A Review of the Nutritional Health Effects of Roselle (Hibiscus sabdariffa L.) Calyces

Xuefang XIE Zhao LIU Xiaodong XIE Yongfa ZHANG

Abstract Roselle (Hibiscus Sabdariffa L.) is a tropical and subtropical plant. This paper reviewed the distribution of roselle in China, and the varieties of roselle grown in China. The main chemical components of roselle calyces were listed, and the nutritional health effects and the latest development and utilization of roselle calyx were summarized, in order to provide a reference for better promotion and cultivation of roselle.

Key words Roselle calyx; Planting distribution; Chemical composition; Nutrition

Roselle (Hibiscus Sabdariffa L.) is a tropical and subtropical economic crop. The plants calyces, seeds, stems and leaves all can be used, and the dried or fresh products of calyx are the most valuable. Roselle, also called as Luoshenkui, Hongjiaokui, Shanqizi, Sudanhong, etc., has jagged leaves, scarlet stems and calyces. The calyces are in a cup shape, with five lobes in purplish red. Thats why the plant is called the name roselle. The plant flowers in summer and autumn, and the flowering period is long. The flowers have a purple-red calyx, white petals, and a yellowish corolla. The leaves are green, and the stems are purple-red. In the flowering season, the plants are colorful, red, green, yellow and white alternately, thus known as "plant ruby".

Distribution of Roselle in China

China began to introduce roselle in 1910, mainly distributed in Guangdong, Guangxi, Yunnan, Zhejiang, Sichuan, Jiangxi and other provinces, also planted in Taiwan and Hainan. In 1958-1962, the Shantou Branch of South China Agricultural University introduced it from South China Agricultural University in Guangzhou［1］. It was first introduced to Fujian from 1940 to 1945 and cultivated in Tongan area［2］. In 1964, Fujian Institute of Economic Plants introduced and planted the plant experimentally. A few years later, it was promoted and cultivated in counties including Yongchun, Changtai and Tongan in Fujian Province at small scales［3］. In 1974, Xiamen Import and Export Corporation began to introduce roselle seeds and planted them in Yongchun County and Tongan County［4］. Xinjiang Shihezi Agricultural College introduced roselle from South China Agricultural University in 1987, and the field planting and pot planting were both successful［5］. By 2003, roselle was produced in the Zhangzhou City of Fujian Province, all over Longhai, Zhangpu, Huaan and Changtai, with an annual output of nearly 10 000 t. Zhangpu County of Fujian Province is known as the "hometown of roselle"［6］. Zhangzhou produces roselle with large red calyces, which have become a natural beverage food and medicinal raw material in developed countries such as the United States, Germany, and the United Kingdom. In 1981, Lujiangba, Baoshan City, Yunnan Province introduced it from Fujian Province［7］. In the same period, it was also planted in Jinghong, Yunnan. In 2008, 200 hm2 of roselle was planted along the Jinsha River Valley in Jiyi Township, Wuding County, Chuxiong City, Yunnan Province, and Roselle has become a long-term economic crop for local farmers. In 1985, Nanxiong County of Guangdong Province began to introduce and plant roselle［8］. Miyi County of Sichuan Province began to plant roselle in 1981, and by 1985, the planting area reached  20 hm2［9］. In 1964, the Institute of Subtropical Crops of Zhejiang Academy of Sciences introduced and planted roselle. In 1984, it was planted in Yueqing County, Qixian County, Jinhua City and Wenzhou City of Zhejiang Province［10］. In 1977, Jiangxi introduced roselle seeds from Sultan by foreign aid workers and planted them in Shangrao. By 1985, Jiangxi Province had developed an area of 266.7 hm2［11］. In 1987, there were also productive cultivation in Wuyuan County, Jiangxi and other places［12］. In Hubei Province, it was introduced from Xiamen, Fujian Province in the spring of 1988 to Xiaogan City, Hubei Province［13］. In 2005, roselle "Jinkui 1" was planted in the Rose Science and Technology Experimental Park in the north of Bucheng Town, Danyang  City, Jiangsu Province, with an annual income of 150 000  yuan/hm2［14］. In Hainan Province, roselle is planted in small quantities or distributed occasionally in the wild in the counties and cities including Danzhou, Lingao, Wenchang, Haikou, Wanning, Qiongzhong, Baoting, Sanya and Ledong［15］. In recent years, Hainan Forestry Research Institute has successfully introduced roselle into Haikou area from Zhizhong Town, Ledong County［16］. In 2017, the output of dried roselle calyces in Nanning area of Guangxi was 1 191-1 365 kg/hm2［17］.

Roselle Varieties Planted in China

According to historical records, there are more than 500 roselle varieties. In 1981, the varieties introduced by Institute of Tropical and Subtropical Economic Crops of Yunnan Academy of Agricultural Sciences included Jijiaohongye, Jijiaoluye and Putongye. Putongye has thick and strong stems with many developed branches, and the calyces are hypertrophic, so it is an ideal variety for calyx［7］. According to the use, there are edible roselle species and hemp speceis［18］. According to the size of roselle plant, there are also high roselle and dwarf roselle, of which high roselle is one of the ideal raw materials for papermaking［19］. According to the ripening time of roselle, it can be divided into early-maturing varieties (Festinatus H. sabdariffa), medium-maturing varieties (Modica-maturationis H. sabdariffa) and late-maturing varieties (tardus-maturationis H. sabdariffa)［20］. According to the sources of germplasm, there are African, Sudanese, Egyptian, Senegal, Indian, Thai and Central America strains［21］. There are "Jinkui 1" jointly developed by Nanjing Agricultural University and Bucheng Town and Meiguiqie 1, Meiguiqie 2 and H190 cultivated by Fujian Academy of Agricultural Sciences［22］.

Chemical Composition of Roselle Calyces

After the petals of roselle are withered, the bracts of calyx soon become purple fleshy pieces, enveloping the fruit. Therefore, in life, the mature calyces are often called the "fruit" of roselle. In addition, because the calyces of roselle are bright and dazzling, some people think they are flowers of roselle, which is actually a misunderstanding. Roselle calyces are rich in proteins, organic acids, anthocyanins, vitamins, amino acids, polyphenols, flavonoids, polysaccharides, minerals, cellulose, hemicellulose and a large number of natural pigments. Roselle pigments are anthocyanins, among which the main chemical components are delphinidin-3-sambubioside and cyanidin-3-glucoside chloride which are non-toxic and have no adverse effects［23］. There are 18 kinds of amino acids in roselle calyces, which are aspartic acid, glutamic acid, proline, leucine, lysine, glycine, valine, alanine,  arginine, serine, isoleucine, threonine, tyrosine, histidine, cystine, cysteine, methionine and phenylalanine［24-25］. The organic acids include hydroxycitric acid, citric acid, ligninic acid, malic acid, and tartaric acid, as well as small amounts of oxalic  acid and ascorbic acid［26］. The total phenolic content in the calyces is as high as 474.09 mg/g, and the total flavonoid content is 148.35 mg/g［27］.

The moisture content of fresh calyces in the field is about 90%, and the drying rate is 1/10. For air-dried calyces, the moisture content and the water swelling ratio are 14-15% and 250%, respectively, and the hot water soluble substance is up to 30%［28］. The fresh calyces contain 0.93% of vitamin C, 0.21% of vitamin B, 0.45% of protein, 1.34% of ash, 1.39% of pectin, 87.86% of water, 0.01% of carotene, 1.76% of starch, and 2.55% of sugar (as measured by glucose)［29］. The dried calyces contain 1%-1.5% of total anthocyanins (pigment), 10%-15% of organic acids such as citric acid and hibiscus acid, 16% of reducing sugar, 3.5%-7.9% of protein and 25% of other non-nitrogen-containing substances, 11% of fiber, 12% of ash and about 1% amino acid［30］. The dried roselle calyces also contain a variety of nutrient elements; and the main elements are sodium, potassium, calcium, magnesium, and trace elements including zinc, iron, manganese and copper［31］. The nutrients contained in roselle calyces will have a certain effect on the pharmacodynamic activity.

Nutritional Health Effect of Roselle Calyces

Roselle calyces are rich in nutrients. Because they are rich in polyphenols, flavonoids, polysaccharides, organic acids, amino acids and other chemical components, they have a variety of biological activity and pharmacological effects. Toxicological tests indicate that they are safe to take, so they have higher nutritional health value. Roselle calyx red color is a natural pigment. It is an anthocyanin extracted from roselle calyces. It has natural color, is non-toxic, and has both nutritional and medicinal value. The Ministry of Health of China (86) Fangzi document No. 66 stipulates that natural colorants such as roselle pigments can be used in foods such as beverages, confectionery and prepared wines without limits. Roselle was listed in the list of new raw food materials ingredients by Ministry of Health and National Health and Family Planning Commission of China in 2004.

Lowering blood pressure

Roselle calyces are rich in phenolic pigments and have a good therapeutic effect on hypertension［32］. The prepared medicaments have the advantages of good effect, high safety and strong tolerance［33］. Treatment of hypertension with roselle has been studied at home and abroad. Herrera-Arellano et al.［34］gave 90 patients with mild to moderate hypertension who had not been treated for at least 1 month, aged 30-80 years, 10 g of dried roselle calyx infusion daily after breakfast, and found that, compared with giving  25 mg of antihypertensive drug captopril twice a day, there was no significant difference in antihypertensive effect. In another randomized, double-blind, lisinopril-controlled clinical trial, 193 participants were given a standard roselle preparation containing 250 mg of total anthocyanins or lisinopril 10 mg daily for 4 weeks. The results showed that the standard preparation is an effective antihypertensive agent with good tolerance and safety. Diane L. McKay et al.［35］conducted a clinical trial to study the antihypertensive effect of roselle tea and found that age, gender or food supplement had no effect on the antihypertensive effect of roselle. These results indicate that drinking a proper amount of roselle tea every day can effectively improve blood pressure condition in patients with prehypertension and mild hypertension. In China, Li  et al.［36］studied the antihypertensive effect of Roselle Antihypertensive Tablets (the extract of roselle calyces plus aluminium hydroxide), in 128 patients with hypertension, and there were significant differences between the blood pressure before and after treatment. Zhang［37］studied the antihypertensive effect of dried roselle calyx extract on spontaneously hypertensive rats (SHR) and found that the antihypertensive effect was achieved by lowering ET content and increasing NO content in blood.

Relaxing the bowels, promoting diuresis, discharging urinary calculi

Roselle is widely used as a beverage in African folks for the treatment of constipation and has a good laxative effect. Haruna［38］found that the water extract of roselle calyces contained saponin-like compounds, which had a laxative effect. After feeding mice with 400 and 800 mg/kg of roselle calyx water extract, a moderate-intensity laxative effect was observed, and there was a significant increase in the wetness of the stool of the mice. Mojiminiyi  et al.［39］and CNAguwa et al.［40］confirmed that roselle calyces have diuretic function. Woottisin et al.［41］gave Wistar rats, roselle calyx extract by oral administration every day, and found that the deposition of oxalate and calcium salts in the kidneys was significantly reduced, and a small amount of stones were detected in the urine. Laikangbam［42］also found that roselle calyx water extract can effectively prevent the formation of stones in the kidneys of male rats.

Preventing and treating diabetes and complications

Mozaffari-iKhosravi H et al.［43-44］carried out randomized and controlled clinical trials on 60 patients with diabetes for 1 month. It was proved that the intake of roselle tea can lower blood sugar and regulate blood lipids, and is beneficial to relieve metabolic disorders in diabetic patients, and drinking roselle infusion has a positive effect on type 2 diabetic patients with mild hypertension. Researchers in the Department of Science and Technology of Mexican University of Science and Technology found that various enzymes contained in roselle calyx extract can decompose glucose, thereby reducing blood sugar［45］, which is similar to the principle of injecting insulin in diabetic patients. Experiments have shown that although the human body can not completely obtain this biological enzyme by drinking roselle flower tea, it can actually reduce the blood sugar concentration to a certain extent. Roselle tea is a high-quality health drink for diabetic patients.

Preventing cardiovascular disease, lowering cholesterol

Roselle calyces contain anthocyanins, isoflavones, flavonoids, protocatechuic acid, abundant organic acids and amino acids, which can lower triglycerides and cholesterol and inhibit the oxidation of low-density lipoproteins. Meanwhile, they can reduce atherosclerosis and reduce thrombosis, and have an effective preventive effect on the occurrence of cardiovascular diseases.   Lin et al.［46］conducted a cholesterol-lowering clinical trial on 42 volunteers aged 18-75 years with a roselle calyx extract capsule preparation. After 2 weeks of treatment, serum cholesterol decreased by 7.8%-8.2%, and after 4 weeks of treatment, serum cholesterol decreased by 8.3%-14.4%. Chen et al.［47］studied the inhibition of arteriosclerosis in white rabbits by a roselle calyx extract. The results showed that administrating white rabbits with the roselle calyx extract exhibited the activity of lowering blood fat and inhibiting arteriosclerosis. Chen et al.［48］also found that mice taking the roselle calyx extract exhibited the effects of reducing cholesterol level and preventing hyperlipidemia.

Promoting uric acid-excreting effect

Prasongwatana et al.［49］studied the promoting effects of roselle on uric acid excretion in 9 patients with no history of kidney stones and 9 patients with history of kidney stones. After 15 d of giving each patient 1.5 g of dried roselle calyx tea each time, twice in the morning and evening, the oxalate, citrate and uric acid excretion and clearance rates of the two groups tended to increase, and the uric acid excretion and clearance rate of participants with stone history increased significantly.

Preventing and treating heavy metal poisoning

Xu et al.［50］used mice to investigate the decorporation effect of roselle calyx extract of lead (II) salt. When the daily dose (calculated with hibiscus acid) reached 300 mg/kg, the decorporation rate of lead (II) salt was doubled. It can improve the initial reaction of chronic lead poisoning at the initial stage, and the urban residents who suffer from severe lead poisoning caused can take the roselle calyx extract as a health drink. The aqueous extract of roselle calyx plays a protective role in cadmium poisoning. Through chronic exposure of rats to cadmium-contaminated environment, it can be seen by detecting alanine aminotransferase in rat plasma and alanine aminotransferase and aspartate aminotransferase activity in liver that roselle calyx extract can significantly reduce liver toxicity caused by cadmium［51］.

Antimicrobial and anti-anemia effects

Studies have shown that the aqueous extract of roselle calyx can significantly inhibit the growth of Staphylococcus aureus, Salmonella typhimurium, Escherichia coli and Pseudomonas aeruginosa, and this antimicrobial activity is independent of external temperature［52-54］, which might be related to its high content of catechins. This is a testament to the fact that residents in the tropics drink roselle to prevent intestinal diarrhea. The water decoction of roselle calyx has a good effect on mineral deficiency and anemia, and increases the concentration of ascorbic acid in the blood, thereby enhancing the absorption of iron, zinc, calcium and magnesium ions［55］. In some places, roselle is called "red peach K" in the folk.

Xuefang XIE et al. A Review of the Nutritional Health Effects of Roselle (Hibiscus sabdariffa L.) calyce

Conclusions and Prospect

In summary, roselle calyces have rich nutrients and good medicinal health functions, and are very beneficial to human health. Roselle calyces have been widely accepted as a medicinal material for health care at home and abroad, and have been widely studied. The hibiscus acid, anthocyanins, polyphenols, flavonoids, and polysaccharides contained in the flower calyces have important health effects for human body, and they are an edible material with good color, aroma and taste. Whether as a food development material or a medicinal material, it is in line with modern peoples pursuit of natural, green and health care. With the gradual improvement of peoples material living standards, the products related to roselle calyces will receive more and more attention and favor, and have good development prospects in the beverage, food and pharmaceutical industries. Adding roselle calyces to foods can not only improve the color and taste of the food, but also can give foods a certain health care function. In particular, the clinical application of related products of roselle calyces in the fields of hypertension and hyperlipidemia is more important for contemporary people. Vigorously developing the roselle industry and improving the products and quality of roselle cultivation are of great significance to promoting rural economic development and increasing farmersincome.

References

［1］LIANG QM. Introducing an emerging economic plant roselle (Hibiscus subdariffa L.)［J］. Journal of Hanshan Normal University, 1982(1):  18-19. (in Chinese)

［2］BU S. Introduction of roselle［J］. Tianjin Food Research, 1982(3):  31-32. (in Chinese)

［3］Tropical Crop Laboratory, Fujian Institute of Economic Plants. Introducing a tropical economic plant——roselle (Hibiscus subdariffa L.)［J］. Subtropical Plant Science, 1974(2): 24-25. (in Chinese)

［4］LI SH, GUAN LQ. Multi-use roselle (Hibiscus subdariffa L.)［J］. Plants, 1980(5): 13. (in Chinese)

［5］ZHOU NY, HU Y. The introduction of Hibiscus subdariffa L. was first successful［J］. Journal of Shihezi University: Natural Science, 1988(2): 82. (in Chinese)

［6］XU LC. Harvest of Zhangpu roselle (Hibiscus subdariffa L.)［J］. China Flower & Penjing, 1988(3): 18-19. (in Chinese)

［7］Institute of Tropical and Subtropical Economic Crops, Yunnan Academy of Agricultural Sciences. Cultivation of roselle (Hibiscus subdariffa L.)［J］. Yunnan Agricultural Science and Technology, 1984(3): 45-46; 22. (in Chinese)

［8］LI M. Roselle (Hibiscus subdariffa L.) settled in Nanxiong County［J］. Guangdong Forestry Science and Technology, 1985(12): 2. (in Chinese)

［9］LU BY, ZHOU JB. Analysis on the adjustment of planting structure in Miyi County［J］. Rural Economy, 1986(1): 24-25. (in Chinese)

［10］ZHANG XC, ZHANG ZH. Preliminary report on introduction and cultivation of new food and beverage plant roselle (Hibiscus subdariffa L.)［J］. Journal of Zhejiang Agricultural Sciences, 1986(5): 243-244. (in Chinese)

［11］LIN MX, ZOU SS. Discussion on introduction of roselle (Hibiscus subdariffa L.) in Jiangxi［J］. China Journal of Chinese Materia Medica, 1989(7): 17-19. (in Chinese)

［12］ZHANG RW, ZOU SH. Roselle (Hibiscus subdariffa L.)——medicine and food plant［J］. Jiangxi Journal of Traditional Chinese Medicine, 1988(1): 34. (in Chinese)

［13］MAO GX, ZHANG GF. Cultivation of roselle (Hibiscus subdariffa L.)［J］. Special Wild Economic Animal and Plant Research, 1989(4): 51. (in Chinese)

［14］SHI R. African "Roselle" (Hibiscus subdariffa L.) is a good helper for becoming rich［J］. Farmers get rich, 2005(23): 13. (in Chinese)

［15］CHEN ZL. Roselle (Hibiscus subdariffa L.) ——New resources for food and medicine［J］. Natural Science Journal of Hainan University, 1986(12): 70-71. (in Chinese)

［16］LIU B, LI GY, GUAN XJ. Introduction and cultivation techniques of roselle (Hibiscus subdariffa L.) in Haikou［J］. Tropical Forestry, 2013(12): 14-16. (in Chinese)

［17］TANG XF, LI CY, ZHAO YH, et al. Roselle introduction trial in Nanning of Guangxi［J］. Southern horticulture, 2017, 28(3): 13-16. (in Chinese)

［18］HUAI ZP. Roselle (Hibiscus subdariffa L.) ［J］. Crops, 1986(3): 21. (in Chinese)

［19］NAWARAT, SERMSRI, CHEN HX. Study on cultivation of Hibiscus sabdariffa var. altissima［J］. Subtropical Plant Science, 1989(2):  59-60. (in Chinese)

［20］GAO H. Study on the differences of physiological and biochemical characteristics of different varieties of roselle (Hibiscus subdariffa L.)［D］. Fuzhou: Fujian Agriculture and Forestry University, 2012. (in Chinese)

［21］KHAFAGA ER, KOEH H, Angewandte Botanik, 1980, 54(5-6): 257-293.

［22］YU JY. Chracteristics and high yield cultivation technical points of roselle ‘H190’［J］. Southeast Horticulture, 2015(2): 58-59. (in Chinese)

［23］LI QS, ZENG JL, XU PP, et al. Study on physicochemical properties and extraction process of roselle red color［J］. Journal of Xiamen University: Natural Science, 1996(6): 923-927. (in Chinese)

［24］JF M. roselle. In Fruits of warm climates. Morton, Miami; 1987:  281-286.

［25］GLEW RH, VANDERJAGT DJ, LOCKETT C, et al. Amino acid, fatty acid, and mineral composition of 24 indigenous plants of Burkina Faso［J］. J Food Comp Anal, 1997, 10(3): 205-221.

［26］ZENG HT, XU X, ZHUO RS. The chemical composition of roselle (Hibiscus subdariffa L.) and its utilization［J］. Subtropical Plant Science, 1980(1): 8-18. (in Chinese)

［27］FORMAGIO ASN, RAMOS DD, VIEIRA MC, et al. Phenolic compounds of Hibiscus sabdariffa and influence of organic residues on its antioxidant and antitumoral properties［J］. Brazilian Journal of Biology, 2015, 75(1): 69-76.

［28］CHEN JB, JI Y, ZHAO SJ. Study on comprehensive utilization of roselle (Hibiscus subdariffa L.) calyces［J］.  Tropical Agricultural Science & Technology, 1987(2): 22-24. (in Chinese)

［29］LI SF, LIU XM, ZHU ZW, et al. Development and utilization of roselle (Hibiscus subdariffa L.) resources［J］. Food Science and Technology, 2003(6): 86-88. (in Chinese)

［30］JU YD, WU WJ. The chemical constituents of roselle (Hibiscus subdariffa L.) and its comprehensive utilization［J］. Chinese Horticulture Abstracts, 2009(12): 171-172. (in Chinese)

［31］LI ZM, DENG L, LIU SY. Analysis research on the nutritive elements composition of the roselle［J］. Chinese Wild Plant Resources, 2008(2): 61-62. (in Chinese)

［32］WU LL. Pharmacokinetic study of anthocyanin-3-glycoside after ingestion of roselle extract［J］. World Notes Plant Med, 2006, 21(1): 35-37. (in Chinese)

［33］HU KZ. Clinical trial of standard extract of roselle (Hibiscus subdariffa L.) in the treatment of hypertension［J］. World Notes Plant Med, 2007, 22(6): 273-274.

［34］HERRERA-ARELLANO A, FLORES-ROMERO S, CHAVEZ-SOTO MA, et al. Effectiveness and tolerability of a standardized extract from Hibiscus sabdariffa in patients with mild to moderate hypertension: A controlled and randomized clinical trial［J］. Phytomedicine, 2004, 11(5): 375-382.

［35］MCKAY DL, CHEN CYO, SALTZMAN E, et al. Hibiscus Sabdariffa L. tea (Tisane) lowers blood pressure in prehypertensive and mildly hypertensive adults［J］. J. Nutr. February 2010, 140(2): 298-303.

［36］LI YS,M HE QC, HUANG XC. Observation on the short-term curative effect of 128 cases of hypertension treated with roselle (Hibiscus subdariffa L.)［J］. Fujian Medical Journal, 1979(4): 64. (in Chinese)

［37］ZHANG SN. Experimental study on blood pressure lowering effect of roselle extract［J］. Journal of Practical Traditional Chinese Medicine, 2015(1): 2-4. (in Chinese)

［38］HARUNA AK. Cathartic Activityof soborodo:The aqueous extract of calyx ofHibiscus sabdarifa L［J］. Phytotherapy Research, 1997(1): 307-307.

［39］MOJIMINIYI FBO, ADEGUNLOYE BJ, EGBENIYI YA, et al. An investigation of the diuretic effect of an aqueous extract of thepetals of Hibiscus sabdariffa［J］. Journal of Medicine and Medical Sciences, 2000(2): 77-80.

［40］AGUWA CN, NDU OO, NWANMA CC, et al. Verification of the folkloric diuretic claim of Hibiscus sabdariffa L. petal extract［J］. Nig. J. Pharm. Res., 2004, 3(1): 1-8.

［41］WOOTTISIN S, HOSSAIN RZ, YACHANTHA C, et al. Effects of Orthosiphon grandiflorus, Hibiscus sabdariffa and Phyllanthus amarus extracts on risk factors for urinary calcium oxalate stones in rats［J］. J Urol, 2012, 76 (4): 646-651.

［42］LAIKANGBAM R, DEVI MD. Inhibition of calcium oxalatecrystal deposition on kidneys of urolithiatic rats by Hibiscus sabdariffa L. extract［J］. Urol Res, 2012, 40(3): 211-218.

［43］MOZAFFARI- KHOSRAVI H, JALALI- KHANABADI BA, AFKHAMI-ARDEKANI M, et al. Effects of sour tea (Hibiscus sabdariffa)on lipid profile and lipoproteins in patients with typeòdiabetes ［J］. J Altern Complement Med, 2009, 15(8): 899-903.

［44］MOZAFFARI- KHOSRAVI H, JALAL-I KHANABADI BA, AFKHAMI-ARDEKANI M, et al. The effects of sour tea (Hibiscus sabdariffa) on hypertensive in patients with type II diabetes［J］. J Hum Hypertens, 2009, 23(1): 48-54.

［45］LI XF, ZHU JJ, ZHANG JF, et al. Reviews of roselle introduction cultivation and application［J］. Acta Agriculturae Shanghai, 2015, 31(5): 136-139. (in Chinese)

［46］LIN TL, LIN HH, CHEN CC, et al. Hibiscus sabdariffa extract reduces serum cholesterol in men and women ［J］. Nutr Res, 2007, 27(3):  140-145.

［47］CHEN CC, HSU JD, WANG SF, et al. Hibiscus sabdariffa extract inhibits the develop-ment of atherosclerosis in cholesterol-fed rabbits ［J］. J Agric FoodChem., 2003(51): 5472-5477.

［48］CHEN CC, CHOU FP, HO YC, et al. Inhibitory effects of Hibiscus sabdariffa L extract on low-density lipoprotein oxidation and anti-hyperlipidemia in fructose-fed and cholesterol- fed rats［J］. J Sci Food Agric, 2004(84): 1989-1996.

［49］PRASONGWATANA V, WOOTTISIN S, SRIBOONLUE P, et al. Urico-suric effect of Roselle (Hibiscus sabdariffa) in normal and renal stone former subjects ［J］. J Ethnopharmacol, 2008, 117(3): 491-495.

［50］XU GS, CHEN WQ. The decorporation effect of roselle (Hibiscus sabdariffa) calyces on lead (II) salt［J］. Journal of Huaqiao University: Natural Science, 1987(11): 406-411. (in Chinese)

［51］ASAGBA SO, ADAIKPOH MA, KADIRI H, et al. Influence of aqueous extract of Hibiscus sabdariffa L. petal on cadimiumtoxicity  in  rats［J］. Biol Trace Elem Res, 2007, 115(1): 47-57

［52］AFOLABI OC, OGUNSOLA FT, COKER AO. Susceptibility of cariogenic Streptococcus mutants to extracts of Garcinia kola, Hibiscus sabdariffa, and Solanum americanum［J］. WEST AFＲIC J MED, 2008, 27(4) : 230．

［53］CHAO CY, YIN MC. Antibacterial effects of roselle calyxextracts and protocatechuic acid in ground beef and applejuice［J］. Foodborne Path ＆ Dis, 2009, 6(2) : 201-206．

［54］LIU K, TSAO S, YIN M. In vitro antibacterial activity of rosellecalyx and protocatechuic acid［J］. Phytotherapy Res, 2005, 19(11) : 942-945．

［55］FALADE OS, OTEMUYIWA IO, OLADIPO A, et al. The chemicalcomposition and membrane stability activity of some herbs used in local therapy for anemia［J］. J Ethnopharmacol, 2005, 102(1): 15-22.

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