Phytochemistry and Pharmacology of Fagopyrum Dibotrys (D. Don) H

Review

Phytochemistry and pharmacology of Fagopyrum dibotrys (D. Don) H. Hara: A review

Hong-Sheng Ruan a,b *, Ling Cao c, Zhi-Bao Chen a, Gui-Yan Jia a, Xiao-Liang Zheng a, and Xue- Gong Qin a aLife Science and Technology College, Heilongjiang Bayi Agricultural University, Daqing, Hei long jiang, 163319, China. bInstitute of Traditional Chinese Medicine, Heilongjiang University of Traditional Chinese Medicine, Haerbin, Hei long jiang, 150040, China. cThe Fifth Hospital Attached Haerbin Medical University, DaQing, Hei long jiang, 163317, China.

Accepted 11 April, 2012

Fagopyrum dibotrys (D. Don) H. Hara, a widely used traditional Chinese herb, belongs to the family of Polygonaceae , and possesses a wide range of ethnomedicinal uses. In recent decades, a great number of chemical and pharmacological studies have been done on F. dibotrys . More than 80 compounds including flavonoids, organic acids, sterides, essential oil and amino acids, as well as vitamins have been found in the herb, with many of them being isolated for the first time from Fagopyrum Mill . Currently, the effective compounds or effective parts have been screened for the pharmacological activity of this herb to exhibit anti-tumor effect, anti-inflammatory, analgesic, antibacterial and other activities. This review aims at providing a comprehensive work about the phytochemistry and pharmacological action of F. dibotrys . Future efforts should concentrate more on in vitro or in vivo studies and clinical trials in order to confirm traditional uses. Especially, the efficacy of F. dibotrys should be further researched in the treatment of anti-tumor and lung abscess.

Key words: Fagopyrum dibotrys , phytochemistry, pharmacological action.

INTRODUCTION

Fagopyrum dibotrys (D. Don) H. Hara (Figure 1) belongs first cited in Dian Nan Ben-Cao (1436 a.d., Ming to the genus Fagopyrum and family Polygonaceae , a Dynasty), a classical masterpiece of Traditional Chinese widely distributed genus. Wild species of Fagopyrum Medicine (TCM). The traditional uses recorded for this grows best in the temperate and hilly regions of countries herb are numerous, and mainly medicinal (Liu et al., in China, India, Nepal, Vietnam, Thailand and the 1981; Xu et al., 1982; Samaiya and Saxena,1989; Zhang Himalayan region (lian, 1998; Wu et al., 2010). et al.,1999; Zhao et al., 2002; Huang, 2008; Jinqiaomai, the roots of this herb, is one of the most Pharmacopoeia Commission of People’s Republic of commonly used traditional Chinese herbs, and is also China, 2010). Several kinds of Chinese pharmaceutical widely accepted as a health product in the Western preparations have been developed, including capsules, countries in recent years, owing to its remarkable and tablets and syrups. In brief, jinqiaomai and jinqiaomai- reliable biological activities, especially in the treatment of containing medicinal preparations are now receiving lung ailments (Liu et al., 1981; Gao and Meng, 1993; considerable attention worldwide, and many scientific Peng et al., 1996). The therapeutic use of the herb was studies have been carried out in chemistry, clinical trial,

*Corresponding author. E-mail: [email protected]. Fax: 186-459-6819297. Ruan et al. 2793

safety, as well as in pharmacology. the volatile fraction. The seeds of the herb possess 18 In recent decades, researches on this genus, mainly amino acids, a number of essential inorganic substances based on its botanical, phytochemical and pharmacolo- and vitamins, such as, asparaginic acid, threonine, gical aspects have taken place. Due to the variability in glutamic acid, serine, sodium, calcium, selenium, the thematic of the studies and the extension of this vitamins B 1, B 2, VPP, VP, etc. (Zhang et al.,1999; Zhao et genus, the purpose of this review is to summarize the al., 2002; Wang et al.,2011). The content of glutamic acid phytochemistry and pharmacological properties of this is the highest. A range of other compounds have also herb in order to facilitate and guide future researches. been isolated from the herb along with the aforementioned constituents, including glycerol monop- almitate, n-butyl-β-D-fructopy-ronoside, glutinol (Shao et PHYTOCHEMISTRY al., 2005), glutinone (Shao et al., 2005; Zhao et al., 2011), daucosterol, 5,5′ -di-α-furaldehyde dimethyl ether, (Tian et The phytochemical study of F. dibotrys can be dated back al.,1997), eriodictyol, acid-4-o-glucoside, p-hydroxyl- to 1951 with rutin first isolated from the plant (Imai and benzaldehyde, Furuya, 1951). So far, more than 80 compounds have 3,5-dimethoxy benzene carbonic, N-trans-coumaroyl been separated and structurally identified from this herb, tyramine, emodin (Zhao et al., 2011), and shakuchirin (Liu among them, flavonoids and organic acid are with the et al., 1998). largest content, in fact, they are the main components In addition, luteolin (1), pratol (2), rhamnetin (3), responsible for the pharmacological activity (Gonzalez et luteolin-7,4′ -dime-thylethe (4), 3,6,3′,4′ -tetrahydroxy-7- al., 2011). methoxyflavon (5), hesper-idin (6), 3,4-dihydroxy Recently, from the polar extracts of the roots of benzamide (7), protocatechuic acid methyl ester (8), cultivated F. dibotrys , some new flavonoids compounds glutinone (9), glutinol (10), n-butyl-β-D-fructopy-ronoside have been isolated, to which was given the trivial names (11), trans-p-hydroxy cinnamic methyl ester (12), luteolin (Shao et al., 2005), rutin (Imai and Furuya, 1951; eriodictyol (13), 3,5-dimethoxy benzene carbonic acid-4- Tian et al., 1997; Wang et al., 2005), quercetin (Tian et O-glucoside (14), and N-trans-coumaroyl tyramine (15) al., 1997; Zhao et al., 2011), isorhamnetin, quercitrin are isolated from Fagopyrum Mill genus for the first time. (Tian et al., 1997; Zhao et al., 2011), pratol, luteolin-7,4′ - Syringic acid (16) is isolated from this plant for the first dime-thylether, rhamnetin, 3,6,3′,4′ -tetrahydroxy-7- time. The structures of the major components (1 to 16) methoxyflavon (Wu et al., 2008), and hesperidi (Yan et are depicted in Figure 2. al., 2006). Meanwhile, 3,4-dihydroxybenzoic acid, gallicacid, (-)-epicatechin, (-)-epicatechin-3-O-gallate acid ester, procyanidin B-2, and procyanidin C-1 from the Pharmacological action alcoholic extract of the plant were isolated (Zhang et al., 1994). The main component was procyanidin B-2 Anti- tumor effect

(0.19%). 5,7,3',4'-tetrahydroxyflavan-3-oldimmer was also Many in vivo and in vitro experiments have demonstrated isolated from F. dibotrys (Liu et al., 1983). that Fr4 is regarded to be the most promising anticancer Organic acids have been known to be important compound in F. dibotrys (Ling et al., 1996; Chen et al., constituents of this herb. Four phenolic acid derivatives 2000, 2002, 2003, 2005, 2006). The main anti-tumor were isolated from the plant. The chemical structures constituent is 5,7,3',4'-tetrahydroxyflavan-3-oldimmer were elucidated as trans-p-hydroxy cinnamic methyl (Figure 1) (Liu et al.,1983). Down regulation of the ester, 3,4-dihydroxy benzamide, protocatechuic acid, and telomerase activity in tumor cells might be contributed to protocatechuic acid methyl ester (Shao et al., 2005). Fr4 induced apoptosis. At the same time, component (E) Benzoic acid, p-hydroxy-benzoic acid (Tian et al., 1997), is the most active agent against the DNA of cancer cells succinic acid (Tian et al., 1997; Zhao et al., 2011), and among the extracts from F. dibotrys (Ma et al., 1989). syringic acid (Zhao et al., 2011) have also been isolated Component (E) inhibits cancer cell growth by directly or from this herb. Moreover, diboside A and lapathoside A indirectly influencing the metabolism of DNA, especially in from acetone-water mixture extract of root of F. dibotrys low concentrations and probably plays the major role. were isolated by Wang et al. (2005). At the same time, Moreover, the extract has notable inhibitory effects steride compounds were isolated from the roots of F. against tumor invasion and metastasis (Liu and Han, dibotrys, such as hecogenin (Liu et al., 1983), β -sitosterol 1998) (Liu et al., 1983; Tian et al., 1997; Wu et al., 2008; Zhao et al., 2011) and β-daucosterol (Yan et al., 2006; Zhao et al., 2011). Extraction of essential oil from F. dibotrys by Anti-inflammatory and analgesic activity using steam distillation and analysis by GC-MS identified 43 compounds (Bai et al., 2007). Among the 43 species, An organic extract from this herb presented topical anti- there were 13 kinds of hydrocarbon compounds and 30 inflammatory activity on chronic inflammation in animal oxygenated hydrocarbon derivatives. N-hexadecanoic models (Cheng et al., 2009). Additionally, the extract acid was the main constituents, accounting for 10.34% of markedly decreased the amount of mice which had 2794 J. Med. Plants Res.

HO O OH

OH OH OH

HO O OH

5,7,3',4'-tetrahydroxyflavan-3-oldimmer Fagopyrum dibotrys (D. Don) H. Hara 1. Branch; 2. Tuberous root

Figure 1. The branch and root of Fagopyrum dibotrys (D.Don) H. Hara and the chemical structure of 5,7,3',4'- tetrahydroxyflavan-3-oldimmer.

tortility and the number of twisting body provoked by Klebsiella pneumonia is related to toll-like receptor2/4 diethylstilbestrol and oxytocin. It also reduced the tension (TLR2/4), myeloid differentiation primary response gene of isolated mouse uterus stimulated by oxytocin (Jia et (88) (MyD88) mRNA and nuclear factor kappa B inhibitor al., 2010). protein ( IκB -α). A decrease in the excessive expression Another study demonstrated that the extract (dose of of TLR2/4, MyD88 mRNA and IκB -α might be obtained by 0.45 to 1.8 g/kg) restrained mouse ear swelling the effect of F. dibotrys on lung injury (Dong et al., 2011). significantly (Bao et al., 2009). In humans, there is a On the other hand, in vitro antibacterial test result demon- claim in the traditional folklore of using it in the treatment strated that the extract showed remarkable inhibition to of lumbago, diarrhea, menstrual pains, postpartum the beta-hemolytic Streptococcus and Pneumococcus , abdominal pains and stomachache (Zhang et al., 1999; but proved weak antimicrobial effect to S. aureus and Zhao et al., 2005). Pseudomonas aeruginosa and was ineffective against K. pneumoniae and E. coli . The protection in vivo to the mice infected with Streptococcus pneumoniae by the Antibacterial activity extract’s effects on bacteria was obvious (Wang et al., 2005). Phenolic acids and flavonoids compounds were The results indicated that all the extracts have strong the major base of antimicrobial function (Wang et al., antibacterial activities in vitro , and the extracts have high 2005). In spite of these recent studies, the identity of the inhibition on Staphylococcus aureus, Escherichia coli, active antibacterial ingredients of F. dibotrys as well as its Bacillus subtilis, Bacillus thuringiensis, Diplococcus mechanisms of action is still questionable. Catarrhalis, Sclerophthora macrospora, Candida albicans, Pestalotia funereal, Rhizoctonia solani, Sclerotinia sclerotiorum, Curvularia lunata (walk) boed, Other pharmacological action Gibberelle zeae (schw) and Trichoderma viride (Feng et al.,2006). Furthermore, ethanol extracts exhibited a wide Within the concentration of 20 to 60 g/kg, the extract spectrum of antibacterial activity, thus confirming the could significantly decrease the activities of rat serum previous result (Ai et al., 2002). alanine transaminase (ALT), and aspartate transaminase Other study concluded that the lung injury induced by (AST), and was capable of protecting the liver from Ruan et al. 2795

OH B A HO O HO O OCH3 OH

O OH O luteolin pratol

OH OH C D H3CO O H3CO O OH OCH3

OH O OH O rhamnetin luteolin-7,4′-dime-thylether

E OH F OH esonitur-O O H3CO O OCH OH 3

HO OH

OH O O 3,6,3′,4′-tetrahydroxy-7-methoxy flavon hesperidi

OH G OH H O H2N OH OH O O

3,4-dihydroxy benzamide protocatechuic acid methyl ester

Figure 2. The structures of the major components; a) luteolin, b) pratol, c) rhamnetin, d) luteolin-7,4′ -dime-thylethe, e) 3,6,3′,4′ - tetrahydroxy-7-methoxyflavon, f) hesper-idin, g) 3,4-dihydroxy benzamide, h) protocatechuic acid methyl ester, i) glutinone, j) glutinol, k) n-butyl-β-D-fructopy-ronoside, l) trans-p-hydroxy cinnamic methyl ester, m) eriodictyol, n) 3,5-dimethoxy benzene carbonic acid-4-O- glucoside, o) N-trans-coumaroyl tyramine, p) syringic acid. 2796 J. Med. Plants Res.

I J

H H H H H H

O HO

glutinone glutinol

K OHOH L O OHO H HO OCH2CH2CH2CH3 H H CH2OH O OH H

n-butyl-β-D-fructopy-ronoside trans-p-hydroxy cinnamic methyl ester

OH M N OGlu HO O OCH3 OH H3CO

OH O COOH eriodictyol 3,5-dimethoxy benzene carbonic acid -4-O -glucoside

O HO P O

H HO N OH

O O OH O N-trans-coumaroyl tyramine Syringic acid

Figure 2. Contd. Ruan et al. 2799

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