Onions- A Global Benefit to Health

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Onions- A Global Benefit to Health

• Gareth Griffiths, Laurence Trueman, Timothy
  Crowther, Brian Tomas and Brian Smith

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Onion FAQ.

• Bulb onions likely originated in central Asia,
  but are not found in the wild.
• Onions are grown in every part of the world where
  plants are farmed.
• Onion is the second most important horticultural
  crop world wide.

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Two Chemical Classes With Perceived Health
Benefits.
Flavonoids -Anthocyanins (Red) -Quercetins
(Yellow) Alkyl cysteine sulphoxides
(ACSOs) -Flavor precursors cleaved by alliinase
enzyme
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ACSOs and Associated Breakdown Products

• Three ACSOs are present in intact onion tissue.
• Upon hydrolysation by alliinase, and subsequent
  spontaneous reactions with each other and nearby
  compounds, ACSOs give rise to 50 sulphur
  containing compounds.
• This wide array of sulphur containing compounds
  contribute to onion flavor and are reported to
  provide benefits to human health.

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Factors Affecting final composition of ACSO
breakdown products.

• Initial concentration and ratios of the three
  ACSO species.
• Availability of alliinase enzyme (tissue
  disruption).
• Type and concentration of other compounds in the
  environment with witch ACSO breakdown products
  react.
• pH temperature of the environment.

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ACSO Breakdown
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Reported Health Benefits of ACSO breakdown
products in Onion

• Anticancer activity through modulation of enzymes
  involved in metabolization of carcinogenic
  compounds.
• Possible lowering of serum cholesterol.
• Lowering systolic blood pressure thinning the
  blood (only compounds found in uncooked pungent
  cultivars).
• Antiasthmatic activity, suppressing reactions
  leading to bronchial restriction.
• Antifungal and antibacterial properties.

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Flavonoid Compounds in Onion

• Flavonols
• Yellow compounds concentrated in the skin of the
  onion.
• Sixteen flavonol compounds have been identified
  in onion.
• Anthocyanins
• Red compounds.
• Four anthocyanin compounds have been identified
  in onion.

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Reported Health Benefits of Flavonoids in Onion

• Antioxidant effects of flavonoids help to protect
  cells from oxidative stress resulting from free
  radical damage, as well as reducing cancer rates
  by protecting DNA from oxidative damage.
• Possible lowering of serum cholesterol by
  quercetin compounds.
• Phenolic flavonoid compounds may provide some
  antibiotic activity.

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Garlic as an Antioxidant The Good The Bad and
The Ugly

• S.K. Banerjee, Pulok K. Mukherjee and S.K. Maulik

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Garlic Health FAQ.

• Garlic has played an important dietary and
  medicinal role for centuries.
• The sale of medicinal garlic preparations is on
  par with that of many prescription drugs.
• A wide array of health claims are made for garlic
  and its various preparations.

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Health Benefits Attributed to Garlic

• Prevention of Cardiovascular disease.
• Reduced Cancer Risk.
• Treatment of microbial infections.
• Antidote for heave metal poisoning.
• Hepatoprotective.

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Garlic and Human Health

• Garlic consumption has been recognized in
  reducing rates of cancer and Cardiovascular
  disease.
• This effect is thought to be largely due to the
  antioxidant properties of the many organosulphur
  compounds found in garlic preparations.

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Various Garlic Preparations Examined for Health
Effects.

• Raw Garlic
• Heat Treated Garlic
• Garlic Powder
• Aged garlic Extract
• Garlic Oil (steam distilled, oil macerated, ether
  extract)
• Garlic Protein

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Garlic preparation method, effects on various
oxidative stress conditions.
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Garlic Organosulphur Compounds

• When Garlic is crushed Allinase enzyme acts on
  Alliin to form allicin.
• Allicin has both antioxidant and oxidative
  properties.
• The many breakdown products of Allicin vary
  across different preparation methods.
• Different garlic preparations are reported to
  have varying antioxidant and disease fighting
  properties.

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Garlic Organosulphur Compounds
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Garlic Organosulphur Compounds Reported Effects.

• Antioxidant (free radical scavenging) protecting
  DNA, Proteins, Lipids, and other compounds from
  oxidative damage.
• Increased endothilial cell NO production, making
  blood vessels more elastic.
• Decreased hepatic cytochrome P450, protecting
  the liver from toxin (acetominophen) induced
  injury.

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Negative Effects Resulting From large Doses of
Garlic.

• Bad Breath
• Anemia.
• Weight loss.
• Lysis of red blood cells.
• Altered cellular architecture in the heart, liver
  and kidneys.