synephrine

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Heiko

Here's a few references on synephrine. Included is one that mention

synephrine as a component of plain old orange juice. It is my understanding

that standard doses of zhi shi do not result in much synephrine intake.

Nevertheless, I was taught that this herb should be used carefully.

As for weight loss, it is my understanding there is no good science behind

this, except that synephrine is similar to ephedrine. This would

actually rule it out in my opinion. Methods that concentrate

the synephrine clearly cause arterial hypertension and are antiasthmatic,

so it does apparently have similar effects and probably similar risks to

ephedrine.Fructus aurantii reduced portal pressure in portal hypertensive rats.

Huang YT, Wang GF, Chen CF, Chen CC, Hong CY, Yang MC

Institute of Traditional Medicine, School of Medicine, National

Yang-Ming University, Taipei, Taiwan.

The purpose of this study was to investigate the effects of Fructus

Aurantii (the unripe fruits of Citrus aurantium L.) on portal hypertensive

rats. Portal hypertension was induced by partial portal vein ligation (PVL)

in Sprague-Dawley rats. Sham-operated (Sham) rats served as controls. Hemodynamic

and in vitro contractile studies were performed at 14 days after surgery.

Both the aqueous extract of Fructus Aurantii and synephrine, one of its

purified principles with pressor activity, were infused into the conscious

PVL and Sham rats via a syringe pump. Fructus Aurantii (1.25, 2.5, &

5.0 mg/kg/min) dose-dependently reduced portal pressure in PVL and Sham

rats, with the percentage change in portal pressure more pronounced in

PVL rats. Mean arterial pressure was dose-dependently elevated by Fructus

Aurantii. Synephrine (0.095, 0.19, & 0.38 mg/kg/min) also dose-dependently

reduced portal pressure and elevated mean arterial pressure in PVL and

Sham rats. Fructus Aurantii (2.8-280 micrograms/ml) induced dose-dependent

contractile responses mainly in aorta and mesenteric artery, but little

response in portal vein. The results showed that Fructus Aurantii infusion

reduced portal pressure, possibly by way of arterial vasoconstriction.

PMID: 7475952, UI: 96077178

Studies on the preparation and evaluation of Kijitsu,

the immature citrus fruits. IV. Biological activities of immature fruits

of different citrus species].

[Article in Japanese]

Hosoda K, Noguchi M, Chen YP, Hsu HY

Wakayama Experimental Station of Medicinal Plants, National Institute

of Hygienic Sciences, Japan.

Biological activities of the 50% ethanolic extract of Kijitsu, dried

immature Citrus fruits prepared from C. hassaku Hort. ex Tanaka (H), C.

natsudaidai Hayata (N) or allied plants (T, A) were observed. Weak toxicities,

weak intestine or uterine relaxant activities, beta-adrenergic activities

were shown by in vitro experiments and antiasthmatic activity by intraperitoneal

administration. These activities among each extract did not differ. The

content of flavonoids (narirutin, naringin hesperidin, neohesperidin) or

synephrine did not show much difference among the four dried immature Citrus

fruits. These results suggest that H can be used for medicine as the substitute

for N, T or A which has been commonly used as Kijitsu. This method is generally

applicable to the proof of the biological equivalency of the crude drug

and its substitutes.

PMID: 1676750, UI: 91295007

Published erratum appears in Anal Biochem 1996 May 1;236(2):378

Determination of synephrine enantiomers in food and

conjugated synephrine in urine by high-performance liquid chromatography

with electrochemical detection.

Kusu F, Matsumoto K, Arai K, Takamura K

School of Pharmacy, Tokyo University of Pharmacy and Life Science, Hachioji,

Japan.

Determination of synephrine enantiomers was made with HPLC with electrochemical

detection using a chiral ligand-exchange column (Sumichiral OA-6000). The

calibration curve for each enantiomer showed good linearity (r = 0.999)

at 1.0-500 pmol injected with a detection limit of 1.0 pmol (signal-to-noise

ratio (S/N) = 3). Relative standard deviation (RSD) was 1.8% at 50 pmol

d-synephrine and 1.6% at 50 pmol l-synephrine. The contents of synephrine

enantiomer in food such as Citrus unshiu fruit, orange juice, and marmalade

were determined. The present method was also used to determine conjugated

synephrine enantiomers in urine following the ingestion of C. unshiu pulp.

l-Synephrine in fruit was converted to the conjugated form of synephrine,

and l-synephrine underwent chiral inversion to d-synephrine in vivo.

PMID: 8833327, UI: 96430199