Secondary Metabolites of Medicinal Plants. Bharat SinghЧитать онлайн книгу.
is used in the treatment of various gynecological disorders, chills, anemia, circulatory disorders, and psychological symptoms. A. gigas Nakai contains several medicinally important constituents such as decursin, decursinol angelate, and immunostimulating polysaccharides. Recently, the cytotoxic activity of decursin as a potential anticancer drug has been reported along with an extracellular immunostimulating polysaccharide produced by suspension cultures of A. gigas (Ahn et al. 1996, 1998). Angelica dahurica var. Formosana is a perennial herb and indigenous plant of Taiwan (Chen et al. 1994) and is normally known as “Bai Zhi” in Chinese as a significant herbal drug used for curing of headache and psoriasis (Zhou 1980). The imperatorin is reported to be the major bioactive principle for treatment of the skin diseases (Zhou et al. 1988).
Angelica gigas root fraction was investigated for the isolation of bergapten, decursinol angelate, decursin, nodakenetin, and nodakenin. The antimicrobial activities of these isolated phytoconstituents were tested against bacterial strains. Out of these phytochemicals tested, decursinol angelate and decursin demonstrated maximum antibacterial activity against Bacillus subtilis with the minimum inhibitory concentrations of 50 and 12.5 μg/ml (Lee et al. 2003). Similarly, the methanolic extract of the dried roots of A. gigas were also used for the determination of coumarins (nodakenin, peucedanone, marmesin, decursinol, 7-hydroxy-6-(2R-hydroxy-3-methylbut-3-enyl)coumarin, demethylsuberosin, decursin, decursinol angelate, and isoimperatorin) by high-performance liquid chromatography coupled with diode-array detection and electrospray ionization tandem mass spectrometry (HPLC-DAD/MS, HPLC-ESI/MS). For the determination of coumarins, the following HPLC conditions were used: reversed-phase C18 column (5 μm, 4.5 mm × 250 mm), gradient acetonitrile-water solvent system, and flow rate of 1.0 ml/min. The analysis of six coumarins (nodakenin, marmesin, decursinol, demethylsuberosin, decursin, and decursinol angelate) with DAD at 330 nm and demonstrated excellent linearity (r(2) = 0.998 − 0.999) in a range of 0.2–250 μg/ml for all the compounds. Each peak was identified with ESI–MS(n), while the remaining compounds (peucedanone, 7-hydroxy-6-(2R-hydroxy-3-methylbut-3-enyl)coumarin, and isoimperatorin) could not been quantified by DAD because these peaks were overlapped with others, so these compounds were determined by HPLC-ESI/MS (Ahn et al. 2008). Similarly, the isoliquiritin was also determined by HPLC from A. gigantis (Hwang et al. 2014).
Angelica dahurica and Angelica pubescentis roots were investigated for the presence of essential oils and their antifungal activities were assessed. The essential oils of A. pubescentis roots exhibited very weak antifungal activity against Colletotrichum acutatum, Colletotrichum fragariae, and Colletotrichum gloeosporioides, while A. dahurica essential oils did not demonstrate any antifungal activity against selected fungi. The essential oils of A. dahurica roots possessed activity against Aedes aegypti and Stephanitis pyrioides. From A. dahurica and A. pubescentis roots, the α-pinene, sabinene, myrcene, 1-dodecanol, and terpinen-4-ol, α-pinene, p-cymene, limonene, and cryptone were isolated and characterized (Tabanca et al. 2014).
2.11.2 Culture Conditions
The effects of GA3 and chlormequat chloride on biomass and quality of A. dahurica var. Formosana plants were investigated. Plants were sprayed with GA3 or chlormequat chloride during rosette growth stage, and coumarin content was analyzed by HPLC. Two coumarins in roots were detected: isoimperatorin and imperatorin. The root content of imperatorin was not affected by application of either GA3 or chlormequat chloride, while isoimperatorin was increased to 127% after treatment with chlormequat chloride. The lowest concentrations of GA3 and chlormequat chloride increased root yield. Authors were observed that GA3 and chlormequat chloride might be used in improving the yield of A. dahurica var. Formosana and maintaining the coumarin content (Hou et al. 2013). The callus induction was achieved from petiole cultured on a culture medium supplemented with 2,4-D and kinetin. By enhancing the phosphate concentration in the basal culture medium to 2 mM and using an ammonium to nitrate ratio of 2 : 1, the production of imperatorin was increased in cell suspension cultures. It was also found that glucose demonstrated better results in enhancing the higher yield of imperatoin when used to be a better carbon source than sucrose and fructose. The supplementation of BA to the culture medium enhanced imperatorin yield, while auxins when used as additives to the culture medium decreased it. Supplementing the medium with Amberlite XAD-7 increased imperatorin yield 140-fold in the cell cultures of A. dahurica var. Formosana (Tsay et al. 1994; Tsay 1999; Cho et al. 2000).
Angelica gigas produces decursin and decursinol angelate, demonstrated neuroprotective, anticancer, and anti-androgen receptor-signaling activities. Explant tissues were co-cultivated with Agrobacterium rhizogenes carrying the pK2GW7-GUS binary vector. After six to eight weeks of co-cultivation with Ag. rhizogenes, kanamycin-resistant roots appeared on explants maintained on hormone-free medium. Isolated hairy roots were transferred in liquid medium containing half-strength Schenk and Hildebrandt salt and sugar. Detection of the neomycin phosphotransferase gene, high levels of β-glucuronidase (GUS) transcripts, and GUS histochemical localization confirmed the integrative transformation (Shi-yu and Kuo-chang 1989; Park et al. 2010). The accumulation of phytosterol and triterpene was increased by Panax ginseng Farnesyl diphosphate synthase genes in the Centella asiatica cell cultures (Kim et al. 2010). Similarly, the flavonoid biosynthesis of Glycyrrhiza uralensis was enhanced by transforming hairy roots by licorice chalcone isomerase gene (Zhang et al. 2009). The production of tropane alkaloids was provoked by transferring the tropinone reductase I genes in hairy root cultures of Anisodus acutangulus (Kai et al. 2009). The levels of hyoscyamine (twofold higher) and scopolamine (eightfold higher) were higher than those of the control in hairy root cultures of An. acutangulus. The phenylpropanoid biosynthesis pathway was induced by transformation of hairy roots of Beta vulgaris by p-hydroxycinnamoyl-CoA hydratase/lyase gene (Rahman et al. 2009).
References
1 Ahn, K.-S., Sim, W.S., and Kim, I.-H. (1996). Decursin: a cytotoxic agent and protein kinase C activator from the root of Angelica gigas. Planta Med. 62: 7–9.
2 Ahn, K.-S., Sim, W.S., Kim, H.M. et al. (1998). Immunostimulating polysaccharide from cell culture of Angelica gigas Nakai. Biotechnol. Lett. 20: 5–7.
3 Ahn, M.J., Lee, M.K., Kim, Y.C., and Sung, S.H. (2008). The simultaneous determination of coumarins in Angelica gigas root by high performance liquid chromatography-diode array detector coupled with electrospray ionization/mass spectrometry. J. Pharm. Biomed. Anal. 46: 258–266.
4 Chen, C.C., Chang, W.T., Chang, Y.S., and Tsay, H.S. (1994). Studies on the tissue culture of Angelica dahurica var. Formosana II. Establishment of cell suspension culture and evaluation of cultural conditions. J. Chin. Med. 5: 123–134.
5 Cho, J.-S., Chun, S.-H., Lee, S.-J. et al. (2000). Development of cell line preservation method for research and industry producing useful metabolites by plant cell culture. Biotechnol. Bioprocess Eng. 5: 372–378.
6 Hou, K., Wen Chen, J., Li, J.Y. et al. (2013). Effect of gibberellic acid and chlormequat chloride on growth, coumarin content and root yield