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Characterization of New Ent-kaurane Diterpenoids of Yunnan Arabica Coffee Beans.

Chu R, Wan LS, Peng XR, Yu MY, Zhang ZR, Zhou L, Li ZR, Qiu MH - Nat Prod Bioprospect (2016)

Bottom Line: Five new ent-kaurane diterpenoids, named mascaroside III-V (1-3), and 20-nor-cofaryloside I-II (4-5), together with seven known diterpenoids, were isolated from methanol extracts of the green coffee beans of Yunnan Arabica Coffee.Their chemical structures were elucidated by extensive spectroscopic analyses.Meanwhile, cytotoxicity assay against HL-60, A-549, SMMC-7721, MCF-7 and SW480 cell lines showed that they have not evident inhibition of cytotoxicity.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China.

ABSTRACT
Five new ent-kaurane diterpenoids, named mascaroside III-V (1-3), and 20-nor-cofaryloside I-II (4-5), together with seven known diterpenoids, were isolated from methanol extracts of the green coffee beans of Yunnan Arabica Coffee. Their chemical structures were elucidated by extensive spectroscopic analyses. Meanwhile, cytotoxicity assay against HL-60, A-549, SMMC-7721, MCF-7 and SW480 cell lines showed that they have not evident inhibition of cytotoxicity.

No MeSH data available.


Related in: MedlinePlus

Key correlations in 2D NMR spectra of compound 1
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Fig2: Key correlations in 2D NMR spectra of compound 1

Mentions: Mascaroside III (1) was isolated as a white amorphous powder. The molecular formula C36H44O13 was deduced from the molecular ion peak at m/z [M + Na]+ 707.2670 (calcd for C36H44O13Na, 707.2674) in HREIMS. The IR spectrum indicated that 1 possessed hydroxyl (3440 cm−1) and α,β-unsaturated ketone (1650 cm−1) groups. The 13C NMR (DEPT) data (Tables 2, 3) showed 36 carbon resonances, attributed to a monosaccharide, a cinnamic acids group and an aglycone moiety, and the aglycone moiety were classified as one methyl (δC 15.7), 7 methylenes (including one oxygenated), 6 methines (including one oxygenated, two olefinic), and 6 quaternary carbons (including one oxygenated, two olefinic, and one carbonyl). These data (Tables 1, 2, 3) were similar to those of mascaroside I [10, 11] except for 10 additional signals for a cinnamic acids group. The coupling constant (J2″, 3″ = 15.9 Hz) suggested the double bond of the cinnamic acid group was trans. Besides, δH 6.80(d, J = 8.2 Hz), 7.10(d, J = 8.2 Hz) were due to ortho-aromatic hydrogen suggested the two oxygenated sp2 quaternary carbons were at C-6″ and C-7″, along with CH3-10″ linked to OH-7″ confirmed by the HMBC correlations from H3-10″ (δH 3.88) to C-7″. Further, the OH-6′ in the glucose and COOH-1″ in trans-cinnamic acids group formed into ester were confirmed by HMBC correlations of H-6′ (δH 4.29, 4.69) to C-1″ (δC 169.5). The relative configuration of glucose anomeric proton was confirmed as β on the basis of the coupling constant (J1′, 2′ = 7.8 Hz). Furthermore, the glucose was identified as D-form by GC analysis comparing with a standard after acid hydrolysis [12, 13]. The relative configuration of 1 was same with mascaroside I by comparison of the NMR data. Furthermore, owing to the greatly predominant occurrence of this enantiomeric form in nature world, and until now, all the kaurene skeleton diterpenoids have been isolated from Coffea arabica were ent-kaurene series. Therefore, compound 1 was confirmed as an ent-kauranoid with the negative specific rotation value (−126.67) confirmed it further. ent-Kauranoid with the configuration of C-20 being α-orientated and H-5, H-9 being β-orientated. The key ROESY correlations of H-11 (δH 3.86)/H-20 (δH 0.78), and H-5 (δH 2.83)/H-9 (δH 1.61), H-9/H-15b (δH 2.12), and H-15b/H2-17 (δH 3.59, 4.71) allowed to assign H-11 as α-orientated, and CH2OH-17 as β-orientated, separately [14]. Hence, the structure of 1 was determined and named as mascaroside III (Fig. 2).Table 1


Characterization of New Ent-kaurane Diterpenoids of Yunnan Arabica Coffee Beans.

Chu R, Wan LS, Peng XR, Yu MY, Zhang ZR, Zhou L, Li ZR, Qiu MH - Nat Prod Bioprospect (2016)

Key correlations in 2D NMR spectra of compound 1
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4940257&req=5

Fig2: Key correlations in 2D NMR spectra of compound 1
Mentions: Mascaroside III (1) was isolated as a white amorphous powder. The molecular formula C36H44O13 was deduced from the molecular ion peak at m/z [M + Na]+ 707.2670 (calcd for C36H44O13Na, 707.2674) in HREIMS. The IR spectrum indicated that 1 possessed hydroxyl (3440 cm−1) and α,β-unsaturated ketone (1650 cm−1) groups. The 13C NMR (DEPT) data (Tables 2, 3) showed 36 carbon resonances, attributed to a monosaccharide, a cinnamic acids group and an aglycone moiety, and the aglycone moiety were classified as one methyl (δC 15.7), 7 methylenes (including one oxygenated), 6 methines (including one oxygenated, two olefinic), and 6 quaternary carbons (including one oxygenated, two olefinic, and one carbonyl). These data (Tables 1, 2, 3) were similar to those of mascaroside I [10, 11] except for 10 additional signals for a cinnamic acids group. The coupling constant (J2″, 3″ = 15.9 Hz) suggested the double bond of the cinnamic acid group was trans. Besides, δH 6.80(d, J = 8.2 Hz), 7.10(d, J = 8.2 Hz) were due to ortho-aromatic hydrogen suggested the two oxygenated sp2 quaternary carbons were at C-6″ and C-7″, along with CH3-10″ linked to OH-7″ confirmed by the HMBC correlations from H3-10″ (δH 3.88) to C-7″. Further, the OH-6′ in the glucose and COOH-1″ in trans-cinnamic acids group formed into ester were confirmed by HMBC correlations of H-6′ (δH 4.29, 4.69) to C-1″ (δC 169.5). The relative configuration of glucose anomeric proton was confirmed as β on the basis of the coupling constant (J1′, 2′ = 7.8 Hz). Furthermore, the glucose was identified as D-form by GC analysis comparing with a standard after acid hydrolysis [12, 13]. The relative configuration of 1 was same with mascaroside I by comparison of the NMR data. Furthermore, owing to the greatly predominant occurrence of this enantiomeric form in nature world, and until now, all the kaurene skeleton diterpenoids have been isolated from Coffea arabica were ent-kaurene series. Therefore, compound 1 was confirmed as an ent-kauranoid with the negative specific rotation value (−126.67) confirmed it further. ent-Kauranoid with the configuration of C-20 being α-orientated and H-5, H-9 being β-orientated. The key ROESY correlations of H-11 (δH 3.86)/H-20 (δH 0.78), and H-5 (δH 2.83)/H-9 (δH 1.61), H-9/H-15b (δH 2.12), and H-15b/H2-17 (δH 3.59, 4.71) allowed to assign H-11 as α-orientated, and CH2OH-17 as β-orientated, separately [14]. Hence, the structure of 1 was determined and named as mascaroside III (Fig. 2).Table 1

Bottom Line: Five new ent-kaurane diterpenoids, named mascaroside III-V (1-3), and 20-nor-cofaryloside I-II (4-5), together with seven known diterpenoids, were isolated from methanol extracts of the green coffee beans of Yunnan Arabica Coffee.Their chemical structures were elucidated by extensive spectroscopic analyses.Meanwhile, cytotoxicity assay against HL-60, A-549, SMMC-7721, MCF-7 and SW480 cell lines showed that they have not evident inhibition of cytotoxicity.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China.

ABSTRACT
Five new ent-kaurane diterpenoids, named mascaroside III-V (1-3), and 20-nor-cofaryloside I-II (4-5), together with seven known diterpenoids, were isolated from methanol extracts of the green coffee beans of Yunnan Arabica Coffee. Their chemical structures were elucidated by extensive spectroscopic analyses. Meanwhile, cytotoxicity assay against HL-60, A-549, SMMC-7721, MCF-7 and SW480 cell lines showed that they have not evident inhibition of cytotoxicity.

No MeSH data available.


Related in: MedlinePlus