Isolation and identification of metabolites from mangosteen roots
Chemical investigation of EtOAc crude extract of mangosteen roots afforded two new benzophenones and one new biphenyl, specifically mangostanones I–III (12, 13 and 18), and one new present in naturally occurring, 4,5-dimethoxy[1,1′-biphenyl]-3-ol (20), together with eighteen identified compounds: isojacareubin (1), α-mangostin (2), β-mangostin (3), γ-mangostin (4), mangostanaxanthone IV (5), dulxanthone D (6), toxyloxanthone B (7), 1,7-dihydroxy-3-methoxy-2-prenylxanthone (8), euxanthone (9), norathyriol (10), 8-deoxygartanin (11), maclurin (14), 2,3′,4,6-tetrahydroxybenzophenone (15), mangaphenone (16), (2-hydroxy-4,6-dimethoxyphenyl)(3-hydroxy-4-methoxyphenyl)methanone (17), garciosine A (19), 3-hydroxy-4-geranyl-5-methoxybiphenyl (21) and epicatechin (22) as proven in Fig. 1. The constructions of the brand new compounds 12, 13 and 18 had been elucidated by evaluation of spectroscopic information, whereas the identified metabolites had been recognized by comparability of their NMR information with these reported within the literature18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36.
Mangostanone I (12) was obtained as a dark-yellow strong. HRESIMS evaluation confirmed a sodium adduct ion peak at m/z 313.0690 [M+Na]+ (calcd for 313.0688, C15H14NaO6). The 1H and 13C NMR spectra of compound 12 (Desk 1) confirmed a sample typical of a benzophenone framework30. The 1H NMR spectrum displayed alerts of a 1,2,4,6-tetrasubstituted benzene ring [δH 6.13 (1H, d, J = 2.0 Hz) and 6.15 (1H, d, J = 2.0 Hz)], a 1,3,5-trisubstituted benzene ring [δH 6.60 (2H, d, J = 2.1 Hz) and 6.51 (1H, d, J = 2.0 Hz)], and two methoxy teams at δH 3.88 (3H, s) and three.61 (3H, s). The 13C NMR spectrum assigned with the assistance of the HSQC information exhibited 15 alerts as a consequence of two methyls, 4 sp2 methines, and 6 non-protonated carbons representing one carbonyl (δC 202.4) and 5 oxygenated carbons. The fragrant protons at δH 6.60 and 6.13 had been correlated with the carbonyl group at δC 202.4 within the HMBC spectrum (Fig. 2), indicating the presence of a benzophenone moiety. The HMBC correlations from 4-OMe (δH 3.86) to C-4 (δC 166.2), H-3 to C-1, C-5, H-5 to C-1, C-3, and 6-OMe (δH 3.59) to C-6 (δC 162.5) confirmed the placement of two methoxy items at C-3 and C-5 on ring A. From the above information, compound 12 was proposed structurally as proven.
Mangostanone II (13) was obtained as a brown-yellow strong with the molecular formulation of C15H14O6 decided by HRESIMS at m/z 299.0537 [M+Na]+ (calcd 299.0532). Certainly, NMR spectroscopic information of 13 had been just like these of mangostanone I (12) (Desk 1), the key distinction was that compound 13 confirmed a resonance for a 1,3,4-trisubstituted benzene ring [δH 7.23 (1H, d, J = 2.0 Hz), 7.09 (1H, dd, J = 8.4, 2.0 Hz), and 6.85 (1H, d, J = 8.4 Hz)], whereas 12 had a 1,3,5-trisubstituted benzene on ring B. As well as, compound 12 had two methoxy teams on ring A, whereas compound 13 confirmed one methoxy at C-4. The placement of the methoxy group at C-4 was indicated by the HMBC correlations of 4-OMe (δH 3.58) to C-4 (δC 161.4).
Mangostanone III (18) was obtained as a white powder. The molecular formulation was C14H14O4 as decided by HRESIMS at m/z 269.0799 [M+Na]+ (calcd 269.0790). The IR spectrum of 18 confirmed absorption bands at 3465 cm−1 without cost hydroxyl group, 3001 cm−1 for fragrant C–H stretch, and 1596 and 1576 cm-1 for C=C stretch. The UV spectrum confirmed absorption bands at λmax at 221 and 267 nm that are typical of a hydroxygenated benzene by-product33. The 1H and 13C NMR spectroscopic information (Desk 1) displayed two meta-coupled fragrant protons at δH 6.78 (d, J = 2.0 Hz, H-2) and 6.63 (d, J = 2.0 Hz, H-6). The remaining resonances at δH 7.42 (2H, dt, J = 8.0, 2.0 Hz, H-2′ and H-6′) and 6.87 (2H dt, J = 8.0, 2.0 Hz, H-3′ and H-5′) recommended a 1,4-disubstituted benzene unit on ring B. The correlation of OH-3 (δH 5.84, s) to C-2 (δC 106.7), C-3 (δC 149.5), and C-4 (δC 134.9) within the HMBC spectrum (Fig. 2) confirmed the placement of hydroxyl group at C-3. The areas of the methoxy teams at C-4 and C-5 had been indicated by the HMBC correlations of OCH3-4 to C-4 (δC 134.9) and OCH3-5 to C-5.
Cytotoxicity of remoted compounds
To analyze anticancer properties of those compounds, preliminary screening of all remoted compounds was noticed by their cytotoxic capability in the direction of two hepatocellular carcinomas (HepG2 and Huh7) utilizing MTT methodology. Sorafenib and doxorubicin had been used as constructive drug controls. The outcomes (Desk 2) confirmed that compounds 1–6 and 11 had been appreciable lively on each cell strains examined with the IC50 worth lower than 40 μM, the compounds, apart from β-(3) and γ-mangostin (4), had been thus subjected to additional anti-migration assay. It’s because α-mangostin (2) with extremely remoted quantities was considered a consultant molecule of the compound collection, in addition to the impact of compound 3 on HCC cells has been reported37.
Anti-migration results on Huh7 cells
To evaluate whether or not candidate compounds may inhibit cell migration, compounds 1, 2, 5, 6 and 11 had been examined in dose- and time-dependent method for wound therapeutic exercise utilizing monolayer Huh7 cells scratch assay. On this experiment, the IC50 worth of candidate compounds had been thought-about in assessing wound therapeutic exercise. Dosage for experiments had been fastened as μM at IC50, (IC50/2), (IC50*2), and three μM following the IC50 worth of sorafenib described in earlier research. Sorafenib is an ordinary drug authorized to deal with many most cancers varieties similar to hepatocellular carcinoma, renal cell carcinoma, and thyroid most cancers38. Due to this, 3 μM had been used to check between examined compounds and commonplace drug in the identical focus. Consequently, compound 6 confirmed fascinating leads to inhibited cells migration. There have been no elevated of tissue restore proportion in all situations, together with on the identical dose of sorafenib (3 μM) since 24 h (Fig. 3a). Moreover, in larger focus we may barely see a change in morphology suggesting that this compound may not too poisonous. Remedy of compounds 1 and 11 led to the inhibition in dose-dependent method and the whole inhibition was noticed on the excessive dose 24 μM with out vital toxicity, whereas compounds 2 and 5 displayed average/weak inhibition at low focus, however poisonous at larger situation (Fig. 3b).
Impact of compound 6 on Huh7 apoptosis
Based mostly on the above outcomes, solely compound 6 was additional subjected to apoptotic evaluation. The concentrations of the compound had been just like these of earlier experiment (at IC50 and two-folds better than IC50 (IC50*2)). Untreated cells had been used as management. The Annexin V/phosphatidylserine (PS) double stain was carried out to review apoptotic cells and decided by Muse® Cell Analyzer. The outcomes indicated that compound 6 was in a position to induce Huh7 apoptosis in dose-dependent method, and it might be seen clearly when handled the cells with a 24 μM focus (Fig. 4). Nonetheless, the completely different between management and 12 μM focus had been barely seen. This consequence correlated with the earlier experiment, clarify the rationale that larger focus was approach too poisonous and result in the rise of cell apoptotic.
Impact of compound 6 on Erk and Bcl-2 household expression
To additional observe the impact of xanthone 6 on associated protein expression, Huh7 cells had been handled with the compound on the identical doses as earlier experiments, 6, 12 and 24 μM, and the extracted protein was subjected to western blot evaluation. As proven in Fig. 5, compound 6 clearly suppressed phosphorylated ERK expression in dose-dependent method. As well as, the compound diminished the expression stage of Bcl-2 and Bcl-XL and elevated the extent of Bax dose-dependently.