Antihypertensive Effects of Brazilian Propolis: Identification of Caffeoylquinic Acids as Constituents Involved in the Hypotension in Spontaneously Hypertensive Rats

Abstract

Recently increases in life-style related diseases like hypertension, arteriosclerosis, heart disease, obesity, diabetes mellitus, and cancers have become a great social problem.1) As regards diseases of circulatory system such as hypertension, arteriosclerosis and heart disease, increasing numbers of people are showing symptoms of hypertension or pre-hypertension stage. Causes leading to hypertension include increase in the volume of body fluid, increase of the resistivity of the blood vessels, increases in factors leading to elevation of the blood pressure or decreases in factors bringing about lowering of the blood pressure.2) These factors induce abnormal increase of blood pressure, either singly or in combination. Clinically, various drugs such as inhibitors of angiotensin converting enzymes, calcium antagonists, b-blockers, angiotensin II receptor antagonists, and hypotensive diuretics have been used for management of hypertension to improve the symptoms.3) In addition, antihypertensive effects have been noted with various food and natural products.4) Recently, various foods with differing hypotensive mechanisms have been specified for use as health foods. These foods have various activities such as the inhibitory activity of peptides derived from milk, 5) fish, 6) or plants, 7) on angiotensin converting enzymes, vasodilatory action by parasympathetic stimulation, 8) or inhibitory effects on release of noradrenaline from sympathetic nerves, 9) respectively. Furthermore, some flavonoids and polyphenol derivatives from natural products have been reported to have vasodilating and hypotensive effects. [10][11][12] In these points, we focused on propolis which has been shown to comprise more than 150 constituents, including cinnamic acid derivatives, flavonoids, and benzoic acids. 13)Propolis is called "bee resin", which is a yellow to dark brown-colored adhesive substance collected from sprouts of plants by honeybees and thought to serve a protective role against potential predators. Propolis has been reported to possess some pharmacological functions in humans such as antibacterial, antioxidative, anti-inflammatory, antitumor, and immunostimulatory activities and has been used in folk medicine.14-24) The composition of propolis primarily depends upon the vegetation of the area from where it was collected and secondarily upon the solvents used for its extraction. 25) Although pharmacological activities of propolis could be related to its chemical composition, 26) water or 90-99.5% ethanol extract of propolis is commonly used for health food and beverages in recent years. Since Baccharis dracunculifolia is an important source of propolis collected from Minas Gerais state, Brazil,27) which is of good quality to provide experimental reproducibility, we have used this Brazilian propolis in the current study.In the course of studies on diverse pharmaceutical activities of propolis, we examined hypotensive effects of Brazilian propolis extracts. Recent study reported that caffeic acid phenethyl ester (CAPE), which is...

The Anti-thrombotic Active Constituents from Centella asiatica

“…33) So, the observation that 2 has an antithrombotic effect supports the fact that 3,5-di-O-caffeoylquinic acid (2) has the anti-hypertensive effect. Compounds such as ester derivatives of quinic acid and caffeic acids are not particularly unusual as natural compounds, but they are normally found only in small quantities.…”

Antihypertensive Effects of Flavonoids Isolated from Brazilian Green Propolis in Spontaneously Hypertensive Rats

“…8) Moreover, in vessels from spontaneously hypertensive rats (SHR), a valuable animal model of essential hypertension in humans, enhanced endothelial superoxide anion production has been described and these effects are related to impairment of endothelium-dependent relaxation. 9,10) Recently the antihypertensive effects of 25% ethanol extract of Brazilian green propolis were reported in SHR 11,12) and the active constituent was shown to be caffeoylquinic acid. 12) However, little information is available about the effects of absolute ethanol extract of Brazilian green propolis and its main constituents on hypertension in SHR.…”

“…9,10) Recently the antihypertensive effects of 25% ethanol extract of Brazilian green propolis were reported in SHR 11,12) and the active constituent was shown to be caffeoylquinic acid. 12) However, little information is available about the effects of absolute ethanol extract of Brazilian green propolis and its main constituents on hypertension in SHR. Generally, propolis is known to yield different constituents depending on the liquid used for extraction and the concentration.…”

A dipeptide YY derived from royal jelly proteins inhibits renin activity

“…Control rats were administered the same volume of gum arabic solution. SBP was measured with a tail-cuff method 0, 1 and 5 h after the administration as described previously (28).…”