Comparative transcriptome analysis of Rheum australe, an endangered medicinal herb, growing in its natural habitat and those grown in controlled growth chambers

Rheum australe is an endangered medicinal herb of high altitude alpine region of Himalayas and is known to possess anti-cancerous properties. Unlike many herbs of the region, R. australe has broad leaves. The species thrives well under the environmental extremes in its niche habitat, therefore an understanding of transcriptome of R. australe to environmental cues was of significance. Since, temperature is one of the major environmental variables in the niche of R. australe, transcriptome was studied in the species growing in natural habitat and those grown in growth chambers maintained at 4 °C and 25 °C to understand genes associated with different temperatures. A total of 39,136 primarily assembled transcripts were obtained from 10,17,74,336 clean read, and 21,303 unigenes could match to public databases. An analysis of transcriptome by fragments per kilobase of transcript per million, followed by validation through qRT-PCR showed 22.4% up- and 22.5% down-regulated common differentially expressed genes in the species growing under natural habitat and at 4 °C as compared to those at 25 °C. These genes largely belonged to signaling pathway, transporters, secondary metabolites, phytohormones, and those associated with cellular protection, suggesting their importance in imparting adaptive advantage to R. australe in its niche.

PHYTOCHEMICAL AND PHARMACOLOGICAL ASPECTS OF ANTHRAQUINONES OF RHEUM AUSTRALE D. DON

Anthraquinones are phenolic compounds known best for their laxative activity. Rheum australe D. Don (Indian rhubarb, Polygonaceae) is a prominent medicinal plant with anthraquinones as the bioactive compounds, among a few others. The online literature search was carried out to collect data on the phytochemistry and pharmacological activity of anthraquinones, particularly those isolated from R. australe. Anthraquinones are commonly found in the genera of Rheum, Senna, Aloe, Frangula, and Rubia, which can be quantitatively and qualitatively determined using both conventional and advanced analytical methods. The anthraquinones of R. australe were found in free and glycosidic forms, which were best extracted by the microwave-assisted extraction method. Various chromatographic techniques were commonly conducted to isolate the pure compounds. In addition to its laxative activity, anthraquinones of R. australe also showed potential antibacterial, cytotoxic, and antioxidant properties.

Ecological status and diversity indices of Panchaule (Dactylorhiza hatagirea) and its associates in Lete village of Mustang district, Nepal

This paper focuses on the ecological status and diversity indices: Simson’s Index (C), Simson’s Index of Dominance (D) and Shannon-Weaver Index (H) of Dactylorhiza hatagirea and its associates- Rheum australe and Rumex nepalensis in Lete village of Mustang District within the Annapurna Conservation Area. The study was conducted during the monsoon season (June/July) of 2013 in the Lete VDC of Mustang District. The study site possessed an area of 4.5 ha. Altogether, 100 circular plots, each with 25 m2 area, were laid out purposively within the study area; the sampling intensity being 5.55%. The relative frequency, the relative density, the abundance, the relative coverage and the Important Value Index of the species were found to be 61.11, 53.91, 1,061.54, 72.2 and 187.24 respectively. Similarly, the Simson’s Index (C), the Simson’s Index of Dominance (D) and the Shannon-Weaver Index of the species were found to be 0.41, 0.59 and 3.27 respectively, indicating relatively even and relatively diverse community. The study showed relatively higher values of all the parameters of D. hatagirea as compared to its associates indicating good ecological value. However, threats remain due to the illegal harvesting of this valuable orchid and overgrazing in the study site.Banko JanakariA Journal of Forestry Information for NepalVol. 26, No. 1, Page: 45-52, 2016