1. EVIDENCE FROM PUBLISHED LITERATURE
THE ROLE OF GARLIC IN THE PREVENTION OF DRUG AND CHEMICAL INDUCED TOXICITY
EVIDENCE FROM PUBLISHED LITERATURE

2. Prof Christian C Ezeala PhD, MSc, AMLSCN, MICR, MSB, CBiol, CSci, FSAFRI, FASI College of Medicine, Nursing, & Health Sciences

3. Background
Drug and chemical induced toxicity is a common cause of hospital admissions in both developed and developing countries
Garlic is widely used as spice and in many traditional medical practices
Garlic has many pharmacologically active constituents
Studies have shown these to exert effective protection against drug and chemical induced toxicity

4. AIM
To present current evidence from published literature on the usefulness of garlic and its products in preventing chemical induced toxicity

5. Objectives
To determine from peer reviewed literature, the toxicity models in which garlic has been reported to exert protective effect;
To articulate suggested mechanisms for this toxicoprotection;
To determine the constituents that were reported to be toxicoprotective
Appraise the studies for their strength of evidence.

6. Methods
Systematic review of literature designed to answer the questions:
“Does garlic prevent drug and chemical induced toxicity?”
By what mechanisms is this protection?
Which constituents protect against toxicity?

7. Article Selection Criteria
Articles that report results of a primary research
Study design is experimental, preclinical or clinical studies inclusive
Studies that involve accidental or intentional chemical or drug induced toxicity in mammalian species, isolated organs, or mammalian cell lines;
Organs or systems toxicity were investigated
Positive and negative controls and/or a standard drug (or standard of care) were included;
Study endpoints included biochemical, hematological, physiological, and/or histological assessments
Time limits – articles published in the last 20 years ( )

8. Literature Search Strategy
Search terms used included “garlic” OR “Allium sativa;” “chemical induced” OR “drug induced;” “toxic*”; “protect*” OR “prevent*”
Search engines and databases used included PubMed/Medline, Google Scholar, Microsoft academic search, and High Wire Press.
Time limits set to articles published between Jan 1994 and December 2013.

9. Data Collection and Analysis
Articles that met the above criteria were analyzed and the following information extracted:
Type of garlic preparation or constituent used
Toxicity model studied
Endpoints measured
Reported mechanisms

10. Toxicity Models

11. Toxicity Models

12. Garlic Preparations or Constituents Used
Fresh garlic
Aged garlic extract
Aqueous extract
Alcoholic or organic extract
Garlic oil
Purified constituents:
Diallyl sulfide (DAS)
Diallyl disulfide (DADS)
Diallyl trisulfide (DATS)
Thiacremonone
S-allylmercaptocysteine (SAMC)
S-allylcysteine (SAC)

13. Chemical Constituents
Allicin (diallyl thiosulphinate)
Diallyldisulphide (DADS)
Alliin (S-allylcysteine sulphoxide)

14. Mechanisms of Toxicoprotection

15. Conclusion
Garlic derived products exert toxicoprotective effects by several mechanisms including antioxidant and anti- inflammatory effects, inhibition of bioactivation by CYP enzymes, and inhibition of apoptosis.
Garlic products used in studies included crude and purified constituents
A wide variety of toxicity models were described including hepatotoxicity, carcinogenesis, and neurobehavioural toxicity.
All the studies were preclinical, posing restrictions on extrapolation of the results to the clinical setting