Article pubs.acs.org/jnp
β‑Dihydroagarofuran-Type Sesquiterpenes from the Seeds of Celastrus monospermus and Their Lifespan-Extending Effects on the Nematode Caenorhabditis elegans Lei Gao,†,‡,⊥ Rujun Zhang,†,⊥ Jianfeng Lan,§ Ruonan Ning,†,‡ Di Wu,§ Di Chen,*,§ and Weimin Zhao*,† †
Department of Natural Product Chemistry and State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, People’s Republic of China ‡ University of Chinese Academy of Sciences, Beijing 100049, People’s Republic of China § State Key Laboratory of Pharmaceutical Biotechnology and MOE Key Laboratory of Model Animals for Disease Study, Model Animal Research Center, Nanjing University, Nanjing 210061, People’s Republic of China S Supporting Information *
ABSTRACT: Seventeen β-dihydroagarofuran-type sesquiterpenes were isolated from the seeds of Celastrus monospermus, and, among them, 15 (1−15) were identified as new natural products. Nine isolates were evaluated for their lifespanextending effect using the standard model animal nematode Caenorhabditis elegans. As a result, all of the tested compounds prolonged the lifespan of C. elegans when compared to the blank control group (p < 0.0001). Among them, celaspermin E (5) extended the average lifespan and maximum lifespan of C. elegans, with effects similar to those of rapamycin, a positive control that has been found experimentally to delay the aging process of yeasts, worms, fruit flies, and mice.
A
mouse model.7 Celastrus monospermus Roxb. is an evergreen vine widely spread across countries of southern and eastern Asia.9 In the present investigation, 15 new β-dihydroagarofuran-type sesquiterpenes, named celaspermins A−O (1−15), along with two known compounds (16 and 17), were identified from the seeds of C. monospermus. Reported herein are the isolation and structural elucidation of these sesquiterpenoids as well as their lifespan-extending effects on the model animal Caenorhabditis elegans.
ging represents the accumulation of changes over time that are concerned with or account for the increasing sensibilities to diseases and death that accompany advancing age.1,2 The free radical theory has suggested that accumulation of free radical damage to cells and tissues is a predominant contributor to aging and is a major cause of cardiovascular and central nervous system deterioration.2 Many diseases, such as Alzheimer’s disease, Parkinson’s disease, cardiovascular disease, cancer, osteoporosis, arthritis, cataracts, type II diabetes, and stroke, are age-related, and their occurrence rises rapidly with advancing age.3,4 Healthy living habits and proper physical exercise may effectively slow down the aging process. In addition, the discovery of antiaging agents has also been pursued from ancient times. Metformin is currently the first compound that is in clinical trials for longevity studies in the United States. Rapamycin, an immunosuppressant for organ transplantation, has also been found to possess an ability to extend the lifespan of yeasts, nematodes, fruit flies, and mice, and inhibition of the target of rapamycin (TOR) has been related with extending lifespan as well as slowing the onset of certain age-related diseases across species.5,6 The seeds of several Celastrus plants have been used in mainland China and India to enhance memory.7,8 Jyothismati oil from the seeds of Celastrus paniculatus is also known as an “elixir of life” in India.7 β-Dihydroagarofuran-type sesquiterpenoids are a major group of constituents found in the genus Celastrus. In a previous investigation, four β-dihydroagarofurantype sesquiterpenes were found to improve memory by reducing the error number and escape time in a scopolamine-induced © XXXX American Chemical Society and American Society of Pharmacognosy
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RESULTS AND DISCUSSION Compound 1 gave a molecular formula of C30H38O11, as indicated by HRTOFMS (m/z 597.2295 [M + Na]+, calcd 597.2312) and NMR data. The 1H NMR spectrum of 1 indicated the presence of four acetyl groups at δ 2.12 (3H, s), 1.93 (3H, s), 1.85 (3H, s), and 1.73 (3H, s), a benzoyl group at δ 8.10 (2H, d, J = 7.3 Hz), 7.57 (1H, t, J = 7.3 Hz), and 7.46 (2H, t, J = 7.3 Hz), and five acylated oxymethine protons at δ 5.74 (1H, d, J = 10.4 Hz), 5.54 (1H, dd, J = 6.4, 3.0 Hz), 5.35 (1H, s), 5.28 (1H, d, J = 6.4 Hz), and 5.17 (1H, td, J = 10.4, 4.4 Hz). Besides the substituent groups, its 13C NMR spectrum indicated that 1 possesses a skeleton based on 15 carbons, including four methyls at δC 31.4 (C-12), 26.8 (C-13), 18.1 (C-14), and 19.6 (C-15), a methylene at δC 32.9 (C-3), seven methine carbons at δC 72.7 (C-1), 69.4 (C-2), 34.9 (C-4), 77.3 (C-6), 53.8 (C-7), 69.2 (C-8), and 72.3 (C-9), and three quaternary Received: July 12, 2016
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DOI: 10.1021/acs.jnatprod.6b00648 J. Nat. Prod. XXXX, XXX, XXX−XXX
Journal of Natural Products
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carbons at δC 89.0 (C-5), 83.5 (C-11), and 50.8 (C-10). All these data suggested that compound 1 is a pentasubstituted β-dihydroagarofuran-type sesquiterpene. The assignments of the substituent groups were determined by an HMBC experiment, in which correlation signals were found between H-9 (δH 5.28) and the carbonyl signal of the benzoate group at δC 166.2 and between H-1 (δH 5.74), H-2 (δH 5.17), H-6 (δH 5.35), and H-8 (δH 5.54) and the carbonyl signals of the acetyl groups at δC 169.3, 170.8, 169.7, and 169.3, respectively. The relative configuration of 1 was established according to NOE signals as well as coupling constant of adjacent protons. The large coupling constant between H-1 and H-2 (J = 10.4 Hz) suggested that both H-1 and H-2 are axially oriented. The NOE correlation signals between H-1 and H-3β, between H-15 and H-2, H-6, H-9, H-14, and between H-6 and H-8 revealed that H-1 is β-configured, while H-2, H-6, H-8, H-9, H-14, and H-15 are α-disposed. The absolute configuration of 1 was confirmed by single-crystal X-ray diffraction analysis using Cu Kα radiation [Flack parameter: 0.08(5)]. In this manner, compound 1 was determined as (1R,2R,4R,5S,6R,7R,8S,9R,10S)-1,2,6,8-tetraacetoxy-9-benzoyloxy-β-dihydroagarofuran and has been assigned the trivial name celaspermin A. The molecular formulas of 2 and 3 were determined to be C35H40O11 and C37H42O11, respectively, according to their HRTOFMS and 13C NMR data. Both compounds displayed similar NMR data to those of 1, except that the acetyl group at C-6 in 1 was replaced by a benzoyl group in 2 and by a cinnamoyl group in 3. Detailed analysis of the 2D NMR spectra enabled the identification of 2 (celaspermin B) and 3 (celaspermin C) as 1α,2β,8β-triacetoxy-6β,9β-dibenzoyloxy-β-dihydroagarofuran and 1α,2β,8β-triacetoxy-6β-cinnamoyloxy-9βbenzoyloxy-β-dihydroagarofuran, respectively. Compound 4, obtained as colorless crystals, showed the molecular formula C30H38O11 according to its HRTOFMS (m/z 597.2325 [M + Na]+, calcd 597.2312) and NMR data. The planar structure of 4 was found to be identical to that of 1 as determined by their 1H−1H COSY, HSQC, and HMBC spectra. The coupling constant between H-1 and H-2 (J = 10.2 Hz) indicated that both H-1 and H-2 are axially oriented. The NOE correlations between H-15 and H-6, H-14 and between H-1 and H-9 suggested that H-1 and H-9 are β-configured, with H-2 and H-6 being α-oriented. No clear splitting was found between H-8 and H-9, which indicated H-8 to be β. Thus, compound 4 (celaspermin D) was characterized as 1α,2β,6β,8α-tetraacetoxy-9α-benzoyloxy-β-dihydroagarofuran. Compound 5 showed the molecular formula C28H34O10, according to its HRTOFMS (m/z 553.2067 [M + Na]+, calcd 553.2050) and NMR data. The arrangement of the substituent groups was established by 1H−13C long-range correlation signals between H-1 (δH 5.61) and the AcO-1 carbonyl carbon (δC 169.8), between H-6 and the AcO-6 carbonyl carbon (δC 169.9), between H-8 (δH 5.52) and the AcO-8 carbonyl carbon (δC 170.0), between H-9 and the BzO-9 carbonyl carbon (δC 165.2), and between H-1 (δH 5.61), H-3α (δH 2.22), H-3β (δH 3.21), H-4 (δH 2.78) and the C-2 ketone carbon (δC 203.5) in its HMBC spectrum. The NOESY cross-peaks between H-9 and H-1, H-12, between H-8 and H-12, and between H-15 and H-6, H-14 indicated that H-1, H-8, and H-9 are β-oriented, while H-6 is α-oriented. Thus, compound 5 (celaspermin E) was determined as 1α,6β,8α-triacetoxy-9α-benzoyloxy-2-oxo-βdihydroxyagarofuran. Celaspermin F (6) showed the molecular formula C28H36O9 as determined by its HRTOFMS (m/z 539.2256 [M + Na]+,
calcd 539.2257) and NMR data. According to the 1H NMR spectrum, three acetyl groups [δ 1.80 (3H, s), 1.97 (3H, s), and 2.13 (3H, s)] and a benzoyl group [δ 7.42 (2H, t, J = 7.6 Hz), 7.51 (1H, t, J = 7.5 Hz), and 8.39 (2H, d, J = 7.5 Hz)] exist in the structure of 6, and four acylated oxymethine protons display at δ 5.25 (1H, d, J = 6.7 Hz), 5.49 (1H, td, J = 10.4, 4.4 Hz), 5.52 (1H, s), and 6.13 (1H, d, J = 10.4 Hz). The planar structure of 6 was established by analyzing its 1D and 2D NMR spectra. In its HMBC spectrum, 1H−13C long-range correlation signals were found between H-1 (δH 6.13) and the AcO-1 carbonyl carbon (δC 169.4), between H-2 (δH 5.49) and the AcO-2 carbonyl carbon (δC 170.9), between H-6 (δH 5.52) and the AcO-6 carbonyl carbon (δC 170.4), and between H-9 and the BzO-9 carbonyl carbon (δC 166.2). The coupling constant between H-1 and H-2 (10.4 Hz) indicated both H-1 and H-2 to be axially oriented, and the NOESY cross-peaks between H-3α and H-2, H-14, H-15, between H-15 and H-6, H-9, H-14, and between the aromatic proton signal at δH 8.39 and H-1 revealed the structure of 6 as 1α,2β,6β-triacetoxy-9β-benzoyloxy-β-dihydroagarofuran. The structures of 7 (celaspermin G) and 8 (celaspermin H) shared several similarities to that of 6, with the exception of the acetyl group at C-6 in 6 being replaced by a cinnamoyl group in 7 and C-8 in 6 being substituted by an α-hydroxy group in 8. The location of the cinnamoyl group in 7 was determined by the 1H−13C long-range correlation signal between H-6 (δH 5.92) and the carbonyl carbon signal at δC 166.1. The relative configuration of the hydroxy group in 8 was ascertained by a NOESY cross-peak between H-8 and H-12. Therefore, the structures of 7 and 8 were proposed as 1α,2β-diacetoxy-6βcinnamoyloxy-9β-benzoyloxy-β-dihydroagarofuran and 1α,2β,6β-triacetoxy-8α-hydroxy-9β-benzoyloxy-β-dihydroagarofuran, respectively. Celaspermin I (9) gave a molecular formula of C32H37NO9 as determined by HRTOFMS (m/z 580.2530 [M + H]+, calcd 580.2547). A nicotinoyl, a benzoyl, and two acetyl groups along with a tetrasubstituted β-dihydroagarofuran skeleton could be identified and connected by analysis of 1H−1H COSY, HSQC, and HMBC spectra. The large coupling constant between H-1 and H-2 (10.4 Hz) indicated that both H-1 and H-2 are axially oriented. Furthermore, the NOESY correlations between H-15 and H-8, H-9 revealed their cis orientation, tentatively assigned as α configuration, while the NOESY correlations between H-1 and the aromatic proton signal (δH 8.29) of the benzoyloxy group at C-9 indicated H-1 to be β-oriented. Therefore, the structure of 9 was proposed as 1α,2β-diacetoxy-8β-nicotinoyloxy-9β-benzoyloxy-β-dihydroagarofuran. Celaspermin J (10) showed the molecular formula C27H36O14, as determined by HRTOFMS (m/z 607.1996 [M + Na]+, calcd 607.2003). According to its 1H NMR data, six acetoxy groups were attached to the β-dihydroagarofuran skeleton. In its HMBC spectrum, 1H−13C long-range correlation signals were found between the signals at δC 198.2 and H-6 (δH 6.34), H-7 (δH 3.01), H-9 (δH 5.59), which was used to locate a carbonyl group at C-8. The NOESY cross-peaks between H-1 (d, J = 3.5 Hz) and H-2, H-3, H-9, between H-6 and H-14, and between H-9 and H-12 supported the structural assignment of this compound as 1α,2α,3α,6β,9α,15-hexaacetoxy-8-oxo-βdihydroagarofuran. According to the 1H and 13C NMR data of 11 (celaspermin H), a cinnamoyl, a benzoyl, and three acetyl groups could be identified in its structure. The planar structure of this compound was determined according to its HMBC spectrum, in B
DOI: 10.1021/acs.jnatprod.6b00648 J. Nat. Prod. XXXX, XXX, XXX−XXX
Journal of Natural Products
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C. elegans have been well-defined, and the aging process between C. elegans and mammals shares many similarities.16,17 Moreover, C. elegans has a relatively short lifespan, which may shorten the testing time necessary and reduce experimental costs, and so it has become a commonly used laboratory model animal to investigate whether an agent has the ability to extend lifespan. It was found that all nine of the tested β-dihydroagarofuranoids significantly extended the lifespan of C. elegans compared to the blank control group (p < 0.0001), as shown in Table 4, Figure 5, and the Supporting Information. Among them, celaspermin E (5) prolonged the average lifespan of C. elegans to an extent similar to that of rapamycin, the positive control used. The pharmacological mechanism of lifespan-extending effects of the above β-dihydroagarofurantype sesquiterpoids deserves further exploration, and evaluation of their antiaging effects on other model animals seems to be warranted.
which cross-peaks were observed between H-1 (δH 5.40) and the AcO-1 carbonyl carbon (δC 170.1), between H-2 (δH 5.53) and the CinO-2 carbonyl carbon (δC 166.2), between H-6 (δH 6.03) and the AcO-6 carbonyl carbon (δC 170.1), between H-8 (δH 5.55) and the AcO-8 carbonyl carbon (δC 170.0), and between H-9 (δH 5.51) and the BzO-9 carbonyl carbon (δC 165.0). In the NOESY spectrum of 11, correlation signals were observed between H-1 (J = 3.7 Hz) and H-3β, H-9, between H3β (ddd, J = 14.9, 6.7, 3.5 Hz) and H-2, H-3α (dd, J = 14.9 Hz, 2,1 Hz), between H-12 and H-8, H-9, and between H-15 and H-6, H-14, which indicated that H-1, H-2, H-8, and H-9 are β-oriented, while H-6 is α-configured. Its ECD spectrum showed a Davidoff-type split curve with a positive first Cotton effect at 273 nm (Δε = 5.95) and a negative second Cotton effect at 231 nm (Δε = −4.56), due to the coupling of the cinnamoyloxy group at C-2 and the benzoyloxy function at C-9. Thus, compound 11 was determined as (1R,2S,4R,5S,6R,7R,8R,9S,10S)1,6,8-triacetoxy-2-cinnamoyloxy-9-benzoyloxy-β-dihydroagarofuran. On the basis of the HRTOFMS and NMR data, the molecular formulas of 12 and 13 were established as C32H40O13 and C30H38O11. Compounds 12 and 13 were found to share the same planar configuration and relative configuration and varied in that an acetoxy group at C-15 in 12 was absent in 13. The relative configurations of 12 and 13 were determined by NOESY experiments and from their 1H NMR coupling constants. The NOE between H-1 (J = 3.3 Hz) and H-3β (dd, J = 15.2, 3.4 Hz), between H-3α (dd, J = 15.2, 2.0 Hz) and H-14, and between H-6 and H-8, H-15 revealed compound 12 (celaspermin L) to be 1α,2α,6β,8β,15-pentaacetoxy-9β-benzoyloxy-β-dihydroagarofuran. Compound 13 (celaspermin M) was determined in the same manner as 1α,2α,6β,8β-tetraacetoxy9β-benzoyloxy-β-dihydroagarofuran. The structure of 14 (C34H39NO11) was found to be comparable in many aspects to that of 13. However, the acetyl group at C-6 in 13 was replaced by a nicotinoyl group in 14. In its 1H NMR spectrum, the H-1 and H-2 signals were overlapped at δH 5.60. The NOESY cross-peaks between the overlapped signals at δH 5.60 and H-3α, H-3β, H-15 along with the small coupling constants between H-2 and H-3α (d, J = 14.5 Hz), H-3β (ddd, J = 14.5, 6.6, 3.0 Hz) indicated that both H-1 and H-2 are equatorially oriented. NOESY cross-peaks were also found between H-15 and H-6, H-8, H-9, H-14. Therefore, compound 14 (celaspermin N) was assigned as 1β,2α,8β-triacetoxy-6β-nicotinoyloxy-9β-benzoyloxy-β-dihydroagarofuran. Compound 15 (celaspermin O; C28H36O9) displayed a high degree of overall structural similarity to 14, except for the absence of the nicotinoyl group at C-6. The structure of 15 was characterized as 1β,2α,8β-triacetoxy-9β-benzoyloxy-β-dihydroagarofuran. The structures of two known compounds (16 and 17) were also identified by comparing their observed and reported NMR data.10,11 β-Dihydroagarofuran-type sesquiterpenoids, as the major secondary metabolites of the seeds of Celastrus plants, have been found to possess diverse biological activities, such as memorypromoting,7,8 antibacterial,12 cytotoxic,13 anti-inflammatory,14 neuroprotective,7 and rat ileum relaxant activities.15 Nine abundant β-dihydroagarofuran-type sesquiterpenes isolated from the seeds of C. monospermus were evaluated for their lifespanextending effects using the model animal Caenorhabditis elegans. The genetic and environmental factors that affect the lifespan of
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EXPERIMENTAL SECTION
General Experimental Procedures. Optical rotations were measured on a PerkinElmer 341 polarimeter, and IR spectra were recorded using KBr disks on a PerkinElmer 577 spectrometer (PerkinElmer, Waltham, MA, USA). ECD spectra were obtained on a JASCO J-810 spectrometer (JASCO Corporation, Tokyo, Japan). NMR experiments were performed on Bruker AM-400, Bruker Advance III 500, Bruker Advance III 600 (Bruker, Ettlingen, Germany), or Varian Mercury Plus-400 (Varian, Palo Alto, CA, USA) instruments using tetramethylsilane as an internal standard. ESIMS analyses were performed on a Shimadzu LC-MS-2020 spectrometer with a Shimadzu SPD-M20 (Shimadzu, Kyoto, Japan) diode array detector using CNW C18 (2.1 × 50 mm, 3.5 μm) or CNW C18 (2.1 × 100 mm, 3.5 μm) columns (Anpel Scientific Instrument Co., Ltd., Shanghai, People’s Republic of China). HRESIMS analyses were performed on a Waters Micromass QTOF Ultima Global mass spectrometer (Waters, Milford, MA, USA). Semipreparative HPLC was performed on a Unimicro EasySep-1010 binary pump system with a Unimicro EasySep-1010 detector (Unimicro, Shanghai, People’s Republic of China) using a YMC-Pack ODS-A column (250 × 20 mm, 5 μm) (YMC Co., Ltd., Kyoto, Japan). Precoated silica gel GF254 plates and silica gel (300−400 mesh) (Qingdao Haiyang Chemical Co., Ltd., Qingdao, People’s Republic of China) were used for TLC and column chromatography, respectively. Plant Material. The seeds of C. monospermus were collected in Yangchun, Guangdong Province, People’s Republic of China, in October 2014. A voucher specimen (no. SIMM1410-22) has been deposited in the herbarium of Shanghai Institute of Materia Medica and was identified by Prof. Peishan Xie of Guangzhou Institute of Drug Control. Extraction and Isolation. The seeds of C. monospermus (45 g) were powdered and extracted ultrasonically with CH2Cl2 at room temperature (1000 mL × 3) to give a crude extract (16 g), which was fractionated on a silica gel (300−400 mesh) column eluted with a petroleum ether/acetone gradient (25:1, 10:1, and 3:1, v/v) to afford seven fractions (Fr. 1−7). Compounds 1 (1.2 g), 4 (140 mg), 10 (980 mg), and 17 (548 mg) were obtained from Fr. 4, 3, 7, and 6, respectively. Fraction 2 (300 mg) was further separated by semipreparative HPLC (acetonitrile/water, 70:30−80:20, v/v, 40 min) to give compounds 6 (8 mg), 15 (8 mg), and 16 (10 mg). Compound 7 (26 mg) was obtained from Fr. 3 (370 mg); compounds 2 (9 mg), 5 (8 mg), 11 (8 mg), 12 (8 mg), and 13 (90 mg) were obtained from Fr. 4 (3200 mg); compound 3 (9 mg) was obtained from Fr. 5 (150 mg); compounds 8 (6 mg) and 9 (6 mg) were obtained from Fr. 6 (350 mg); and compound 14 (9 mg) was obtained from Fr. 7 (150 mg) by using the same instrument and similar eluent system as used in the separation of Fr. 2. (1R,2R,4R,5S,6R,7R,8S,9R,10S)-1,2,6,8-Tetraacetoxy-9-benzoyloxy-β-dihydroagarofuran (1): colorless, monoclinic crystals (petroleum ether/acetone); [α]24 D +40 (c 0.3, MeOH); IR (KBr) νmax 1745, C
DOI: 10.1021/acs.jnatprod.6b00648 J. Nat. Prod. XXXX, XXX, XXX−XXX
5.35 s
2.47 d (3.0)
5.54 dd (6.4, 3.0)
5.28 d (6.4)
1.55 s
1.41 s
1.12 d (7.6)
1.47 s
6
7
8
9
12
13
14
15
1.53 s
1.15 d (7.6)
1.47 s
1.58 s
5.34 d (6.3)
5.66 dd (6.3, 3.0)
2.65 d (3.0)
5.59 s
2.62 m
2.35 td (12.6, 5.2)
1.51 s
1.15 d (7.6)
1.47 s
1.57 s
5.31 d (6.2)
5.61 dd (6.4, 3.0)
2.57 d (3.0)
5.50 s
2.52 m
2.32 td (12.6, 5.7)
1.56 s
1.15 d (7.6)
1.42 s
1.49 s
5.02 s
5.20 d (3.0)
2.50 d (3.0)
5.74 s
2.46 m
2.29 td (12.7, 5.8)
1.80 dd (12.7, 3.6)
5.20 td (10.2, 3.2)
5.69 d (10.2)
4
1.41 s
1.04 d (7.6)
1.50 s
1.64 s
5.76 d (5.2)
5.52 t (4.6)
2.60 d (4.0)
5.98 s
2.78 m
3.21 dd (13.0, 7.0)
2.22 dd (13.0, 1.5)
5.61 s
5
D
a
6.18 5.48 1.92 2.46 2.07 2.15 2.44 5.98 5.74 1.77 1.26 1.10 1.38
d (10.3) td (10.3, 4.4) dd (12.5, 3.6) td (12.5, 6.1) m d (13.2); 2.25 dd (13.3, 5.0) brs dd (6.0, 3.3) d (6.1) s s d (7.8) s
9a
Recorded in pyridine-d5.
1 2 3α 3β 4 6 7 8 9 12 13 14 15
no.
dd (2.8, 1.2) m d (0.9) d (0.9) s s s d (8.0) d (12.8); 4.83 d (12.8)
4.83 2.65 6.34 3.01 5.59 1.43 1.41 1.25 4.43
5.88 d (3.1) 5.37 td (3.1, 1.2)
10 5.40 5.53 1.87 2.41 2.35 6.03 2.55 5.55 5.51 1.57 1.44 1.33 1.75
d (3.9) brs dd (14.9, 2.1) ddd (14.9, 6.7, 3.6) m s d (4.4) brs brs s s d (8.7) s
11 5.69 5.57 1.81 2.43 2.41 5.92 2.48 5.78 5.58 1.58 1.43 1.19 4.42
d (3.3) brs dd (15.2, 2.0) dd (15.2, 3.4) m s d (3.2) dd (6.6, 3.2) d (6.6) s s d (7.4) d (13.0); 4.92 d (13.0)
12
6a
1.41 s
5.55 5.57 1.79 2.41 2.35 5.42 2.49 5.61 5.25 1.54 1.41 1.21 1.52
13 d (3.3) dd (6.6, 3.3) dd (14.8, 3.3) ddd (14.8, 6.5, 3.3) m s d (2.7) dd (6.0, 2.7) d (6.0) s s d (7.7) s
1.08 d (7.7)
1.48 s
1.51 s
5.25 d (6.7)
2.43 m; 2.19 dd (15.7, 3.4)
2.22 m
5.52 s
2.43 m
2.43 m
1.91 dd (10.8, 4.5)
5.49 td (10.4, 4.4)
6.13 d (10.4)
Table 2. 1H NMR Data of the Carbon Framework of Compounds 9−15 (δ ppm, J in Parentheses) in CDCl3
Recorded in pyridine-d5.
2.43 m
4
a
2.27 td (12.6, 5.7)
3β
5.19 td (10.3, 4.3)
1.80 ddd (12.6, 4.8, 1.9) 1.85 ddd (12.6, 4.6, 1.8) 1.82 ddd (12.6, 4.8, 1.5)
5.20 td (10.4, 5.0)
5.17 td (10.4, 4.4)
3α
5.77 d (10.3)
3
2
5.79 d (10.4)
2
5.74 d (10.4)
1
1
no.
Table 1. 1H NMR Data of the Carbon Framework of Compounds 1−8 (δ ppm, J in Parentheses) in CDCl3 7
5.60 5.60 1.84 2.47 2.52 5.68 2.67 5.71 5.30 1.57 1.45 1.23 1.57
14 s s d (14.5) ddd (14.5, 6.6, 3.0) m s d (6.2) dd (6.0, 3.0) d (6.2) s s d (7.6) s
1.46 s
1.16 d (7.6)
1.44
1.45
5.03 d (6.8)
2.47 m; 2.18 dd (16.5, 3.1)
2.31 m
5.47 s
2.54 m
2.35 td (12.7, 5.7)
1.83 ddd (12.7, 4.7, 1.8)
5.19 td (10.5, 4.4)
5.78 d (10.5)
8
5.54 5.54 1.78 2.43 1.96 2.18 2.27 5.45 5.25 1.50 1.22 1.26 1.44
15 s s d (15.2) ddd (15.2, 6.5, 2.9) m d (12.5); 2.30 m m dd (6.3, 3.0) d (6.0) s s d (8.1) s
1.57 s
1.15 d (7.5)
1.43 s
1.36 s
4.88 s
4.27 d (3.0)
2.43 d (3.0)
5.92 s
2.46 m
2.28 td (12.4, 5.6)
1.80 ddd (12.4, 4.6, 2.0)
5.20 td (10.3, 4.5)
5.70 d (10.3)
Journal of Natural Products Article
DOI: 10.1021/acs.jnatprod.6b00648 J. Nat. Prod. XXXX, XXX, XXX−XXX
Journal of Natural Products
Article
Table 3. 13C NMR Data of the Carbon Framework of Compounds 1−15 in CDCl3 no.
1
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
72.7 69.4 33.0 34.9 89.0 77.3 53.8 69.2 72.3 50.8 83.5 26.8 31.4 18.1 19.6
a
2 d d t d s d d d d s s q q q q
72.8 69.4 33.1 35.3 89.3 78.0 53.9 69.2 72.4 50.9 83.5 26.8 31.7 18.2 19.7
3 d d t d s d d d d s s q q q q
72.7 69.4 33.1 35.1 89.2 77.3 53.8 69.2 72.4 50.9 83.6 26.9 31.6 18.1 19.7
4 d d t d s d d d d s s q q q q
73.0 69.4 33.0 34.9 89.7 75.7 53.1 76.3 76.9 51.8 82.5 25.8 31.0 18.1 19.6
6a
5 d d t d s d d d d s s q q q q
82.3 203.5 43.8 38.7 89.8 75.0 52.5 71.5 73.0 54.4 82.9 24.3 30.8 17.9 13.5
d s t d s d d d d s s q q q q
74.0 70.1 33.8 35.8 90.0 79.6 49.4 32.5 73.9 52.9 83.9 26.6 31.2 18.3 19.8
7 d d t d s d d t d s s q q q q
73.2 69.6 33.1 35.3 89.3 79.6 49.0 32.3 73.3 52.5 83.3 26.3 30.9 18.3 19.8
9a
8 d d t d s d d t d s s q q q q
73.3 69.5 33.1 34.9 89.9 75.5 55.5 74.9 80.4 51.4 82.2 31.2 25.9 18.1 20.1
d d t d s d d d d s s q q q q
73.6 69.8 33.8 40.9 87.3 36.1 49.4 72.3 73.6 50.8 83.4 26.0 31.8 18.4 19.3
10 d d t d s s d d d s s q q q q
72.6 d 69.9 d 73.6 d 37.5 d 90.8 s 75.4 s 64.2 d 198.2s 78.8 d 51.3 s 83.6 s 30.5 q 25.2 q 15.4 q 60.1 q
11 76.4 70.0 31.3 33.6 90.8 75.0 52.6 71.5 74.6 48.6 82.0 24.3 20.6 18.6 13.9
12 d d d d s d d d d s s q q q q
71.2 69.7 30.9 33.4 89.2 76.4 53.7 70.5 68.8 52.4 83.2 26.7 31.2 18.0 64.5
13 d d t d s s d d d s s q q q t
70.9 70.1 31.1 33.9 89.5 77.3 53.8 68.9 72.4 48.5 83.3 26.7 31.4 18.6 20.4
14 d d t d s s d d d s s q q q q
70.8 69.9 31.1 34.2 89.7 78.5 53.9 68.8 72.3 48.5 83.3 26.7 31.7 18.7 20.4
15 d d t d s d d d d s s q q q q
71.0 70.4 31.2 39.3 86.9 36.0 48.7 70.4 72.8 47.8 82.6 25.2 31.3 19.3 20.1
d d t d s d d d d d s q q q q
Recorded in pyridine-d5. 1α,2β,8β-Triacetoxy-6β-cinnamoyloxy-9β-benzoyloxy-β-dihydroagarofuran (3): white, amorphous powder; [α]26 D +57 (c 0.07, MeOH); IR (KBr) νmax 1763, 1718, 1638, 1453, 1373, 1284, 1248, 1093, 1022, 766, 715 cm−1; 1H NMR data (CDCl3) δ 1.74 (3H, s, AcO-1), 1.93 (3H, s, AcO-2), 1.86 (3H, s, AcO-8), CinO-6 and BzO-9 [8.12 (2H, d, J = 7.2 Hz), 7.73 (1H, d, J = 16.0 Hz), 7.56 (3H, m), 7.46 (2H, t, J = 7.7 Hz), 7.41 (3H, m), 6.45 (1H, d, J = 16.0 Hz)], for other signals, see Table 1; 13C NMR data (CDCl3) δ AcO-1 [20.6 (q), 169.3 (s)], AcO-2 [21.2 (q), 170.8 (s)], AcO-8 [20.8 (q), 169.3 (s)], CinO-6 and BzO-9 [146.4 (d), 134.1 (s), 133.3 (d), 131.0 (d), 130.6 × 2 (d), 129.7 (s), 129.1 × 2 (d), 128.4 × 2 (d), 128.3 × 2 (d), 117.3 (d), 165.7 (s), 166.2 (s)], for other signals, see Table 2; HRTOFMS m/z 685.2610 [M + Na]+ (calcd for C37H42O11Na, 685.2625). 1α,2β,6β,8α-Tetraacetoxy-9α-benzoyloxy-β-dihydroagarofuran (4): colorless crystals; [α]24 D −23 (c 0.1, MeOH); IR (KBr) νmax 1748, 1721, 1605, 1459, 1369, 1236, 1099, 1034, 721 cm−1; 1H NMR data (CDCl3) δ 1.68 (3H, s, AcO-1), 2.20 (3H, s, AcO-2), 2.10 (3H, s, AcO-6), 1.93 (3H, s, AcO-8), BzO-9 [8.07 (2H, d, J = 7.8 Hz), 7.56 (1H, t, J = 7.3 Hz), 7.45 (2H, t, J = 7.6 Hz)], for other signals, see Table 1; 13C NMR data (CDCl3) δ AcO-1 [20.7 (q), 169.3 (s)], AcO2 [21.3 (q), 169.5 (s)], AcO-6 [21.4 (q), 170.0 (s)], AcO-8 [21.2 (q), 170.8 (s)], BzO-9 [133.6 (d), 130.6 × 2 (d), 129.1 (s), 128.3 × 2 (d), 165.3 (s)], for other signals, see Table 3; HRTOFMS m/z 597.2325 [M + Na]+ (calcd for C30H38O11Na, 597.2312). 1α,6β,8α-Triacetoxy-9α-benzoyloxy-2-oxo-β-dihydroagarofuran (5): white, amorphous powder; [α]24 D −42 (c 0.1, MeOH); IR (KBr) νmax 1757, 1730, 1275, 1230, 1117, 709 cm−1; 1H NMR data (CDCl3) δ 1.59 (3H, s, AcO-1), 2.13 (3H, s, AcO-6), 2.13 (3H, s, AcO-8), BzO9 [8.02 (2H, d, J = 8.2 Hz), 7.59 (1H, t, J = 7.4 Hz), 7.46 (2H, t, J = 7.7 Hz)], for other signals, see Table 1; 13C NMR data (CDCl3) δ AcO-1 [20.2 (q), 169.8 (s)], AcO-6 [21.4 (q), 169.9 (s)], AcO-8 [21.0 (q), 170.0 (s)], BzO-9 [133.6 (d), 129.7 × 2 (d), 129.7 (s), 128.8 × 2 (d), 165.2 (s)], for other signals, see Table 3; HRTOFMS m/z 553.2067 [M + Na]+ (calcd for C28H34O10Na, 553.2050). 1α,2β,6β-Triacetoxy-9β-benzoyloxy-β-dihydroagarofuran (6): white, amorphous powder; [α]20 D −2 (c 0.1, CH2Cl2); IR (KBr) νmax 1748, 1709, 1370, 1284, 1245, 1099, 1025, 718 cm−1; 1H NMR data (C5D5N) δ 1.80 (3H, s, AcO-1), 1.97 (3H, s, AcO-2), 2.13 (3H, s, AcO-6), BzO-9 [8.39 (2H, d, J = 7.5 Hz), 7.51 (1H, t, J = 7.5 Hz), 7.42 (2H, t, J = 7.6 Hz)], for other signals, see Table 1; 13C NMR data (C5D5N) δ AcO-1 [20.9 (q), 169.4 (s)], AcO-2 [21.3 (q), 170.9 (s)], AcO-6 [21.5 (q), 170.4 (s)], BzO-9 [133.7 (d), 131.2 × 2 (d), 131.1 (s), 128.9 × 2 (d), 166.2 (s)], for other signals, see Table 3; HRTOFMS m/ z 539.2256 [M + Na]+ (calcd for C28H36O9Na, 539.2257). 1α,2β-Diacetoxy-6β-cinnamoyloxy-9β-benzoyloxy-β-dihydroagarofuran (7): white, amorphous powder; [α]24 D +49 (c 0.06, MeOH); IR (KBr) νmax 1745, 1709, 1638, 1453, 1379, 1278, 1245, 1102, 1015, 772, 715 cm−1; 1H NMR data (CDCl3) δ 1.71 (3H, s, AcO-1), 1.94 (3H, s, AcO-2), CinO-6 and BzO-9 [8.11 (2H, d, J = 7.8 Hz), 7.71
Table 4. Lifespan-Extending Effects of Compounds 1, 2, 4−6, 11, 12, 15, and 16 lifespan (days) compound
mean
max
DMSO 1 2 4 5 6 11 12 15 16 DMSO rapamycin
13.28 15.23 17.00 15.54 18.25 15.18 15.23 15.44 14.90 15.38 13.11 18.06
17 23 23 23 27 19 21 23 23 23 19 27
lifespan extensiona 15% 28% 17% 37% 14% 15% 16% 12% 16% 38%
nb 64 60 59 59 59 65 61 59 61 63 57 72
pc
