Vivancos and co-workers found a synergistic action of polyphenols from olive oil and wine and beta-sitosterol led to the modulation of the effects of oxidized LDL on oxidative stress and prostaglandin E2 synthesis. Oxidized LDL stimulates the transformation of macrophages into foam cells, which play an important role in the development of atherosclerosis. The researchers were especially interested in the protective effect on atherosclerosis of phytochemicals which are typically found in the Mediterranean diet, such as resveratrol, tyrosol and beta-sitosterol. They measured the effect of these phytochemicals on the production of hydrogen peroxide, arachidonic acid, and prostaglandin E2 by macrophages, stimulated by oxidized LDL. Both resveratrol and tyrosol reduced the production these indicators and the presence of beta-sitosterol further increased this effect [1].
A Korean study led by Choi showed that beta-sitosterol, a phytochemical found in Aloe Vera, may explain the wound healing effect of the plant. Their study concluded that beta-sitosterol has therapeutic angiogenic effects on damaged blood vessels. Angiogenesis is the process involving the growth of new blood vessels from pre-existing vessels. Their in-vivo experiment showed that beta-sitosterol enhanced new blood vessel formation in brains and significantly improved the motion recovery after ischaemia/reperfusion-damaged gerbils. The phytochemicals also enhanced the expressions of many proteins related to angiogenesis [2].
[1] Vivancos M, Moreno JJ. " Effect of resveratrol, tyrosol and beta-sitosterol on oxidised low-density lipoprotein-stimulated oxidative stress, arachidonic acid release and prostaglandin E2 synthesis by RAW 264.7 macrophages." Br J Nutr. 2008 Jun;99(6):1199-207.
[2] Choi S, Kim KW, Choi JS, Han ST, Park YI, Lee SK, Kim JS, Chung MH. "Angiogenic activity of beta-sitosterol in the ischaemia/reperfusion-damaged brain of Mongolian gerbil." Planta Med. 2002 Apr;68(4):330-5.
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