Synthesis and Biological Evaluation of Novel Allobetulon/Allobetulin-Nucleoside Conjugates as AntitumorAgents.

Allobetulin is structurally similar tobetulinic acid, inducing the apoptosis of cancer cells with low toxicity. However, both of them exhibited weak antiproliferation against several tumor cell lines. Therefore, the new series of allobetulon/allobetulin-nucleoside conjugates 9a-10i were designed and synthesized for potency improvement. Compounds 9b, 9e, 10a, and 10d showed promising antiproliferative activity toward six tested cell lines, compared to zidovudine, cisplatin, and oxaliplatin based on their antitumor activity results. Among them, compound 10d exhibited much more potent antiproliferative activity against SMMC-7721, HepG2, MNK-45, SW620, and A549 human cancer cell lines than cisplatin and oxaliplatin. In the preliminary study for the mechanism of action, compound 10d induced cell apoptosis and autophagy in SMMC cells, resulting in antiproliferation and G0/G1 cell cycle arrest by regulating protein expression levels of Bax, Bcl-2, and LC3. Consequently, the nucleoside-conjugated allobetulin (10d) evidenced that nucleoside substitution was a viable strategy to improve allobetulin/allobetulon's antitumor activity based on our present study.

New phorbol ester derivatives as potent anti-HIV agents.

Tigliane esters show many biological activities, including anti-HIV-1 activity. Our aim in this study was to establish structure-anti-HIV activity relationships for four series of tigliane-type diterpenoids. We synthesized and evaluated 29 new phorbol ester derivatives for anti-HIV activity and for cytotoxicity against human tumor cell lines. Among them, three derivatives, two phorbol-13-monoesters (5d and 5e) and a phorbol-12,13-diester (6a), showed significant anti-HIV activity. We found that better anti-HIV activity was often associated with a shorter acyl ester at C-13. Particularly, compounds with a phenyl ring in the ester side chain exhibited excellent anti-HIV activity and had good safety indexes. Due to its significant anti-HIV potency with a high selectivity index, phorbol-12,13-dicinnamoate (6a) was chosen as the potential candidate for further preclinical trials.

Diosgenin Derivatives as Potential Antitumor Agents: Synthesis, Cytotoxicity, and Mechanism of Action.

Thirty-two new diosgenin derivatives were designed, synthesized, and evaluated for their cytotoxic activities in three human cancer cell lines (A549, MCF-7, and HepG2) and normal human liver cells (L02) using an MTT assay in vitro. Most compounds, especially 8, 18, 26, and 30, were more potent when compared with diosgenin. The structure-activity relationship results suggested that the presence of a succinic acid or glutaric acid linker, a piperazinyl amide terminus, and lipophilic cations are all beneficial for promoting cytotoxic activity. Notably, compound 8 displayed excellent cytotoxic activity against HepG2 cells (IC50 = 1.9 µM) and showed relatively low toxicity against L02 cells (IC50 = 18.6 µM), showing some selectivity between normal and tumor cells. Studies on its cellular mechanism of action showed that compound 8 induces G0/G1 cell cycle arrest and apoptosis in HepG2 cells. Predictive studies indicated that p38α mitogen-activated protein kinase (MAPK) is the optimum target of 8 based on its 3D molecular similarity, and docking studies showed that compound 8 fits well into the active site of p38α-MAPK and forms relatively strong interactions with the surrounding amino acid residues. Accordingly, compound 8 may be used as a promising lead compound for the development of new antitumor agents.

Synthesis and in vitro anticancer activities of biotinylated derivatives of glaucocalyxin A and oridonin.

Fourteen glaucocalyxin A biotinylated derivatives, one glaucocalyxin C biotinylated derivative, and two oridonin biotinylated derivatives were designed and synthesized. Their structures were confirmed from 1H NMR, 13C NMR and HRMS data. The derivatives were evaluated for cytotoxic activities against lung (A549), cervical cancer cell line HeLa derivative (KB), multidrug-resistant KB subline (KB-VIN), triple-negative breast (MDA-MB-231), and estrogen receptor-positive breast (MCF-7) cancer cell lines.[Formula: see text].

Development of anti-influenza agents from natural products.

The influenza pandemic continues to threaten public health due to its high morbidity and mortality rates, despite some successes in antiviral research. Natural drugs are important alternative therapies in the treatment of and recovery from influenza and have been the subjects of intense investigation during the last few decades. Many reports have shown that the development of novel bioactive chemicals extracted from natural drugs has significant advantages. Oseltamivir is a successful case of an anti-influenza drug synthesized using two natural products, quinic acid, and shikimic acid, as starting materials. In China, traditional Chinese medicine (TCM) plays an important role in the treatment of influenza. TCM herbal extracts and prescriptions or their isolated bioactive constituents have shown significant therapeutic and preventive effects against influenza. For example, the roots of Isatis indigotica (Banlangen) fight viral infection by targeting both the virus and the host and have significantly different effects than those of synthetic chemicals. Lianhuaqingwen capsule exerts its anti-influenza activity by regulating the immune response to interfere with both viral and host reactions and might well be an alternative therapeutic option to treat influenza virus infection. This paper reviews the chemical ingredients, crude extracts, and TCM prescriptions with anti-influenza activity reported during the period of 2010-September 2019. We hope that this comprehensive review will not only fuel research on anti-influenza active natural products and TCM research but also provide a promising alternative candidate for further anti-influenza drug development.

Recent advances in natural anti-HIV triterpenoids and analogs.

The human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS) epidemic is one of the world's most serious health challenges. Although combination antiretroviral therapy provides effective viral suppression, current medicines used against HIV cannot completely eradicate the infectious disease and often have associated toxicities and severe side effects in addition to causing drug resistance. Therefore, the continued development of new antiviral agents with diverse structures and novel mechanisms of action remains a vital need for the management of HIV/AIDS. Natural products are an important source of drug discovery, and certain triterpenes and their analogs have demonstrated potential as pharmaceutical precursors for the treatment of HIV. Over the past decade, natural triterpenoids and analogs have been extensively studied to find new anti-HIV drugs. This review discusses the anti-HIV triterpenoids and analogs reported during the period of 2009-2019. The article includes not only a comprehensive review of the recent anti-HIV agent development from the perspective of medicinal chemistry, but also discusses structure-activity relationship analyses of the described triterpenoids.

Cucurbitane-Type Triterpenoids from the Vines of Momordica charantia and Their Anti-inflammatory Activities.

Seven new cucurbitane-type triterpenoids, kuguaovins A-G (1-7), and five known ones were isolated from the rattans of wild Momordica charantia. Their structures were established by spectroscopic data analyses, including 1D and 2D NMR, IR, and MS techniques. The absolute configurations of the cucurbitanes were determined from NOESY data and partially by X-ray crystallographic analysis. In pharmacological studies, compounds 1-7 and 9-12 exhibited weak anti-inflammatory effects (IC50 = 15-35 µM), based on an anti-NO production assay.

Kalshiolin A, new lignan from Kalimeris shimadai.

The Asian plant Kalimeris shimadai has been used as food and ethnologic medicine for over a thousand years. In this study, we isolated and identified one new lignan, kalshiolin A (1), and 12 known lignans (2-13). The structures were characterized by the comprehensive analyses of spectroscopic data (HR-ESI-MS, IR, 1D, and 2D-NMR) and the absolute configuration of 1 was determined from ECD calculations. The new compound 1 was also screened for cytotoxic activity but did not show significant potency (IC50 35.9-43.3 µM) against A549, MDA-MB-231, MCF7, KB, and KB-VIN cell lines.

Kalshinoids A-F, Anti-inflammatory Sesquiterpenes from Kalimeris shimadae.

In a study of the potential anti-inflammatory constituents from Kalimeris shimadae, six new sesquiterpenes, kalshinoids A-F (1-6), together with 21 known compounds (7-27), were isolated. The structures and absolute configurations of the new compounds were discerned from extensive spectroscopic analysis, and the absolute configurations of kalshinoids A, B, E, and F were established by ECD calculations. Furthermore, the identified compounds were tested for anti-inflammatory activity as assessed by inhibition of tumor necrosis factor-alpha (TNF-α) in THP-1 cells. Three sesquiterpenes [kalshinoid F, 4(15)-eudesmen-1ß,7,11-triol, and 4α,10α,11-trihydroxy-1ßH,5ßH-guai-7(8)-ene] reduced levels of TNF-α in lipopolysaccharide-stimulated THP-1 cells in a concentration-dependent manner and were more potent than dexamethasone. These natural sesquiterpenes merit further investigation as possible anti-inflammatory agents.

Discovery of an Oleanolic Acid/Hederagenin-Nitric Oxide Donor Hybrid as an EGFR Tyrosine Kinase Inhibitor for Non-Small-Cell Lung Cancer.

Natural triterpenoids, such as oleanolic acid (OA) and hederagenin, display anti-lung cancer effects, and nitric oxide (NO) is associated with some oncogenic signaling pathways. Accordingly, 17 OA/hederagenin-NO donor hybrids were designed, synthesized, and evaluated against tumor cells. The most potent compound, 13, significantly inhibited the proliferation of five tumor cell lines (IC50 4.6-5.2 µM), while hederagenin inhibited the growth of only A549 tumor cells (IC50 > 10 µM). Furthermore, compound 13 showed stronger inhibitory effects on EGFR-LTC kinase activity (IC50 0.01 µM) than hederagenin (IC50 > 20 µM) and inhibited the proliferation of gefitinib-resistant H1975 (IC50 8.1 µM) and osimertinib-resistant H1975-LTC (IC50 7.6 µM) non-small-cell lung cancer (NSCLC) cells. Moreover, compound 13 produced the most NO in H1975 tumor cells, which indicated that NO may play a synergistic role. Collectively, compound 13, a novel hederagenin-NO donor hybrid with a different chemical structure from those of the current FDA-approved EGFR-targeted anti-NSCLC drugs, may be a promising lead compound for the treatment of NSCLC expressing gefitinib-resistant EGFR with a T790 M mutation or osimertinib-resistant EGFR-LTC with an L858R/T790M/C797S mutation. This work should shed light on the discovery of new anti-NSCLC drugs targeting EGFR from natural products.

Development of a Validated UPLC-MS/MS Method for Analyzing Major Ginseng Saponins from Various Ginseng Species.

Ginsenosides, which contain one triterpene and one or more sugar moieties, are the major bioactive compounds of ginseng. The aim of this study was to develop and optimize a specific and reliable ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method for the analysis of twelve different resources of ginseng. The six marker compounds of ginsenoside Rb1, ginsenoside Rb2, ginsenoside Rc, ginsenoside Rd, ginsenoside Re, and ginsenoside Rg1, as well as an internal standard, were separated by a reversed-phase C-18 column with a gradient elution of water and methanol-acetonitrile. The multiple-reaction monitoring (MRM) mode was used to quantify and identify twelve market products. The results demonstrated that not only is the logarithm of its partition coefficient (cLog P; octanol-water partition coefficient) one of the factors, but also the number of sugars, position of sugars, and position of the hydroxyl groups are involved in the complicated separation factors for the analytes in the analytical system. If the amount of ginsenoside Rb1 was higher than 40 mg/g, then the species might be Panax quinquefolius, based on the results of the marker ginsenoside contents of various varieties. In summary, this study provides a rapid and precise analytical method for identifying the various ginsenosides from different species, geographic environments, and cultivation cultures.

Carbazole Alkaloids from Clausena anisum-olens: Isolation, Characterization, and Anti-HIV Evaluation.

Two new carbazole alkaloids (1,2) and six known carbazole alkaloids (3-8) were isolated from Clausena anisum-olens. Their structures were elucidated based on extensive spectroscopic analysis. All isolated compounds (1-8) were evaluated for their anti-HIV effects on virus replication in MT-4 lymphocytes infected by HIV-1NL4-3 Nanoluc-sec virus, and new carbazole alkaloid 1 exhibited anti-HIV activity with an EC50 value of 2.4 µg/mL and SI of 7.1.

New Dammarane-type Saponins from Gynostemma pentaphyllum.

Six new dammarane-type saponins, gypenosides CP1-6 (16), along with 19 known compounds 7⁻25, were isolated and characterized from the aerial parts of Gynostemma pentaphyllum. Among these compounds, eight dammarane-type saponins, 2, 5, 6, 7, 11, 12, 13, and 15, exhibited the greatest antiproliferative effects against two human tumor cell lines (A549 and HepG2).

Investigation of Interactive Activity of Electro-Acupuncture on Pharmacokinetics of Sildenafil and Their Synergistic Effect on Penile Blood Flow in Rats.

Erectile dysfunction (ED) is a disorder found in males throughout the world, which negatively affects relationships with partners with advancing age. Hence, in this study, we tested a combined novel treatment of electro-acupuncture (EA) and sildenafil citrate against ED. In addition to EA therapy, the sildenafil citrate, a phosphodiesterase 5 inhibitor, is a widely recognized drug that has achieved considerable success in the treatment of ED. However, the combined effect of both the EA and sildenafil has not yet been investigated. Hence, we aimed to examine the effect of EA on the pharmacokinetics and pharmacodynamics of sildenafil in rat plasma. The pharmacokinetic parameters were determined using ultra performance liquid chromatography (UPLC) after EA and sildenafil administration (10 mg/Kg). Following this, the pharmacodynamics was studied via blood flow pattern using developing Doppler images of the lower body and penis. The pharmacokinetic studies demonstrated that sildenafil significantly increases by administration of low-frequency EA. Further, the pharmacodynamic studies using Doppler imaging revealed an elevated blood flow in rat penis compared with lower body during combined treatment of sildenafil and low-frequency EA. These data indicate a synergistic therapeutic effect of EA and sildenafil for the treatment of ED.

Pharmacokinetics of Schizandrin and Its Pharmaceutical Products Assessed Using a Validated LC-MS/MS Method.

Schisandra chinensis has been used as an important component in various prescriptions in traditional Chinese medicine and, more recently, in Western-based medicine for its anti-hepatotoxic effect. The aim of this study was to develop a selective, rapid, and sensitive ultra-performance liquid chromatography-tandem mass spectrometry method for pharmacokinetic studies of schizandrin in rats. Liquid-liquid extraction was used for plasma sample preparation. A UHPLC reverse-phase C18e column (100 mm × 2.1 mm, 2 µm) coupled with a mobile phase of methanol-0.1% formic acid (85:15, v/v) was used for sample separation. A triple quadrupole tandem mass spectrometer was used to detect the analytes in the selected reaction monitoring mode. The linear range of schizandrin in rat plasma was 5.0-1000 ng/mL (r² > 0.999), with a lower limit of quantification of 5 ng/mL. The method was validated with regard to accuracy, intra-day and inter-day precision, linearity, stability, recovery, and matrix effects in rat plasma, which were acceptable according to the biological method validation guidelines developed by the FDA. This method was successfully applied to a pharmacokinetic study after oral administration of 3 g/kg and 10 g/kg of Schisandra chinensis products, which yielded a maximum concentration of schizandrin of 0.08 ± 0.07 and 0.15 ± 0.09 µg/mL, respectively. A parallel study design was used to investigate the oral bioavailability of single compound of schizandrin and the herbal extract, the single compound of pure schizandrin (10 mg/kg, i.v.), pure schizandrin (10 mg/kg, p.o.), and the herbal extract of Schisandra chinensis (3 g/kg and 10 g/kg, p.o.) were given individually. The dose of Schisandra chinensis (3 g/kg) equivalent to schizandrin (5.2 mg/kg); the dose of Schisandra chinensis (10 g/kg) equivalent to schizandrin (17.3 mg/kg). The result demonstrated that the oral bioavailability of schizandrin was approximately 15.56 ± 10.47% in rats, however the oral bioavailability of herbal extract was higher than single compound. The method was successfully applied to the pharmacokinetic study of pure schizandrin after oral administration of its pharmaceutical industry products in rats.

The Herb-Drug Pharmacokinetic Interaction of 5-Fluorouracil and Its Metabolite 5-Fluoro-5,6-Dihydrouracil with a Traditional Chinese Medicine in Rats.

BACKGROUND: Xiang-Sha-Liu-Jun-Zi-Tang (XSLJZT) is the most common traditional formula given to colorectal and breast cancer patients in Taiwan, according to a statistical study of the National Health Insurance Research Database. 5-Fluorouracil (5-FU) is widely used as the first line of treatment for colorectal cancer. Thus, the aim of study is to investigate the pharmacokinetic interaction of XSLJZT and 5-FU. METHODS: To investigate the herb-drug interaction of XSLJZT with 5-FU as well as its metabolite 5-fluoro-5,6-dihydrouracil (5-FDHU) using pharmacokinetics, a high-performance liquid chromatography (HPLC) system coupled with a photodiode array detector was developed to monitor 5-FU and 5-FDHU levels in rat blood. Rats were divided into three cohorts, one of which was administered 5-FU (100 mg/kg, iv-intravenous) alone, while the other two groups were pretreated with low and high doses of XSLJZT (600 mg/kg/day or 2400 mg/kg/day for 5 consecutive days) in combination with 5-FU. RESULTS: The results demonstrated that 5-FU level was not significantly different between the group treated with only 5-FU and the group pretreated with a normal dose of XSLJZT (600 mg/kg/day). However, pharmacokinetic analysis revealed that pretreatment with a high dose of XSLJZT (2400 mg/kg/day) extended the residence time and increased the volume of distribution of 5-FU. No significant distinctions were found in 5-FDHU pharmacokinetic parameters at three doses of XSLJZT. CONCLUSIONS: Overall, the pharmacokinetic results confirm the safety of coadministering 5-FU with XSLJZT, and provide practical dosage information for clinical practice.

Herb-Drug Interaction between the Traditional Hepatoprotective Formulation and Sorafenib on Hepatotoxicity, Histopathology and Pharmacokinetics in Rats.

Sorafenib has been used as a standard therapy for advanced hepatocellular carcinoma (HCC). In Asia, patients with HCC are potentially treated with the combination of sorafenib and Chinese herbal medicines to improve the efficiency and reduce the side effects of sorafenib. However, limited information about the herb-drug interactions is available. We hypothesize that the Chinese herbal medicine may exert hepatoprotective effects on the sorafenib-treated group. The aim of this study is to investigate the pharmacokinetic mechanism of drug-drug interactions of sorafenib including interacting with hepatoprotective formulation, Long-Dan-Xie-Gan-Tang formulation (LDXGT) and with two cytochrome P450 3A4 (CYP3A4) inhibitors, grapefruit juice and ketoconazole. Liver enzyme levels and histopathology of liver slices were used to evaluate sorafenib-induced hepatotoxicity and the potential hepatoprotective effects of the LDXGT formulation on subjects treated with the combination of sorafenib and the herbal medicine. In this study, a validated HPLC-photodiode array analytical system was developed for the pharmacokinetic study of sorafenib in rats. As the result of the pharmacokinetic data, pretreatment with the LDXGT formulation did not significantly interact with sorafenib compared with sorafenib oral administration alone. Furthermore, grapefruit juice and ketoconazole did not significantly affect sorafenib metabolism. Furthermore, pretreatment with variable, single or repeat doses of the LDXGT formulation did not suppress or exacerbate the sorafenib-induced hepatotoxicity and histopathological alterations. According to these results, the LDXGT formulation is safe, but has no beneficial effects on sorafenib-induced hepatotoxicity. A detailed clinical trial should be performed to further evaluate the efficacy or adverse effects of the LDXGT formulation in combination with sorafenib in humans.

Identification of a Multicomponent Traditional Herbal Medicine by HPLC-MS and Electron and Light Microscopy.

BACKGROUND: Commercial pharmaceutical herbal products have enabled people to take traditional Chinese medicine (TCM) in a convenient and accessible form. However, the quantity and quality should be additionally inspected. To address the issue, a combination of chemical and physical inspection methods were developed to evaluate the amount of an herbal formula, Xiang-Sha-Liu-Jun-Zi-Tang (XSLJZT), in clinical TCM practice. METHODS: A high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS) method with electrospray ionization was developed to measure the herbal biomarkers of guanosine, atractylenolide III, glycyrrhizic acid, dehydrocostus lactone, hesperidin, and oleanolic acid from XSLJZT. Scanning electron microscopy (SEM) photographs and light microscopy photographs with Congo red and iodine-KI staining were used to identify the cellulose fibers and starch content. Furthermore, solubility analysis, swelling power test, and crude fiber analysis were contributed to measure the starch additive in pharmaceutical products. RESULTS: The results demonstrated large variations in the chemical components of different pharmaceutical brands. The SEM photographs revealed that the starch was oval, smooth, and granular, and that the raw herbal powder appears stripy, stretched, and filiform. The stained light microscopy photographs of all of the pharmaceutical products showed added starch and raw herbal powder as extenders. CONCLUSION: The developed chemical and physical methods provide a standard operating procedure for the quantity control of the herbal pharmaceutical products of XSLJZT.