Sesame Oil/Seeds Binds to and Prevents Bioaccumulation of Certain Toxic Heavy Metals

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Heavy metals become toxic when they are not metabolized by the body and accumulate in the soft tissue.

Two recent studies have shown that the lignans from sesame seeds and oil have the ability to bind to toxic heavy metals and prevent their bioaccumulation in the body.

Sesame seeds contain the following lignans:

  • sesamolin
  • sesamin
  • pinoresinol
  • lariciresinol

Both pinoresinol and lariciresinol are lignans that are also found in olive oil and the Brassica genus of plants more informally known as cruciferous vegetables, cabbages, or mustard plants.

Figure 1.  Black and White Sesame Seeds

Study 1

This research study from February 2014 showed the the possible use and beneficial effects of sesame oil and sesamol during heavy metal toxicity treatment.  Sesame oil (a natural edible oil) and sesamol (an active antioxidant) are potently beneficial for treating lead- and iron-induced hepatic and renal toxicity and have no adverse effects. Sesame oil and sesamol significantly inhibit iron-induced lipid peroxidation by inhibiting the xanthine oxidase, nitric oxide, superoxide anion, and hydroxyl radical generation. In addition, sesame oil is a potent inhibitor of pro-inflammatory mediators, and it attenuates lead-induced hepatic damage by inhibiting nitric oxide, tumor necrosis factor-α, and interleukin-1β levels.  1  

Study 2

A more recent study from January 2016 demonstrated that black sesame pigment (BSP) was shown to effectively bind:

  • cadmium
  • lead
  • mercury

This study compared the lignans in black sesame seeds against three phytochemicals, caffeic acid, ferulic acid, and coniferyl acid, for their ability to bind toxic heavy metals.  Compared with black sesame seeds, caffeic acid was able to bind the most heavy metals. 

Lignans in black sesame seeds are responsible for heavy metal binding. Left: Model pigments representing digested lignans were compared to ground black sesame seeds (BSP) for heavy metal removal. Right: Caffeic acid and the suggested binding sites for cadmum (Cd2+), lead (Pb2+), and mercury (Hg2+)

Figure 2.  Left: Model pigments representing digested lignans were compared to ground black sesame seeds (BSP) for heavy metal removal. Right: Caffeic acid and the suggested binding sites for cadmum (Cd2+), lead (Pb2+), and mercury (Hg2+)  (Source:  Efficient Binding of Heavy Metals by Black Sesame Pigment: Toward Innovative Dietary Strategies To Prevent Bioaccumulation)

BSP at 0.05 mg/mL removed the metals at 15 μM to a significant extent (>65% for cadmium and >90% for mercury and lead), with no changes following simulated digestion. The maximum binding capacities at pH 7.0 were 626.0 mg/g (lead), 42.2 mg/g (cadmium), and 69.3 mg/g (mercury). In the presence of essential metals, such as iron, calcium, and zinc, BSP retained high selectivity toward heavy metals.  2