Bioassay-guided isolation of antibacterial and anti-inflammatory components from Atractylodes lancea.

A bioassay-guided isolation from Atractylodes lancea (Thunb.) DC. obtained 22 compounds, including eight previously undescribed sesquiterpenoids and polyacetylenes (1, 3 and 12-17), as well as fourteen known analogues, and their structures were confirmed by extensive spectroscopic methods. This study evaluated their antibacterial activity against methicillin resistant Staphylococcus aureus (MRSA) for the first time, as well as anti-inflammatory activity. Most of them, including new compounds, showed varying degrees of antibacterial activity against S. aureus and MRSA. Notably, compound 21 exhibited significant antibacterial activity against four different bacteria (MIC 6.25-20.00 µg/mL). This suggested that 21 may have the potential to be developed into a broad-spectrum antibacterial agent. Moreover, except for 9 and 11, most compounds exhibited great anti-inflammatory activity (IC50 1.92-37.91 µM), and iNOS might be a potential target of these compounds according to the molecular docking analysis.

Neolignans with anti-inflammatory activity from Piper kadsura (Choisy) Ohwi.

Two novel neolignans, piperkadsurenin A (1) and kadsurenin N (2), along with six known neolignans (3-8) and two lignans (9-10) were isolated from the stems of Piper kadsura (Choisy) Ohwi. Extensive spectroscopic data interpretation and ECD calculations were used to identify the structures of the new compounds 1 and 2. Especially, compound 1 represents the first example of neolignan with cyclopenta[b]pyran framework. The anti-inflammatory efficacy of compounds 1-10 in vitro was systematically assessed through NO production inhibitory assay. Compounds 3 and 7 significantly inhibited LPS-induced NO generation in RAW 264.7 cells, with IC50 values of 34.29 ± 0.82 and 47.5 ± 5.81 µM, respectively.

Alkaloids from Piper longum Exhibit Anti-inflammatory Activity and Synergistic Effects with Chemotherapeutic Agents against Cervical Cancer Cells.

Piper longum L. is widely cultivated for food, medicine, and other purposes in tropical and subtropical regions. Sixteen compounds including nine new amide alkaloids were isolated from the roots of P. longum. The structures of these compounds were determined by spectroscopic data. All compounds showed better anti-inflammatory activities (IC50 = 1.90 ± 0.68-40.22 ± 0.45 µM) compared to indomethacin (IC50 = 52.88 ± 3.56 µM). Among the isolated compounds, five dimeric amide alkaloids exhibited synergistic effects with three chemotherapeutic drugs (paclitaxel, adriamycin, or vincristine) against cervical cancer cells. Moreover, these dimeric amide alkaloids also enhanced the efficacy of paclitaxel in paclitaxel-resistant cervical cancer cells. The combination treatment of one of these dimeric amide alkaloids and paclitaxel promoted cancer cell apoptosis, which is related to the Src/ERK/STAT3 signaling pathway.

Dual regulation of Akt and glutathione caused by isoalantolactone effectively triggers human ovarian cancer cell apoptosis.

Ovarian cancer is one of leading causes of cancer death in gynecological tumor. Isoalantolactone (IL), present in several medicinal plants, exhibits various biological activities, and its mechanism underlying anti-ovarian cancer activity needs to be further investigated. Here, we find that IL inhibits the proliferation of SKOV-3 and OVCAR-3 cells by causing G2/M phase arrest and inducing apoptosis. Moreover, IL decreases intracellular glutathione (GSH) level, and induces reactive oxygen species (ROS) generation in SKOV-3 cells. Furthermore, IL induces inactivation of Akt which is required for the cytotoxicity of IL. In addition, overexpression of Akt attenuates the IL-induced growth inhibition and ROS generation. GSH supplementation moderately increases the expression of phospho-Akt. Further investigation reveals that pretreatment with L-buthionine-sulfoximine (a GSH biosynthesis inhibitor) restores the Akt-mediated attenuation of growth inhibition induced by IL. Moreover, co-treatment with IL and wortmannin (an Akt pathway inhibitor) increases the growth inhibition attenuated by pretreatment with N-acetyl-L-cysteine (a precursor for GSH biosynthesis). These results indicate that inactivation of Akt and downregulation of GSH level induced by IL are related to each other. In conclusion, combined targeting Akt and GSH is an effective strategy for cancer therapy and IL can be a promising anticancer agent for further exploration.

The bioactive amide alkaloids from the stems of Piper nigrum.

Piper nigrum is an important aromatic plant, and its fruits (black and white pepper) are commonly used as food additives and spices. However, its stems were disposed as wastes. This research comprehensively investigated bioactive alkaloids of the stems, eight new dimeric amide alkaloids and eight known compounds were obtained. All obtained compounds showed excellent anti-inflammatory activity. Additionally, the dimeric amide alkaloids enhanced the anticancer effect of paclitaxel against cervical cancer cells. These results demonstrate that the stems of P. nigrum could be the sustainable source of bioactive alkaloids for development and utilization in the food and health fields.

Bioactive sesquiterpenes from Inula helenium.

Twenty-one eudesmane-type sesquiterpenes, including five new compounds, were isolated from the roots of Inula helenium. The structures of the new compounds (1-5) were determined by extensive spectroscopic data interpretation, single-crystal X-ray diffraction analysis and ECD calculations. Six compounds can synergistically enhance cisplatin effect against ovarian cancer cells, the structure - activity relationship for the synergistic effect of these compounds with cisplatin was revealed for the first time, which provides useful clues to develop novel sensitizers to overcome drug resistance in cancer. In addition, fifteen sesquiterpenes exhibited significant anti-inflammatory activity, which provided promising candidates for development of anti-inflammatory agent.

Biological activities of the extracts and compounds from the bark of Pterocarya hupehensis skan.

This study was undertaken in order to investigate the antioxidant, anti-inflammatory and antimicrobial activities of various fractions and compounds obtained from the bark of P. hupehensis. The ethyl acetate fraction exhibited strong antioxidant, anti-inflammatory and antimicrobial effects. Six compounds were isolated from this fraction, three of which showed antioxidant activity and anti-inflammatory activity. The biological activities and the active compounds of P. hupehensis were reported for the first time.

Bioactive pterocarpans from Trigonella foenum-graecum L.

Trigonella foenum-graecum L. (fenugreek) is used as a leafy vegetable and spice in China and North African countries. However, the biochemical components of its aerial parts were rarely explored. In this study, the bioactivities of the various extract fractions from the aerial parts of this edible plant were assessed, the ethyl acetate extract fraction exhibited strong antioxidant and anti-inflammatory effects. Through bioassay-guided isolation, one new pterocarpan (1), as well as twelve known pterocarpans (2-13) were obtained, nine of them (5-13) were first reported in the fenugreek, four pterocarpans (9, 11-13) had strong antioxidant activity, eleven pterocarpans (1-3, 5-12) possessed obvious anti-inflammatory activity. This study indicates that pterocarpans are main bioactive components of this edible plant. Apart from its nutritional value as food, the aerial parts of this plant can also be further explored as functional foods or antioxidants in food industry.

Anti-inflammatory and antitumour activity of various extracts and compounds from the fruits of Piper longum L.

OBJECTIVES: To explore effective extraction method and to find active constituents, we investigated the biological activity of three extracts and isolated active compounds from the fruits of Piper longum L. METHODS: Three extracts from the fruits were obtained by reflux, ultrasonic and supercritical fluid extraction, respectively. Active compounds were isolated by the bioassay-guided method. The anti-inflammatory activity, antiproliferation activity and cytotoxicity were evaluated. The apoptosis was detected by Hoechst 33258 staining assay. The relevant proteins were investigated by Western blot assay. KEY FINDINGS: The anti-inflammatory activity and cytotoxicity of supercritical fluid extract (SE) were stronger than those of the other two extracts. Among all isolated compounds, the anti-inflammatory activity of eight compounds was stronger than that of indomethacin, and compounds 8, 9, 11, 14 and 15 were found to possess anti-inflammatory effect for the first time. Compounds 1, 2, 3 and 14 exhibited significant cytotoxicity against cancer cells. SE and piperine were found to reduce colony formation, inhibit cell migration and promote apoptosis through increasing cleaved PARP and the ratio of Bax/Bcl-2. CONCLUSIONS: The anti-inflammatory and antitumour effects of SE were better than those of the other two extracts. The compounds responsible for the activity were elucidated. SE and piperine inhibit cell growth through apoptosis.

Alkaloids from Piper nigrum Synergistically Enhanced the Effect of Paclitaxel against Paclitaxel-Resistant Cervical Cancer Cells through the Downregulation of Mcl-1.

In the current study, nine amide alkaloids, including two new dimeric amides and a new natural product, were identified from Piper nigrum. Among them, seven compounds sensitized paclitaxel-resistant cervical cancer cells HeLa/PTX to paclitaxel. Piperine was a major component obtained from Piper nigrum, and its sensitization mechanism was investigated. Combination treatment enhanced cell apoptosis, which was mediated by downregulation of phospho-Akt and Mcl-1. Piperine (50 µM) combined with paclitaxel (200 nM) downregulated Mcl-1 protein expression with a decrease of 35.9 ± 9.5% ( P < 0.05). Moreover, overexpression of Mcl-1 attenuated the inhibitory effect of this combination. Furthermore, combination treatments of six dimeric amide alkaloids and paclitaxel all downregulated Mcl-1 protein expression with a decrease ranging from 23.5 ± 9.7% to 41.7 ± 7.2% ( P < 0.05). We reveal, for the first time, that dimeric amide alkaloids from plants possess a remarkable sensitization effect on cancer cells to paclitaxel.

Scutellarin synergistically enhances cisplatin effect against ovarian cancer cells through enhancing the ability of cisplatin binding to DNA.

Platinum resistance is a major limitation in the treatment of ovarian cancer. Combination of natural compounds with platinum-based agents is a new strategy for cancer chemotherapy. Recently, we found that scutellarin sensitized the anticancer effect of cisplatin to ovarian cancer cells. How scutellarin interacts with cisplatin and sensitizes its effect is unclear. Here, we found that the combination treatment of scutellarin and cisplatin enhanced apoptosis in ovarian cancer cells via increasing the extent of platinum-DNA adducts and the ratio of Bax/Bcl-2. The changes in UV-visible spectra indicated that scutellarin could form complex with cisplatin. Moreover, combination treatment prevented BamH1 digestion on pBR322 plasmid DNA more effectively suggesting that their interaction might cause a greater conformational change in the DNA, which finally induced the DNA strand breaks and enhanced apoptotic signaling pathway response. Our study supports that scutellarin acts as a potential sensitizer to cisplatin treatment and the combination of scutellarin and cisplatin may be a novel therapeutic strategy to overcome platinum resistance of ovarian cancer.

Protocatechuic acid inhibits the growth of ovarian cancer cells by inducing apoptosis and autophagy.

Protocatechuic acid (PCA), present in many fruits and vegetables, exhibited various biological activities. Here, we provided evidence that it could be developed as a potential chemotherapeutic agent against human ovarian cancer. We found that PCA treatment significantly reduced the cell viability and colony formation of OVCAR-3, SKOV-3, and A2780 cells. OVCAR-3 cells were selected as a test model system for investigating molecular mechanism. PCA treatment induced cell cycle arrest in G2 /M phase, the activation of poly (ADP-ribose) polymerase (PARP) and caspase-3, the upregulation of Bax and downregulation of Bcl-2 in OVCAR-3 cells. We also observed that PCA treatment significantly caused upregulation of autophagy-related protein LC3-II and induced GFP-LC3 puncta formation. Furthermore, cotreatment with PCA and autophagy inhibitor attenuated the cytotoxicity induced by PCA in OVCAR-3 cells. Moreover, our results showed that PCA increased the intracellular levels of glutathione and decreased intracellular reactive oxygen species that might be related to the inhibition effect of PCA on OVCAR-3 cells. Our data revealed that PCA could modulate apoptosis and autophagy, suggesting the potential of PCA for chemoprevention and chemotherapy of ovarian cancer.

Sensitisation of ovarian cancer cells to cisplatin by flavonoids from Scutellaria barbata.

Combination of natural components with anticancer drugs is a new strategy for cancer chemotherapy to increase antitumour responses. In this study, we investigated the sensitisation effects of nine flavonoids from Scutellaria barbata to cisplatin (CDDP) on human ovarian cancer cells. The combinations of three flavonoids with CDDP showed the synergistic effects. The intracellular reactive oxygen species and the antioxidant activity were measured. The data suggest that the synergistic effects of flavonoids with CDDP on ovarian cancer cells did not directly correlate with their redox properties, but could be associated with the positions of hydroxyl group and methoxy group of flavonoids.

Cytotoxic constituents of ethyl acetate fraction from Dianthus superbus.

The ethyl acetate fraction (EE-DS) from Dianthus superbus was found to possess the cytotoxic activity against cancer cells in previous study. To investigate cytotoxic constituents, the bioassay-guided isolation of compounds from EE-DS was performed. Two dianthramides (1 and 2), three flavonoids (3-5), two coumarins (6 and 7) and three other compounds (8-10) were obtained. Structures of isolated compounds were identified by spectroscopic analysis. Cytotoxicity of the compounds against HepG2 cells was evaluated. Compound 1 showed the strongest cytotoxicity, compounds 10, 4, 3 and 5 had moderate cytotoxicity.

Emodin regulates apoptotic pathway in human liver cancer cells.

Emodin, a natural anthraquinone, has been reported to possess antiproliferative effects in many cancer cell lines. However, anticancer mechanism against human liver cancer remains unclear. In this study, we observed that emodin induced apoptosis in HepG2 cells and caused a significant accumulation of cells in the G1 phase. Western blot data showed that emodin treatment caused the increasing of release of cytochrome c into cytosol from mitochondria and the activation of caspase-8 and caspase-9, which suggest that the intrinsic and extrinsic pathways could be involved. Emodin treatment also resulted in a dose-dependent accumulation of intracellular reactive oxygen species. Furthermore, emodin increased the protein level of p53 and decreased the protein level of NF-κB/p65 in HepG2 cells, which indicated these two regulators might play a role in emodin-induced apoptosis. Computational modeling showed that emodin could directly bind to the BH3 domain of Bcl-2 through forming one hydrogen bond with Ala146 residue in Bcl-2. From these examinations, emodin not only significantly downregulated expression of Bcl-2 but also inhibited the heterodimerization of Bcl-2 with Bax because of strong interaction between emodin and Bcl-2. These suggest that emodin induces apoptosis in liver cancer cell line through a multifaceted complex cascade of events.

Alantolactone induces activation of apoptosis in human hepatoma cells.

Alantolactone, a sesquiterpene lactone, possesses anti-inflammatory property. In this study, we provide evidence that it could be developed as a novel agent against human liver cancer. We observed that alantolactone treatment to HepG2, Bel-7402 and SMMC-7721 cells, human liver cancer cell lines resulted in a dose-dependent inhibition of cell growth. We selected HepG2 cell line as a test model system. Alantolactone treatment of HepG2 cells resulted in a dose-dependent induction of apoptosis and arrest of cells in G2-M phase. This induction of apoptosis seems to be mediated via modulating the protein levels of Bcl-2 family and activation of caspases. Moreover, caspase-8 and Bid activation, loss of mitochondrial transmembrane potential and cytochrome c release suggest the existence of a cross-talk between the death receptor and the mitochondrial pathways. We also observed that alantolactone treatment of cells resulted in a dose-dependent decrease in NF- κB/p65. In addition, a significant and progressive increase in the level of p53 protein in alantolactone-treated cells was observed. Taken together, our data suggest that alantolactone could be developed as an agent against human liver cancer.

Activation of apoptosis by ethyl acetate fraction of ethanol extract of Dianthus superbus in HepG2 cell line.

Dianthus superbus L. is commonly used as a traditional Chinese medicine. We recently showed that ethyl acetate fraction (EE-DS) from ethanol extract of D. superbus exhibited the strongest antioxidant and cytotoxic activities. In this study, we examined apoptosis of HepG2 cells induced by EE-DS, and the mechanism underlying apoptosis was also investigated. Treatment of HepG2 cells with EE-DS (20-80 µg/ml) for 48 h led to a significant dose-dependent increase in the percentage of cells in sub-G1 phase by analysis of the content of DNA in cells, and a large number of apoptotic bodies containing nuclear fragments were observed in cells treated with 80 µg/ml of EE-DS for 24 h by using Hoechst 33258 staining. These data show that EE-DS can induce apoptosis of HepG2 cells. Immunoblot analysis showed that EE-DS significantly suppressed the expressions of Bcl-2 and NF-κB. Treatment of cells with EE-DS (80 µg/ml) for 48 h resulted in significant increase of cytochrome c in the cytosol, which indicated cytochrome c release from mitochondria. Activation of caspase-9 and -3 were also determined when the cells treated with EE-DS. The results suggest that apoptosis of HepG2 cells induced by EE-DS could be through the mitochondrial intrinsic pathway. High performance liquid chromatography (HPLC) data showed that the composition of EE-DS is complicated. Further studies are needed to find the effective constituents of EE-DS.

Anticancer, antioxidant and antimicrobial activities of the essential oil of Lycopus lucidus Turcz. var. hirtus Regel.

This study was designed to examine the anticancer, antioxidant and antimicrobial activities of the essential oil from Lycopus lucidus Turcz. var. hirtus Regel. The essential oil treatment to six human cancer cell lines resulted in a dose-dependent inhibition of cell growth. The cytotoxicity of the essential oil on liver carcinoma and breast cancer cell lines was significantly stronger than on other cell lines. The essential oil can induce apoptosis of the liver carcinoma cell line Bel-7402 and decrease the intracellular GSH level. The antioxidant effect of the essential oil was evaluated by using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and hydroxyl radical (OH) scavenging assays. The essential oil exhibited moderate antioxidant activity. The antimicrobial activity of the essential oil was evaluated against eight microorganisms using the disc diffusion and broth microdilution methods. The essential oil also showed moderate antimicrobial activity. These suggest that the essential oil could hold a good potential for use in the pharmaceutical industry.

Antitumor activity of chloroform fraction of Scutellaria barbata and its active constituents.

Scutellaria barbata (SB) is widely used as an antitumor agent in China, but the antitumor components of SB are still unclear. The antitumor activity of various fractions of an ethanol extract of SB was studied in six human malignant cell lines. Bio-based assays showed that non-polar and low-polar solvent fractions of SB had dose-dependent cytotoxicities on six cancer cell lines. The IC(50) values of these fractions on the cancer cell lines tested ranged from 16 to 70 microg/mL after 48 h of treatment. Among them, the chloroform fraction (CE-SB) had the strongest cytotoxicity on cancer cell lines with a lower cytotoxic effect on a normal liver cell line. Bel-7402 cell apoptosis induced by CE-SB was examined using Hoechst 33258 staining, agarose gel electrophoresis and flow cytometry. CE-SB dose-dependently decreased the S phase content. Treatment with CE-SB caused cytochrome c release and activation of caspase-9. The antitumor activity of CE-SB in vivo was also evaluated. At 60 mg/kg/day, CE-SB significantly inhibited the solid tumor proliferation and increased the life span of ascites tumor bearing mice (p < 0.01). CE-SB was subjected to bioassay-guided isolation of the active compounds by chromatography on silica gel and Sephadex LH-20. Phytol, wogonin, luteolin and hispidulin were obtained as cytotoxic constituents.

Chemical composition and antimicrobial activity of the essential oil of Scutellaria barbata.

The essential oil of Scutellaria barbata was obtained by hydrodistillation with a 0.3% (v/w) yield and analysed by GC and GC-MS. The main compounds in the oil were hexahydrofarnesylacetone (11.0%), 3,7,11,15-tetramethyl-2-hexadecen-1-ol (7.8%), menthol (7.7%) and 1-octen-3-ol (7.1%). The antimicrobial activity of the oil was evaluated against 17 microorganisms using disc diffusion and broth microdilution methods. The gram-positive bacteria, including methicillin-resistant Staphlococcus aureus, were more sensitive to the oil than gram-negative bacteria and yeasts.