I am partial to an occasional slice of pizza despite my health-driven dietary compulsions. I love to sprinkle generous amounts of oregano on the slices and have often wondered what the health properties of that pungent herb are. I recently learned that oregano is rich in rosmarinic acid and therefore, as my grandmother used to say “it is good for you.” I review some of the things the literature says about rosmarinic acid here.
“Rosmarinic acid, C18H16O8, is a natural polyphenol antioxidant carboxylic acid found in many Lamiaceae herbs used commonly as culinary herbs such as lemon balm, rosemary, oregano, sage, thyme and peppermint (ref).” It has anti-inflammatory, anti-bacterial, anti-viral, radio-protective, photo-protective, anti-allergenic and anti-oxidant properties. It is somewhat structurally related to curcumin and resveratrol and is an ester of caffeic acid. (See the blog entry Phytochemicals – focus on caffeic acid.)
Rosmarinic acid induces apoptosis in some cancer cell lines. The 2009 paper Salvia Fruticosa, Salvia Officinalis, and Rosmarinic Acid Induce Apoptosis and Inhibit Proliferation of Human Colorectal Cell Lines: The Role in MAPK/ERK Pathway states “Aromatic plants of the genus Salvia (sage) have been attributed many medicinal properties, which include anticancer activity. In the present study, the antiproliferative and proapoptotic effects of water extracts of Salvia fruticosa (SF) and Salvia officinalis (SO) and of their main phenolic compound rosmarinic acid (RA) were evaluated in two human colon carcinoma-derived cell lines, HCT15 and CO115, which have different mutations in the MAPK/ERK and PI3K/Akt signaling pathways. These pathways are commonly altered in CRC, leading to increased proliferation and inhibition of apoptosis. Our results show that SF, SO, and RA induce apoptosis in both cell lines, whereas cell proliferation was inhibited by the two sage extracts only in HCT15. SO, SF, and RA inhibited ERK phosphorylation in HCT15 and had no effects on Akt phosphorylation in CO115 cells. The activity of sage extracts seems to be due, at least in part, to the inhibition of MAPK/ERK pathway.”
Rosmarinic acid has anti-oxidative activity. Several publications point to this effect such as the 2008 paper Antioxidant activities of rosemary (Rosmarinus Officinalis L.) extract, blackseed (Nigella sativa L.) essential oil, carnosic acid, rosmarinic acid and sesamol. The 2007 study Water and methanolic extracts of Salvia officinalis protect HepG2 cells from t-BHP induced oxidative damage states “The most abundant phenolic compounds present in the extracts were rosmarinic acid and luteolin-7-glucoside. Both extracts, when co-incubated with the toxicant, protected significantly HepG2 cells against cell death. The methanolic extract, with a higher content of phenolic compounds than the water extract, conferred better protection in this in vitro model of oxidative stress with liver cells.” A 2006 study Phenolic compounds protect HepG2 cells from oxidative damage: relevance of glutathione levels compared the antioxidant capabilities of several polyphenols “If the effects of quercetin are given the reference value 1, the compounds rank in the following order according to inhibition of cell death: luteolin (4.0) > quercetin (1.0) > rosmarinic acid (0.34) > luteolin-7-glucoside (0.30) > caffeic acid (0.21). The results underscore the importance of the compound’s lipophilicity in addition to its antioxidant potential for its biological activity.”
A 2007study The effects of essential oils and aqueous tea infusions of oregano (Origanum vulgare L. spp. hirtum), thyme (Thymus vulgaris L.) and wild thyme (Thymus serpyllum L.) on the copper-induced oxidation of human low-density lipoproteins looked at “the antioxidative capacity effect of essential oils and aqueous tea infusions obtained from oregano, thyme and wild thyme on the oxidation susceptibility of low-density lipoproteins (LDL). — The strong protective effect of aqueous tea infusions is proposed to be the consequence of large amounts of polyphenols, namely rosmarinic acid and flavonoids (quercetin, eriocitrin, luteolin-7-O-glucoside, apigenin-7-O-glucoside, luteolin, apigenin), with the most pronounced effect in the case of oregano.” This is interesting and would seem to be a good argument for drinking oregano tea(ref), something I have never quite done.
I have written about several other phytochemicals in this blog and in my treatise ANTI-AGING FIREWALLS THE SCIENCE AND TECHNOLOGY OF LONGEVITY. See, for example, yesterday’s post Nrf2 and cancer chemoprevention by phytochemicals. Who would think that, after a bout of dental x-rays, eating a slice of pizza with a generous layer of oregano sprinkled on it could be a good thing to do from a radioprotective viewpoint?