Abstract
The methanolic extract from the dried rhizomes of Curcuma comosa cultivated in Thailand was found to inhibit the release of β-hexosaminidase as a maker of degranulation from rat basophil leukemia (RBL-2H3) cells. Two new diarylheptanoids, diarylcomosols IV and V, were isolated from the methanolic extract. The chemical structures of the new compounds were elucidated on the basis of chemical and physicochemical evidence. The isolated diarylheptanoids showed inhibitory activity, and the structural requirements of the active constituents for the inhibition were clarified.
Avoid common mistakes on your manuscript.
Introduction
A Zingiberaceae plant, Curcuma comosa, is widely distributed in tropical and subtropical regions of Asia, especially Thailand, Indonesia, and Malaysia. The rhizome of C. comosa has been used as an aromatic stomachic and anti-inflammatory [1, 2]. In the course of our studies on bioactive constituents from Thai traditional medicine [3–7], we previously reported the isolation from the rhizomes of C. comosa and the structure elucidation of diarylcomosols I (16), II (11), and III (3), and known compounds (3R′,5S′)-3,5-dihydroxy-1-(4′-hydroxy-3′,5′-dimethoxyphenyl)-7-(4″-hydroxy-3′-methoxyphenyl)heptane (4, 0.0067 %) [8], (3R′,5S′)-3,5-dihydroxy-1-(3′,4′-dihydroxyphenyl)-7-(4″-hydroxyphenyl)heptane (5, 0.0064 %) [9], (+)-hannokinol (6, 0.011 %) [10], (3R,5R)-3,5-diacetoxy-1-(3,4-dihydroxyphenyl)-7-(4-hydroxyphenyl)heptane (7, 0.0039 %) [9], (3R,5R)-3-acetoxy-5-hydroxy-1-(4-hydroxyphenyl)-7-(3,4-dihydroxyphenyl)heptane (8, 0.049 %) [9], (3R,5R)-3-acetoxy-5-hydroxy-1,7-bis(3,4-dihydroxyphenyl)heptane (9, 0.0027 %) [9], (3R,5R)-dihydroxy-1-(3,4-dihydroxyphenyl)-7-(4-hydroxyphenyl)heptane (10, 0.0044 %) [9], (3R)-1,7-bis(4-hydroxyphenyl)-(6E)-6-hepten-3-ol (12, 0.0042 %) [11], (E)-1,7-bis(4-hydroxyphenyl)-6-hepten-3-one (13, 0.0033 %) [11], platyphyllone (14, 0.0088 %) [12], (5R)-5-hydroxy-1-(4-hydroxyphenyl)-7-(4-hydroxy-3-methoxyphenyl)-3-heptanone (15, 0.0039 %) [13], and 1,7-bis(4-hydroxyphenyl)hepta-4E,6E-dien-3-one (17, 0.016 %) [14] with inhibitory effects on melanogenesis [15]. As a continuing study, we found that the methanolic (MeOH) extract from the dried rhizomes of C.comosa showed inhibitory activities on the release of β-hexosaminidase as a maker of degranulation from rat basophil leukemia (RBL-2H3) cells. From the MeOH extract, we have isolated two new diarylheptanoids, diarylcomosols IV (1) and V (2). The inhibitory effects of the isolated compounds were also investigated. This paper deals with the structure elucidation of the new constituents (1 and 2) and the antiallergic activity of the isolated compounds (Fig. 1).
Results and discussion
A MeOH extract of the thermally-dried rhizomes of C. comosa showed inhibitory activities on the release of β-hexosaminidase from RBL-2H3 cells [inhibition (%): 12.7 ± 3.2 (p < 0.01) at 100 μg/mL]. The MeOH extract was partitioned into an EtOAc–H2O (1:1, v/v) mixture to furnish an EtOAc-soluble fraction (7.9 %) and an aqueous layer. The aqueous layer was further extracted with 1-butanol to give 1-butanol- (2.8 %) and H2O- (15.3 %) soluble fractions. The EtOAc-soluble fractions were found to have significant inhibitory effects [inhibition (%): 28.2 ± 4.5 (p < 0.01) at 100 μg/mL]. The EtOAc-soluble fraction, a predominant bioactive portion, was subjected to normal- and reversed-phase silica-gel column chromatography and repeated HPLC to give two new diarylheptanoids, diarylcomosols IV (1, 0.0022 %) and V (2, 0.013 %).
Diarylcomosol IV (1) was isolated as pale yellow oil. The IR spectrum of 1 suggested the presence of hydroxy (3,590 cm−1) and aromatic ring (1,606, 1,525 cm−1). In the EIMS of 1, a molecular ion peak [M]+ was observed at m/z 348 and the molecular formula C19H24O6 was determined by HRMS measurement of the molecular ion peak. The 1H-NMR and 13C-NMR (methanol-d 4) spectra of 1 (Table 1), which were assigned by various NMR experiments, showed signals assignable to five methylenes [δ 2.47 (2H, m, H-1a,7a), 2.55 (2H, m, H-1b,7b), 1.68 (4H, m, H2-2,6), and 1.58 (2H, m, H2-4)], two methines each bearing an oxygen function [δ 3.74 (2H, br-s, H-3, 5)], and two aromatic rings [δ 6.61 (2H, d, J = 1.9 Hz, H-2′,2″), 6.64 (2H, d, J = 7.9 Hz, H-5′,5″), 6.48 (2H, dd, J = 1.9, 7.9 Hz, H-6′,6″)]. From the DQF COSY and HMBC experiments (Fig. 2), the planar structure of 1 was determined to be the same as (3R,5R)-3,5-dihydroxy-1,7-bis(3,4-dihydroxyphenyl)heptane [16]. However, small differences in the 1H- and 13C-NMR spectrums were observed at the positions of C-2, 3, 4, 5, and 6. In addition, 1 was optically inactive, suggesting that the relative configuration at C-3 and C-5 was the syn type. On the basis of all this evidence, the chemical structure of diarylcomosol I (1) was determined to be (3R,5S)-3,5-dihydroxy-1,7-bis(3,4-dihydroxyphenyl)heptane.
Diarylcomosol V (2) was isolated as pale yellow oil. In the EIMS of 2, a molecular ion peak [M]+ was observed at m/z 432 and the molecular formula C23H28O8 was determined by HRMS measurement of the molecular ion peak. The IR spectrum of 2 suggested the presence of hydroxy, aromatic ring, and ester. The 1H-NMR and 13C-NMR (methanol-d 4) spectra of 2 (Table 1) showed signals assignable to five methylenes, two methines each bearing an oxygen function, two aromatic rings, and two acetoxy groups [δ 1.96 (6H, s, 3,5-OCOCH 3)]. From the DQF COSY and HMBC experiments (Fig. 2), the planar structure of 2 was determined to be the same as (3S,5S)-3,5-diacetoxy-1,7-bis(3,4-dihydroxyphenyl)heptane [17]. Next, small differences in the 1H- and 13C-NMR spectrums were observed at the positions of C-2, 3, 4, 5, 6, and acetoxy groups. In addition, 2 was optically inactive, suggesting that the relative configuration at C-3 and C-5 was the syn type. On the basis of all this evidence, the chemical structure of diarylcomosol V (2) was determined to be (3R,5S)-3,5-diacetoxy-1,7-bis(3,4-dihydroxyphenyl)heptane.
In the course of our studies on antiallergic constituents from natural medicines [18–20], we previously reported that some triterpenes and oleanane-type triterpene oligoglycosides showed inhibitory effects on histamine release from rat exudate cells induced by an antigen–antibody reaction [21, 22] and on β-hexosaminidase release induced by dinitrophenylated bovine serum albumin (DNP-BSA) from RBL-2H3 cells sensitized with anti-DNP immunoglobulin E (IgE) [23–25]. As a continuation of this study, we examined the effects of diarylheptanoids on the release of β-hexosaminidase from RBL-2H3 cells. As shown in Table 2, all diarylheptanoids isolated from C. comosa displayed greater potency for inhibiting the release of β-hexosaminidase from RBL-2H3 cells [inhibition: > 51.9 % (p < 0.01) at 100 μM] than a reference compound, ketotifen [inhibition: 44.2 % (p < 0.01) at 100 μM]. Next, the structural requirements of the active sesquiterpenes were examined. Interestingly, compounds 3 [inhibition: 72.0 % (p < 0.01) at 30 μM] and 4 [inhibition: 54.7 % (p < 0.01) at 30 μM], with methoxy groups attached to the aromatic ring, showed stronger inhibitory effects than compound 5 [inhibition: 25.5 % (p < 0.01) at 30 μM], lacking a methoxy group. This result means that methylation of hydroxy groups attached to the aromatic ring increases the inhibitory effects. Among the isolates, compounds 3 and 15 showed potent inhibitory effects [IC50 = 14.8, 18.7 μM, respectively].
Experimental
General
The following instruments were used to obtain physical data: specific rotations, Horiba SEPA-300 digital polarimeter (l = 5 cm); IR spectra, Thermo Electron Nexus 470; EIMS and HREIMS, JEOL JMS-GCMATE mass spectrometer; 1H-NMR spectra, JEOL JNM-LA 500 (500 MHz) spectrometer; 13C-NMR spectra, JEOL JNM-LA 500 (125 MHz) spectrometer; HPLC, Shimadzu SPD-10AVP UV–VIS detector. COSMOSIL 5C18-MS-II (250 × 4.6 mm i.d., 250 × 10 mm i.d. and 250 × 20 mm i.d.) columns were used for analytical and preparative purposes. The following materials were used for chromatography: normal-phase silica gel column chromatography, Silica gel BW-200 (Fuji Silysia Chemical, Ltd., 150–350 mesh); reversed-phase silica gel column chromatography, Chromatorex ODS DM1020T (Fuji Silysia Chemical, Ltd., 100–200 mesh); TLC, precoated TLC plates with Silica gel 60F254 (Merck, 0.25 mm) (ordinary phase) and Silica gel RP-18 F254S (Merck, 0.25 mm) (reversed phase); reversed-phase HPTLC, precoated TLC plates with Silica gel RP-18 WF254S (Merck, 0.25 mm). Detection was achieved by spraying with 1 % Ce(SO4)2–10 % aqueous H2SO4 followed by heating.
Plant material
The thermally-dried and sliced rhizomes of C. comosa, cultivated in Thailand, were purchased from Mae Chu Co. Ltd. (Nara, Japan) in 2012, and identified by one of the authors (M.Y.). A voucher specimen is on file in our laboratory (KPU CC-2012-1).
Extraction and isolation
The dried rhizomes (4.0 kg) were extracted three times with methanol under reflux for 3 h. Evaporation of the solvent under reduced pressure provided a MeOH extract (1,050 g, 26.3 %). A part of the MeOH extract (120 g) was partitioned into an EtOAc–H2O (1:1, v/v) mixture to furnish an EtOAc-soluble fraction (36.0 g, 7.9 %) and an aqueous phase. The aqueous phase was further extracted with 1-butanol to give a 1-butanol-soluble fraction (13.0 g, 2.8 %) and a H2O-soluble fraction (70.0 g, 15.3 %). The EtOAc-soluble fraction (36.0 g) was subjected to normal phase silica gel column chromatography [1.0 kg, n-hexane → n-hexane–CHCl3 (5:1 → 2:1 → 1:2 v/v) → CHCl3 → CHCl3–MeOH (200:1 → 50:1 → 10:1 → 5:1 v/v) → MeOH] to give eight fractions [Fr.EA1, Fr.EA2, Fr.EA3, Fr.EA4, Fr.EA5, Fr.EA6 (5.1 g), Fr.EA7 (7.4 g), Fr.EA8]. Fraction EA6 (5.1 g) was further separated by reversed phase silica gel column chromatography [150.0 g, MeOH–H2O (20:80 → 30:70 → 40:60 → 50:50 → 60:40, → 70:30, → 85:15 v/v) → MeOH] to give nine fractions [Fr.EA6-1, Fr.EA6-2, Fr.EA6-3, Fr.EA6-4 (341.4 mg), Fr.EA6-5, Fr.EA6-6 (392.0 mg), Fr.EA6-7, Fr.EA6-8, Fr.EA6-9 (568.2 mg)]. Fraction EA6-4 (341.4 mg) was purified by HPLC [H2O–MeCN–AcOH (850: 150: 3, v/v/v)] to give 6 (50.3 mg). Fraction EA6-6 (392.0 mg) was purified by HPLC [H2O–MeCN–AcOH (730:270:3, v/v/v)] to give 3 (53.1 mg), 4 (30.8 mg), 14 (40.1 mg), and 15 (17.8 mg). Fraction EA6-9 (568.2 mg) was purified by HPLC [H2O–MeCN–AcOH (600:400:3, v/v/v)] to give 7 (17.8 mg), 11 (15.0 mg), 13 (15.1 mg), and 17 (72.0 mg). Fraction EA7 (7.4 g) was further separated by reversed phase silica gel column chromatography [150 g, MeOH–H2O (30:70 → 40:60 → 50:50 → 60:40, → 70:30, → 80:20 v/v) → MeOH] to give nine fractions [Fr.EA7-1, Fr.EA7-2 (0.98 g), Fr.EA7-3, Fr.EA7-4 (0.80 mg), Fr.EA7-5 (0.60 g), Fr.EA7-6, Fr.EA7-7, Fr.EA7-8, Fr.EA7-9]. Fraction EA7-2 (0.98 g) was subjected to normal phase silica gel column chromatography [30.0 g, n-hexane → n-hexane–CHCl3 (1:1 → 1:2 v/v) → CHCl3 → CHCl3–MeOH (50:1 → 10:1 → 5:1 v/v) → MeOH] to give three fractions [Fr.EA7-2-1, Fr.EA7-2-2, Fr.EA7-2-3 (83.5 mg)]. Fraction EA7-2-3 (83.5 mg) was purified by HPLC [H2O–MeCN–AcOH (800:200:3, v/v/v)] to give 5 (20.3 mg) and 10 (29.1 mg). Fraction EA7-4 (0.80 g) was purified by HPLC [H2O–MeCN–AcOH (650:350:3, v/v/v)] to give 2 (58.0 mg), 8 (225.0 mg), and 9 (12.4 mg). Fraction EA7-5 (0.60 g) was purified by HPLC [H2O–MeCN–AcOH (550:450:3, v/v/v)] to give 1 (10.1 mg), 12 (19.3 mg), and 16 (8.1 mg).
Diarylcomosol IV (1)
Pale yellow oil; IR (KBr): ν max 3,590, 1,606, 1,525 cm−1; 1H-NMR (500 MHz) and 13C-NMR (125 MHz) measured in methanol-d 4: given in Table 1; EIMS: m/z 348 [M]+; HREIMS: m/z 348.1575 (calcd for C19H24O6 [M]+: m/z 348.1573).
Diarylcomosol V (2)
Pale yellow oil; IR (KBr): ν max 3,610, 1,606, 1,528, 1,375 cm−1; 1H-NMR (500 MHz) and 13C-NMR (125 MHz) measured in methanol-d 4: given in Table 1; EIMS: m/z 432 [M]+; HREIMS: m/z 432.1787 (calcd for C23H28O8 [M]+: m/z 432.1784).
Effects on the release of β-hexosaminidase from RBL-2H3 cells
The inhibitory effects of the test samples on the release of β-hexosaminidase from RBL-2H3 cells [Cell No. JCRB0023, obtained from Health Science Research Resources Bank (Osaka, Japan)] were evaluated by a method reported previously [23]. Briefly, RBL-2H3 cells were dispensed into 48-well plates at a concentration of 4 × 104 cells/well using Eagle’s Minimum Essential Medium (MEM, Sigma) containing fetal calf serum (10 %), penicillin (100 units/ml), streptomycin (100 μg/ml), and 0.45 μg/ml of anti-DNP IgE, and these were incubated overnight at 37 °C in 5 % CO2 for sensitization of the cells. The cells were then washed twice with 200 μl of Siraganian buffer [119 mmol/l NaCl, 5 mmol/l KCl, 0.4 mmol/l MgCl2, 25 mmol/l piperazine-N,N′-bis(2-ethanesulfonic acid) (PIPES), and 40 mmol/l NaOH, pH 7.2], and incubated in 80 μl of Siraganian buffer [5.6 mmol/l glucose, 1 mmol/l CaCl2, and 0.1 % bovine serum albmin (BSA) were added] for an additional 10 min at 37 °C. Aliquots (10 μl) of test sample solution were added to each well and incubated for 10 min, followed by the addition of 10 μl of antigen (DNP-BSA, final concentration 10 μg/ml) at 37 °C for 10 min to stimulate the cells to evoke allergic reactions (degranulation). The reaction was stopped by cooling in an ice bath for 10 min. The supernatant (40 μl) was transferred into a 96-well microplate and incubated with 40 μl of substrate (1 mmol/l p-nitrophenyl-N-acetyl-β-d-glucosaminide) in 0.1 mol/l citrate buffer (pH 4.5) at 37 °C for 2 h. The reaction was stopped by adding 200 μl of stop solution (0.1 mol/l Na2CO3/NaHCO3, pH 10.0). The absorbance was measured using a microplate reader at 405 nm. The test sample was dissolved in dimethylsulfoxide (DMSO), and the solution was added to Siraganian buffer (final DMSO concentration 0.1 %).
The percent inhibition of the release of β-hexosaminidase by the test material was calculated using the following equation:
Control (C): DNP-BSA (+), test sample (–); Test (T): DNP-BSA (+), test sample (+); Blank (B): DNP-BSA (–), test sample (+); Normal (N): DNP-BSA (–), test sample (–).
Under these conditions, it was calculated that 10–15 % of β-hexosaminidase was released from the cells in the control groups by determination of the total β-hexosaminidase activity after treatment with 0.05 % Triton X-100.
Statistics
Values were expressed as mean ± SEM. One-way analysis of variance following Dunnett’s test was used for statistical analysis. Probability (p) values less than 0.05 were considered significant.
References
Sodsai A, Piyachaturawat P, Sophasan S, Suksamrarn A, Vongsakul M (2007) Suppression by Curcuma comosa Roxb. of pro-inflammatory cytokine secretion in phorbol-12-myristate stimulated human mononuclear cells. Int Immunopharmacol 7:524–531
Jantaratnotai N, Utaisincharoen P, Piyachaturawat P, Chongthammakun S, Sanvarinda Y (2006) Inhibitory effects of Curcuma comosa on NO production and cytokine in LPS-activated microglia. Life Sci 78:571–577
Qu Y, Xu F, Nakamura S, Matsuda H, Pongpiriyadacha Y, Wu L, Yoshikawa M (2009) Sesquiterpenes from Curcuma comosa. J Nat Med 63:102–104
Nakamura S, Nakashima S, Tanabe G, Oda Y, Yokota N, Fujimoto K, Matsumoto T, Sakuma R, Ohta T, Ogawa K, Nishida S, Miki H, Matsuda H, Muraoka O, Yoshikawa M (2013) Alkaloid constituents from flower buds and leaves of sacred lotus (Nelumbo nucifera, Nymphaeaceae) with melanogenesis inhibitory activity in B16 melanoma cells. Bioorg Med Chem 21:779–787
Matsuda H, Asao Y, Nakamura S, Hamao M, Sugimoto S, Hongo M, Pongpiriyadacha Y, Yoshikawa M (2009) Antidiabetogenic constituents from the Thai traditional medicine Cotylelobium melanoxylon. Chem Pharm Bull 57:487–494
Matsumoto T, Nakamura S, Nakashima S, Fujimoto K, Yoshikawa M, Ohta T, Ogawa K, Matsuda H (2014) Structures of lignan dicarboxylates and terpenoids from the flower buds of Cananga odorata and their inhibitory effects on melanogenesis. J Nat Prod 77:990–999
Matsumoto T, Nakamura S, Fujimoto K, Ohta T, Ogawa K, Yoshikawa M, Matsuda H (2014) Structures of constituents isolated from the flower buds of Cananga odorata and their inhibitory effects on aldose reductase. J Nat Med 68:709–716
Ma J, Jin X, Yang L, Liu ZL (2004) Diarylheptanoids from the rhizomes of Zingiber officinale. Phytochemistry 65:1137–1143
Li J, Liao CR, Wei JQ, Chen LX, Zhao F, Qiu F (2011) Diarylheptanoids from Curcuma kwangsiensis and their inhibitory activity on nitric oxide production in lipopolysaccharide-activated macrophages. Bioorg Med Chem Lett 21:5363–5369
Veith M, Dettner K, Boland W (1996) Stereochemistry of an alcohol oxidase from the defensive secretion of larvae of the leaf beetle Phaedon armoraciae (Coleoptera: Chrysomelidae). Tetrahedron 52:6601–6612
Li J, Zhao F, Li MZ, Chen LX, Qiu FJ (2010) Diarylheptanoids from the rhizomes of Curcuma kwangsiensis. J Nat Prod 73:1667–1671
Smite E, Lundgren LN, Andersson R (1993) Arylbutanoid and diarylheptanoid glycosides from inner bark of Betula pendula. Phytochemistry 32:365–369
Shin D, Kinoshita K, Koyama K, Takahashi K (2002) Antiemetic principles of Alpinia officinarum. J Nat Prod 65:1315–1318
Ali MS, Tezuka Y, Awale S, Banskota AH, Kadota S (2001) Six new diarylheptanoids from the seeds of Alpinia blepharocalyx. J Nat Prod 64:289–293
Matsumoto T, Nakamura S, Nakashima S, Yoshikawa M, Fujimoto K, Ohta T, Morita A, Yasui R, Kashiwazaki E, Matsuda H (2013) Diarylheptanoids with inhibitory effects on from the rhizomes of Curcuma comosa in B16 melanoma cells. Bioorg Med Chem Lett 21:5178–5181
Yokosuka A, Mimaki Y, Sakagami H, Sashida Y (2002) New diarylheptanoids and diarylheptanoid glucosides from the rhizomes of Tacca chantrieri and their cytotoxic activity. J Nat Prod 65:283–5181
Kikuzaki H, Kobayashi M, Nakatani N (1991) Constituents of Zingiberaceae. Part 4. Diarylheptanoids from rhizomes of Zingiber officinale. Phytochemistry 30:3647–3651
Matsuda H, Morikawa T, Ueda K, Managi H, Yoshikawa M (2002) Structural requirements of flavonoids for inhibition of antigen-induced degranulation, TNF-α and IL-4 production from RBL-2H3 cells. Bioorg Med Chem 10:3123–3128
Matsuda H, Morikawa T, Mangi H, Yoshikawa M (2003) Antiallergic principles from Alpinia galanga: structural requirements of phenylpropanoids for inhibition of degranulation and release of TNF-α and IL-4 in RBL-2H3 cells. Bioorg Med Chem Lett 13:3197–3202
Matsuda H, Tewtrakul S, Morikawa T, Nakamura S, Yoshikawa M (2004) Anti-allergic principles from Thai zedoary: structural requirements of curcuminoids for inhibition of degranulation and effect on the release of TNF-α and IL-4 in RBL-2H3 cells. Bioorg Med Chem 12:5891–5989
Yoshikawa M, Shimada H, Komatsu H, Sakurama T, Nishida N, Shimoda H, Matsuda H, Tani T (1997) Medicinal foodstuffs. VI. Histamine release inhibitors from kidney bean, the seeds of Phaseolus vulgaris L.: chemical structures of sandosaponins A and B. Chem Pharm Bull 45:877–882
Yoshizumi S, Murakami T, Kadoya M, Matsuda H, Yoshikawa M (1998) Medicinal foodstuffs. XI. Histamine release inhibitors from wax gourd, the fruits of Benincasa hispida COGN. Yakugaku Zasshi 118:188–192
Matsuda H, Nakamura S, Fujimoto K, Moriuchi R, Kimura Y, Ikoma N, Hata Y, Muraoka O, Yoshikawa M (2010) Medicinal flowers. XXXI. Acylated oleanane-type triterpene saponins, sasanquasaponins I-V, with antiallergic activity from the flower buds of Camellia sasanqua. Chem Pharm Bull 58:1617–1621
Yoshikawa M, Nakamura S, Kato Y, Matsuhira K, Matsuda H (2007) Medicinal flowers. XIV. New acylated oleanane-type triterpene oligoglycosides with antiallergic activity from flower buds of chinese tea plant (Camellia sinensis). Chem Pharm Bull 55:598–605
Morikawa T, Nakamura S, Kato Y, Muraoka O, Matsuda H, Yoshikawa M (2007) Bioactive saponins and glycosides. XXVIII. New triterpene saponins, foliatheasaponins I, II, III, IV, and V, from tencha (the leaves of Camellia sinensis). Chem Pharm Bull 55:293–298
Acknowledgments
This work was supported in part by JSPS KAKENHI Grant Number 25460144.
Author information
Authors and Affiliations
Corresponding author
Electronic supplementary material
Below is the link to the electronic supplementary material.
Rights and permissions
About this article
Cite this article
Matsumoto, T., Nakamura, S., Fujimoto, K. et al. Structure of diarylheptanoids with antiallergic activity from the rhizomes of Curcuma comosa . J Nat Med 69, 142–147 (2015). https://doi.org/10.1007/s11418-014-0870-8
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s11418-014-0870-8