Chemical composition and product quality control of turmeric (Curcuma longa L.) - CORE

[Pages:29]Stephen F. Austin State University

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2011

Chemical composition and product quality control of turmeric (Curcuma longa L.)

Shiyou Li

Stephen F Austin State University, Arthur Temple College of Forestry and Agriculture, lis@sfasu.edu

Wei Yuan

Stephen F Austin State University, Arthur Temple College of Forestry and Agriculture, yuanw@sfasu.edu

Guangrui Deng

Ping Wang

Stephen F Austin State University, Arthur Temple College of Forestry and Agriculture, wangp@sfasu.edu

Peiying Yang

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Li, Shiyou; Yuan, Wei; Deng, Guangrui; Wang, Ping; Yang, Peiying; and Aggarwal, Bharat, "Chemical composition and product quality control of turmeric (Curcuma longa L.)" (2011). Faculty Publications. Paper 1.

This Article is brought to you for free and open access by the Agriculture at SFA ScholarWorks. It has been accepted for inclusion in Faculty Publications by an authorized administrator of SFA ScholarWorks. For more information, please contact cdsscholarworks@sfasu.edu.

Authors Shiyou Li, Wei Yuan, Guangrui Deng, Ping Wang, Peiying Yang, and Bharat Aggarwal

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28

Pharmaceutical Crops, 2011, 2, 28-54

Open Access

Chemical Composition and Product Quality Control of Turmeric (Curcuma longa L.)

Shiyou Li*,1, Wei Yuan1, Guangrui Deng1, Ping Wang1, Peiying Yang2 and Bharat B. Aggarwal3

1National Center for Pharmaceutical Crops, Arthur Temple College of Forestry and Agriculture, Stephen F. Austin State University, Nacogdoches, TX 75972, USA 2Department of General Oncology, Integrative Medicine Program, M.D. Anderson Cancer Center, University of Texas, Houston, TX 77030, USA 3Cytokine Research Laboratory, Department of Experimental Therapeutics, M.D. Anderson Cancer Center, University of Texas, Houston, TX 77030, USA

Abstract: Chemical constituents of various tissues of turmeric (Curcuma longa L.) have been extensively investigated. To date, at least 235 compounds, primarily phenolic compounds and terpenoids have been identified from the species, including 22 diarylheptanoids and diarylpentanoids, eight phenylpropene and other phenolic compounds, 68 monoterpenes, 109 sesquiterpenes, five diterpenes, three triterpenoids, four sterols, two alkaloids, and 14 other compounds. Curcuminoids (diarylheptanoids) and essential oils are major bioactive ingredients showing various bioactivities in in vitro and in vivo bioassays. Curcuminoids in turmeric are primarily accumulated in rhizomes. The essential oils from leaves and flowers are usually dominated by monoterpenes while those from roots and rhizomes primarily contained sesquiterpenes. The contents of curcuminoids in turmeric rhizomes vary often with varieties, locations, sources, and cultivation conditions, while there are significant variations in composition of essential oils of turmeric rhizomes with varieties and geographical locations. Further, both curcuminoids and essential oils vary in contents with different extraction methods and are unstable with extraction and storage processes. As a result, the quality of commercial turmeric products can be markedly varied. While curcumin (1), demethoxycurcumin (2), and bisdemethoxycurcumin (5) have been used as marker compounds for the quality control of rhizomes, powders, and extract ("curcumin") products, Ar-turmerone (99), -turmerone (100), and -turmerone (101) may be used to control the product quality of turmeric oil and oleoresin products. Authentication of turmeric products can be achieved by chromatographic and NMR techniques, DNA markers, with morphological and anatomic data as well as GAP and other information available.

Keywords: Turmeric, Curcuma longa L., rhizomes, ground turmeric, turmeric oils, turmeric oleoresin, curcuminoids, curcumin, sesquiterpenes, marker compounds, adulteration, standardization.

INTRODUCTION

Turmeric (Curcuma longa L.) is a rhizomatous herbaceous perennial plant of the ginger family, Zingiberaceae. It is native to tropical South Asia but is now widely cultivated in the tropical and subtropical regions of the world. The deep orange-yellow powder known as turmeric is prepared from boiled and dried rhizomes of the plant. It has been commonly used as spice and medicine (Rhizome Curcumae Longae), particularly in Asia. In Ayurveda medicine, turmeric is primarily used as a treatment for inflammatory conditions and in traditional Chinese medicine, it is used as stimulant, aspirant, carminative, cordeal, emenagogue, astringent, detergent, diuretic and martirnet [1-3]. In India and China, wild turmeric (C. aromatica Salisb., commonly called as Kasthuri manjal or yujin) is sometimes used as turmeric production [4]. This species is known as C. wenyujin Y.H. Chen et C. Ling in China. It was also occasionally used to substitute Rhizome Curcumae

*Address correspondence to this author at the National Center for Pharmaceutical Crops, Arthur Temple College of Forestry and Agriculture, Stephen F. Austin State University, Nacogdoches, TX 75972, USA; Tel: 936-468-2071, 936-468-5600; Fax: 936-468-7058; E-mail: lis@sfasu.edu

Longae but recently it has been separated as Rhizoma Wenyujin Concisum in the 2005 version of the Pharmacopoeia of People's Republic of China [5]. In Thailand and some other countries, C. domestica Val. is also used as the scientific name of turmeric [6-8] although it is recognized as a synonym of C. longa [9].

There are extensive in vitro and in vivo investigations on turmeric extracts (ethanol, methanol, water, and ethyl acetate extracts) or "pure" active "curcumin" (actually it was a mixture of three major curcumnnioids in many cases) powder over the last half century. The role of curcumin (1), one of the most studied chemopreventive agents, on antiinflammatory and cancer activity has been well appreciated [3, 10-19]. Data from cell culture, animal research, and clinical trials indicate that curcumin may have potential as a therapeutic agent in diseases such as inflammatory bowel disease, pancreatitis, arthritis, and chronic anterior uveitis [3, 20]. The anti-cancer effect has been reported in a few clinical trials, mainly as a chemoprevention agent in colon and pancreatic cancer, cervical neoplasia and Barrets metaplasia [16]. The compound modulates several molecular targets and inhibits transcription factors (NF-kB, AP-1), enzymes (COX-1, COX-2, LOX), cytokines (TNF, IL-1, IL-6) and

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2011 Bentham Open

Chemical Composition and Product Quality Control of Turmeric (Curcuma longa L.)

Pharmaceutical Crops, 2011, Volume 2 29

antiapoptotic genes (BCL2, BCL2L1) [21-24]. As a result, curcumin (1) is able to induce apoptosis and has antiangiogenic activity [25, 26].

Turmeric extracts or the active curcuminoids have also shown hepato- and cardioprotective [27, 28], hypoglycemic [29, 30], anti-amyloidogenic [31], antifungal [32], parasiticidal [33, 34], antioxidant [35, 36], and chemo-resistance and radio-resistance activities [16]. Recent in vitro and in vivo studies and clinical trials in China and USA suggest that curcumin might be one of the most promising compounds for the development of Alzheimer's disease therapies [37]. Accumulating evidences suggest that curcumin (1) may regulate lipid metabolism, which plays a central role in the development of obesity and its complications [38]. Recently, it was found that curcumin (1) and demethoxycurcumin (2) can reduce lead-induced memory deficits in rates [39]. Turmeric oils/oleoresin or a major compound ar-turmerone (99) have shown antimicrobial [40-43], larvicidal [44], and antioxidant activities [45]. Essential oils of Curcuma also exerts triglyceride-lowering activity on serum as well as liver triglycerides [46].

Curcuma longa is often cultivated to harvest rhizomes (Fig. 1) for ground turmeric powder as a spice and food coloring agent (used alone or in mustard paste or curry powder). The plant has also been recognized as a pharmaceutical crop for production of standardized therapeutic extracts (STEs) or small therapeutic molecules (STMs) [47]. India is the largest producer of turmeric supplying over 90% of the world's demand [48]. The country produced about 716,900 Mt of turmeric from approximately 161,300 hectares of crops during 2004-2005 [49]. China also has cultivated turmeric for both domestic use and export. There are about 70 cultivars or varieties of C. longa cultivated in India, some important regional trade varieties of turmeric are `Rajapuri', `Duggirala', `Cuddappah', `Berhampur', `Erode', `Nizamabad', `Koraput', `Kasturi', `Chaya', `Kodur', `Salem', `Waigon', `Alleppey', `Karur', `Tekurpeta' [2]. Turmeric is valued primarily for curcumin (1). Thus, curcumin (1) content has been an important factor in developing and selecting cultivar or variety for turmeric production and in determining the price of turmeric [50]. For example, PTS-10 and PTS-24, two clones were selected for rhizome yield and high dry recovery and both can yield 9.3% curcumin (1) [51]. Curcumin (1) can also be produced by chemical synthesis but the synthetic curcumin (1) is not used as a food additive. The main pharmaceutical products from turmeric are dried whole rhizomes, ground turmeric, turmeric oils, turmeric oleoresin, and curcumin (maybe actually mixture of three curcuminoids) [49, 52] (Table 1).

CHEMICAL CONSTITUENTS

Of 110 species of the genus Curcuma L., only about 20 species have been studied phytochemically [53]. Curcuma longa is the most chemically investigated species of Curcuma. To date, at least 235 compounds, primarily phenolic compounds and terpenoids have been identified, including diarylheptanoids (including commonly known as curcuminoids), diarylpentanoids, monoterpenes, sesquiterpenes, diterpenes, triterpenoids, alkaloid, and sterols, etc.

Fig. (1). Curcuma longa is primarily cultivated for turmeric rhizomes and their products (The upper picture shows the plants cultivated at the SFA Mast Arboretum, Stephen F. Austin State University in Nacogdoches, Texas, USA and the lower picture shows rhizomes and ground turmeric as well as curry powder. Photos by S.Y. Li).

Phenolic Compounds

Diarylheptanoids and Diarylpentanoids

Over 300 diarylheptanoids have been reported in the family Zingiberaceae and some non-closely related families [54]. Curcuminoids belong to the group of diarylheptanoids (or diphenylheptanoids) having an aryl-C7-aryl skeleton (119). These yellow pigments are usually used as food coloring agents and they are the main active compounds in turmeric. Usually, these polyphenols are present in 3-15% of turmeric rhizomes with curcumin (1) as the principal compound. Curcumin (C21H20O5) (1), also known as diferuloyl methane or 1,6-heptadiene-3,5-dione-1,7-bis(4-hydroxy-3-methoxyphenyl)-(1E,6E), was isolated in 1815 [49] and its chemical structure was determined in 1910 [55]. The compound is a yellow-orange powder with a molecular weight of 368.37. It is water insoluble but can be dissolved well in ethanol, methanol, actone, and dimethysulfoxide. Commercial "curcumin" is usually a mixture of three curcuminoids. For example, the composition of a commercial "curcumin" is about 71.5% curcumin (curcumin I) (1), 19.4% demethoxycurcumin (curcumin II) (2), and 9.1% bisdemethoxycurcumin (curcumin III) (5) [56]. These three major curcuminoids are also found in some other species of Curcuma but have lower concentrations, e.g., C. amada Roxb. [57], C. aeruginosa

30 Pharmaceutical Crops, 2011, Volume 2 Table 1. Main products of turmeric (Curcuma longa)

Li et al.

Product

Description

Uses

Dried

Preparation: mother rhizomes (egg-shipped primary rhizomes) and finger rhizomes (cylindrical and Medicine (Rhizoma Cur-

Whole Rhi-

multibranched secondary rhizomes) are usually boiled separately for about 40-60 min under slightly cumae Longae) and process

zome

alkaline conditions in copper, galvanized iron or earth vessels and then sun-dried on bamboo mats of other turmeric products

for 10-15 days to reduce the moisture to 10-11%

Harvest: usually 7-9 months after planting during January-March

Appearance: orange-brown, pale yellow or red-yellow

Chemical Composition: may contain 3-15% cucuminoids and 1.5 to 5% essential oils

Ground Turmeric

Preparation: Powder is prepared from dried finger rhizomes (60-80 mesh) Appearance: yellow or red-yellow powder Chemical Composition: The contents of active ingredients curcuminoids and essential oils may decrease

during the process and exposure to light, it is appropriate to pack the powder in a UV protective container (e.g., fiber hard drums, glass packs, etc.)

Spice: as alone or in curry powder and pastes

dye: for food, textile, cosmetic

Medicine: Ayurveda, medicine

e.g., in Chinese

Dietary supplement

Tumeric Oils

Preparation: Extract from dried rhizomes (ground turmeric) or leaves by steam distillation or supercritical CO2 extraction

Chemical Composition: essential oils from leaves is usually dominated by monoterpenes while the oil from rhizomes mainly contains sesquiterpenes

Appearance: yellow to brown viscous liquid Refractive Index: 1.4850-1.5250 Flash Point: 78?C Solubility in Water: insoluble

Spice, medicine, and dietary supplement

Tumeric Oleoresin

Preparation: Extract from dried rhizomes by solvent extraction with aceone, dichloromethane, 1,2dichloroethane, methanol, ethanol, isopropanol and light petroleum (hexanes) or supercritical CO2extraction. Graded by the content of curcuminoids or color value

Chemical Composition: 37-55% curcuminoids and up to 25% essential oil Appearance: yellow-dark reddish brown oily fluids Refractive Index: 1.4850-1.5250 Flash Point: 78?C Solubility in Water: insoluble

Food coloring, medicine, and dietary supplement

Curcumin

(turmeric yellow, kurkum)

Preparation: obtained by solvent extraction from ground turmeric rhizomes and purification of the extract by crystallization. The suitable solvents include aceone, carbon dioxide, ethanol, ethyl acetate, hexane, methanol, , isopropanol

Chemical Composition: the product is often the mixture of curcumin and its demethoxy- and bisdemethoxy- derivatives in turmeric in varying proportions. The three major curcuminoids may account no less than 90%. Minor compounds may include oils and resins naturally occurring in turmeric rhizomes

Appearance: yellowish to orange red crystalline powder Molecular Formula: C21H20O6 Molecular Weight: 368.38 Solubility in Water: insoluble

Medicine and dietary supplement

Roxb. [58, 59], C. aromatica [53], C. chuanyujin Roxb. [60], C. heyneana Val. & Zijp. [59], C. mangga Val. &. Zijp. [59], C. soloensis Val. [59], C. xanthorrhiza Roxb. [58, 61], and Curcuma zedoaria (Berg.) Rosc. [62]. It expected that these

common curcuminoids may occur in some other species of Curcuma although there are no chemical investigations con-

ducted on most of the 110 species of the genus. Some minor

and rare curcuminoids of C. longa or their analogs may be

identified in other species. For example, cyclocurcumin (17)

with cyclization of the seven-carbon unit as a pyrone ring, was only found in C. longa [53, 63]. Recently, 3?demthoxycyclocurcumin was isolated from C. xanthorrhiza [64].

Chemical Composition and Product Quality Control of Turmeric (Curcuma longa L.)

Pharmaceutical Crops, 2011, Volume 2 31

OO

R1

R2

H3C O

HO

1 R 1=OC H3,R 2=O CH 3

OH

2 R 1=OC H3,R 2=H

HO

3 R1=OH, R2=OCH3

4 R1=OH, R2=H

5 R 1=H,R 2=H

OO

R1

R2

OO 6

O OH O

HO

7 R 1=OC H3,R 2=H

OH

HO

11

8 R 1=OC H3,R 2=O CH 3

9 R 1=H,R 2=H

10 R 1=H ,R 2=O CH 3

OH O OH

R1

R2

HO

12 R 1=O CH 3, R2=H

OH

13 R 1=H , R 2=OC H 3

14 R 1=O CH 3, R2=OC H 3

15 R 1=H , R 2=H

HO O

R1

1 6 R1=H ,R2=H

O

1 7 R1=OC H 3,R 2=OC H 3

OCH3 OH

OH OH R2

H 3C O HO

O 18

O OCH3

OH

HO

19

OH

O R1

HO 20 R 1=H ,R 1=H 21 R 1=O CH 3,R 1=H 22 R 1=O CH 3,R 1=OC H 3

OH O R2

O

R2

OH

O

HO

R1

23 R 1=H ,R 2=O CH 3 24 R 1=OC H 3,R2=H

25 R 1=OC H 3,R2=OC H 3

HO OCH3

26

O

HO OCH3 27

O OH HO

HO OCH3

28

O HO

O

OH HO

OCH3 29

O

OCH3 30

No. Compound Name 1 curcumin (curcumin I) 2 demethoxycurcumin (curcumin II) 3 1-(4-hydroxy-3-methoxyphenyl)-7-(3, 4-dihydroxyphenyl)-1, 6-heptadiene-3, 5-dione 4 1-(4-hydroxyphenyl)-7-(3, 4-dihydroxyphenyl)-1, 6-heptadiene-3, 5-dione 5 bisdemethoxycurcumin (curcumin III) 6 tetrahydroxycurcumin 7 5-hydroxyl-1-(4-hydroxy-3-methoxyphenyl)-7-(4-hydroxyphenyl)-4,6-heptadiene-3-one 8 5-hydroxyl-1,7-bis(4-hydroxy-3-methoxyphenyl)-4,6-heptadiene-3-one 9 1,7-bis(4-hydroxyphenyl)-1-heptene-3,5-dione

Compound Type Diarylheptanoid Diarylheptanoid Diarylheptanoid Diarylheptanoid Diarylheptanoid Diarylheptanoid Diarylheptanoid Diarylheptanoid Diarylheptanoid

Ref. [65, 66] [65, 66]

[67] [67] [65] [65] [68] [68, 69] [68]

32 Pharmaceutical Crops, 2011, Volume 2

Li et al. Contd....

No. Compound Name 10 5-hydroxyl-7-(4-hydroxy-3-methoxyphenyl)-1-(4-hydroxyphenyl)-4,6-heptadiene-3-one 11 3-hydroxy-1,7-bis-(4-hydroxyphenyl)-6-heptene-1,5-dione 12 1,5-dihydroxy-1-(4-hydroxy-3-methoxyphenyl)-7-(4-hydroxyphenyl)-4,6-heptadiene-3-one 13 1,5-dihydroxy-1-(4-hydroxyphenyl)-7-(4-hydroxy-3-methoxyphenyl)-4,6-heptadiene-3-one 14 1,5-dihydroxy-1,7-bis(4-hydroxy-3-methoxyphenyl)-4,6-heptadiene-3-one 15 1,5-dihydroxy-1,7-bis(4-hydroxyphenyl)-4,6-heptadiene-3-one 16 1,5-epoxy-3-carbonyl-1,7-bis(4-hydroxyphenyl)-4,6-heptadiene 17 cyclocurcumin 18 1,7-bis(4-hydroxy-3-methoxyphenyl)-1,4,6-heptatrien-3-one 19 1,7-bis-(4-hydroxyphenyl)-1,4,6-heptatrien-3-one 20 1,5-bis(4-hydroxyphenyl)-penta-(1E,4E)-1,4-dien-3-one 21 1-(4-hydroxy-3-methoxyphenyl)-5-(4-hydroxyphenyl)-1, 4-pentadiene-3-one 22 1,5-bis(4-hydroxy-3-methoxyphenyl)-penta-(1E,4E)-1,4-dien-3-one 23 4"-(4"'-hydroxyphenyl)-2"-oxo-3"-butenyl-3-(4'-hydroxyphenyl-3'-methoxy)-propenoate 24 4"-(4"'-hydroxyphenyl-3-methoxy)-2"-oxo-3"-butenyl-3-(4'-hydroxyphenyl)-propenoate 25 calebin-A 26 (E)-4-(4-hydroxy-3-methoxyphenyl)but-3-en-2-one 27 (E)-ferulic acid 28 (Z)-ferulic acid 29 vanillic acid* 30 vanillin

Compound Type

Ref.

Diarylheptanoid

[68]

Diarylheptanoid

[67]

Diarylheptanoid

[67]

Diarylheptanoid

[67]

Diarylheptanoid

[67]

Diarylheptanoid

[67]

Diarylheptanoid

[7]

Diarylheptanoid

[70]

Diarylheptanoid

[69]

Diarylheptanoid

[71]

Diarylpentanoid

[71]

Diarylpentanoid

[67]

Diarylpentanoid

[72]

Phenylpropene

[73]

Phenylpropene

[73]

Phenylpropene

[65]

Phenylpropene

[72]

Phenylpropene

[72]

Phenylpropene

[72]

Phenolic

[72]

Phenolic

[72]

There are three diarylpentanoids (or diphenylpentanoids) with a five-carbon chain between two phenyl groups (20-22).

Curcuminoids have shown different activities. A recent study suggested that curcumin (1) had the relative higher potency for suppression of tumor necrosis factor (TNF)induced nuclear factor-kB (NF-B) activation than that of demethoxycurcumin (2) and bisdemethoxycurcumin (5), while tetrahydrocurcumin (6) without the conjugated bonds in the central seven-carbon chain was completely inactive [21]. The results suggest that the methoxy groups on the phenyl ring has critical role but conjugated bonds in the central seven-carbon chain also important for curcuminoids' NF-B activity [21]. However, the suppression of proliferation of various tumor cell lines by curcumin (1), demethoxycurcumin (2), and bisdemethoxycurcumin (5) was found to be comparable; indicating the methoxy groups play minimum role in the anti-proliferative effects of curcuminoids [21]. A further investigation of structure-activity relationship is needed by using pure curcuminoids.

It was interesting to mention that synergistic effect of mixture of compounds in turmeric had been observed. For example, it was found that methanolic and chloroformic extracts of turmeric demonstrated nematocidal activity against Toxocara canis [63]. All the substances including cyclocur-

cumin (17) did not show activity when applied independently, but the activity was observed when they were mixed, suggesting a synergistic action between them.

Because the difficulty in separation of three curcuminoids each other, the commercially pure compounds of curcumin (1), demethoxycurcumin (2), and bidemethoxycurcumin (5) available as authentic samples are limited. According to our analysis, the commercial "pure" curcumin (1) (labeled as 94%) actually has only purity of about 70%. Therefore, at least some existing studies and discoveries on "curcumin" actually used the mixture of three curcuminoids. However, a pure (>95%) curcumin (1) becomes important for bioassays and mechanism investigations as well as clinical trials. Research on bioactivity of curcuminoids are primarily focused on the above three major curcuminoids (1, 2, and 5), and bioactivities of minor curcuminoids remain elusive.

Phenylpropenes and Other Phenolic Compounds

Six monomeric phenylpropenes (23-28), vanillic acid (29), and vanillin (30) were identified in C. longa.

Terpenes

To date, at least 185 compounds of terpenes have been isolated or detected from leaves, flowers, roots and rhizomes

Chemical Composition and Product Quality Control of Turmeric (Curcuma longa L.)

Pharmaceutical Crops, 2011, Volume 2 33

of C. longa, including 68 monoterpenes (31-98), 109 sesquiterpenes (99-207), five diterpenes (208-212), and three triterpenoids (213-215).

Monoterpenes

The volatile oils from leaves and flowers of C. longa were usually dominated by monoterpenes, particularly pcymene (31), -phellandrene (-felandrene) (35), terpinolene

(terpenoline) (40), p-cymen-8-ol (55), cineole (77), and myrcene (82) while the major part of the oil from roots and rhi-

zomes contained sesquiterpenes [49, 74, 75]. This chemical

characteristic can be useful in identification of leaves or flowers of C. longa used to substitute its rhizome for turmeric oil production. In total, 68 monoterpenes (31-98) have been identified from various tissues of C. longa [75-82].

31

32

33

34

O

HO

HO

OH

35

36

HO

HO

OH HO

37

38

O

39

40

O

41

42

43

44

45

46

47

48

49

50

O O

O

O O

OH

OH

51

52

OH

59 60

O 68

53

54

55

56

57

58

O HO

O

O

64

61

62

63

OH

O

AcO

OH

OH

OH

69

70

71

65

72

73

O O 66

67

O O

74

H 75

O

H

76

78

77

O 79

O 80

81 O

82

83

O

OH

86

87

O

HO 91

O

O 92

O

84

O

85 HO

OH O

O

88

89

90

OH O

93

94

OH HO O

95

96

97

98

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