Plants used to treat infectious disease - III

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Plants used to treat infectious disease - III

• Plant Products as Antimicrobial Agents

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Plant Products

• Long history of use as antimicrobials
• Very few have made the transition from herbal
  remedies to mainstream drugs
• Often much weaker than antibiotics
• Renewed interest largely due to antibiotic
  resistance

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Chaulmoogra Oil
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Leprosy - Hansens Disease

• Chronic skin disease endemic to tropical and
  subtropical areas
• Caused by bacterium, Mycobacterium leprae
• Bacterium discovered by Gerhard Hansen - one of
  the first bacteria associated with a disease
• Transmitted contact between susceptible people??
• It has the potential to produce mutilation of
  extremities and disfigurement of the face
• Apparently two forms
• Tuberculoid type may be limited to a few nerves
  and skin area
• Lepromatous type is disseminated throughout the
  body

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Hansens disease in 2004

• 407,791 new cases detected worldwide
• Around 100 cases occurring in the United States
• WHO listed Brazil, Madagascar, Mozambique,
  Tanzania, and Nepal as having 90 of cases
• Worldwide 1-2 million persons are permanently
  disabled as a result of Hansen's disease

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Chaulmoogra Oil

• Mentioned in the Hindu Vedas over 2000 years ago
  as helping in curing leprosy
• Oil reached Europe in the mid-nineteenth century,
  but source was unknown
• Joseph Rock traveled Asia in 1920's, identified
  source of chaulmoogra as Hydnocarpus trees of
  India and surrounding countries
• Rock sent seeds to Hawaii, where Hydnocarpus
  plantations were started
• The only effective treatment for leprosy until
  sulfa drugs were used in 1946

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Chaulmoogra Oil

• Earlier use in Hawaii
• Alice Ball (1892-1916) worked on chaulmoogra oil
  to treat leprosy
• Died in 1916 (24 yrs old) - work was taken over
  by Arthur Dean who initially got credit for work
  with chaulmoogra oil

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Chaulmoogra Oil

• Source seeds of Hydnocarpus wightiana and
  Hydnocarpus anthelmintica is triglyceride of
  fatty acids containing cyclopentenyl group
• Given by injection to patients with leprosy
• Symptoms went away and bacteria disappeared from
  nasal secretions but relapse often occurred
• Early cases were completely cured
• More established cases had relapse
• Today standard treatment is combined drug therapy
  3 antibiotics dapsone, rifampin, and
  clofazimine

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Herbal Remedies
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Herbal Remedies

• Many herbal remedies on the mass market are known
  to have antimicrobial activity
• One example berberine
• Several herbal remedies containing the alkaloid
  berberine show antimicrobial activity against a
  variety of bacteria, fungi, protozoans, worms,
  chlamydia, and viruses
• Extracts of these plants used in Ayurvedic and
  Chinese medicine for about 3000 years

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Berberine containing herbals and plant part used
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Berberine research on-going

• Much of the research focused on its use in cases
  of diarrhea, including that caused by Vibrio
  cholerae and Escherichia coli
• In one study, berberine had antimicrobial
  activity against gram-positive and gram-negative
  bacteria, fungi, and protozoa
• Berberine has been also shown to inhibit HIV-1
  reverse transcriptase

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Berberine as an antimicrobial

• Activity still weak compared to antibiotics
• Possibly do to MDR pumps in bacterial cell
  membranes
• Research focus on MDR inhibitors in Berberis
  fremontii and other species of berberine
  containing plants

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Herbs and Spices
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Herbs and spices

• Herbs are aromatic leaves or seeds from plants of
  temperate origin
• Spices are aromatic fruits, flowers, bark or
  other plant parts of tropical origin
• While herbs and spices are mainly associated with
  cooking, they are also used, as natural dyes, in
  perfume, cosmetics, and traditionally used in
  medicine

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Essential Oils

• Value of herbs and spices due to essential oils
• Most commonly found in leaves, flowers, and
  fruits where they occur in glandular trichomes
• Chemically, essential oils are most commonly
  terpenes, but may be phenolics

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History of spices

• Early history
• Ebers Papyrus
• Ancient Greece and Rome
• Dark Ages
• Venice and Genoa Marco Polo
• Prince Henry of Portugal
• Age of Exploration
• 16th to 19th centuries

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Herbs and spices

• Over the past 30 years dozens of studies have
  focused on the antimicrobial properties of herbs
  and spices
• Most spices have antimicrobial properties
• Growing feeling that the enduring value of spices
  is actually due to these antimicrobial properties
• Paul Sherman from Cornell one of the leading
  proponents of this hypothesis

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Why use spices?

• Obvious answer is that they impart pleasing
  tastes to foods
• Why do people find taste appealing?
• Why are there preferences for certain spices in
  cuisine of different regions?

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Predictions based on spice use

• Sherman and his students developed an
  antimicrobial hypothesis
• If spices kill microorganisms or inhibit their
  growth or production of toxins, then spice use
  would protect us from food borne illness and food
  poisoning
• To test the hypothesis, they developed critical
  predictions

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Antimicrobial activity

• Prediction 1 - Spices used in cooking exhibit
  antimicrobial activity
• Overwhelming evidence that most spices have
  antimicrobial properties
• Inhibition of bacterial especially important
  because they are more common in food poisoning
  than fungi

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Spice use in hotter countries

• Prediction 2 Use of spices should be greater in
  hot climates where unrefrigerated foods spoil
  quickly
• Looked at spice use in traditional recipes and
  correlated it with temperature
• Use of spices greater in hotter area
• Percent of recipes calling for at least one spice
  and the number of different spices were all
  greater in warmer countries - especially true for
  highly inhibitory spices (inhibited 75 of
  bacteria tested)

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Spices kill food-borne bacteria

• Prediction 3 Spices used in each country should
  be particularly effective against the local
  bacteria
• Unfortunately no lists of native food-borne
  bacteria
• Sherman et al looked at effectiveness of native
  recipes in killing 30 common food-borne bacteria
• As annual temp increased, the estimated percent
  of bacteria that would be inhibited also increased

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More spices used with meats

• Prediction 4 Within a country meat recipes
  should be spicier than vegetable recipes
• Unrefrigerated meats associated with more
  food-borne disease outbreaks and food poisoning
• Meat-based recipes from all 36 countries called
  for an average of 3.9 spices, significantly more
  than 2.4 spices in average vegetable recipes

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More spices in hotter areas

• Prediction 5 Within a country, recipes from
  lower latitudes and altitudes should be spicier
  than higher latitudes and altitudes
• Difficult to find recipes tied to altitude
• In US and China, recipes from southern latitudes
  used a greater variety of spices and spices used
  more often
• Southern recipes contained spices more likely to
  kill or inhibit bacteria

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Alternate Hypotheses

• Spices disguise the smell and taste of spoiled
  foods - ignores dangers of spoiled meats which
  could be deadly
• Spices used as medicines - dosage is different
  and all people use the food
• Spices used in hotter climates because it helped
  increase perspiration (only works for chilis and
  horseradish)
• Spices used because they taste good - some spices
  initially distasteful - yet people continue to use