Caffeoyl triterpenes from pear (Pyrus pyrifolia Nakai) fruit peels and their antioxidative activities against oxidation of rat blood plasma

Effects of topping on rhizome, and analysis of chemical composition, antioxidant activity and α-amylase and α-glucosidase inhibition of the aerial parts in Polygonatum cyrtonema

Polygonatum cyrtonema is a perennial plant, and it has long been used in traditional Chinese medicine for food and medicine. The medicinal part of P.cyrtonema is the rhizome; however, the aerial part has not been studied. To understand the effect of the topping of aerial parts on the yield and chemical components of rhizomes, as well as the chemical constituents, antioxidant, and in vitro hypoglycemic activities of the aerial stem, leave, and flower parts of P.cyrtonema, the present study was conducted. The results showed that compared to the control (CK) treatment, the topping of the aerial part increased rhizome weight gain coefficient (3.43) and the total saponin content (37.60 mg/g) significantly (P<0.01) than the CK treatment. The contents of total phenols and total flavonoids in PCL and PCF were significantly (P<0.01) higher than those in rhizomes; however, the polysaccharide content (10.47%) in PCR (whole rhizome) was higher than that in PCS (3.65%), PCL (5.99%), and PCF (4.76%) content. The protein and amino acid contents in PCS, PCL, and PCF were higher than those in rhizomes. The protein and amino acid contents in PCS, PCL, and PCF were higher than those in rhizomes. PCS, PCL, and PCF showed strong antioxidant activity (DPPH, ·OH, ABTS, and FRAP), which were better than traditional medicinal parts (the rhizome).In vitro hypoglycemic results showed that PCS, PCL, and PCF had certain inhibitory activities on α-amylase and α-glucosidase (66.25% and 52.81%), which were close to the hypoglycemic activity of rhizomes (67.96% and 52.22%). The leaf extracts also showed better inhibitory activity. To sum up, the topping measures can improve yield and total saponin content of the rhizomes from P.cyrtonema, which can be applied to improve production. The stems, leaves, and flowers had a much stronger antioxidant and hypoglycemic activities and higher the total polyphenols, flavonoids, proteins, and amino acid content. Therefore, stems, leaves, and flowers of Polygonatum can be fully developed according to different needs. they are typically used in animal feed, food storage and cosmetics.

Evaluation of Nutritional Value, Fatty Acids and Polyphenols Profiles of Pyrus amygdaliformis L. Grown in North-East Kurdistan Regional Government, Iraq

The present research evaluated some chemical composition in tissues from the leaves, seed, and fruits P. amygdaliformis. In leaf samples, phenolics compounds are predominated, whereas, in fruit samples, sugars, organic acid predominated. Among phenolic compounds, chlorogenic acid and fumaric acid were found in the highest amount in leaf tissue. In addition, the amounts of minerals in the fruit tissue had high values. In the P. Amigdaliformis seed oil, oleic and linoleic acid were the primary fatty acids. This study shows that these wild pears have beneficial natural compounds and can also be used as a new source of natural oil.

Bioactive small-molecule constituents of Lao plants

Laos has a rich plant diversity, and medicinal plants are used extensively in Lao traditional medicine for the treatment of a variety of human diseases. However, only a relatively small number of these plants have been investigated for their major components with potential antitumor, anti-infective, and other types of bioactivities. These species include Asparagus cochinchinensis, Diospyros quaesita, Gongronema napalense, Marsypopetalum modestum, Nauclea orientalis, Rourea minor, Stemona pierrei, and Stemona tuberosa. Thus far, the bioactive compounds isolated from these Lao plants include alkaloids, glycerol esters, phenolic compounds such as lignans and stilbenoids, steroids, and triterpenoids. Of these, the norlignan, nyasol (1b), the triterpenes, pyracrenic acid [3β-O-trans-caffeoylbetulinic acid (3)] and betulinic acid (3b), and the dimeric thiopyridine, dipyrithione (5), were found to show both cancer cell cytotoxicity and anti-infective activity. The present review focuses on examples of promising lead compounds isolated from Lao plants, with their possible development as potential therapeutic agents being discussed. It is hoped that this contribution will provide useful information on higher plants growing in Laos to help stimulate future discoveries of potential agents for the treatment of cancer, infections, and other diseases.

Triterpenoids with antiproliferative activities from the twigs and leaves of Melaleuca linariifolia

One new pentacyclic triterpenoid, urs-12,16-dien-3-one (1), together with twelve known pentacyclic triterpenoids (2‒13), were isolated from the twigs and leaves of Melaleuca linariifolia. Their structures were characterized by their 1D- and 2 D-NMR spectra analysis and mass spectra studies. Furthermore, all isolated compounds were tested the inhibitory effect on proliferation of six human cancer cell lines in vitro, including NCI-H441, NCI-H460, A549, SKOV3, hela, and caki-1 cells. Among them, compounds 3, 5, 7, 9, 12, and 13 exhibited moderate antiproliferative activities with IC₅₀ values ranging from 3.85 to 33.31 μM.

3-O-trans-caffeoyloleanolic acid improves acute lung injury via anti-inflammation and antioxidative stress-involved PI3K/AKT pathway

3-O-trans-caffeoyloleanolic acid (COA) is a pentacyclic triterpenoid compound, with significant anti-inflammatory effects. In this study, we report the protective effects of COA on lipopolysaccharide (LPS)-induced acute lung injury (ALI) and explored its mechanism of action. LPS was used to construct in vivo mouse ALI models to observe the effects of COA pretreatment on lung pathology, inflammation, and oxidative stress. In vitro, mouse alveolar macrophages MH-S cells were cultured and stimulated with LPS to investigate the effects of COA pretreatment on inflammation and oxidative stress. Western blotting was used to investigate the expression of iNOS, TLR4, p-p65, p-AKT, and p-PI3K from in vivo and in vitro samples. The results showed that COA significantly improved lung injury, inhibited neutrophil infiltration, prevented macrophage infiltration, inhibited the release of inflammatory factors, reduced oxidative stress, and down-regulated the expression of iNOS, TLR4, p-p65, p-AKT, and p-PI3K in ALI mice caused by LPS. In vitro, COA inhibited the release of inflammatory factors, reduced oxidative stress, and down-regulated the expression of iNOS, TLR4, p-p65, p-AKT, and p-PI3K in MH-S cells stimulated with LPS. Of interest, the protective effects of COA were significantly attenuated in MH-S cells pretreated with the PI3K phosphopeptide activator 740Y-P with no effect on TLR4 expression observed. Taken together, these findings confirm the protective effects of COA on ALI. We further demonstrate that the anti-inflammation and antioxidant effects of COA are mediated through its effects on PI3K/AKT and potentially TLR4.

Phenylpropanoid-conjugated pentacyclic triterpenoids from the whole plants of Leptopus lolonum induced cell apoptosis via MAPK and Akt pathways in human hepatocellular carcinoma cells

Our present and previous phytochemical investigations on Leptopus lolonum have resulted in the isolation of almost 30 phenylpropanoid-conjugated pentacyclic triterpenoids (PCPTs). During the continuous study on PCPTs, this kind of triterpenoid ester is considered as a natural product with low toxicity because of it's widely distribution in natural plants and edible fruits including kiwi fruit, durian, jujube, pawpaw, apple and pear. In the present work, we report the isolation, structural elucidation and cytotoxic evaluation of four new PCPTs (1-4) which obtained from L. lolonum. In addition, the possible biosynthesis pathway for 28-norlupane triterpenoid and potent effect of phenylpropanoid moiety for increasing the cytotxic effect of triterpenoids were also discussed. Among these compounds, compound 1 exhibited the highest cytotoxic effect on HepG2 cells with IC₅₀ value of 11.87 μM. Further flow cytometry and western blot analysis demonstrated that 1 caused G1 cell cycle arrest by up-regulated the expression of phosphorylated p53 protein in HepG2 cells and induced cell apoptosis via MAPK and Akt pathways. These results emphasized the potential of PCPTs as lead compounds for developing anti-cancer drugs.

New phenylpropanoid-conjugated pentacyclic triterpenoids from the whole plants of Leptopus lolonum with their antiproliferative activities on cancer cells

Most of Euphorbiaceae plants are considered as folk medicinal plants because of their various pharmacological effects. However, there are eight Leptopus genus plants which belong to Euphorbiaceae have never be investigated. Thus, four Leptopus genus plants were collected to study their chemical constituents and pharmacological activities. In the present work, the cytotoxicities of the extracts of four Leptopus genus plants were evaluated before phytochemical experiments. And nine new phenylpropanoid-conjugated pentacyclic triterpenoids, along with twenty-two known compounds were isolated from the whole plants of Leptopus lolonum. The structures of these new compounds were unequivocally elucidated by HRESIMS and 1D/2D NMR data. All triterpenoids were screened for their cytotoxicities against four cancer cell lines including HepG2, MCF-7, A549 and HeLa. Among these isolates, the triterpenoid with a phenylpropanoid unit showed increasing cytotoxicity on cancer cells, which suggested the importance of the phenylpropanoid moiety.

Triterpenoids and Other Non-Polar Compounds in Leaves of Wild and Cultivated Vaccinium Species

The purpose of the current study was to identify and quantify triterpenoids and other non-polar compounds in the leaves of three high bush blueberry cultivars (Vaccinium corymbosum L. var. Bluegold, var. Bluecrop and var. Elliott) and three natural populations of Vaccinium species (Vaccinium uliginosum L., Vaccinium myrtillus L. and Vaccinium vitis-idaea L.) by means of gas chromatography mass spectrometry (GC-MS) and high-performance liquid chromatography with diode array detector (HPLC-DAD). Metabolite profiles differed significantly among the Vaccinium species analyzed, as well as among the populations of the same species. The populations of V. vitis-idaea predominantly contained relative concentrations of phytosterols (varying between 10.48% of total ion current (TIC) and 22.29% of TIC) and almost twice the content of triterpenes (from 29.84% of TIC to 49.62% of TIC) of the other berry species investigated. The leaves of V. corymbosum varieties biosynthesized the highest relative amount of fatty acids, while the leaves of the populations of V. uliginosum had the highest relative concentrations of fatty alcohols. The results of principal component analysis (PCA) and hierarchical cluster analysis (HCA) showed that the diverse populations of each berry species analyzed differed from each other, most likely due to variations in the climatic and geographical conditions of their localities.

Triterpenoids from Celastrus orbiculatus Thunb. inhibit RANKL-induced osteoclast formation and bone resorption via c-Fos signaling

Fourteen triterpenes, lup-20(29)-ene-3β,6β-diol (1), betulin (2), lupeol caffeate (3), 3β-caffeoyloxylup-20(29)-en-6α-ol (4), betulin-3β-yl-caffeate (5), 3β-trans-feruloylbetulin (6), betulinaldehyde 3-caffeate (7), 3-O-trans-caffeoylbetulinic acid (8), dammarenediol II 3-caffeate (9), 12-oleanene-3β,6α-diol (10), 11α-hydroxy-3β-amyrin (11), nivadiol (12), 29-hydroxyfriedelin (13), and celastrusin A (14) were isolated from Celastrus orbiculatus Thunb. and evaluated for their activity on receptor activator of nuclear factor κB ligand (RANKL)-induced osteoclast differentiation in bone marrow macrophages (BMMs). Compounds betulin (2), betulin-3β-yl-caffeate (5), 3β-trans-feruloylbetulin (6), and 3-O-trans-caffeoylbetulinic acid (8) significantly inhibited osteoclast formation in a dose-dependent manner. Among these, betulin-3β-yl-caffeate (5) exhibited the most potent inhibitory activity. We demonstrated that betulin-3β-yl-caffeate (5) suppressed F-actin-ring formation and bone resorption activity. At the molecular level, betulin-3β-yl-caffeate (5) inhibited RANK-induced expression of c-Fos and the induction of nuclear factor of activated T cells 1 (NFATc1), a key transcription factor for osteoclast formation, and it also downregulated mRNA expression of osteogenesis-associated marker genes including tartrate-resistant acid phosphatase (TRAP), dendritic cell-specific transmembrane protein (DC-STAMP), and matrix metalloprotein (MMP). These results indicate that betulin-3β-yl-caffeate (5) may be a promising candidate for the treatment of osteoclast-related diseases such as osteoporosis.

New caryophyllene-type sesquiterpene and flavonol tetraglycoside with sixteen known compounds from sword bean (Canavalia gladiata)

Eighteen compounds including new caryophyllene-type sesquiterpene and flavonol tetraglycoside were purified and isolated from sword beans (Canavalia gladiata). Two new compounds, (Z,1R,7S,9S)-7-hydroxy-11,11-dimethyl-8-methylenebicyclo[7.2.0]undec-4-ene-4-carboxylic acid (2) and kaempferol-7-O-α-l-dirhamnopyranosyl(1 → 2;1 → 6)-O-β-d-glucopyranosyl(1 → 2)-O-α-l-rhamnopyranoside (9), were identified. Other known compounds including methyl gallate (1), (2S,3S,4E,8E)-2-aminooctadeca-4,8-diene-1,3-diol 1-O-β-d-glucopyranoside (3), (2S,3S,4E,8Z)-2-aminooctadeca-4,8-diene-1,3-diol 1-O-β-d-glucopyranoside (4), lupeol (5), trilinolein (6), 1,6-di-O-galloyl β-d-glucopyranoside (7), N-(2-methoxybenzoyl)homoserine (8), dihydrophaseic acid (10), dillenetin (11), kaempferol-7-O-[2-O-β-d-glucopyranosyl-6-O-α-l-rhamnopyranosyl]-α-l-rhamnopyranoside (12), canavalioside (13), kaempferol-3-O-[2-O-β-d-glucopyranosyl-6-O-α-l-rhamnopyranosyl]-β-d-glucopyranoside (14), kaempferol-3-O-(2,6-O-α-l-dirhamnopyranosyl)-β-d-glucopyranoside (15), kaempferol-3-O-rutinoside (16), gladiatoside A₁ (17), and gladiatoside B₁ (18) were identified. The chemical structures of these compounds were determined by ESI-MS and NMR analyses.

Compositional characterization of Pyrus ussuriensis Maxim and their antioxidant activities and induction of apoptosis in Bel-7402 cell

In this work, a comparison study on active sites (the total phenolic, total flavonoids, and total triterpenes contents) and antioxidant activities (DPPH, ABTS, and FRAP assays) of different fractions from Pyrus ussuriensis Maxim was evaluated. Moreover, the inhibition capability on human hepatocarcinoma cells Bel-7402 cells and the mechanism was also discussed. Results showed that the ethyl acetate fraction significantly scavenged DPPH and ABTS⁺ radicals, exhibited ferric ion reducing antioxidant, and inhibited Bel-7402 cells proliferation. In addition, oleanolic acid was the dominant compound act on the Bel-7402 cells in the extract and it induced apoptosis by the caspase pathway and induced cell cycle arrest at the G0/G1 phase by inhibiting the cyclin D1/CDK4 pathway. The extracts of P. ussuriensis Maxim were confirmed to have anti-oxidative and antiproliferative effects against Bel-7402 cell in vitro. PRACTICAL APPLICATIONS: Fruits and vegetables which contain high levels of antioxidants can help to reduce the risk of chronic diseases such as cancer. Pyrus ussuriensis Maxim is a kind of edible and medical fruit with multiple bioactivities, whereas the capability to anti-lung cancer activity has not been investigated. The extracts of P. ussuriensis Maxim were revealed to have anti-oxidative and antiproliferative effects against Bel-7402 cell in vitro. Accordingly, it is the first time to verify that oleanolic acid was the main chemical components of P. ussuriensis with antitumor potential.

Triterpenoids from the barks of Juglans hopeiensis

Nine undescribed triterpenoids (jughopenoids A-I), including seven nortriterpenoids and two normal triterpenoids, together with fourteen known analogues, were isolated from the barks of Juglans hopeiensis Hu. The structures of the undescribed triterpenoids were established by integrated spectroscopic analysis and single crystal X-ray diffraction. Jughopenoid A represented an unprecedented lupane-type nortriterpenoid with a five-membered lactone ring A. Selected isolates were tested for their cytotoxic effects against human HT-29 colon carcinoma, human HepG2 hepatocellular carcinoma, and human PC-3 prostate cancer cell lines. Their immunosuppressive activities against ConA-induced T cell proliferation and LPS-induced B cell proliferation were also evaluated.

Three new triterpenoids with their bioactives from the roots of Rosa cymosa

Three new triterpenoids, 2α, 3α, 20β, 23-tetrahydroxyurs-13 (18)-en-28-oic-acid (1) (Figure 1), 2β, 3α, 20β, 23-tetrahydroxyurs-13(18)-en-28-oic-acid (2), and 2α, 3α-dihydroxyurs-12(13), 18(19)-dien-28-oic-acid (3) were isolated from the roots of R. cymosa. Their structures were elucidated by extensive spectroscopic methods, including NMR, MS, and IR spectroscopic analyses data. All the isolates were evaluated for their α-glucosidase inhibitory and anti-inflammatory activities in vitro. The results showed that compound 2 displayed moderate anti-inflammatory activity with IC₅₀ value of 9.4 μM.

Two New Ursane-type Triterpenoid Glycosides from Ilex Cornuta

Ilex cornuta (I. cornuta) is a traditional Chinese medicine (TCM) that has been used in clinical practice for hundreds of years. In order to provide more information about the chemical basis of its pharmacological effects, phytochemical investigation on the roots of I. cornuta was conducted in this study. The roots of the plant were firstly extracted with 95% EtOH, and then the crude was partitioned with petroleum ether, EtOAc and n-butyl alcohol. Different chromatographies were employed to isolate the crude step by step and the crude was further purified by semipreparative high performance liquid chromatography (HPLC). As a result, two new triterpenoid saponins (1, 2), together with 12 known compounds (3-14), were isolated from the roots of I. cornuta. Their structures were determined based on nuclear magnetic resonance (NMR), mass spectrum (MS) technologies, chemical reactions as well as gas chromatography (GC). Compounds 4, 6, 8, 11, 12 and 13 were isolated from this genus for the first time. The structures of compounds 1 and 2 were determined as 3β-O-α-D-xylopyranosyl-(1→3)-α-L-2-O-acetylarabinopyranosyl-(1→2)-β-D glucopyranosyl-23-hydroxyl-20α(H)-urs-12-en-28-oic acid 28-O-β-D-glucopyranosyl ester (1) and 3β-O-α-D-xylopyranosly-(1→3)-α-L-2-O-acetylarabinopyranosyl-(1→2)-β-Dglucopyranosyl- 19α,23-dihydroxyl-20α(H)-urs-12-en-28-oic acid 28-O-β-D-glucopyranosyl ester (2).

Isolation of five proanthocyanidins from pear (Pyrus pyrifolia Nakai) fruit peels

Five proanthocyanidins, two B-type dimers and three A-type trimers, were purified and isolated from the fruit peels of Pyrus pyrifolia Nakai cv. Chuhwangbae. The isolated compounds were identified as (-)-epicatechin gallate-(4β → 8)-(-)-epicatechin (Hahashi et al. in Ann Biol Res 3:3200-3207, 2012), (-)-epicatechin-(4β → 8)-(-)-epicatechin (procyanidin B2) (Tanrioven and Eksi in Food Chem 93:89-93, 2005), (-)-epicatechin-(4β → 8, 2β → O-7)-(-)-epicatechin-(4β → 8)-(-)-epicatechin (cinnamtannins B1) (Salta et al. in J. Fun. Food 2: 153-157, 2010), (-)-epicatechin-(4β → 8)-(-)-epicatechin-(4β → 8, 2β → O-7)-(-)-epicatechin (aesculitannin A) (Challice and Westwood in Phytochemistry 11: 37-44, 1972), and (-)-epicatechin-(4β → 6)-(-)-epicatechin-(4β → 8, 2β → O→7)-(-)-epicatechin (Es-Safi et al. in J Agric Food Chem 54: 6969-6977, 2006). Their structures were determined by nuclear magnetic resonance and mass spectrometry. The three A-type proanthocyanidin trimers were identified for the first time from pear.

Potential cancer chemopreventive and anticancer constituents from the fruits of Ficus hispida L.f. (Moraceae)

ETHNOPHARMACOLOGICAL RELEVANCE

Ficus hispida L.f. (Moraceae) has been used as alternative for traditional medicine in the treatment of various ailments including cancer-cure. The aim of this study was to evaluate the cancer chemopreventive and anticancer activities of crude extracts of F. hispida, with the objective to screen the inhibition of Epstein-Barr virus early antigen, and cytotoxic active components, and provide foundation for potential applications of this promising medical plant.

MATERIALS AND METHODS

Compounds were isolated from the MeOH extract of F. hispida fruits, and their structure elucidation was performed on the basis of extensive spectroscopic analysis. The isolated compounds were evaluated for their inhibitory activities against the Epstein-Barr virus early antigen (EBV-EA) activation induced by 12-O-tetradecanoylphorbol 13-acetate (TPA) in Raji cells, and cytotoxic activities against human cancer cell lines (HL60, A549, SKBR3, KB, Hela, HT29, and HepG2) and a normal cell (LO2) using MTT method. For the compound with potent cytotoxic activity, its apoptosis inducing activity was evaluated by the observation of ROS generation level expression, and membrane phospholipid exposure and DNA fragmentation in flow cytometry. The mechanisms of the apoptosis induction were analyzed by Western blotting.

RESULTS

Nineteen compounds, 1-19, including two new isoflavones, 3'-formyl-5,7-dihydroxy-4'-methoxyisoflavone (2) and 5,7-dihydroxy-4'-methoxy-3'- (3-methyl-2-hydroxybuten-3-yl)isoflavone (3), were isolated from the MeOH extract of F. hispida fruits. Five compounds, isowigtheone hydrate (1), 2, 3, 9, and 19, showed potent inhibitory effects on EBV-EA induction with IC₅₀ values in the range of 271-340 molar ratio 32 pmol^-1 TPA. In addition, five phenolic compounds, 1-3, 10, and 13, exhibited cytotoxic activity against two or more cell lines (IC₅₀ 2.5-95.8μM), as well as compounds 1 and 3 were also displayed high selectivity for LO2/HepG2 (SI 23.5 and 11.8, respectively), while the compound 1-induced ROS generation leads to activated caspases-3, -8, and -9 apoptotic process in HL60 cells.

CONCLUSION

This study has established that the MeOH extract of F. hispida fruits contains isoflavones, coumarins, caffeoylquinic acids, along with other compounds including phenolics and steroid glucoside as active principles, and has demonstrated that the chemical constituents of F. hispida may be valuable as potential chemopreventive and anticancer agents.

Metabolism and antioxidant effect of malaxinic acid and its corresponding aglycone in rat blood plasma

Malaxinic acid (MA) is a phenolic acid compound, found mainly in pear fruits (Pyrus pyrifolia N.), that is isoprenylated on the C-3 position of benzoic acid. Recently, the effects of prenylated phenolics on health have received much interest owing to their reported potent beneficial biological effects. We conducted a comparative study in rats to determine the metabolism, pharmacokinetics, and antioxidative activities of MA and its corresponding aglycone (MAA). MA and MAA were orally administered to rats (Sprague-Dawley, male, 6 weeks old) and their metabolites in plasma were analyzed. In addition, the MA metabolites in plasma were separated and the structures were confirmed via NMR and HR-MS analyses. The antioxidative activities of MA and MAA were evaluated by measuring their inhibitory effects on the 2,2'-azobis(2-amidinopropane)dihydrochloride- or copper ion-induced lipid peroxidation of rat plasma. MA was not absorbed in the intact form (the glucoside); both MA and MAA were absorbed as MAA and its metabolite form (glucuronide or sulfate). Moreover, the observed metabolite was the glucuronate of MAA rather than the glucuronide or sulfate. Concentrations of the free form of aglycone (MA administration, 4.6 ± 2.2μM; MAA administration, 7.2 ± 2.3μM) and total MAA (MA administration, 19.6 ± 4.4μM; MAA administration, 21.7 ± 3.3μM) in plasma reached a maximum at 15min after the oral administration of MA and MAA, respectively. The relative inhibitory effects on the formation of cholesteryl ester hydroperoxides in plasma collected at 15min after the oral administration of MA, MAA, and p-hydroxybenzoic acid (p-HBA) were as follows: MAA > MA ≥ p-HBA > control. Although the majority of MA and MAA is metabolized to conjugates, the compounds may contribute to the antioxidant defenses in the blood circulation owing to the presence of a phenolic hydroxyl group in the free form.

Antioxidant phenolic compounds isolated from wild Pyrus ussuriensis Maxim. fruit peels and leaves

Thirteen phenolic compounds were isolated from pear (Pyrus ussuriensis Maxim.) peels and leaves extracts by using various column chromatography techniques with a guided DPPH (1,1-diphenyl-2-picrylhydrazyl) radical-scavenging assay, the result of antioxidant activity of phenolic compounds is then verified by measurement of ROS (reactive oxygen species). The isolated compounds were identified as rutin (1), (-)-catechin (2), orobol (3), daidzein (4), tricin 4'-O-[threo-β-guaiacyl-(7″-O-methyl)-glyceryl] ether (5), tricin 4'-O-[threo-β-guaiacyl-(7″-O-methyl-9″-O-acetyl)-glyceryl] ether (6), 5,7,3',5'-tetrahydroxyflavanone (7), artselaeroside A (8), trilobatin (9), 3-(2,4,6-trihydroxyphenyl)-1-(4-hydroxyphenyl)-propan-1-one (10), quercetin-3-O-(3″-O-galloyl)-α-l-rhamnopyranoside (11), apigenin (12) and quercetin (13) on the basis of nuclear magnetic resonance spectroscopy along with comparison with literature data. Among these compounds, quercetin and quercetin-3-O-(3″-O-galloyl)-α-l-rhamnopyranoside exhibited potent DPPH radical-scavenging activity with IC₅₀ (Half Maximal Inhibitory Concentration) value of 6.06 and 9.60μg/mL, respectively. The results revealed that P. ussuriensis could be used in the fields of food and medicine to prevent human aging diseases.

Bioactive Triterpenoids from the Twigs of Chaenomeles sinensis

Chaenomeles sinensis has been consumed traditionally for the treatment of throat diseases, diarrhea, inflammatory diseases, and dry beriberi. Repeated chromatography of the CHCl₃-soluble fraction from the 80% MeOH extract of C. sinensis twigs led to the isolation of three new triterpenoids, sinenic acid A (1), 3β-O-cis-feruloyl-2α,19α-dihydroxyurs-12-en-28-oic acid (2), and 3β-O-cis-caffeoylbetulin (3), together with 20 analogues. The chemical structures of 1-3 were determined using diverse NMR techniques and HRMS data analysis, chemical methods, and computational approaches supported by advanced statistics (CP3). All the purified compounds were evaluated not only for their cytotoxicity against four human tumor cell lines (A549, SK-OV-3, SK-MEL-2, and HCT-15) but for their potential neuroprotective effects through induction of nerve growth factor in C6 glioma cells. Their anti-inflammatory effects were also assessed by measuring nitric oxide levels in lipopolysaccharide-insulted murine microglia BV2 cells.

A biphenyl derivative from the twigs of Chaenomeles speciosa

In our continuing search for bioactive constituents of Korean medicinal sources, we investigated an 80% MeOH extract of the twigs of Chaenomeles speciosa. Column chromatographic purification of the CHCl₃ fraction resulted in the isolation of a new biphenyl derivative (1), along with four known biphenyl compounds (2-5) and six triterpenes (6-11). The chemical structure of the new compound was determined on the basis of spectroscopic analyses including 1D and 2D NMR data. Among isolates, compound 3 exhibited potent cytotoxic activities against SK-OV-3, SK-MEL-2, and XF498 cell lines (IC₅₀=5.91, 4.22, and 6.28μM, respectively). Also, Compounds 9 and 10 showed strong anti-neuroinflammatory activities (IC₅₀ 2.38, and 6.70μM, respectively).

Enhancement of antioxidative and antimicrobial activities of immature pear (Pyrus pyrifolia cv. Niitaka) fruits by fermentation with Leuconostoc mesenteroides

Immature pear (Pyrus pyrifolia cv. Niitaka) fruits were fermented with Leuconostoc mesenteroides and Aspergillus oryzae, which are commonly used as starters for manufacturing fermented foods. Fermented immature pear fruit extracts (FIPF) by L. mesenteroides showed significantly higher radical-scavenging activity using DPPH, ABTS, superoxide anion, and hydroxyl radicals and reducing power capacity than unfermented immature pear fruit extracts. L. mesenteroides-FIPF more effectively inhibited the formation of cholesteryl ester hydroperoxide in copper ion-induced rat blood plasma. In addition, the L. mesenteroides-FIPF strongly inhibited tyrosinase activity and the growth of pathogenic skin bacteria. In contrast, enhanced antioxidative and antibacterial activities were not apparent in A. oryzae-FIPF. The antioxidative and antimicrobial activities of the fermented and unfermented immature pear fruits were correlated with the flavonoid contents. These results indicate that fermentation enhances antioxidative and antimicrobial activities of immature pear fruits.

Two new lignan glycosides from the fruits of Pyrus ussuriensis

Two new lignan glycosides, ussuriensislignan A (1) and ussuriensislignan B (2), together with seventeen known compounds (3-19), were isolated from the fruits of Pyrus ussuriensis. Their structures were determined by various spectroscopic methods. This is the first report of the isolation of lignans (compounds 1-3) from the genus Pyrus, and compounds 3-6, 12-16 were reported from Pyrus for the first time.

Change in chemical constituents and free radical-scavenging activity during Pear (Pyrus pyrifolia) cultivar fruit development

Changes in chemical constituent contents and DPPH radical-scavenging activity in fruits of pear (Pyrus pyrifolia) cultivars during the development were investigated. The fruits of seven cultivars (cv. Niitaka, Chuhwangbae, Wonhwang, Hwangkeumbae, Hwasan, Manpungbae, and Imamuraaki) were collected at 15-day intervals after day 20 of florescence. Vitamins (ascorbic acid and α-tocopherol), arbutin, chlorogenic acid, malaxinic acid, total caffeic acid, total flavonoids, and total phenolics were the highest in immature pear fruit on day 20 after florescence among samples at different growth stages. All of these compounds decreased gradually in the fruit during the development. Immature pear fruit on day 35 or 50 after florescence exhibited higher free radical-scavenging activity than that at other times, although activities were slightly different among cultivars. The chemical constituent contents and free radical-scavenging activity were largely different among immature fruits of the pear cultivars, but small differences were observed when they matured.