Mechanistic Study of the Biomimetic Synthesis of Flavonolignan Diastereoisomers in Milk Thistle

Althagafy, Hanan S.; Meza‐Avina, Maria Elena; Oberlies, Nicholas H.; Croatt, Mitchell P.

doi:10.1021/jo4011377

Cited by 64 publications

(40 citation statements)

References 50 publications

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“…Melatonin (1.0 mg/L) showed maximum accumulation of silybin A (1.45 mg/g), silychristin (1.08 mg/g) and silybin B (7.43 mg/g) under continuous light as compared to other treatments (Table 3.). Silybin (A & B) are considered as primary compounds in Milk thistle extract as previously reported [62,64], which is in accordance with our study. Continuous light has profound effect on biological synthesis of precious secondary metabolites.…”

Section: Effect Of Light and Melatonin On Silymarinsupporting

confidence: 93%

Interactive Effects of Light and Melatonin on Biosynthesis of Silymarin and Anti-inflammatory Potential in Callus Cultures of Silybum marianum L.

Shah¹,

Ullah²,

Drouet³

et al. 2019

Preprint

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Silybum marianum L. is a well-known medicinal herb, primarily used in liver protection. Light strongly affects several physiological processes along with secondary metabolites biosynthesis in plants. Herein, S. marianum was exploited for in vitro potential under different light regimes in the presence of melatonin. The optimum callogenic response occurred in combination of 1.0 mg/L α-naphthalene acetic acid and 0.5 mg/L 6-Benzylaminopurine under photoperiod. Continuous light associated with melatonin treatment increased total flavonoid content (TFC), total phenolic content (TPC) and antioxidant potential, followed by photoperiod and dark treatments. The increased level of melatonin has a synergistic effect on biomass accumulation under continuous light and photoperiod, while adverse effect was observed under dark condition. More detailed phytochemical analysis showed maximum total silymarin content (11.92 mg/g DW) when placed under continuous light + 1.0 mg/L melatonin. Individually, the level of silybins (A and B), silydianin, isolsilychristin and silychristin was found highest under continuous light. Anti-inflammatory activities were also studied and highest percent inhibition was recorded against 15-LOX for cultures cultivated under continuous light (42.33%). The current study helps to better understand the influence of melatonin and different light regimes on silymarin production as well as antioxidant and anti-inflammatory activities in S. marianum callus extracts.

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Section: Effect Of Light and Melatonin On Silymarinsupporting

confidence: 93%

Interactive Effects of Light and Melatonin on Biosynthesis of Silymarin and Anti-inflammatory Potential in Callus Cultures of Silybum marianum L.

Shah¹,

Ullah²,

Drouet³

et al. 2019

Preprint

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“…It is noteworthy that taxifolin and coniferyl alcohol are the precursors of silybin, which is catalyzed by ascorbate peroxidase (APX1) ( Figure S2). In this reaction, the APX1 oxidizes coniferyl alcohol to a radical that couples with equimolar of taxifolin to form silybin [49,50]. APXs are commonly considered to be detoxifiers that eradicate peroxides, such as H 2 O 2 and O 2 − , by utilizing ascorbate as the electron donor [51].…”

Section: Discussionmentioning

confidence: 99%

The Impact of Drought Stress on Antioxidant Responses and Accumulation of Flavonolignans in Milk Thistle (Silybum marianum (L.) Gaertn)

ElSayed

El-hamahmy

Rafudeen

et al. 2019

Plants

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Biosynthesis and accumulation of flavonolignans in plants are influenced by different environmental conditions. Biosynthesis and accumulation of silymarin in milk thistle (Silybum marianum L.) were studied under drought stress with respect to the antioxidant defense system at the physiological and gene expression level. The results revealed a reduction in leaf chlorophyll, ascorbic acid, and glutathione contents. In contrast, H2O2, proline, and antioxidative enzyme activities, such as superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), ascorbate peroxidase (APX), and glutathione reductase (GR), were increased. These results confirmed that milk thistle undergoes oxidative stress under drought stress. Furthermore, transcription levels of APX, SOD, CAT, 1-Cys-Prx, and PrxQ were significantly increased in milk thistle under drought stress. Overall this suggests that protection against reactive oxygen species and peroxidation reactions in milk thistle are provided by enzymatic and non-enzymatic antioxidants. Flavonolignans from milk thistle seeds after different drought treatments were quantified by high-performance liquid chromatography (HPLC) and showed that severe drought stress enhanced the accumulation of silymarin and its components compared with seeds from the control (100% water capacity). Silybin is the major silymarin component and the most bioactive ingredient of the milk thistle extract. Silybin accumulation was the highest among all silymarin components in seeds obtained from drought-stressed plants. The expression of the chalcone synthase (CHS) genes (CHS1, CHS2, and CHS3), which are associated with the silybin biosynthetic pathway, was also increased during drought stress. These results indicated that milk thistle exhibits tolerance to drought stress and that seed derived from severe drought-stressed plants had higher levels of silymarin.

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“…purple (Asteraceae). They are formed by oxidative coupling of a taxifolin flavanonol precursor and a coniferyl alcohol [4–5]. The standardized extract of S. marianum fruits is known as silymarin and has long been used for the treatment of chronic inflammatory liver diseases [6] and more recently for prostate cancer chemoprevention [7].…”

Section: Introductionmentioning

confidence: 99%

Chemotaxonomic and biosynthetic relationships between flavonolignans produced by Silybum marianum populations

et al. 2017

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Flavonolignans constitute an important class of plant secondary metabolites formed by oxidative coupling of one flavonoid and one phenylpropanoid moiety. The standardized flavonolignan-rich extract prepared from the fruits of Silybum marianum is known as silymarin and has long been used medicinally, prominently as an antihepatotoxic and as a chemopreventive agent. Principal component analysis of the variation in flavonolignan content in S. marianum samples collected from different locations in Egypt revealed biosynthetic relationships between the flavonolignans. Silybin A, silybin B, and silychristin are positively correlated as are silydianin, isosilychristin, and isosilybin B. The detection of silyamandin in the extracts of S. marianum correlates with isosilychristin and silydianin content. The positive correlation between silydianin, isosilychristin, and silyamandin was demonstrated using quantitative 1H nuclear magnetic resonance spectroscopy (qHNMR). These correlations can be interpreted as evidence for the involvement of a flavonoid radical in the biosynthesis of the flavonolignans in S. marianum. The predominance of silybins A & B over isosilybin A & B in the silybin-rich samples is discussed in light of the relative stabilities of their respective radical flavonoid biosynthetic intermediates.

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Mechanistic Study of the Biomimetic Synthesis of Flavonolignan Diastereoisomers in Milk Thistle

Cited by 64 publications

References 50 publications

Interactive Effects of Light and Melatonin on Biosynthesis of Silymarin and Anti-inflammatory Potential in Callus Cultures of Silybum marianum L.

Interactive Effects of Light and Melatonin on Biosynthesis of Silymarin and Anti-inflammatory Potential in Callus Cultures of Silybum marianum L.

The Impact of Drought Stress on Antioxidant Responses and Accumulation of Flavonolignans in Milk Thistle (Silybum marianum (L.) Gaertn)

Chemotaxonomic and biosynthetic relationships between flavonolignans produced by Silybum marianum populations

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