lignans and neolignans
TRANSCRIPT
LIGNANS AND NEOLIGNANS WITH THEIR POTENTIAL BIOLOGICAL ACTIVITY
Presented to
SIR TANVEER KHAN
Presented by
ZAINAB JAVED
MPhil Pharmacognosy
THE UNIVERSITY OF LAHORE
OBJECTIVES
What are lignans and Neolignans What are their sources Role of lignans and neolignans in plants and
human body
LIGNANS
COUMESTANS ISOFLAVONES
PHYTOESTROGENS(substances found in plants
having estrogen like activities)
LIGNANS
In 1936, Haworth defined lignans as
“Phenylpropanoid dimers consisting of two phenyl propane units (C6C3) linked by their central C8 carbon.”
LIGNAN STRUCTURE:
Phenylpropane unit Lignan
NEOLIGNANS
In 1972, Gottileib defined neolignan as
“Phenylpropanoid dimers consisting of two phenylpropane units (C6C3)
linked in a manner other than C8-C8' linkage”
NEOLIGNAN STRUCTURE:
OCCURRENCE OF LIGNANS
Widely distributed in plants.
Usually occur in root, stem, bark, fruits and seed parts of plant.
SOURCES OF LIGNANS
1. FLAX SEEDS:
Secoisolariciresinol Diglucoside (SDG)
1 ounce of flaxseed contains 85mg of lignans
2. SESAME SEEDS:
Sesamin
1 ounce of sesame seeds contain 11 mg of lignans
3. PUMPKIN SEEDS:
Secoisolariciresinol
4. SUNFLOWER SEED: Larisiresinol
OTHER SOURCES
SOURCES LIGNANS
Wheat 7-hydroxymatairesinol
Corn 7-hydroxymatairesinol
Strawberry Pinoresinol
Pea Pinoresinol
Broccoli Larisiresinol
METABOLISM OF LIGNANS
Plant lignans
Mammalian lignans or Enterolignans (enterolactone, enterodiol)
Intestinal
bacteria
OCCURRENCE OF NEOLIGNANS
Narrow distribution Isolated from magnoliales and piperales. Neolignans isolated from stem bark of Magnolia
obovata are Magnolol Honokiol 4-methoxyhonokiol Obovatol
Neolignan isolated from stem of Piper kadsura Kadsurenone
ROLE OF LIGNANS IN PLANTS
Participate in defensive mechanism against pathogens due to its anti-viral, anti-bacterial and anti-fungal properties.
OVERVEIW OF ESTROGENS
Steroidal hormone mainly present in females but also in men.
Mainly secreted by ovaries, minute quantity by adrenal cortex.
3 forms: estradiol, estrone, estriol. Synthesized from cholesterol and transported
by albumin and globulin in plasma. Role in maturation of sperms in males.
ROLE OF ESTROGENS IN FEMALES
Promote cellular proliferation and tissue growth.
Contribute to development of secondary sexual characters (hair distribution, voice, body shape)
Increases osteoblastic activity and thus its lack lead to osteoporosis.
Increases fat deposition in subcutaneous tissues
Causes the skin to develop a texture that is soft and smooth
MECHANISM OF ACTION OF ESTROGENS
Estrogens bind with estrogen receptors and form hormone-receptor complex which in turn binds with DNA and induces transcription of mRNA.
2 types of estrogen receptors1. ER-α (uterus, heart, liver, kidneys)2. ER-β (ovaries, other tissues)
BIOLOGICAL ACTIVITIES ESTROGEN RECEPTOR – DEPENDENT
ACTIVITIES:
Phytoestrogens bind to estrogen receptors and either Mimic the estrogenic effects (low dose) Antagonizes the estrogenic effects(high dose)
Anti-estrogenic activity is important in prevention of cancer.
BREAST CANCER Estrogens contribute to cause breast
cancer by stimulating the proliferation of breast cells.
BREAST CANCER High blood levels of enterolactone are
associated with a lower incidence of breast cancer.
The new study, published in EUROPEAN JOURNAL OF CANCER PREVENTION reports that women with high plasma level of enterolactone was associated with 58% reduction in breast cancer risk.
34% in breast cancer cell growth after giving
SDG daily for 30 days.
PROSTATE CANCER
A new study from SWEDEN concluded that diet rich in lignans could reduce the risk of prostate cancer risk by 26%
The in-vitro study from NEWZEALAND report that enterolactone may prevent spread of prostate cancer by regulating genes which produce important effects on apoptosis of
prostate cancer cells.
OVARIAN CANCER
In a case-control study of lignans and endometrial cancer, U.S. women with the highest intakes of plant lignans had the lowest risk of endometrial and ovarian cancer, but the reduction in risk was statistically significant in postmenopausal women only.
HOT FLUSHES IN MENOPAUSAL WOMEN
Enterolactone helps with estrogen balance, researchers have found that it is a safe and natural alternative to help buffer the hormonal fluctuations during menopause. This in turn helps to alleviate the accompanying symptoms of hot flashes and night sweats.
ESTROGEN RECEPTOR INDEPENDENT ACTIVITIES
ANTI-OXIDANT EFFECT Lignans exhibit very strong antioxidant
properties, thus it can protect the body from the effects of oxidation which can lead to a series of chronic diseases.
CARDIOVASCULAR DISEASE
Increased blood levels of enterolactone have been shown to reduce oxidation of blood lipids and reduce risk of heart disease by offering antioxidant and anti-inflammatory protection.
HAIR GROWTH AND ACNE
INHIBIT 5-alpha reductase
INHIBIT
TESTOSTERONE
DHT(DIHYDROTESTOSTERONE)
HAIR LOSS AND ACNE
ANTI-VIRAL EFFECT
Lignans suppresses the integration of proviral DNA into cellular genome.
BIOLOGICAL ACTIVITIES OF NEOLIGNANS
ANTI-MICROBIAL EFFECT Anti-bacterial effect Anti-fungal effect
INHIBITION OF PLATELET ACTIVTING FACTOR Kadsurenone antagonizes the activity
of PAF
ANTI-OXIDANT EFFECT
Honokiol and magnolol have been evaluated as antioxidants. These neolignans protected mitochondrial respiratory chain enzyme activity against NADPH-induced per oxidative stress and protected red cells against oxidative haemolysis.
ANTI-DEPRESSANT EFFECT
Magnolol has showed anti-depressant and anxiety reduced effects.
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