Constituents of Eugenia sandwicensis with potential cancer chemopreventive activity

Triterpenoid saponins and C21 steroidal glycosides from Gymnema tingens and their glucose uptake activities

Four new triterpenoid saponins, tigensides A-D (1-4), and one new C21 steroid, tipregnane A(9), together with six known compounds were isolated from the EtOAc fraction of the roots and stems of Gymnema tingens. The chemical structures of the new compounds were determined based on their spectroscopic data, including IR, UV, NMR, and mass spectrometric analysis. All compounds were isolated for the first time. Compounds 1-11 promoted glucose uptake in the range of 1.12 to 2.52 fold, respectively. Compound 2 showed the most potent glucose uptake, with 2.52 fold enhancement. Additionally, compound 2 showed a medium effect on the GLUT4 translocation activity in L6 cells in further study.

Lignans and terpenoids from Gaultheria leucocarpa var. yunnanensis and their anti-inflammatory and antioxidant activities

Six new compounds, including three lignans (1a, 1b, and 2), two abietane-type diterpenoids (3 and 4), and a triterpenoid (5), together with 13 known compounds (6a, 6b, and 7-17) were isolated from the aerial parts of Gaultheria leucocarpa var. yunnanensis. Their structures were elucidated by analysis of spectroscopic data involving NMR, IR, UV, and HRESIMS. The absolute configurations of lignans were confirmed by experimental and calculated ECD spectra. The anti-inflammatory and antioxidant activities of the isolates were evaluated. Compounds 12, 13, and 15 showed inhibitory effects against the LPS-induced production of NO in BV-2 microglial cells with the IC₅₀ values of 30.50, 23.26, and 13.02 μM, respectively. In addition, compounds 2 and 7 performed moderate DPPH radical scavenging activities.

New pentacyclic triterpenoids isolated from Leptopus chinensis and their hepatoprotective activities on tert-butyl hydroperoxide-induced oxidative injury

Eight unknown pentacyclic triterpenoids (1-4 and 8-11), along with eight known analogues (5-7 and 12-16) have been first isolated from the dried whole plant of Leptopus chinensis. The structures of the new compounds were determined by comprehensive spectroscopic methods, including 1D and 2D NMR, as well as HRESIMS measurements. Meanwhile, the hepatoprotective activities of the isolated compounds were preliminarily evaluated, and the results indicated that compounds 2, 5 and 16 possess potent protective effects on tert-butyl hydroperoxide (t-BHP)-induced oxidative injury in vitro, and further study revealed that 16 significantly alleviates t-BHP-induced hepatotoxicity by effectively improving cell viability and decreasing reactive oxygen species (ROS) generation and the cell apoptosis rate in HepG2 cells.

Triterpenoids from Liquidambar Fructus induced cell apoptosis via a PI3K-AKT related signal pathway in SMMC7721 cancer cells

A previously undescribed taraxerene-type triterpenoid possessing a class of rare natural taraxerene triterpenoid possessing skeleton with 14, 28-lactone, two undescribed oleane-type triterpenoids, and twenty-five known triterpenoids were isolated from Liquidambar formosana (Hamamelidaceae). The structures of undescribed compounds were determined on the basis of 1D and 2D NMR spectroscopic, HR-ESI-MS, and X-ray crystallographic data analysis. Among the isolates, ursolic acid, 3,6-dion-20(29)-lupen-28-oic acid, and 3-oxo-12α-hydroxyoleanan-28,13β-olide induced a significant apoptosis in SMMC7721 cells in the flow cytometer experiment with apoptosis rates of 94.5%, 57.3% and 89.9% at 8.0 μM, respectively, exhibiting near equivalent apoptosis-inducing abilities to that positive drug taxol (apoptotic rate of 71.2% at 1.4 μM). Mechanism studies suggested that these three compounds could regulate the mitochondrial pathway by up-regulating the expressions of pro-apoptotic factors (Bad and Bax) and activating caspase-3 and caspase-9 to induce apoptosis. Further studies indicated that the pro-apoptotic effects of these three compounds were associated with PI3K-AKT pathway inhibition. Taken together, these studies provide evidence that triterpenoids from L. Fructus are promising candidates for the hepatocellular carcinoma therapy.

Biological evaluation of secondary metabolites from the roots of Myrica adenophora

Bioassay-guided fractionation of the roots of Myrica adenophora led to isolation of 24 known compounds and hitherto unknown compounds, including three A-type proanthocyanidins [adenodimerins A-C], two esters of sucrose [myricadenins A and B ], and the phenolic glycoside 6'-O-galloyl orbicularin. Spectroscopic analyses were used to determine their structures. Adenodimerin A, myricananin C, and myricetin showed strong 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activities, with SC50 values of 7.9, 16.3, and 15.9 μM, respectively. Adenodimerin A, myricanone, myricananin C, (-)-myricanol, myricanol 11-O-β-D-glucopyranoside, and myricetin showed stronger 2,2'-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid (ABTS) radical scavenging activities than the positive control, with SC50 values of 7.5, 19.6, 12.0, 22.3, 19.6, and 15.6 μM, respectively. 5-Deoxymyricanone, porson, 12-hydroxymyricanone (-)-myricanol, and (+)-galeon exhibited anti-tubercular activity against Mycobacterium tuberculosis H37Rv in vitro and MICs values of 25.8, 40.0, 35.8, 30.0, and 15.0 μg/mL, respectively. Myricadenin A, myricanone, myricananin C, and (-)-myricanol exhibited anti-inflammatory activities in the iNOS assay with EC50 values of 18.1, 1.00, 13.0, and 7.5 μM, respectively.

Antioxidant Capacity and Phenolic Content of four Myrtaceae Plants of the South of Brazil

Antioxidant compounds can be useful to prevent several degenerative diseases or as preservative in food and toiletries. Species of the Myrtaceae family are able to accumulate phenolic substances and those are closely related to the antioxidant activity due to their capacity to scavenge free radicals, protect against lipid peroxidation and quench reactive oxygen species. These facts prompted us to investigate the antioxidant capacity of the ethanolic extracts of the leaves of four Myrtaceae plants collected of the south of Brazil: Eugenia chlorophylla O. Berg., Eugenia pyriformis Cambess, Myrcia laruotteana Cambess and Myrcia obtecta (Berg) Kiacrsk. The antioxidant potential was performed using the DPPH (a single electron transfer reaction based assay) and ORAC (Oxygen Radical Absorbance Capacity, a hydrogen atom transfer reaction based assay) assays. Moreover, the total soluble phenolic content was also measured using the Folin-Ciocalteu reagent. A preliminary evaluation of the ethanolic extracts of these Myrtaceae plants revealed high levels of phenolic compounds (343.7-429.3 mg GAE) as well as high antioxidant activity according to both methods (1338 a 3785 μmol of TE/g of extract in ORAC and SC50 in the range of 1.70 and 33.7 μg/mL in the DPPH). The highest antioxidant activity obtained by DPPH assay was exhibited by ethanol extract of the leaves of E. pyriformis (1.70 μg/mL), followed by extracts of M. laruotteana (3.38 μg/mL) and M. obtecta (6.66 μg/mL). In comparison with controls, in the DPPH assay, the extract of E. pyriformis was more active than trolox (SC50 = 2.55 μg/mL), while the extracts of M. laruotteana and M. obtecta were more actives than quercetin (SC50 = 7.80 μg/mL). In the ORAC assay, all species also show good antioxidant capacity (>1000 μmol of TE/g). Initial HPLC-UV/DAD and ESIMS confirmed the presence of phenolic acids constituents in the ethanol extracts. The results indicate the presence of compounds possessing promising antioxidant/free-radical scavenging activity in the analyzed extracts of Myrcia and Eugenia plants of the south of Brazil.

Chemical Composition and Larvicidal Activity of Eugenia triquetra Essential Oil from Venezuelan Andes

The chemical constituents of the essential oil obtained by hydrodistillation of the leaves of Eugenia triquetra O. Berg, collected in Táchira State, Venezuela, were identified by GC-MS analysis. Twenty-six components, which made up 88.5% of the oil, were identified. The major constituents were linalool (17.5%), limonene (16.9%), α-pinene (11.6%), β-pinene (8.7%), and p-cymene (3.7%). The essential oil was tested against third-instar larvae of Aedes aegypti, showing a LC50 value of 64.8 ± 5.6 ppm.

Phytochemical Analyses and Gastroprotective Effects of Eugenia Umbelliflora (Myrtaceae) on Experimental Gastric Ulcers

Phytochemical studies of Eugenia umbelliflora Berg. (Myrtaceae) resulted in the isolation of: taraxerol, α-amyrin, β-amyrin, betulin and betulinic acid from the leaves, as well as trimethoxy ellagic acid from the fruits. Given that several triterpenes were found in the extracts, and that these possess gastroprotective activity, the gastroprotective activity of E. umbelliflora leaf extract was evaluated using ethanol, indomethacin, and stress-induced ulcer models in mice. The crude methanol extract was administrated (v.o) in doses of 50, 125 and 250 mg/kg. The results showed that E. umbelliflora leaves display gastroprotective activity, as demonstrated by significant inhibition of ulcer formation in the different models. The results suggest that the gastroprotective activity may be attributed, at least in part, to the triterpenes.

Topical antiinflammatory activity and chemical composition of the epicuticular wax from the leaves of Eugenia beaurepaireana (Myrtaceae)

In order to verify the topical antiinflammatory effect of epicuticular wax from leaves of Eugenia beaurepaireana, it was tested in mice croton oil-induced inflammation. Our findings show that topical application of Eugenia beaurepaireana epicuticular wax was significantly active in inhibiting both oedema (Inhibitory dose 50 % (ID50) = 0.31 (0.26 - 0.39) mg.ear -1, inhibition = 79 ± 6 %) and tissue myeloperoxidase activity (indicative of polymorphonuclear leukocytes influx) (ID50 =0.34 (0.20 - 0.41) mg.ear -1, inhibition = 77 ± 4 %) in mice ear treated with croton oil. Two main compounds were detected on epicuticular wax of E. beaurepaireana. These compounds were identified as α- and β-amyrin by flame ionization detection (GC-FID) and spectroscopic methods (IR, NMR ¹H and 13C). In conclusion, the results indicate a topical antiinflammatory activity for the Eugenia specie studied and, that, at least in part, α- and β-amyrin are responsible for this activity.

Bioactive cembrane diterpenoids of Anisomeles indica

Five new cembrane-type diterpenoids with a trans-fused alpha-methylene-gamma-lactone (1-5), a new flavonoid glucoside (6), and 17 known compounds were isolated from a methanol extract of Anisomeles indica. The structures of 1-6 were elucidated by spectroscopic analysis, and the absolute configuration of compound 1 was determined using the modified Mosher's method. Compound 8 (4,5-epoxovatodiolide) exhibited cytotoxicity against a small panel of human cancer cell lines. Additionally, compounds 4 and 7 (ovatodiolide) exhibited selective antiplatelet aggregation activities toward collagen, while compounds 4, 5, and 8 showed inhibitory effects on antiplatelet aggregation induced by thrombin.

New Acylated Flavonol Diglycosides of Cynanchum Acutum

Three new acylated flavonol diglycosides that were characterized as quercetin 3- O-(6′”- O-E-isoferuloyl)-sophoroside (1), quercetin 3- O-(6′”- O-Z-isoferuloyl)-sophoroside (2) and quercetin 3- O-[2″- O-( E-6″′- O-isoferuloyl)-β-D-glucopyranosyl]-β-D-galactopyranoside (3), along with twelve known metabolites, have been isolated from the leaves of Cynanchum acutum L. The latter were identified as quercetin 3- O-β-D-neohesperidoside (4), rutin (5), quercetin 3- O-sophoroside (6), kaempferol 3- O-β-D-rutinoside (7), quercitrin (8), isoquercitrin (9), hyperin (10), guaijaverin (11), quercetin 7- O-β-D-glucopyranoside (12), quercetin (13), scopoletin (14) and ( E)-3-(3,4-dihydroxyphenyl)-propenoic acid (15). All metabolites have been isolated for the first time from the genus Cynanchum, except for 9 and 14. The structures were determined on the basis of chromatographic behavior, acid hydrolysis, chemical and physicochemical evidence (UV, HRESI-MS/MSn, 1H, 13C NMR, 1H-1H COSY, HSQC and HMBC). The chloroform extract and compounds 8 and 10 exhibited lethal effects towards brine shrimp, Artemia salina.

Effect of Sapthaparna (Alstonia scholaris Linn) in modulating the benzo(a)pyrene-induced forestomach carcinogenesis in mice

The chemopreventive effect of various doses of hydroalcoholic extract of Alstonia scholaris (ASE) was studied on the benzo(a)pyrene (BaP) induced forestomach carcinoma in female mice. The treatment of mice with different doses, i.e. 1, 2 and 4 mg/ml ASE in drinking water before, during and after the treatment with carcinogen, exhibited chemopreventive activity. The highest activity was observed for 4 mg/ml ASE, where the tumor incidence (93.33%) was reduced by 6.67%. Similarly, the tumor multiplicity reduced (61.29%) significantly (P<0.02) at 4 mg/ml in the pre-post-ASE treated group. However, the pre or post-treatment of mice with 4 mg/ml ASE did not show chemopreventive activity. These findings are corroborated by micronucleus assay, where treatment of mice with ASE before, during and after carcinogen treatment reduced the frequency of micronuclei (MN) in the splenocytes in a dose dependent manner. The MN frequency reached a nadir at 4 mg/ml ASE, the highest drug dose which showed maximum chemopreventive action. The ASE treatment not only reduced the frequency of splenocytes bearing one MN but also cells bearing multiple MN indicating the efficacy of ASE in inhibiting mutagenic changes induced by BaP. The pre or post-treatment of mice with 4 mg/ml ASE also significantly reduced the frequency of BaP-induced MN in the splenocytes of treated animals.

A new acylated triterpene from the roots of Chaenomeles japonica

A new acylated triterpene together with prunasin, (-)-epicatechin, daucosterol, and three triterpenes, ursolic, oleanolic, and pomolic acids was isolated from the root of Chaenomeles japonica (THUNB.) LINDL. (Rosaceae) and determined to be 3-O-(E)-3, 5-dihydroxycinnamoylursolic acid on the basis of NMR and FAB-MS experiments.