Garlic is one of those foods you constantly hear about. One day it is saving your heart. Another day it is boosting your immune system. Romans ate it for courage, I eat it for taste. Many people avoid it for its smell. You may even cry over it.

But your neurons will thank you the most for eating it. A recent study from the Medical University of South Carolina reveals that garlic is an excellent means of killing brain tumors. More details after the jump.

Garlic contains several different organosulphur compounds, notably diallyl sulfide (DAS), diallyl disulfide (DADS), and diallyl trisulfide (DATS). DADS in particular was noted as being able to cause cell death in leukemia and breast cancer. It was theorized these organosulfer compounds may have similar abilities against glioblastoma cells. Glioblastoma is the most prevalent and deadly form of brain cancer. Over 50% of brain cancer is in the form of glioblastoma. The 5-year survivability rate is as low as 3% and there is no known cure. Preventative measures have a wide range of side effects, none of which are enjoyable.

DADS and DAS were tested first against two types of glioblastoma, T98G and U87MG cells. Both organosulphur compounds decreased cell viability and increased cell apoptosis. Both compounds also increased production of reactive oxygen species (ROS), which in turn induces the p38 MAPK pathway. The p38 MAPK pathway is associated with apoptosis while its cousins, p42/44 MAPK pathways, induce cytoprotective properties and are often triggered together. DADS and DAS triggered only p38, resulting in only cell death.

(A)T98G cell and (B) U87MG cell viability after exposure to varying amounts of DADS and DAS

In addition to p38, the compounds activate the JNK1 pathway which is also associated with cell death. Ca²⁺ concentrations were markedly higher in cells treated with DADS/DAS. Ca²⁺ is often a good signal of cell death and causes destruction on its own in high enough quantities (for example, depolarizing microtubules). Importantly, DADS/DAS induced the expression of CAD. CAD enters the nucleus and degrades chromosomal DNA.

It was found that the usage of DATS was even more effective than either DADS or DAS. Smaller quantities could be used to gain the same level of cell death associated with DADS/DAS. These findings clearly show that organosulphur compounds present in garlic are an effective method to trigger cell death in glioblastomal cells. The method of cell death included several different pathways all triggered by ROS. This is promising news for a disease that is extremely difficult to treat and is often fatal.

Proposed pathway leading to apoptosis

References

Das A, Banik N, Ray S. Garlic compounds generate reactive oxygen species leading to activation of stress kinases and cysteine proteases for apoptosis in human glioblastoma T98G and U87MG cells. Cancer (2007) 5:1083-1095, 10.1002/cncr.22888