Framboise, Rubi idaei folium, rubus
Botanical Name / Family
Rubus idaeus (synonym: Rubus strigosus) (family Rosaceae [roses])
Plant Part Used
Raspberry leaves have a tannin content of between 13% and 15%, as well as flavonoids such as rutin and quercetin, volatile oils, organic acids and vitamin C.
Although the fruits of the raspberry are used asa luxury food source, midwives have used raspberry leaves since ancient times to prepare the uterus for childbirth. Raspberry has also been used as an antidiarrheal and an astringent to treat inflammations of the mucous membranes of the mouth and throat. It has also been used for disorders of the gastrointestinal and respiratory tracts and as an ingredient in dietary drinks.
Raspberry leaf: Main Actions
Raspberry leaf contains a number of active constituents and their therapeutic actions have been reviewed. Currently, evidence of activity comes from in vitro and in vivo studies.
Raspberry leaf has demonstrated a variable effect on uterine muscle tone. It contains a smooth muscle stimulant, an anticholinesterase and an antispasmodic. The results of animal studies indicate that raspberry can either reduce or initiate uterine contractions. It appears to inhibit uterine contractions in samples from pregnant test animals, but has no effect in non-pregnant ones. Samples from human pregnant uteri respond with contraction effects; however, no effect was seen on non-pregnant uteri samples. Overall, it appeared that raspberry leaf extract promoted more regular contractions that generally became less frequent.
A more recent preliminary study produced similar results with fractions of raspberry leaf extract, both stimulating and relaxing uterine muscle in pregnant rats. There is evidence of at least two components of raspberry leaf extract that exhibit relaxant activity in an in vitro guinea pig ileum preparation.
In addition to the high tannin content, which may exert an antidiarrheal action, raspberry cordial and juice were found to significantly reduce the growth of several species of bacteria, including Salmonella, Shigella and Escherichia coll, but no antimicrobial activity was detected in the leaf extract or tea.
Raspberry leaf exhibits anti-inflammatory activity because of its high tannin content, which has been found to inhibit COX. When applied topically to mucous membranes, tannins have a local anti-inflammatory effect, produce capillary vasoconstriction and decrease vascular permeability.
The high tannin content of the leaf is responsible for the astringent activity.
Raspberry leaf: Other Actions
Raspberry ketone, which is an aromatic compound with similar structure to capsaicin and synephrine, has been shown in vivo to prevent and improve obesity and fatty liver though increasing norepinephrine-induced lipolysis in white adipocytes.