Physalins (13,L4-Seco-16,24-Cyclosteroids) Produciton in Physalis Minima (LINN.)
Physalis minima produces physalins, and these ell-steroidal lactone compounds have great potentials in phannaceutical industry. However, no detail infonnation on the biosynthetic background of physalins in either intact plants or in cultured plant tissues. Therefore, this study was carried out to...
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| Format: | Thesis |
| Language: | English English |
| Published: |
2001
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| Subjects: | |
| Online Access: | http://psasir.upm.edu.my/id/eprint/9339/1/FSAS_2001_60.pdf |
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| Summary: | Physalis minima produces physalins, and these ell-steroidal lactone
compounds have great potentials in phannaceutical industry. However, no detail
infonnation on the biosynthetic background of physalins in either intact plants or in
cultured plant tissues. Therefore, this study was carried out to determine the physalins
distribution in intact plants and in cultured plant tissues: callus, cell suspensions and
hairy roots. Factors that control the growth and physalins production in plant tissue
culture levels such as medium compositions, physical factors and precursors were also
elucidated to improve the physalins productivity. The results showed that physalins
accumulation in specific plant tissues of intact plants varied between 0.07 to 5.76 mg
g-t DW. Physalin contents increased two folds as the plant matured. Physalin A
accumulated mostly in young fruits (3.82 mg g⁻¹ DW), physalin B in young leaves
(1.56-3.20 mg g⁻¹ DW) and flower buds (2.88-3.60 mg g⁻¹ DW), physalin D in flower
buds (4.65-5.83 mg g⁻¹ DW), physalin F in older leaves (4.51-9.89 mg g⁻¹ DW),
physalin J in immature and ripe fruit calyx (2.14-3.96 mg g⁻¹ DW), and physalin N in
young and old leaves (2.68-4.48 mg g⁻¹ DW). In addition, the accumulation level of
physalins in specific tissues was different among plants collected from different
locations. In cultured plant tissues, the content of physalin B and F in hairy roots were found to be higher (1.95-17.01 mg g⁻¹ DW) than that in intact plants, but lower in
callus (1.51-1.91 mg g⁻¹ DW) and cell suspension (0.67-1.95 mg g⁻¹ DW) cultures.
Higher physalins production in callus and suspension cultures were obtained in cells
derived from leaves followed by root and stem explants. Cell suspension and hairy
root cultures were also capable of excreting physalins at lower concentration into
culture medium. The study on the effect of medium compositions has shown that
higher physalins production in callus. cell suspension and hairy root cultures were
obtained in 1/2MS (half strength), MS (full strength) and B5 (full strength) basal
media, each supplemented with 2.5, 3.5 and 3.5% (w/v) sucrose, respectively. An
auxin-cytokinin interaction was observed to be important for callus cultures, as these
two classes of phytohonnones afe required for higher growth and physalins
production. Higher physalins production in callus culture was obtained in medium
supplemented with a combination of 2,4-D and kinetin (9.0:4.5 1lM). However, the
addition of cytokinin in cell suspension culture appeared to stimulate irregular
compact globular cells and growth of many root-like structures in the cell clumps.
Higher physalins production in cell suspension was obtained in cultures supplemented
with 9.0-18.0 µM NAA or 18.0 µM lAA. Meanwhile, in hairy root cultures,
phytohormones often caused a growth disorganisation. The addition of 3-4 J,J.M NAA
increased the physalins production. Further investigations on hairy root cultures have
shown that physaJins accumulated mainly in mature part of root tissues. Inoculum of
different root morphology did not significantly influence growth and physalins
production. Meanwhile, the increase in number of inoculum root tips and medium
volume resulted in changes of certain growth parameters. Hairy root cultures were
capable to grow in pH values between 4.0-9.0, and higher physalins production was
obtained at pH 5.0-7.0. Physalin productions in hairy roots also increased up to 1. 2.1 folds when cultured under dark conditions supplemented with alanine, leucine and
valine. |
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