BackgroundThe genus Swertia is reported to contain potent bitter compounds like iridoids, xanthones and c-glucoflavones that are known to heal many human disorders. In contrast to high ethnomedicinally valued Swertia chirayita, its other species have not been studied extensively, in spite of their common use in traditional medicinal system in Nepalese communities. So, the present study attempts to investigate the content of total polyphenols, flavonoids, antioxidant activity and estimate the rough content of amarogentin, swertiamarin and mangiferin from different species of Swertia from Nepalese Himalayas.MethodsWhole plant parts of S. chirayita (SCH), S. angustifolia (SAN), S. paniculata (SPA), S. racemosa (SRA), S. nervosa (SNE), S. ciliata (SCI) and S. dilatata (SDI) were collected; total phenolic and flavonoid contents were quantified spectrophotometrically and in vitro DPPH free radical scavenging assay was measured. Thin layer chromatography was performed on TLC aluminium plates pre-coated with silica gel for identification of swertiamarin, amarogentin and mangiferin from those species and semi quantitative estimation was done using GelQuant.NET software using their standard compounds.ResultsThe phenolic content was highest in the methanol extract of SCH (67.49 ± 0.5 mg GAE/g) followed by SDI, SRA, SNE, SCI, SPA and SAN. The contents of flavonoids were found in the order of SCH, SPA, SRA, SNE, SDI, SCI and SAN. Promising concentration of phenolics and flavonoids produced promising DPPH free radical scavenging values. The IC50 values for the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging test was lowest in SCH (23.35 ± 0.6 μg/ml), even lower than the standard ascorbic acid among the seven studied species. A significant correlation of 0.977 was observed between the polyphenol content and antioxidant values. The TLC profile showed the presence of all three major phytochemicals; amarogentin, swertiamarin and mangiferin in all of the plant samples.ConclusionAmong the seven studied species, SCH showed anticipating results in total phenol content, flavonoid content and DPPH radical scavenging test. The less considered species of Swertia can be a potential source of bioactive amarogentin, and other useful therapeutic compounds in the alarming status of Swertia chirayita as shown by the phytochemical analysis.Electronic supplementary materialThe online version of this article (doi:10.1186/s13104-015-1753-0) contains supplementary material, which is available to authorized users.

Swertia chirayita is a native Himalayan herb typically found in the altitude of 1500 to 3100m. Swertia species are commonly used as primary medicines in fever, digestive and enteric diseases; especially S. chirayita is of principal importance. The pharmacological and ethno-medicinal perspective of the plant is well understood traditionally and pharmaceutically. Its secondary metabolites including glycosides and xanthones show promising bioactivity making it a powerful herb. Mixing of Swertia chirayita with its other species is done routinely in chiretta trade. Extensive wild collection and lack of sustainable conservation has led to the vulnerable status of the wild cultivar. DOI: http://dx.doi.org/10.3126/ijasbt.v2i4.11281 Int J Appl Sci Biotechnol, Vol. 2(4): 389-392

Various species of Gentiana find their use to treat various digestive and topical ailments in traditional medicine in Nepal. The present work reports the results of preliminary phytochemical analysis and biological activities of extracts of four different species of Gentiana (G. depressa, G.ornata, G. urnula, and G. capitata) from Nepal Himalaya. Furthermore, the study also reports a semi-quantitative estimation of major bioactive compounds in those extracts. The total flavonoid content was found to be highest (19.09±0.97mgQE/g) in methanol extracts of G. capitata and lowest (4.22±0.66 mgQE/g) in aqueous extracts of G. urnula. The highest amount (79.2±19.19 mgGAE/g) of total phenolic content was observed in methanolic extracts of G. depressa, while the lowest amount (37.11±2.18 mgGAE/g) was observed in aqueous extract of G. urnula. The methanol extract of G. depressa showed the best antioxidant activity among the Gentiana species tested. Extracts of all the species tested showed weak antibacterial activity even at the highest concentration of the extract. Semi-quantitative estimation showed that swertiamarin was in higher quantities than amarogentin and mangiferin. The highest concentration of swertiamarin and mangiferin (0.109±0.013 mg/g and 0.018±0.001 mg/g, respectively) was identified in G. ornata, while the highest concentration of amarogentin (0.075±0.005 mg/g) was observed in G. capitata. These results justify the folklore use of these species in traditional medicinal practices in Nepal.