Medicinal Plants Classification Biosynthesis and ... - Index of

Biosyntheses and Bioactivities of Flavonoids in the Medicinal...
elicitors indicated that flavones behaved as phytoanticipins because major flavones of S.
baicalensis manifested a distinct antimicrobial activity. The results of the short-term
treatment of S. baicalensis roots with methyl ether of jasmonic acid showed that stress biotic
factors could considerably increase the content of physiologically active flavones [Kuzovkina
et al., 2005]. In addition, a transformed hairy root clone of S. baicalensis was established
following infection with Agrobacterium rhizogenes ATCC15834. Three root clones of S.
baicalensis were obtained, and the most active strain-the SR-03 clone was examined for its
growth and baicalin content under various culture conditions. The root growth and baicalin
content were maximized in a Schenk and Hildebrandt medium supplemented with 4 and 6%
sucrose, respectively. The accumulation of baicalin in transformed hairy roots was enhanced
through exposure to various elicitors methyl jasmonate, salicylic acid, and various
concentrations of fungal cell wall. The accumulation of baicalin in the elicited cultures
ranged from 10.5 to 18.3 mg/g dry weight of the roots, which was 1.5- to 3-fold the amount
attained in controls [Hwang, 2006].
Using different explants of in vitro seed grown S. baicalensis Georgi plantlets, hairy
roots were induced following inoculation of Agrobacterium rhizogenes strains A(4)GUS,
R1000 LBA 9402 and ATCC11325. The A(4)GUS proved to be more competent than other
strains and the highest transformation rates were observed in cotyledonary leaf explant
(42.6%). The transformed roots appeared after 15-20 d of incubation on hormone free
Murashige and Skoog medium. The results obtained by PCR, Southern hybridization and RT-
PCR confirmed integration and expression of left and right termini-linked Ri T-DNA
fragment of the Ri plasmid from A(4)GUS into the genome of S. baicalensis hairy roots. All
the clones showed higher growth rate than non-transformed root and accumulated
considerable amounts of the root-specific flavonoids. Baicalin content was 14.1-30.0% of dry
root mass which was significantly higher than that of control field grown roots (18%). The
wogonin content varied from 0.08 to 0.18 % among the hairy root clones which was also
higher than in non-transformed roots (0.07 %) [Tiwari et al., 2008]. An approach of
combining flow cytometry analysis with morphological and chemical profiling was used to
assess the genetic stability and bioactive compound diversity in a S. baicalensis Georgi
germplasm collection that was clonally maintained in vitro for a period of over 6 years.
Germplasm lines, acclimatized to ex vitro conditions, exhibited distinctive plant growth and
bioactive compound production capacities. The high level of genetic stability observed in in
vitro maintained S. baicalensis lines opens up a variety of opportunities such as allowing
long-term aseptic preservation and easy distribution of well-characterized germplasm lines of
this medicinal plant species. This study represents a novel approach for continuous
maintenance, monitoring, and production of medicinal plant tissues with specific chemistry
[Alan et al., 2007].
5. Analytical Methods
The rapid qualitative and quantitative analyses of structurally closely related compounds
have been an important issue of medicinal chemistry. The active components must be
extracted from plant or raw medical material samples prior to analysis. Several extraction
143