Triterpenoids from Melia toosendan

Meliasanines A-L, tirucallane-type triterpenoids from Melia toosendan with anti-inflammatory properties via NF-κB signaling pathway

Meliasanines A-L, twelve previously unreported tirucallane-type triterpenoids, together with fifteen known ones, have been isolated from the stem bark of Melia toosendan. Their structures and absolute configurations were determined based on HRESIMS, and NMR, combined with calculated ECD and single-crystal X-ray diffraction analyses. Subsequently, all compounds except 10 were evaluated for their inhibitory effect on the production of nitric oxide induced by lipopolysaccharide in RAW264.7 macrophage cells. The results indicated that seven compounds (1, 13, 14, 16, 20, 22, and 23) exhibited significant NO inhibitory effects, with IC50 values ranging from 1.35 to 5.93 μM, which were more effective than the positive control indomethacin (IC50 = 13.18 μM). Moreover, the corresponding results of Western blot analysis revealed that meliasanine A (1) can significantly suppress the protein expression of inducible nitric oxide synthase and cyclooxygenase 2 in a concentration-dependent manner. The mechanism study suggested that meliasanine A exerts an anti-inflammatory effect via the nuclear factor-κB signaling pathway by suppressing phosphorylation of P65 and IκBα.

Triterpenoids from the fruits of Melia azedarach L. and their cytotoxic activities

Eleven undescribed tetracyclic triterpenoids, meliazedarachins A-K, along with twenty-six known compounds were isolated from the fruits of Melia azedarach L.. Their structures were determined by HRESIMS, UV, IR, NMR, X-ray diffraction, electronic circular dichroism (ECD) spectra, and the modified Mosher's method. The cytotoxic activities of all the isolates were measured. Meliazedarachin K and mesendanin N showed cytotoxicity against five human cancer cell lines with IC₅₀ values ranging from 9.02 to 31.31 μM. Meliazedarachin K showed significant cytotoxicity against HCT116 cell line with IC₅₀ value of 9.02 ± 0.84 μM. 21α-methylmelianodiol showed significant cytotoxicity against HCT116 and RKO cell lines with IC₅₀ values of 10.16 ± 1.22 and 8.57 ± 0.80 μM, respectively.

Tirucallane Triterpenoids from the Stems and Stem Bark of Cornus walteri that Control Adipocyte and Osteoblast Differentiations

Cornus walteri Wanger (Cornaceae) has been broadly used in traditional East Asian medicine for the treatment of various disorders, including skin inflammation and diarrhea. As part of our efforts to identify structurally and/or biologically new compounds from Korean medicinal plants, we have explored potentially new bioactive constituents from C. walteri. In the present study, seven triterpenoids (1–7) were isolated from C. walteri stems and stem bark. Compounds 1–3 were new tirucallane triterpenoids (cornusalterins N-P) and compounds 4–7 were isolated for the first time from C. walteri. The structures of the new compounds were determined based on 1D and 2D NMR spectroscopic data interpretations and HR-ESIMS, as well as a computational method coupled with a statistical procedure (DP4+). The regulatory effects of the isolated triterpenoids (1–7) on mesenchymal stem cell (MSC) differentiation to adipocytes and osteoblasts were examined in the C3H10T1/2 cell line. Although these compounds had little effect on MSC differentiation to osteoblasts, lipid droplet formation in adipocyte-differentiated MSCs decreased in the presence of the seven triterpenoids. Compounds 1 and 4 each had a relatively distinct correlation between dose and efficacy, showing adipogenesis suppression at higher concentrations. Our findings demonstrate that the active compounds 1 and 4 can exert beneficial effects in regulation of adipocyte differentiation.

Meliacarpinin-Type Limonoids from the Bark of Melia toosendan

Three new meliacarpinin-type limonoids, toosendanes A⁻C (1⁻3), along with three, known meliacarpinins (4⁻6) were isolated from the bark of Melia toosendan. Their structures, along with their absolute configurations, were elucidated, based on detailed analyses. These included HRESIMS and 1D/2D-NMR, modified Mosher's method, and electronic circular dichroism (ECD). Limonoids 2 and 3 showed moderate inhibitory activity on LPS-activated, RAW 264.7 macrophages.

New triterpenoids with diverse side-chains from the barks of Melia Toosendan

Nine new euphane- and apotirucallane-type triterpenoids (Toosendines A-I; 1-9), along with three known tirucallane-type compounds were isolated from the barks of Melia toosendan. Their structures were elucidated based on detailed spectroscopic analyses (HRESIMS, 1D/2D-NMR) and circular dichroism spectra. Results of bioactivities screening exhibited that compounds 1, 4 and 5 showed remarkable NO inhibitory activities in LPS-activated RAW 264.7 macrophages, meanwhile, compounds 1 and 4 showed moderate cytotoxicities against U2OS human cancer cell line.

New Triterpenoids from the Stems of Cornus walteri

A new 28-norlupane triterpenoid, 3-acetate-28-norlup-20(29)-en-3β-hydroxy-17β-hydroperoxide (1) and a new tirucallane triterpenoid, cornusalterin M (2), together with one known triterpenoid, 3-acetate-28-norlup-20(29)-en-3β,17β-diol (3), were isolated from a MeOH extract of the stems of Cornus walteri. The chemical structures of the new compounds (1 and 2) were elucidated based on comprehensive one- and two-dimensional (1D and 2D) NMR spectroscopic experiments and high resolution-electrospray ionization (HR-ESI)-MS. Among the isolates, compound 1 was a relatively rare triterpenoid identified as a 28-norlupane-type triterpene with a 17β-hydroperoxide group and compound 3 was previously reported but only as a synthetic product. The cytotoxic activities of the isolated compounds 1-3 were evaluated by determining their inhibitory effects on human tumor cell lines (A549 (non-small cell lung carcinoma), SK-OV-3 (ovary malignant ascites), SK-MEL-2 (skin melanoma), and HCT-15 (colon adenocarcinoma)).

Crystal structure of 16-hy-droxy-4,4,10,13,14-penta-methyl-17-(6-methyl-hept-5-en-2-yl)-4,5,6,9,10,11,12,13,14,15,16,17-dodeca-hydro-1H-cyclo-penta-[a]phenanthren-3(2H)-one

The title compound, C30H48O2, contains a fused four-ring triterpenoid system. In the mol-ecule, the two cyclo-hexane rings adopt a chair conformation and a twist boat conformation, respectively, the central cyclo-hexene ring adopts a half-chair conformation whereas the five membered ring adopts an envelope conformation. In the crystal, O-H⋯O hydrogen bonds between the hy-droxy and carbonyl groups of adjacent mol-ecules link the mol-ecules into supra-molecular chains propagating along the b-axis direction.

Triterpenoids

This review covers the isolation and structure determination of triterpenoids reported during 2012 including squalene derivatives, lanostanes, holostanes, cycloartanes, cucurbitanes, dammaranes, euphanes, tirucallanes, tetranortriterpenoids, quassinoids, lupanes, oleananes, friedelanes, ursanes, hopanes, serratanes, isomalabaricanes and saponins; 348 references are cited.

Limonoids from the fruits of Cipadessa cinerascens

A new limonoid, 3-de(2-methylbutanoyl)-3-propanoylcipadesin (1), along with 10 known limonoids and 1 known triterpenoid, was isolated from the fruits of Cipadessa cinerascens. Their structures were elucidated on the basis of spectroscopic analysis. All compounds were evaluated for their antimicrobial activities, and compounds 6 and 12 showed weak antimicrobial activities against MRSA 82(#) and MRSA 92(#).

New triterpenoids with protein tyrosine phosphatase 1B inhibition from Cedrela odorata

Two new apotirucallane-type triterpenoids, cedrodorols A-B (1 and 2), along with seven known compounds (3-9), were isolated from the twigs and leaves of Cedrela odorata. Their structures were elucidated on the basis of extensive spectroscopic analysis. Compounds 1 and 2 showed significant inhibitory activity against protein tyrosine phosphatase 1B (PTP1B) with the IC50 values of 13.09 and 3.93 μg/ml, respectively.

11β-HSD1 inhibitors from Walsura cochinchinensis

A search for inhibitors of 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) from Walsura cochinchinensis yielded 10 new limonoids, cochinchinoids A-J (1-10), and two new triterpenoids, 3-epimesendanin S (11) and cochinchinoid K (12). Their structures were assigned on the basis of spectroscopic data, with the absolute configurations of 1 and 12 being established by X-ray diffraction analysis. Of these compounds, cochinchinoid K (12) displayed inhibitory activity against mouse 11β-HSD1 with an IC50 value of 0.82 μM.

Bioactive limonoid and triterpenoid constituents of Turraea pubescens

Eleven new limonoids, turrapubins A-K (1-11), and three new triterpenoids (12-14), along with 14 known compounds, were isolated from the twigs of Turraea pubescens. The structures of 1-14 were elucidated on the basis of NMR and MS analysis. Compounds 12, 16, 18, and 19 exhibited inhibitory activities against lipopolysaccharide-induced nitric oxide production in RAW264.7 cells. In addition, compounds 2, 11, 18, and 26 exhibited inhibitory activities against brine shrimp larvae (Artemia salina) at 100 ppm with the corrected mortality ranging from 81.7% to 100%.