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Planta Med 2002; 68(11): 1020-1023
DOI: 10.1055/s-2002-35648
Original Paper
Natural Product Chemistry
© Georg Thieme Verlag Stuttgart · New York

Antioxidative 7-Oxodehydropodocarpane-Type Trinorditerpenes from the Bark of Taiwania cryptomerioides

Yueh-Hsiung Kuo1 , Shih-Chang Chien1 , Ching-Chuan Kuo1
  • 1Department of Chemistry, National Taiwan University, Taipei, Taiwan, Republic of China
Further Information

Prof. Yueh-Hsiung Kuo

Department of Chemistry, National Taiwan University

Taipei 106

Taiwan R.O.C.

Email: yhkuo@ccms.ntu.edu.tw

Phone: +886-223638146

Fax: +886-223636359

Publication History

Received: November 16, 2001

Accepted: June 29, 2002

Publication Date:
26 November 2002 (online)

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Table of Contents #

Abstract

Five new 7-oxopodocarpane-type trinorditerpenes together with 1β,13,14-trihydroxy-8,11,13-podocarpatrien-7-one (1) were isolated from the bark of Taiwania cryptomerioides. By using NMR and other spectral methods, the structures of five new compounds, 14-hydroxy-13-methoxy-8,11,13-podocarpatriene-3,7-dione (2), 1β,14-dihydroxy-13-methoxy-8,11,13-podocarpatrien-7-one (3), 13,14-dihydroxy-8,11,13-podocarpatriene-3,7-dione (4), 3β,13,14-trihydroxy-8,11,13-podocarpatrien-7-one (5), and 1β,13,14-trihydroxy-8,11,13-podocarpatriene-2,7-dione (6), were elucidated. Compounds 1, 4, 5, and 6 exhibited strong antioxidative activity.

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Key words

Taiwania cryptomerioids - Taxodiaceae - podocarpane - antioxidative activity

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Introduction

Podocarpane-type diterpenoid (trinorabietane) derivatives are not very common. They are present in the genera Azadirachta [1], [2], [3], [4], [5], Humirianther [6], Micrandropsis [7], Podocarpus [8], and Azadirachta indica. In addition, Azadirachta indica is rich in podocarpane diterpenoids. In our previous reports about studies of the components of heartwood [9] and bark [10], [11] of Taiwania cryptomerioides, podocarpane diterpenes were not observed. The first new podocarpane derivative, 1β,13,14-trihydroxy-8,11,13-podocarpatrien-7-one (1), was isolated from the leaves of T. cryptomerioides (Taxodiaceae) by Lin [12]. Because the mother fraction of nimbionone and nimbionol (podocarpane diterpenoid) showed significant antibacterial activity [3], we were encouraged to study the chemical constituent of its bark again, and found eleven new podocarpane derivatives [13], [14]. Now we continued to investigate the more polar fraction of the same extract and isolated compound 1 and five new podocarpane diterpenoids.

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Materials and Methods

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General experimental procedures

Melting points were determined with a Yanagimoto micromelting point apparatus and are uncorrected. IR spectra were recorded on a Perkin-Elmer 781 spectrophotometer. 1H- and 13C-NMR spectra were performed on Bruker DMX-400 at 400 and 100 MHz in CDCl3 solution with tetramethylsilane (TMS) as an internal standard. EIMS, UV, and specific rotations were taken on a JEOL JMS-HX 300, a JOEL JMS-HX 110, and a JASCO DIP-180 digital polarimeter, respectively. Extracts were chromatographed on silica gel (Merk 70 - 230 mesh, 230 - 400 mesh, ASTM) and purified with a semi-preparative normal-phase HPLC column (250 × 10 mm, 7 μm, LiChrosorb Si 60) taken on LDC Analytical-III.

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Plant material

The bark of T. cryptomerioides was collected in Tai-Chun, Taiwan, in 1996. The plant material was identified by Mr. Muh-Tsuen Gun, National Taiwan University. A voucher specimen (no. 013 542) has been deposited at the Herbarium of the Department of Botany of the National Taiwan University, Taipei, Taiwan.

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Extraction and isolation

Air dried pieces of bark of T. cryptomerioides (12 kg) were extracted three times with acetone (60 L) at room temperature (7 d for each time). The acetone extract was evaporated under vacuum to leave a dark residue, which was suspended in H2O (8 L), and then partitioned (3 × ) with 1 L of ethyl acetate. The EtOAc fraction (360 g) was chromatographed on a silica gel column (10 × 70 cm, Merk 70 - 230 mesh) using n-hexane, EtOAc, and MeOH of increasing polarity as eluent to obtain 9 fractions: fr. 1 [8000 mL, n-hexane/EtOAc (19 : 1)], fr. 2 [7000 mL, n-hexane/EtOAc (9 : 1)], fr. 3 [6000 mL, n-hexane/EtOAc (8 : 2)], fr. 4 [10 000 mL, n-hexane/EtOAc (7 : 3)], fr. 5 [8000 mL, n-hexane/EtOAc (1 : 1)], fr. 6 [9000 mL, n-hexane/EtOAc (1 : 3)], fr. 7 (8000 mL, EtOAc), fr. 8 [7000 mL, EtOAc/MeOH (1 : 1)], fr. 9 (6000 mL, MeOH). The fr. 6 was subjected to re-chromatography on a silica gel column (5 × 15 cm, Merck 230 - 400 mesh) eluted with n-hehane/EtOAc (2 : 3) to obtain 7 frs (each 1000 ml, fr. 6A - fr. 6G). HPLC of fr. 6E on a normal-phase column with CH2Cl2/EtOAc (4 : 1) as eluent, 3 ml/min, afforded 2 (23 mg), 3 (106 mg), 4 (14 mg), 6 (8 mg), retention time: 14.1, 15.3, 7.1, 6.7 min, respectively. The fr. 6F and fr. 6G was purified by using the same column with CH2Cl2/EtOAc (7 : 3) as eluent, 3 ml/min, to yield 1 (24 mg) and 5 (12 mg), retention time: 6.5 and 10.4 min, respectively.

14-Hydroxy-13-methoxy-8,11,13-podocarpatriene-3,7-dione (2): light yellow powder, m. p. 169 - 170 °C; [α]D 24: -23.4 ° (c 0.21, CHCl3); UV: λmax MeOH (log ε) = 224.5 (4.15), 269.0 (3.88), 354.0 (3.38) nm; IR (dry film) νmax = 3300 - 2700, 3040, 1704, 1639, 1593, 1472, 1265, 1050, 809 cm-1; 1H-NMR (CDCl3), see text; 13C-NMR (CDCl3), see Table [1]; EIMS (70 eV): m/z = 302 [M+] (100), 287 (15), 259 (9), 245 (10), 203 (21); HREIMS: m/z = 302.1520 (calcd. for C18H22O4, 302.1512).

1β,14-Dihydroxy-13-methoxy-8,11,13-podocarpatrien-7-one (3): light yellow plates, m. p. 88 - 89 oC; [α]D 23: -29.7o (c 0.2, CHCl3); UV: λmax MeOH (log ε) = 223.5 (4.20), 272.0 (4.10), 358.0 (3.65) nm; IR (dry film) νmax = 3529, 3200 - 2700, 1633, 1580, 1520, 1251, 1036, 824, 758 cm-1; 1H-NMR (CDCl3), see text; 13C-NMR (CDCl3), see Table [1]; EIMS (70 eV): m/z = 304 [M+] (100), 289 (4), 271 (6), 245 (18), 205 (23); HREIMS: m/z = 304.1673 (calcd. for C18H24O4, 304.1668).

13,14-Dihydroxy-8,11,13-podocarpatriene-3,7-dione (4): amorphous solid; [α]D 24: -17.1 ° (c 0.43, CHCl3); UV: λmax MeOH (log ε) = 224.5 (4.18), 272.5 (3.96), 357.5 (3.52) nm; IR (dry film): νmax = 3425, 3200 - 2700, 1709, 1634, 1602, 1480, 1271, 756 cm-1; 1H NMR (CDCl3), see text; 13C-NMR (CDCl3), see Table [1]; EIMS (70 eV): m/z = 288 [M+] (100), 273 (26), 245 (24), 231 (28), 189 (26); HREIMS: m/z = 288.1367 (calcd. for C17H20O4, 288.1356).

3β,13,14-Trihydroxy-8,11,13-podocarpatrien-7-one (5): amorphous solid; [α]D 18: + 7.3 ° (c 0.14, CHCl3); UV: λmax MeOH (log ε) = 225.0 (4.09), 272.5 (4.01), 360.0 (3.48) nm; IR (dry film) νmax = 3423, 3200 - 2500, 1632, 1600, 1474, 1278, 1256, 755, 658 cm-1; 1H-NMR (CDCl3), see text; 13C-NMR (CDCl3), see Table [1]; EIMS (70 eV): m/z = 290 [M+] (47), 257 (35), 236 (28), 189 (39), 83.9 (100); HREIMS: m/z = 290.1514 (calcd. for C17H22O4, 290.1512).

1β,13,14-Trihydroxy-8,11,13-podocarpatriene-2,7-dione (6): amorphous solid; [α]D 21: -31.0° (c 0.26, CHCl3); UV λmax MeOH (log ε) = 225.5 (4.21), 273.5 (4.08), 357.0 (3.77) nm; IR (dry film): νmax = 3456, 3200 - 2700, 1717, 1635, 1607, 1510, 1260, 1127, 1045, 758 cm-1; 1H-NMR (CDCl3), see text; 13C-NMR (CDCl3), see Table [1]; EIMS (70 eV): m/z = 304 [M+] (80), 231 (100), 191 (43), 190 (40), 149 (57); HREIMS: m/z = 304.1309 (calcd. for C17H20O5, 304.1305).

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Determination of the scavenging effect on DPPH radicals

This method was adapted from that of Shimada et al. [15]. Basically, the tested samples were added into a methanol solution of DPPH to make the final concentration 300 μM. After thorough mixing, the solutions were kept in the dark for 90 min. Thereafter, the absorbency of the samples was measured using an automated microplate reader (OPTImaxTM, Molecular Devices, California, U.S.A.) at 517 nm against methanol without DPPH as the blank reference. Each sample was quadruplicated in the test, and the values were averaged. For the determination of EC50 (EC50: the efficient concentration of antioxidant decreasing initial DPPH concentration by 50 %), each sample was made into seven different concentrations for DPPH test. EC50 was obtained by interpolation from linear regression analysis.

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Results and Discussion

The high resolution mass spectrum and 13C-NMR data (Table [1]) of compound 2 showed a molecular formula of C18H22O4. Its UV spectrum exhibited absorptions at 224.5, 269.0, 354.0 nm suggesting that 2 had a phenone moiety. IR absorptions were attributable to a strong hydrogen bonding hydroxy group (3300 - 2700 cm-1), an aromatic group (3040, 1593, 1472 cm-1), cyclohexanone (1704 cm-1), and a conjugated carbonyl (1639 cm-1). The 1H-NMR spectrum showed three methyl singlet signals at δ 1.10, 1.16 and 1.38 (H-18, H-19, H-20). A three-proton singlet at δ 3.84 was assigned to the phenolic methyl group. Two vicinal aromatic protons resonated at δ 6.70 (d, J = 8.5 Hz, H-11) and 7.00 (d, J = 8.5 Hz, H-12), but no isopropyl group was observed in its 1H-NMR spectrum. In the 13C-NMR spectrum, three of six aromatic carbon signals appeared at δ 145.5, 146.8 and 153.1, and those signals were assigned to C-9, C-13 and C-14, respectively. The above data confirmed that 2 was a 8,11,13-podocarpatriene with one hydroxy and one methoxy group attached to the aromatic ring. A low-field singlet at δH 12.89 indicated a hydrogen-bonded hydroxy proton (C-14) and a carbonyl (δC 205.1, C-7) group. One of carbonyl groups was situated at C-3 (δC 214.0) which was revealed from the low-field signals of H-18 (δ 1.10), H-19 (δ 1.16) and H-20 (δ 1.36) [2], [4]. Further evidence was obtained from HMBC correlations between C-3 and H-18 and H-19. A signal typical of Hβ-1 in dehydroabietanes and dehydropodocarpanes at δ 2.53 [13], [14] showed absorptions at lower fields than ascribed to an inductive effect of the C-3 ketone group. The Hβ-1 signal overlapped with Hα-2 (δ 2.49), and showed NOESY correlation with H-20, H-11, Hβ-2 (δ 2.82 m) and Hα-1 [δ 1.96 (td, J = 13.4, 4.5 Hz), NOESY correlation with Hα-2 and H-5]. An ABX system at δ 2.23 (1H, dd, J = 14.0, 3.6 Hz), 2.64 (1H, dd, J = 18.1, 3.6 Hz) and 2.86 (1H, dd, J = 18.1, 14.0 Hz) was observed and was assigned to H-5 and H-6, respectively. Meanwhile, H-12 and MeO-13 (δ 3.84) show correlation in NOESY spectrum, establishing the structure of the aromatic ring. The assignment is also supported by HMQC and HMBC experiments. Therefore, 2 is 14-hydroxy-13-methoxy-8,11,13-podocarpatriene-3,7-dione.

Compound 3 has the molecular formula C18H24O4 (through peak matching of the molecular ion and 13C-NMR spectroscopy). The UV spectrum (λmax 223.5, 272.0, 358.0 nm) showed characteristic absorptions of phenone moiety, and its IR spectrum displayed peaks for hydroxy (3529 cm-1) and conjugated carbonyl (1633 cm-1) groups. The 1H-NMR spectrum showed a singlet of each methyl at δ 0.89 (H-18), 0.96 (H-19) and 1.19 (H-20). One exchangeable phenolic proton at δ 12.94 indicates that the hydroxy group (3200 - 2700 cm-1) is attached at C-14 with a strong hydrogen bond to the C-7 (δC 206.1) carbonyl group. Three signals at δ 1.79 (obscured by H-2), 2.69 (1H, dd, J = 19.0, 4.5 Hz), 2.77 (1H, dd, J = 19.0, 13.5 Hz) were assigned as H-5 and H-6, respectively. A typical Hβ-1 signal (δ 2.0 - 2.4) for dehydroabietane and dehydropodocarpane-type derivatives was not observed. A carbinyl methine signal at δ 3.98 (t, J = 8.0 Hz) was assigned as Hα-1 (axial), which had NOESY correlation with H-5 (δ 1.79). H-11 (δ 7.64, d, J = 8.6 Hz) in 3 also appeared at relatively lower field, as in 1β,13,14-trihydroxy-8,11,13-podocarpatriene (1) [12], [14], due to the deshielding by the C-1 equatorial hydroxy group. The other phenyl proton (δ 6.97, d, J = 8.6 Hz) has NOESY correlation with phenolic methyl group (δ 3.84). The above data agree with the structure of 3 being 1β,14-dihydroxy-13-methoxy-8,11,13-podocarpatrien-7-one.

The molecular formula for compound 4 is C17H20O4 based on its HREIMS and 13C-NMR data. On comparing the of 1H- and 13C-NMR spectra of 4 and 2, the only difference is a hydroxy group at C-13 in 4 instead of a methoxy group in 2. The UV absorptions (λmax 224.5, 272.5 and 357.5 nm) and the signal at δ 12.70 (exchangeable with D2O) confirmed the presence the C-7 carbonyl and C-14 hydroxy group. Three lower field singlet methyl groups at δ 1.12 (H-18), 1.17 (H-19) and 1.39 (H-20) proved to be in accord with a 3,7-dioxodehydropodocarpane. Two ortho-phenyl protons showed at δ 7.08 (1H, d, J = 8.4 Hz) and 6.69 (1H, d, J = 8.4 Hz). The latter proton was assigned as H-11 due to having an NOE correlation with Hβ-1 [δ 2.56, overlapping with H-2 (δ 2.50 and 2.84, each 1H, m)]. The signal at δ 1.98 (td, J = 13.5, 5.0 Hz) was assigned as Hα-1 ascribing to its coupling pattern and NOE correlation with Hα-2 (δ 2.50) and H-5. Based on the chemical shift and coupling pattern, an ABX system signals at δ 2.26 (1H, dd, J = 14.0, 3.5 Hz), 2.66 (1H, dd, J = 18.0, 3.5 Hz), and 2.89 (1H, dd, J = 18.0, 14.0 Hz) was assigned as H-5, Hα-6 and Hβ-6, respectively. Finally, an exchangeable signal at δ 5.67 is C-13 phenolic proton. In addition of HMBC, NOESY and COSY techniques, the structure 4 is in agreement with 13,14-dihydroxy-8,11,13-podocarpatriene-3,7-dione.

EIMS (m/z 290), 13C-NMR data and HREIMS confirmed the molecular formula C17H22O4 of compound 5. It contained three singlet methyl groups (δ 1.03, 0.93, and 1.18), two ortho-phenyl protons [δ 6.66 and 7.05 (each 1H, d, J = 8.3 Hz)], and a carbinyl methine proton [δ 3.32 (dd, J = 11.4, 4.3 Hz)] attributable to its 1H-NMR data. The UV absorptions (λmax 225.0, 272.5, 360.0 nm) and conjugated ketone associated strong hydrogen bond (νmax 1632 cm-1; δ 12.77) confirmed the C-7 carbonyl and C-15 hydroxy group. The signals at δ 2.72 (1H, dd, J = 18.3, 4.7 Hz), 2.75 (1H, dd, J = 18.3, 12.0 Hz), and 1.81 (1H, obscured by other signals) was assigned as H2 - 6, and H-5, respectively. The typical dehydroabietane Hβ-1 signal also presented at δ 2.32 (1H, dt, J = 13.1, 3.4 Hz). An exchangeable phenolic proton (δ 5.60, br s) and Hα-1 proton [δ 1.65 (td, J = 13.1, 3.4 Hz)] were obviously observed in the 1H-NMR spectrum. Comparison of 1H- and 13C-NMR (Table [1]) spectra of 5 and 4, showed as only difference a hydroxy group at C-3 in 5 instead of an oxo group at C-3 in 4. The structural elucidation was aided by 2D NMR techniques including HMQC, HMBC, NOESY and COSY. Therefore the structure of 5 was assigned as 3β,13,14-trihydroxy-8,11,13-podocarpatrien-7-one.

Seventeen 13C-NMR signals (Table [1]) including six aromatic and two ketone signals (δC 209.0 and 204.8) indicated that compound 6 is a dehydropodocarpane. Two ortho-phenyl protons [δ 7.09 and 7.55 (each 1H, d, J = 8.6 Hz, H-12, H-11)], two exchangeable phenolic protons (δ 5.59 and 12.70) and UV absorptions (λmax 225.5, 273.5, 357 nm) illustrated two hydroxy and one ketone functionalities situated at C-13, -14, and -7, respectively. The low field H-11 phenyl proton decided the presence of C-1β hydroxy group as in 3. H-1 signal displayed at low field (δ 4.53, s) diagnosed the secondary ketone at C-2. The chemical shift of three singlet methyl groups [δ 1.13 (H-18), 0.96 (H-19) and 1.09 (H-20)], two equivalent methylene protons [δ 2.82 (2H, d, J = 8.3 Hz, H-6)] and a complex of 3H signals at δ 2.40 - 2.51 (H2 - 3 and H-5) are all similar to compound 4. Therefore, compound 6 can be assigned as 1β,13,14-trihydroxy-8,11,13-podocarpatriene-2,7-dione, the structure being further confirmed by HMBC and NOESY methods.

Podocarpane-type diterpenes are not common in nature. Many podocarpane derivatives are found in the bark of T. cryptomerioides. The oxidation at C-3 in tricyclic diterpene compounds is common, but at C-1 or C-2 is rare. The simultaneous oxidation at C-1 and C-2 as acyloin functionality (as in 6) is very unique.

Reactive oxygen species (ROS) and oxygen free radicals play important roles, both beneficial and detrimental, in aerobic life processes [16]. Excess free radical has been implicated in a variety of pathophysiological phenomena, such as inflammation, aging, atherosclerosis, cancer, rheumatoid arthritis, hepatotoxicity, and reprefusion injury [17], [18]. DPPH is a free radical compound and has been used extensively to predict the antioxidant activities of various chemicals [19], [20], [21], [22], [23]. The isolated six compounds 1 - 6 were tested as scavenger of DPPH and ascorbic acid and α-tocopherol were used as standards. The scavenging activities were shown in Table [2]. Compounds 1, 4, 5, and 6 with catechol moiety exhibit higher activity than α-tocopherol and near the activity of ascorbic acid.

Table 1 13C-NMR spectral data of compounds 2 - 6 (100 MHz in CDCl3)
C 2 3 4 5 6
1 36.8 76.4 36.8 36.1 80.8
2 34.5 29.8 34.5 27.5 209.0
3 214.0 39.0 214.1 77.9 52.9
4 47.1 33.1 47.2 38.8 49.6
5 49.2 48.3 49.5 48.7 47.8
6 36.3 35.9 36.2 35.7 35.7
7 205.1 206.1 205.2 206.3 204.8
8 114.9 115.6 114.8 114.8 114.8
9 145.5 147.0 145.4 147.2 145.0
10 37.1 43.6 37.2 37.4 38.9
11 113.4 115.7 114.2 113.8 116.6
12 117.8 117.8 121.1 121.0 121.3
13 146.8 146.6 143.3 142.9 143.5
14 153.1 152.8 149.6 149.5 149.5
18 24.7 31.9 24.9 27.5 32.0
19 21.5 21.0 21.5 15.0 21.9
20 22.9 16.8 22.9 23.6 18.1
OCH3 56.1 56.1
Table 2 EC50 of podocarpane derivatives from the bark of T. cryptomerioides in scavenging DPPH radicals
Components EC50 (μg/mL)
Ascorbic acid 11.1 ± 2.2
α-Tocopherol 30.8 ± 5.4
1 12.2 ± 1.5
2 49.9 ± 4.9
3 301 ± 5.4
4 15.6 ± 2.4
5 14.5 ± 2.0
6 38.7 ± 3.6
The reaction was started by addition of DPPH (final concentration = 300 μM) to test the sample containing methanol solution. The decrease of absorbance of DPPH at 517 nm was recorded spectrophotometrically 90 min after mixing. Each sample was quadruplicated in the test, and the values were averaged. For the determination of EC50 (EC50: the efficient concentration of antioxidant decreasing initial DPPH concentration by 50 %), each sample was made into seven different concentrations for DPPH test. EC50 was obtained by interpolation from linear regression analysis.
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Acknowledgements

This research was supported by grant from the National Science Council of the Republic of China.

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References

  • 1 Majumder P L, Maiti D C, Kraus W, Bokel M. Nimbidiol, a modified diterpenoid of the root-bark of Azadirachta indica .  Phytochemistry. 1987;  26 3021-3
    CrossrefPubMedSearch in Google Scholar
  • 2 Ara I, Siddiqui B S, Faigi S, Siddiqui S. Terpenoids from the stem bark of Azadirachta indica .  Phytochemistry. 1988;  27 1801-4
    CrossrefPubMedSearch in Google Scholar
  • 3 Siddiqui S, Ara I, Faigi S, Mahmood T, Siddiqui B S. Phenolic tricyclic diterpenoids from the bark of Azadirachta indica .  Phytochemistry. 1988;  27 3903-7
    CrossrefPubMedSearch in Google Scholar
  • 4 Ara I, Siddiqui B S, Faigi S, Siddiqui S. Tricyclic diterpenoids from the bark of Azadirachta indica .  Journal of Natural Products. 1988;  51 1054-61
    CrossrefPubMedSearch in Google Scholar
  • 5 Ara I, Siddiqui B S, Faigi S, Siddiqui S. Three new diterpenoids from the bark of Azadirachta indica .  Journal of Natural Product. 1990;  53 816-20
    PubMedSearch in Google Scholar
  • 6 Zoghbl M DGB, Roque N F, Gottlieb H F. Humirianthenolides, new degraded diterpenoids from Humirianthera rupestris .  Phytochemistry. 1981;  20 1669-73
    CrossrefPubMedSearch in Google Scholar
  • 7 Alvarenga M AD, Silva J D, Gottlieb H E, Gottlieb O R. Diterpenoids from Micrandropsis scleroxylon .  Phytochemistry. 1981;  20 1159-63
    CrossrefPubMedSearch in Google Scholar
  • 8 Cambie R C, Mander L M. Chemistry of the podocarpaceae-VI: Constituents of the heartwood of Podocarpus totara G. Benn.  Tetrahedron. 1962;  18 465-75
    CrossrefPubMedSearch in Google Scholar
  • 9 Lin Y T, Cheng Y S, Kuo Y H. Extractive components from the wood of Taiwania cryptomerioides Hayata: A new sesquiterpene polyalcohols, cadinan-3α,4α,9α-triol.  Journal of Chinese Chemical Society. 1970;  17 111-3
    PubMedSearch in Google Scholar
  • 10 Kuo Y H, Lin Y T, Lin Y T. Taiwanin H, a new lignan from the bark of Taiwania cryptomerioides Hayata.  Journal of Chinese Chemical Society. 1985;  32 381-3
    PubMedSearch in Google Scholar
  • 11 Kuo Y H, Lin Y T, Lin Y T. Two new diterpenes 6β-hydroxy-7β-methoxyroyleanone and 6β-acetoxy-7β-methoxyroyleanone from the bark of Taiwania cryptomerioides Hayata.  Chemistry Express. 1987;  2 217-20
    PubMedSearch in Google Scholar
  • 12 Lin W H, Fang J M, Cheng Y S. Diterpenoids and steroids from Taiwania cryptomerioides .  Phytochemistry. 1998;  48 1391-7
    CrossrefPubMedSearch in Google Scholar
  • 13 Kuo Y H, Chang C I, Lee C K. Six podocarpane-type trinorditerpenes from the bark of Taiwania cryptomerioides .  Chemical & Pharmaceutical Bulletin. 2000;  48 597-9
    PubMedSearch in Google Scholar
  • 14 Kuo Y H, Chang C I. Podocarpane-type trinorditerpenes from the bark of Taiwania cryptomerioides .  Journal of Natural Products. 2000;  63 650-2
    CrossrefPubMedSearch in Google Scholar
  • 15 Shimada K, Fujikawa K, Yahara K, Nakamura K. Antioxidative properties of xanthan on the autooxidation of soybean oil in cyclodextrin emulsion.  Journal of Agricultural and Food Chemistry. 1992;  40 945-8
    CrossrefPubMedSearch in Google Scholar
  • 16 Halliwell B. Reactive oxygen species in living systems: source, biochemistry, and role in human disease.  American Journal of Medicine. 1991;  91 14S-22S
    PubMedSearch in Google Scholar
  • 17 Kehrer J p. Free radicals as mediators of tissue injury and disease.  Critical Reviews in Toxicology. 1993;  23 21-48
    PubMedSearch in Google Scholar
  • 18 Jacob R A, Burri B J. Oxidative damage and defense.  American Journal of Clinical Nutrition. 1996;  63 9855-905
    PubMedSearch in Google Scholar
  • 19 Dinis T CP, Madeira V MC, Almeida L M. Action of phenolic derivatives (acetaminophen, salicylate, and 5-aminosalicylate) as inhibitors of membrane lipid peroxidation and as peroxyl radical scavengers. Arch. Biochem.  Biophys.. 1994;  315 161-9
    PubMedSearch in Google Scholar
  • 20 Wang M F, Li J G, Rangarajan M, Shao Y, LaVoie E J, Huang T -C, Ho C -T. Antioxidative phenolic compounds from sage (Salvia officinalis). J. Agric.  Food Chem.. 1998;  46 4869-73
    PubMedSearch in Google Scholar
  • 21 Chen Y, Wang M, Rosen R T, Ho C -T. 2,2′-Diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging active compounents from Polygonum multiflorum Thunb. J. Agric.  Food Chem.. 1999;  47 2226-8
    PubMedSearch in Google Scholar
  • 22 Constantin M, Bromont C, Fickat R, Massingham R. Studies on the activity of bepridil as a scavenger of free radicals. Biochem.  Pharmacol.. 1990;  40 1615-22
    PubMedSearch in Google Scholar
  • 23 Yokozawa T, Chen C -P, Dong E, Tanaka T, Nonaka G -I, Nishioka I. Study on the inhibitory effect of tannins and flavonoids against the 1 - 2-picrylhydrazyl radical. Biochem.  Pharmacol.. 1998;  56 213-22
    PubMedSearch in Google Scholar

Prof. Yueh-Hsiung Kuo

Department of Chemistry, National Taiwan University

Taipei 106

Taiwan R.O.C.

Email: yhkuo@ccms.ntu.edu.tw

Phone: +886-223638146

Fax: +886-223636359

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References

  • 1 Majumder P L, Maiti D C, Kraus W, Bokel M. Nimbidiol, a modified diterpenoid of the root-bark of Azadirachta indica .  Phytochemistry. 1987;  26 3021-3
    CrossrefPubMedSearch in Google Scholar
  • 2 Ara I, Siddiqui B S, Faigi S, Siddiqui S. Terpenoids from the stem bark of Azadirachta indica .  Phytochemistry. 1988;  27 1801-4
    CrossrefPubMedSearch in Google Scholar
  • 3 Siddiqui S, Ara I, Faigi S, Mahmood T, Siddiqui B S. Phenolic tricyclic diterpenoids from the bark of Azadirachta indica .  Phytochemistry. 1988;  27 3903-7
    CrossrefPubMedSearch in Google Scholar
  • 4 Ara I, Siddiqui B S, Faigi S, Siddiqui S. Tricyclic diterpenoids from the bark of Azadirachta indica .  Journal of Natural Products. 1988;  51 1054-61
    CrossrefPubMedSearch in Google Scholar
  • 5 Ara I, Siddiqui B S, Faigi S, Siddiqui S. Three new diterpenoids from the bark of Azadirachta indica .  Journal of Natural Product. 1990;  53 816-20
    PubMedSearch in Google Scholar
  • 6 Zoghbl M DGB, Roque N F, Gottlieb H F. Humirianthenolides, new degraded diterpenoids from Humirianthera rupestris .  Phytochemistry. 1981;  20 1669-73
    CrossrefPubMedSearch in Google Scholar
  • 7 Alvarenga M AD, Silva J D, Gottlieb H E, Gottlieb O R. Diterpenoids from Micrandropsis scleroxylon .  Phytochemistry. 1981;  20 1159-63
    CrossrefPubMedSearch in Google Scholar
  • 8 Cambie R C, Mander L M. Chemistry of the podocarpaceae-VI: Constituents of the heartwood of Podocarpus totara G. Benn.  Tetrahedron. 1962;  18 465-75
    CrossrefPubMedSearch in Google Scholar
  • 9 Lin Y T, Cheng Y S, Kuo Y H. Extractive components from the wood of Taiwania cryptomerioides Hayata: A new sesquiterpene polyalcohols, cadinan-3α,4α,9α-triol.  Journal of Chinese Chemical Society. 1970;  17 111-3
    PubMedSearch in Google Scholar
  • 10 Kuo Y H, Lin Y T, Lin Y T. Taiwanin H, a new lignan from the bark of Taiwania cryptomerioides Hayata.  Journal of Chinese Chemical Society. 1985;  32 381-3
    PubMedSearch in Google Scholar
  • 11 Kuo Y H, Lin Y T, Lin Y T. Two new diterpenes 6β-hydroxy-7β-methoxyroyleanone and 6β-acetoxy-7β-methoxyroyleanone from the bark of Taiwania cryptomerioides Hayata.  Chemistry Express. 1987;  2 217-20
    PubMedSearch in Google Scholar
  • 12 Lin W H, Fang J M, Cheng Y S. Diterpenoids and steroids from Taiwania cryptomerioides .  Phytochemistry. 1998;  48 1391-7
    CrossrefPubMedSearch in Google Scholar
  • 13 Kuo Y H, Chang C I, Lee C K. Six podocarpane-type trinorditerpenes from the bark of Taiwania cryptomerioides .  Chemical & Pharmaceutical Bulletin. 2000;  48 597-9
    PubMedSearch in Google Scholar
  • 14 Kuo Y H, Chang C I. Podocarpane-type trinorditerpenes from the bark of Taiwania cryptomerioides .  Journal of Natural Products. 2000;  63 650-2
    CrossrefPubMedSearch in Google Scholar
  • 15 Shimada K, Fujikawa K, Yahara K, Nakamura K. Antioxidative properties of xanthan on the autooxidation of soybean oil in cyclodextrin emulsion.  Journal of Agricultural and Food Chemistry. 1992;  40 945-8
    CrossrefPubMedSearch in Google Scholar
  • 16 Halliwell B. Reactive oxygen species in living systems: source, biochemistry, and role in human disease.  American Journal of Medicine. 1991;  91 14S-22S
    PubMedSearch in Google Scholar
  • 17 Kehrer J p. Free radicals as mediators of tissue injury and disease.  Critical Reviews in Toxicology. 1993;  23 21-48
    PubMedSearch in Google Scholar
  • 18 Jacob R A, Burri B J. Oxidative damage and defense.  American Journal of Clinical Nutrition. 1996;  63 9855-905
    PubMedSearch in Google Scholar
  • 19 Dinis T CP, Madeira V MC, Almeida L M. Action of phenolic derivatives (acetaminophen, salicylate, and 5-aminosalicylate) as inhibitors of membrane lipid peroxidation and as peroxyl radical scavengers. Arch. Biochem.  Biophys.. 1994;  315 161-9
    PubMedSearch in Google Scholar
  • 20 Wang M F, Li J G, Rangarajan M, Shao Y, LaVoie E J, Huang T -C, Ho C -T. Antioxidative phenolic compounds from sage (Salvia officinalis). J. Agric.  Food Chem.. 1998;  46 4869-73
    PubMedSearch in Google Scholar
  • 21 Chen Y, Wang M, Rosen R T, Ho C -T. 2,2′-Diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging active compounents from Polygonum multiflorum Thunb. J. Agric.  Food Chem.. 1999;  47 2226-8
    PubMedSearch in Google Scholar
  • 22 Constantin M, Bromont C, Fickat R, Massingham R. Studies on the activity of bepridil as a scavenger of free radicals. Biochem.  Pharmacol.. 1990;  40 1615-22
    PubMedSearch in Google Scholar
  • 23 Yokozawa T, Chen C -P, Dong E, Tanaka T, Nonaka G -I, Nishioka I. Study on the inhibitory effect of tannins and flavonoids against the 1 - 2-picrylhydrazyl radical. Biochem.  Pharmacol.. 1998;  56 213-22
    PubMedSearch in Google Scholar

Prof. Yueh-Hsiung Kuo

Department of Chemistry, National Taiwan University

Taipei 106

Taiwan R.O.C.

Email: yhkuo@ccms.ntu.edu.tw

Phone: +886-223638146

Fax: +886-223636359

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