The roselle (Hibiscus sabdariffa) is a species of Hibiscus native to the Old World tropics, used for the production of bast fibre and as an infusion. It is an annual or perennial herb or woody-based subshrub, growing to 2–2.5 m (7–8 ft) tall. The leaves are deeply three- to five-lobed, 8–15 cm (3–6 in) long, arranged alternately on the stems.
The flowers are 8–10 cm (3–4 in) in diameter, white to pale yellow with a dark red spot at the base of each petal, and have a stout fleshy calyx at the base, 1–2 cm (0.39–0.79 in) wide, enlarging to 3–3.5 cm (1.2–1.4 in), fleshy and bright red as the fruit matures. It takes about six months to mature.
The flowers are 8–10 cm (3–4 in) in diameter, white to pale yellow with a dark red spot at the base of each petal, and have a stout fleshy calyx at the base, 1–2 cm (0.39–0.79 in) wide, enlarging to 3–3.5 cm (1.2–1.4 in), fleshy and bright red as the fruit matures. It takes about six months to mature.
Roselle is associated with
traditional medicine and is reported to be used as treatment for several
diseases such as hypertension and urinary tract infections.
The effectiveness of Hibiscus sabdariffa
L. (HS) in the treatment of risk factors associated with cardiovascular
disease is assessed in this review by taking a comprehensive approach
to interpreting the randomized clinical trial (RCT) results in the
context of the available ethnomedical, phytochemical, pharmacological,
and safety and toxicity information. HS decoctions and infusions of
calyxes, and on occasion leaves, are used in at least 10 countries
worldwide in the treatment of hypertension
and hyperlipidemia with no reported adverse events or side effects. HS
extracts have a low degree of toxicity with a LD50 ranging from 2,000 to
over 5,000mg/kg/day. There is no evidence of hepatic or renal toxicity
as the result of HS extract consumption, except for possible adverse
hepatic effects at high doses. There is evidence that HS acts as a
diuretic, however in most cases the extract did not significantly
influence electrolyte levels. Animal studies have consistently shown
that consumption of HS extract reduces blood pressure in a dose
dependent manner. In RCTs, the daily consumption of a tea or extract
produced from HS calyxes significantly lowered systolic blood pressure
(SBP) and diastolic blood pressure (DBP) in adults with pre to moderate
essential hypertension
and type 2 diabetes. In addition, HS tea was as effective at lowering
blood pressure as the commonly used blood pressure medication
Captropril, but less effective than Lisinopril. Total cholesterol,
low-density lipoprotein cholesterol (LDL-C), and triglycerides were
lowered in the majority of normolipidemic, hyperlipidemic, and diabetic
animal models, whereas high-density lipoprotein cholesterol (HDL-C) was
generally not affected by the consumption of HS extract. Over half of
the RCTs showed that daily consumption of HS tea or extracts had
favorable influence on lipid profiles including reduced total
cholesterol, LDL-C, triglycerides, as well as increased HDL-C.
Anthocyanins found in abundance in HS calyxes are generally considered
the phytochemicals responsible for the antihypertensive and
hypocholesterolemic effects, however evidence has also been provided for
the role of polyphenols and hibiscus
acid. A number of potential mechanisms have been proposed to explain
the hypotensive and anticholesterol effects, but the most common
explanation is the antioxidant effects of the anthocyanins inhibition of
LDL-C oxidation, which impedes atherosclerosis, an important
cardiovascular risk factor. This comprehensive body of evidence suggests
that extracts of HS are promising as a treatment of hypertension
and hyperlipidemia, however more high quality animal and human studies
informed by actual therapeutic practices are needed to provide
recommendations for use that have the potential for widespread public
health benefit.
Although Roselle has well documented hypotensive effects, there is currently insufficient evidence to support the benefit of Roselle for either controlling or lowering blood pressure due to a lack of of well designed studies that measure the efficacy of Roselle on patients with hypertension.
Ngamjarus,
Chetta; Pattanittum, Porjai; Somboonporn, Charoonsak (2010). "Roselle
for hypertension in adults". In Ngamjarus, Chetta. Cochrane Database of Systematic Reviews. doi:10.1002/14651858.CD007894.pub2
A double blind, placebo controlled, randomized trial was conducted to
determine the effect of Roselle leaf extract on a group of 60 subjects
with serum LDL values in the range of 130-190 ml/dl (<130 ml/dl is a goal value for most patients)
and no history of coronary heart disease. The experimental group
received 1g of Roselle leaf extract while the placebo group received a
similar amount of maltodextrin in addition to dietary and physical
activity advice. Both groups had decreases in body weight, LDL
cholesterol, and triglycerides that can likely be attributed to the
dietary and physical activity advice. At a dose of of 1g/day, Roselle
leaf extract did not appear to have a blood lipid lowering effect.
Kuriyan, R; Kumar, DR; r, R; Kurpad, AV (2010). "An
evaluation of the hypolipidemic effect of an extract of Hibiscus
Sabdariffa leaves in hyperlipidemic Indians: a double blind, placebo
controlled trial". BMC Complementary and Alternative Medicine 10: 27. doi:10.1186/1472-6882-10-27. PMC 2906418. PMID 20553629
Also Hibiscus sabdariffa has shown in vitro antimicrobial activity against E. coli.
Fullerton M, Khatiwada J, Johnson JU, Davis
S, Williams LL"Determination of Antimicrobial Activity of Sorrel
(Hibiscus sabdariffa) on Esherichia coli O157:H7 Isolated from Food,
Veterinary, and Clinical Samples." J Med Food. 2011 May 6
A review stated that specific extracts of H. sabdariffa exhibit activities against atherosclerosis, liver disease, cancer, diabetes and other metabolic syndromes.
Lin, HH;
Chen, JH; Wang, CJ (2011). "Chemopreventive properties and molecular
mechanisms of the bioactive compounds in Hibiscus sabdariffa Linne". Current medicinal chemistry 18 (8): 1245–54. PMID 21291361.
0 Comments:
Post a Comment