conclusion: The study identifies diverse phytochemicals in R.arboreum extracts and highlights their potential applications in pharmaceuticals, nutraceuticals, and functional foods, owing to the superior antioxidant activity of leaf extracts compared to flowers.

Exploring the impact of polyphenolic compounds on the chromatic characteristics in flowers of Rhododendron arboreum Sm. collected from different altitudinal locations.

Rhododendron arboreum Sm. flowers grow in the Himalayan region and have traditionally been used in beverages and food. These wild edible Himalayan flowers are known for their sweet-sour flavor and beautiful scarlet red color. The primary pigments responsible for the scarlet red color of these flowers are anthocyanins. In the present study, we conducted chemo-profiling and elucidated the chromatic characteristics of R. arboreum flower petals growing in the wild in different altitudinal areas. The content of anthocyanins, phenolics, and other flavonoids was determined in R.arboreum flower petals collected from 38 different locations in two provinces in India (Himachal Pradesh and Uttarakhand) to obtain a distinguishable chemical index. A UHPLC method has also been developed and validated for the quantitative analysis. Besides, the color characteristics of each collected floral sample were also analyzed. Chemometric analysis (principal component analysis [PCA] and heatmap analysis) revealed that floral samples collected from different altitudes exhibited similar chemical diversity, whereas statistical analysis (bivariate linear correlation) revealed a positive correlation between the color parameter a*/b* and cyanidin glycosides. Besides, non-targeted metabolomics analysis was carried out, which resulted in the tentative identification of 150 metabolites. The results revealed that there is a direct influence of accumulated anthocyanins to color parameter a*/b* values in the floral samples irrespective of altitude.

Documentation on traditional medicine used for Menstrual Disorders among The Poumai-Naga Women in Senapati District, Manipur

Menstruation is a natural and biological phenomenon in women of reproductive age. It is often associated with certain disorders. Millions of women across the globe are challenged with social stigmas and taboos related to menstruation. This paper aims to assess and compare the menstrual health information between rural and urban areas and explore the herbal medicine used by the Poumai-Naga community to combat menstrual disorders. Respondents included 5 traditional medicine practitioners and 230 women. An interview and survey questionnaire were employed to meet the objectives. After cross checking from literature published in menstrual disorders from different states of India and abroad, nine medicinal plants were noted to be extensively used by the people. Rhododendron arboreum Sm. was not found to be reported in any of the literature to treat menstrual disorders. Results also showed that women heavily rely on and prefer traditional medicine and home remedies over modern medicine. Though Traditional Herbal Medicine is used globally, it may come with undocumented risks. And therefore, it is recommended to test and validate every potential herb passing through the proper channel for proper and safe use.

Contradistinctive floral attributes, pollination guilds and their consequence on the outcrossing rate in two elevational morphs of Rhododendron arboreum Sm.

Infraspecific floral trait variations may appear in response to elevational differences in alpine plant species. There is enormous information on the selection of such morphs mediated by biotic and/or abiotic variables. Whether such differences contribute to differences in reproductive strategy and mating outcomes is rarely investigated. We investigated these aspects in two distinct elevational floral morphs (Red and Pink) of Rhododendron arboreum Sm. in Western Himalaya. The red morphs occupy the lower elevations while pink morphs the higher elevations. The two morphs differ in floral traits like phenology, dimension, display, quality of floral rewards, and pollinators that happen to influence interaction with available pollinator pool at each elevation. The pink morph exhibits entomophily, while the red ones show ornithophily. Although experimental pollinations established that both the morphs are self-compatible, selfing results in significantly lower fruit-set than either cross- or open-pollinations. The outcrossing rate in the red morph, as determined by using simple sequence repeat (SSR) markers, was higher (tm=0.82) than that in the pink morph (tm=0.76), with a tendency of the latter to be shifting towards mixed-mating strategy. However, the extent of biparental inbreeding was comparable among the two morphs. It is inferred that the differences in the mating outcomes among the morphs in the tree species are linked to those emerging from floral traits and the pollination by different functional groups of floral visitors.

Vitro bioactivities and simulated gastrointestinal digestion studies on Guras-based traditional fermented drinks collected from Singalila ridge of the Himalayas

Guras or Rhododendron wine and its distilled form (Raksi) are popular traditional and therapeutic drinks served in the Rhododendron growing regions of the Himalayas, mainly in the northern and northeastern part of India, Nepal and Indo-Nepal Singalila ridge. In this research, lali Guras (Rhododendron arboreum Sm.) based traditional beverages such as unfermented decoction (as control), fermented Guras wine and distilled spirit Guras ko Raksi were collected from Singalila ridge of the Himalayas for analysis. In vitro experiments such as physicochemical and qualitative and quantitative biochemical tests; antioxidant assays (DPPH and iodometric assay); antibacterial assay; and simulated gastrointestinal digestion were carried out. Phytochemically rich unfermented decoction exhibited the best results in total phenolic content assay (82.18±1.13 mg/100 mL gallic acid equivalent) and fatty acid quantification (1.86±0.08%) test while the wine was found to be the most potential sample in all bioactivity tests. The wine was found to contain high amounts of glycoside and fermented distilled liquor Guras Raksi showed high presence of glycerol. Both the fermented samples exhibited high rate of digestion in simulated human digestion system compared to the phenolic rich unfermented decoction. This research validated the therapeutic potential of these Guras-based beverages in high-altitude conditions like Singalila by focusing on their biochemistry.

A comprehensive review on phytochemistry, health benefits and therapeutic potential of Rhododendron arboreum Sm.

A comprehensive review on phytochemistry, health benefits and therapeutic potential of Rhododendron arboreum Sm.

Vegetation diversity, structure, composition and carbon stock of community managed forests of Mid-hills, Nepal

Abstract. Joshi P, Joshi R, Sapkota RP, Panta M, Chand P. 2023. Vegetation diversity, structure, composition and carbon stock of community managed forests of Mid-hills Nepal. Asian J For 7: 29-36. Depending on management practices, forests can serve as both carbon sinks and sources. The goal of reducing carbon emissions and increasing the carbon sink is thought to be feasible if carbon reservoirs in current forests are protected and conserved. This study was objectively conducted to assess the vegetation diversity, structure, and carbon stock of the Mid-hills of Nepal. The study was undertaken in the Lanta Community Forest, Jajarkot District, Nepal, which has an extent of 38.65 hectares. Data for vegetation analysis and carbon stock assessment were collected using systematic random sampling using quadrats of 10×10 m with a total number of 35 quadrats. Within each quadrat, individual trees and bamboo were identified in the sites, and their height (m) and DBH (cm) were measured. Density, frequency, basal area, and Important Value Index (IVI) were calculated as structural parameters of vegetation. The Above-Ground Tree Biomass (AGTB) and Below-Ground Tree Biomass (BGTB) were calculated using an allometric equation based on tree diameter, height, and wood-specific gravity. The species diversity, species richness, and evenness were found to be 2.2, 2.35, and 0.83, respectively. A total of 14 tree species, with 723 individuals and one bamboo species were recorded. Rhododendron arboreum Sm. had the highest tree density with 211 trees/ha, while Tsuga dumosa (D.Don) Eichler had the highest IVI. Total wood volume, biomass, and total carbon stock were estimated at 15.37 m3 ha-1, 31.99 t ha-1, and 15.03 t ha-1, respectively. There was a strong negative correlation (r = -0.59) between R. arboreum and R. campanulatum D. Don and a strong positive correlation (r = +0.65) between Malus sikkimensis and Machilus species. For the preservation and sustainable management of community forests, information regarding the structure, composition, and dominance of tree species is provided by the study. The establishment of community forests is thus demonstrated in this article as a means of promoting the protection and preservation of regional biodiversity.

GC-MS (Gas chromatography and mass spectroscopy) analysis of methanol leaf extract of Rhododendron arboreum Sm. of District Sirmaur, Himachal Pradesh

Plants are a rich source of secondary metabolites or chemical constituents with interesting biological activities. Therefore, a thorough validation of the herbal agents has emerged as a new branch of science emphasizing and prioritizing the standardization of the natural drugs and products because several of these phytochemicals have complementary and overlapping mechanism of action. Mass spectrometry coupled with chromatographic separations such as Gas chromatography (GC-MS) is generally used for direct analysis of components existing in traditional medicines and medicinal plants. Gas chromatography separates the components of the mixture and mass spectroscopy analyses each of these components separately. In recent years, GC-MS studies have been increasingly applied for the analysis of medicinal plants as this technique has proved to be a valuable method for the analysis of non-polar components, volatile essential oils, fatty acids, lipids, alkaloids etc. The present study was aimed to find out the bioactive compounds present in methanol extract of Rhododendron arboreum Sm. by using Gas chromatography and Mass spectroscopy. GC-MS chromatogram showed 10 peaks indicating the presence of ten phytochemical constituents in this plant. The results revealed Limonene (18.48%), Caryophyllene (13.01%), 3-Heptanoicacid methyl ester (11.00%) and Phenol, 2-(2-methyl-2-propenyl) (5.52%) as the major components in the methanol extract. The results support the use of R. arboreum in traditional medicines for controlling bacterial, degenerative and other diseases. Thus, the present study approves the medicinal value of this plant and scientifically validates it for use as a component of medicinal preparations.
 Keywords: Rhododendron arboreum, methanol, leaf extract, phytochemicals, Gas chromatography and Mass spectroscopy (GC-MS)

Evaluation of anticancer potential of methanolic leaf and flower extracts of Rhododendron arboreum Sm in AGS gastric adenocarcinoma cell line

Evaluation of anticancer potential of methanolic leaf and flower extracts of Rhododendron arboreum Sm in AGS gastric adenocarcinoma cell line

Assessment of Antimicrobial and Antioxidant Activities of Four Ethnomedicinal Plants Used by Magars in Nawalpur District, Nepal

Ethnobotanical survey in the Magar villages in Nawalpur district, Gandaki province, Nepal revealed that root of Phanera vahlii (Wight & Arn.) Benth, bark of Rhododendron arboreum Sm. and flower of Woodfordia fruticosa (L.) Kurz, have been in use for diarrhea and dysentery. Root of Thalictrum foliolosum DC. has been used for the treatment of rheumatic pain. The study aimed to evaluate antimicrobial and antioxidant effects as well as total phenol content in Phanera vahlii, Rhododendron arboreum, Woodfordia fruticosa and Thalictrum foliolosum. Total phenol content (TPC) was estimated using Folin-Ciocalteu method. 2, 2-Diphenyl-1-picrylhydrazyl (DPPH) free radical and hydrogen peroxide scavenging assays were used to evaluate the antioxidant capacity. Antibacterial effect was established by the Agar well diffusion assay. The minimum TPC value of 65.78±3.44 mg GAE/g dry extract was estimated in 70% methanolic extract of Thalictrum foliolosum and maximum TPC value of 258.40±6.26 mg GAE/g dry extract was estimated in 70% methanolic extract of Woodfordia fruticosa. IC50 value range 21.59±0.26 µg/ml in Rhododendron arboreum to 1124.79±3.69 µg/ml in Thalictrum foliolosum was calculated in DPPH free radical scavenging assay. Scavenging of DPPH free radical range from 12.40% to 94% at 100 µg/mL concentration of 70% methanolic extracts were estimated and scavenging of hydrogen peroxide range from 36% to 73%. The maximum zone of inhibition (ZOI) against Escherichia coli at loading dose of 5 mg of the extract observed was 18±0.73 mm by 70% methanolic extract of Woodfordia fruticosa and its minimum inhibition concentration (MIC) was <1.56 µg /ml.The extracts efficiently inhibited the growth of Escherichia coli verifying the rural knowledge. At the same time, the extracts displayed efficient antioxidant activity.

Anthropogenic disturbance impact on forest composition and dominance-diversity: A case of an ecosensitive region of Garhwal Himalaya, India

A total of twenty four forest types were selected along altitudinal and disturbance gradients on various aspects to analyse the composition, diversity and distribution of tree species in an ecosensitive region of Garhwal Himalaya. A significant impact of anthropogenic/human induced disturbance was recorded on the existing community parameters, consequently the density, Total Basal Cover (TBC) and species diversity values were decreased with increseasing disturbance intensity. The overall density was recorded in the range from 411 trees ha−1 to 840 trees ha−1, whereas the TBC values existed between 21.72 m2 ha−1 to 95.41 m2 ha−1. The canopy structure of the forest (mostly in moderate disturbance condition) has significantly (P ≤0.05, r = 0.439), whereas the light attenuation significantly but negatively (P≥0.05, r = −0.445) impacted the growth of ground herbaceous vegetation. The Cedrus deodara (Roxb. ex D.Don) G.Don (between 1600 and 3000 m asl), Lyonia ovalifolia (Wall.) Drude (1832–3000 m asl) and Rhododendron arboreum Sm. (1832–3000 m asl) species have shown a very wide ecological amplitude for their range distribution in study area. The Canonical Correspondence Analysis has categorized the canopy forming tree species into different patches by identifying the prominent disturbance indices/parameters according to their niche resource requirement in the study area. The obtained dominance-diversity curves reflected mostly the geometric type of model for trees, however lognormal to log type of models for shrubs and herbaceous vegetation. Overall, this study reviews enough evidences of species susceptibility towards fragmentation of habitats because of anthropogenic disturbance. Moreover, the current species range distribution records will help to develop baseline datasets for existing tree species to access in future for their range shift from the conventional habitats due to climate change and notify them as climate sensitive species in Himalaya.

Altitudinal variation in flower color and attraction pattern of Rhododendron arboreum Sm. in central Himalayan Region of Uttarakhand, India

Abstract This study highlights the importance of flower color variation and attraction as a mechanism for pollination and protection of floral parts. As part of this study, a survey relating to flower color variation and differences in spotting pattern (nectar guides) was conducted on Rhododendron arboreum, a widespread tree species in the mountainous region of Uttarakhand state, at 43 different altitudinal locations. Seven original color morphs of flowers and five types of spot variation in the nectar guide were observed. The study underlines the role of flower color polymorphism in both pollination and adaptation to varied environmental conditions. Further, the significance of nectar guides in directing the visitor to the reward is discussed. This study has the potential to enhance existing knowledge about flower color variation and attraction to the environment.

PHYTOCHEMICAL COMPOSITION AND BIOLOGICAL ACTIVITIES OF CRUDE EXTRACT FROM FLOWERS AND LEAVES OF Rhododendron arboreum Sm. FROM NORTHERN THAILAND

Rhododendron arboreum Sm. has wide applications in food and beverage, medicines, and cosmetics because the plant contains bioactive phytochemical components. In Thailand, other than for horticultural purposes, scant literature describes the potential applications of this Rhododendron species. Phytochemical composition, biological activity, and cell cytotoxicity of R. arboreum Sm. flower petal and leaf extracts were determined. Ethanolic extracts of fresh and dried flower petals (FF and DF, respectively) and dried leaves (DL) of R. arboreum were prepared by maceration with 60% ethanol for 7 days. Extraction yields of both FF and DF were higher than DL (19.22, 16.76, and 8.50% for FF, DF, and DL, respectively). Preliminary qualitative phytochemical screening showed different compositions in diverse plant parts. Saponins and tannins were present in every extract, with anthraquinones detected only in flowers and terpenoids only in leaves. Total phenolic (TPC) and flavonoid contents (TFC) were highest in DL (405.21 mg gallic acid equivalent and 127.30 mg catechin equivalent per g of dry extract, respectively), followed by DF and FF. Antioxidant properties were determined using two radical scavenging assays as 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2-azinobis(3-ethyl-benzthiazoline-6-sulfonic acid (ABTS). Results indicated that all extracts exhibited better inhibitory activity against DPPH radical than ABTS radical as evidenced by lower IC50 range 24.65-48.15 ìg/mL for DPPH and 65.19-76.36 ìg/mL for ABTS, respectively. A positive correlation coefficient between the two antioxidant assays and TPC and TFC of Rhododendron extracts indicated antioxidant potential distributed in both components. No cytotoxicity was recorded in the three extracts, with concentrations less than 500 μg/mL for both 3-(4,5-dimethylthiazol-2yl)-2,5-diphenyltetrazolium bromide (MTT) and CellTiter-Blue® assay. In vitro studiesexhibited dose-dependent and strong anti-melanogenic and anti-inflammatory activities ranging from 50 to 250 μg/mL for FF, DF, and DL. Results identified various bioactive constituents with potential biological activity (antioxidant, antiinflammatory, and anti-melanogenic), while non-cytotoxicity in R. arboreum flower and leaf extracts suggested the possibility of further applications as a functional ingredient in cosmetics.

Distribution pattern of Rhododendron arboreum in mountainous region of India: A review for possible adaptation against the climate change and anthropogenic drivers

Rhododendron is an economically and ecologically one of the most important plants of India. Of the many species, Rhododendron arboreum Sm. is the only one to be found in the Western Ghats and in the Indian Himalayan Regions. Due to rise in temperature and change in climatic conditions, this species, like others, is also experiencing a change in its habitat. Therefore, the study of this species becomes more important as it, besides being a keystone species, is also a source of income generation to the people residing in the Indian Himalayan Regions. It is threatened not only from climate change but also from forest fire and over-exploitation. Through Habitat Niche Modelling of Rhododendron arboreum we can predict its distribution, thus helping us in understanding its future condition. This will also provide us an insight to its mitigations measures to the threats imposed by changing climate and/or over-exploitation. This review is a small effort in this direction.

Standardization of recipe for the preparation of drink from rhododendron (Rhododendron arboreum Sm.) flower extract

Standardization of recipe for the preparation of drink from rhododendron (Rhododendron arboreum Sm.) flower extract

Influence of different treatments and techniques on rooting behaviour of Rhododendron arboreum Sm. In Indian Himalayas

Rhododendron arboreum Sm. a wild flowering tree is on the verge of extinction from natural habitat due to overexploitation of its flowers and slow regeneration rate. The objective of this research was to explore the effective method for propagation of this species vegetatively, therefore, to maintain its genetic identity and population. In this context, effectiveness of vegetative propagation methods like FRI-Wire Technique and Air Layering in combination with root promoting hormones such as Indole 3- Butyric Acid (IBA), Indole Acetic Acid (IAA) and Napthelene Acetic Acid (NAA) at concentration of 1000 ppm (ppm), 2500 ppm and 5000 ppm each were evaluated through well designed experiments. Air Layering method failed to produce roots on this species, whereas, FRI-Wire Technique showed a remarkable success for rooting in the month of April with hormones IAA and NAA at 1000 ppm and 2500 ppm concentrations and no response from IBA. Branch sizes of length 45--51 cm, when treated with 2500 ppm IAA concentration performed significantly better and produced 66.66% rooting in comparison to other treatments with the technique.

Comparative assessment of Rhododendron (Rhododendron arboreum Sm.) flowers extract beverages through biochemical analysis and its quality evaluation during storage

Comparative assessment of Rhododendron (Rhododendron arboreum Sm.) flowers extract beverages through biochemical analysis and its quality evaluation during storage

THERAPEUTIC APPLIANCE OF IMPERILED MEDICINAL PLANT PULLAS-RHODODENDRON ARBOREUM SM.: A SHORT PERIODICAL ANALYSIS FROM ANCIENT TO MODERN ERA

Rhododendron arboreum Sm. the world’s most famous rhododendron, is known as national flower of Nepal. The word Rhododendron is derived from Greek word rhodo mean rose and dendron means tree. It is often called Rhodies. The flowers being sweet and sour taste are used in the preparation of squash, jams, jellies and local brew. It is used in folklore medicine to treat many disorders and often used as a substitute to another famous plant drug Rohitaka. Pharmaceuticals companies and traditional practitioners of Nepal are using its bark, as a substitute of Rohitaka i.e. Tecomella undulate (Sm.) Seem. The present review highlights some potential therapeutics from ancient to modern era in order to explore the gap as well as bring out certain suggestive approaches from exploration of its ancient traditional therapeutics/properties to future conservation of this plant species.

Utilization of Edible Rhododendron (Rhododendron arboreum Sm.) Flowers for Development of Spiced Beverage (Appetizer) and Its Shelf Life Evaluation during Storage

In India, various types of unexplored edible flowers are being utilized traditionally as food and medicine by the rural communities since ancient time only during their flowering time due to short post harvest life. These flowers are rich in phytochemical (e.g. polyphenolics, anthocyanins) which possess numerous health benefits. So, the present investigations were conducted to develop a spiced beverage/appetizer (spiced squash) from rhododendron flower petals and its quality evaluation during storage. Different combinations of petals extract and total soluble solids (TSS) were tried to standardize proper combination for spiced beverage. Appetizer recipe (T3) prepared with 35% extract, 40°B TSS and 1.20% acid was found to be best based on quality characteristics of the product. The best-selected appetizer recipe was packed in glass and PET bottles and stored for 6 months under ambient (15-25°C) and refrigerated temperature conditions (4-7°C). Overall effect of packaging and storage revealed that various quality characteristics like TSS, apparent viscosity, reducing and total sugars of appetizer increased slightly, whereas, other chemical characteristics like acidity, ascorbic acid, anthocyanins, total phenols and sensory characteristics scores of colour, body, taste, aroma, overall acceptability score decreased slightly during storage. The quality of beverage was retained better in glass bottles under refrigerated condition as compare to ambient storage condition.