Natural Products and Their Derivatives against Human Herpesvirus Infection.

Herpesviruses establish long-term latent infection for the life of the host and are known to cause numerous diseases. The prevalence of viral infection is significantly increased and causes a worldwide challenge in terms of health issues due to drug resistance. Prolonged treatment with conventional antiviral drugs is more likely to develop drug-resistant strains due to mutations of thymidine nucleoside kinase or DNA polymerase. Hence, the development of alternative treatments is clearly required. Natural products and their derivatives have played a significant role in treating herpesvirus infection rather than nucleoside analogs in drug-resistant strains with minimal undesirable effects and different mechanisms of action. Numerous plants, animals, fungi, and bacteria-derived compounds have been proved to be efficient and safe for treating human herpesvirus infection. This review covers the natural antiherpetic agents with the chemical structural class of alkaloids, flavonoids, terpenoids, polyphenols, anthraquinones, anthracyclines, and miscellaneous compounds, and their antiviral mechanisms have been summarized. This review would be helpful to get a better grasp of anti-herpesvirus activity of natural products and their derivatives, and to evaluate the feasibility of natural compounds as an alternative therapy against herpesvirus infections in humans.

Bioactive scalemic caged xanthones from the leaves of Garcinia bracteata.

Four pairs of previously undescribed caged xanthones (1-4) and twelve known caged xanthones (5-16) were isolated from the leaf extract of Garcinia bracteata. Their structures were unambiguously elucidated on the basis of spectroscopic methods. The planar structure and relative configuration of 1 was confirmed by X-ray crystallographic analysis. The enantiomers of compounds 1, 2, 4 were further resolved by semi-preparative chiral HPLC, and the absolute configurations of enantiomers of compounds 1 and 4 were determined by measurement and calculation of electronic circular dichroism (ECD) spectra and specific rotations. The inhibitory activities of the isolated compounds against human HeLa, A549, PC-3, HT-29, and WPMY-1 cell lines were assayed, and garcibractatin A (4) showed the most potent inhibitory activities in vitro with IC50 values from 1.11 to 2.93 µM. A preliminary structure-activity relationship has been discussed, and some helpful conclusions have been drawn.

Oblongifolin C suppresses lysosomal function independently of TFEB nuclear translocation.

Lysosomes are the terminal organelles of the autophagic-endocytic pathway and play a key role in the degradation of autophagic contents. We previously reported that a natural compound oblongifolin C (OC) increased the number of autophagosomes and impaired the degradation of P62, most likely via suppression of lysosomal function and blockage of autophagosome-lysosome fusion. However, the precise mechanisms of how OC inhibits the lysosome-autophagy pathway remain unclear. In the present study, we investigated the effect of OC on transcription factor EB (TFEB), a master regulator of lysosomal biogenesis, lysosomal function and autophagy. We showed that treatment with OC (15 µM) markedly enhanced the nuclear translocation of TFEB in HeLa cells, concomitantly reduced the interaction of TFEB with 14-3-3 proteins. We further demonstrated that OC caused significant inhibition of mTORC1 along with TFEB nuclear translocation, and OC-mediated TFEB nuclear translocation was dependent on mTORC1 suppression. Intriguingly, this increased nuclear TFEB was accompanied by reduced TFEB luciferase activity, increased lysosomal pH and impaired cathepsin enzyme activities. In HeLa cells, treatment with OC (7.5 µM) resulted in about 30% of cell death, whereas treatment with hydroxycitrate, a caloric restriction mimetic (20 µM) did not affect the cell viability. However, cotreatment with OC and hydroxycitrate caused significantly great cytotoxicity (>50%). Taken together, these results demonstrate that inhibition of lysosome function is mediated by OC, despite evident TFEB nuclear translocation.

Cytotoxic Prenylated Xanthones from the Leaves of Garcinia bracteata.

Six new prenylated xanthones (1: -6: ) and seventeen known xanthones were isolated from extracts of Garcinia bracteata leaves. Their structures were determined by extensive NMR and MS spectroscopic data analysis. The inhibitory activities of the isolates were assayed on HeLa, A549, PC-3, HT-29, and WPMY-1 cell lines. Compounds 1: and 15: -17: showed moderate inhibitory effects on tumor cell growth, with IC50s ranging from 3.7 to 14.7 µM.

Oblongifolin C and guttiferone K extracted from Garcinia yunnanensis fruit synergistically induce apoptosis in human colorectal cancer cells in vitro.

Oblongifolin C (OC) and guttiferone K (GUTK) are two anticancer compounds extracted from Garcinia yunnanensis Hu, but they act by different mechanisms. In this study we investigated whether a combination of OC and GUTK (1:1 molar ratio) could produce synergistic anticancer effects against human colorectal cancer cells in vitro. For comparison, we also examined the anticancer efficacy of ethanol extracts from G yunnanensis fruit, which contain OC and GUTK up to 5%. Compared to OC and GUTK alone, the combination of OC and GUTK as well as the ethanol extracts more potently inhibited the cancer cell growth with IC50 values of 3.4 µmol/L and 3.85 µg/mL, respectively. Furthermore, OC and GUTK displayed synergistic inhibition on HCT116 cells: co-treatment with OC and GUTK induced more prominent apoptosis than treatment with either drug alone. Moreover, the combination of OC and GUTK markedly increased cleavage of casapse-3 and PARP, and enhanced cellular ROS production and increased JNK protein phosphorylation. In addition, the combination of OC and GUTK exerted stronger effects under nutrient-deprived conditions than in complete medium, suggesting that autophagy played an essential role in regulating OC- and GUTK-mediated cell death. OC and GUTK are the main components that contribute to the anticancer activity of G yunnanensis and the compounds have apoptosis-inducing effects in HCT116 cells in vitro.

Bioassay-Guided Isolation of Prenylated Xanthone Derivatives from the Leaves of Garcinia oligantha.

Four new dihydroxanthone derivatives (1-4), four new tetrahydroxanthone derivatives (5-8), two new xanthone derivatives (9 and 10), and two known caged tetrahydroxanthones were isolated from extracts of the leaves of Garcinia oligantha by bioassay-guided fractionation. These structures of the new compounds were elucidated by NMR and MS spectroscopic data analysis, and the absolute configurations of compounds 1 and 5-7 were determined by electronic circular dichroism and/or single-crystal X-ray diffraction analysis. Compounds 6-9 were shown to be unusual xanthone derivatives with an isopropyl group, which was confirmed by the X-ray crystallographic structure of compound 8. The inhibitory activities of these isolates against four human tumor cell lines (A549, HepG2, HT-29, and PC-3) were assayed, and compounds 1, 2, 5, 11, and 12 showed inhibitory effects on tumor cell growth, with IC50 values ranging from 2.1 to 8.6 µM.

Yiguanjian decoction and its ingredients inhibit angiogenesis in carbon tetrachloride-induced cirrhosis mice.

BACKGROUND: Cirrhosis is associated with angiogenesis and disruption of hepatic vascular architecture. Yiguanjian (YGJ) decoction, a prescription from traditional Chinese medicine, is widely used for treating liver diseases. We studied whether YGJ or its ingredients (iYGJ) had an anti-angiogenic effect and explored possible mechanisms underlying this process. METHODS: Cirrhosis was induced with carbon tetrachloride (CCl4) (ip) in C57BL/6 mice for 6 weeks. From week 4 to week 6, cirrhotic mice were randomly divided into four groups: sorafenib-treated, YGJ-treated and iYGJ-treated mice and placebo. Serum biochemistries, hydroxyproline (Hyp) content and histopathological changes of hepatic tissues were measured as were α-smooth muscle actin (α-SMA), collagen I, CD31, vascular endothelial growth factor (VEGF), VEGF receptor (VEGFR) 2 and hypoxia-inducible factor (HIF)-1α. RESULTS: Both YGJ and iYGJ improved serum biochemistries. Changes of histopathology showed that YGJ and iYGJ reduced hepatic tissue necroinflammatory and collagen fiber deposition in cirrhosis mice. Compared to the CCl4 treated animals, Hyp, α-SMA, collagen I, CD31, VEGF, VEGFR, and HIF-1α expression decreased in YGJ and iYGJ groups. CONCLUSIONS: YGJ and iYGJ inhibited liver angiogenesis in cirrhotic mice treated with CCl4 by inhibiting the HIF-1α/VEGF signaling pathway, suggesting that anti-angiogenic effects of YGJ and iYGJ are associated with improving the hepatic hypoxic microenvironment.

Cytotoxic and anti-inflammatory prenylated benzoylphloroglucinols and xanthones from the twigs of Garcinia esculenta.

Five new prenylated benzoylphloroglucinol derivatives, garciesculentones A-E (1-5), a new xanthone, garciesculenxanthone A (6), and 15 known compounds were isolated from the petroleum ether extract and the EtOAc-soluble fraction of a 80% (v/v) EtOH extract of Garcinia esculenta. The structures of the new compounds were elucidated by 1D- and 2D-NMR spectroscopic analysis and mass spectrometry. Experimental and calculated ECD and a convenient modified Mosher's method were used to determine the absolute configurations. The cytotoxicity of these compounds were evaluated by MTT assay against three human cancer cell lines (HepG2, MCF-7, and MDA-MB-231) and against normal hepatic cells (HL-7702). In addition, these isolates were evaluated for their inhibitory effects on interferon-γ plus lipopolysaccharide-induced nitric oxide production in RAW264.7 cells.

Prenylated benzoylphloroglucinols and xanthones from the leaves of Garcinia oblongifolia with antienteroviral activity.

An acetone extract of the leaves of Garcinia oblongifolia showed antiviral activity against enterovirus 71 (EV71) using a cytopathic effect inhibition assay. Bioassay-guided fractionation yielded 12 new prenylated benzoylphloroglucinols, oblongifolins J-U (1-12), and five known compounds. The structures of 1-12 were elucidated by spectroscopic analysis including 1D- and 2D-NMR and mass spectrometry methods. The absolute configurations were determined by a combination of a Mosher ester procedure carried out in NMR tubes and ECD calculations. Compared to ribavirin (IC50 253.1 µM), compounds 1, 4, and 13 exhibited significant anti-EV71 activity in vitro, with IC50 values of 31.1, 16.1, and 12.2 µM, respectively. In addition, the selectivity indices of these compounds were 1.5, 2.4, and 3.0 in African green monkey kidney (Vero) cells, respectively.

Xanthine oxidase inhibitors from Garcinia esculenta twigs.

The EtOAc-soluble portion of the 80 % (v/v) EtOH extract from the twigs of Garcinia esculenta exhibited strong xanthine oxidase inhibition in vitro. Bioassay-guided purification led to the isolation of 1,3,6,7-tetrahydroxyxanthone (3) and griffipavixanthone (8) as the main xanthine oxidase inhibitors, along with six additional compounds (1, 2, 4-7), including two new compounds (1 and 2). This enzyme inhibition was dose dependent with an IC50 value of approximately 1.2 µM for 3 and 6.3 µM for 8. The inhibitory activity of 3 was stronger than the control allopurinol (IC50 value: 5.3 µM). To our knowledge, compound 8 is the first bixanthone that demonstrated potent XO inhibitory activity in vitro. The structures of the new compounds were established by spectroscopic analysis, and the optical properties and absolute stereochemistry of racemic (±) esculentin A (2) were further determined by the calculation of the DP4 probability and analysis of its MTPA ester derivatives.

[Research progress of chemistry and anti-cancer activities of natural products from Chinese Garcinia plants].

Garcinia plants are one of the rich sources of natural xanthones and benzophenones which have attracted a great deal of attention from the scientists in the fields of chemistry and pharmacology. Recently, many structurally unique constituents with various bioactivities, especially anti-tumor activity, have been isolated from Garcinia plants. This concise review focused on the anti-cancer activity natural products isolated from Chinese Garcinia plants, and the research finding by authors and collaborators over the past several years were cited.

[Dynamic change of lipid peroxidation-related protein expression and the intervention effects of Yiguanjian decoction in a rat model of CCl4-induced liver fibrosis].

To investigate the dynamic change of lipid peroxidation-related protein expression and the intervention effects of Yiguanjian (YGJ) Decoction on liver fibrosis induced by CCl4 in rat. Fifty-seven male Wistar rats were randomly divided into a liver fibrosis group (n = 39) and a normal group (n = 18). The liver fibrosis was treated with peritoneal injection of 50% CCl4 for nine weeks. At the end of weeks 3 and 6 of CCl4 treatment, six rats were sacrificed to assess the status of liver fibrosis. At the end of week 7, the remaining -fibrotic rats were randomly divided into an untreated model group (M, n=15) and a YGJ-treated group (n = 12). The YGJ group was administered daily, oral YGJ Decoction for three weeks, concomitant with continued CCl4 treatment. The M group and normal group received the same treatment oral regimen and volume of distilled water. At the end of week 8, four rats in group M were sacrificed to observed the fibrosis status. At the end of week 9, the fibrotic rats were sacrificed for sampling. Liver function, histological changes, contents of hydroxyproline (Hyp) and malondialdehyde (MDA), activity of super oxidase dismutase (SOD) and L-glutathione (GSH), protein expression of heat shock protein (HSP)70, heme oxygenase (HO)-1, transferrin, peroxiredoxin (Prxd) 6 and liver fatty acid binding protein (L-FABP) were detected. Compared with normal group-, the MDA content was increased significantly in M group at week 6 (M: 4.23+/-0.45 nmol/mg vs. normal: 2.22+/-0.59 nmol/mg, F = 60.13, P less than 0.01) and week 9 (M: 6.29+/-1.23 nmol/mg vs. normal: 2.22+/-0.59 nmol/mg, F = 66.99, P less than 0.01), but the SOD activity was decreased significantly at the same time points [week 6: (M: 196.94+/-39.20 U/mg vs. normal: 264.50+/-30.44 U/mg, F = 11.12, P less than 0.01]); [week 9: (M: 152.2+/-51.65 U/mg vs. normal: 264.50+/-30.44 U/mg, F = 23.11, P less than 0.01)], as were the GSH content [week 6: (M: 48.47+/-7.27 nmol/mg vs. 60.74+/-9.04 nmol/mg, F = 6.71, P less than 0.05]]; [week 9: (M: 37.89+/-9.01 nmol/mg vs. 60.74+/-9.04 nmol/mg, F = 24.06, P less than 0.01]]. Compared with group M at week 9, the YGH-treated model group had markedly decreased MDA (YGJ: 4.25+/-0.86 nmol/mg vs. M: 6.29+/-1.23 nmol/mg, F = 19.52, P less than 0.01], but significantly increased SOD (YGJ: 198.35+/-46.48 U/mg vs. 152.21+/-51.65 U/mg, F = 4.65, P less than 0.05] and GSH (YGJ: 53.73+/-7.54 nmol/mg vs. M: 37.89+/-9.01 nmol/mg, F = 19.23, P less than 0.01). Compared to normal rats at week 9, group M had significantly higher protein levels of HSP70 (normal: 1.21+/-0.06 vs. M: 0.58+/-0.07, F = 166.87, P less than 0.01) and HO-1 (normal: 1.11+/-0.06 vs. M: 0.58+/-0.06, F = 123.96, P less than 0.01), but significantly decreased levels of Prxd6 (normal: 0.04+/-0.05 vs. M: 1.49+/-0.05, F = 1215.85, P less than 0.01), transferrin (normal: 0.67+/-0.03 vs. M: 1.67+/-0.04, F = 301.35, P less than 0.01), and L-FABP (normal: 0.24+/-0.02 vs. M: 1.44+/-0.14, F = 219.05, P less than 0.01). Compared to group M at week 9, the YGJ treatment group showed significantly reduced HSP70 (YGJ: 0.82+/-0.04 vs. M: 1.21+/-0.06, F = 92.31, P less than 0.01) and HO-1 (YGJ: 0.90+/-0.04 vs. 1.11+/-0.06, F = 26.89, P less than 0.01), but significantly increased Prxd6 (YGJ: 0.88+/-0.11 vs. 0.04+/-0.05, F = 150.17, P less than 0.01), transferrin (YGJ: 1.36+/-0.13 vs. 0.24+/-0.02, F = 237.19, P less than 0.01), and L-FABP (YGJ: 1.04+/-0.12 vs. 0.67+/-0.03, F = 27.53, P less than 0.01). YGJ treatment of fibrotic liver rats reduces lipid peroxidation damage by preventing generation of oxidizing substances.

A review on computational approaches that support the researches on traditional Chinese medicines (TCM) against COVID-19.

BACKGROUND: COVID-19 highly caused contagious infections and massive deaths worldwide as well as unprecedentedly disrupting global economies and societies, and the urgent development of new antiviral medications are required. Medicinal herbs are promising resources for the discovery of prophylactic candidate against COVID-19. Considerable amounts of experimental efforts have been made on vaccines and direct-acting antiviral agents (DAAs), but neither of them was fast and fully developed. PURPOSE: This study examined the computational approaches that have played a significant role in drug discovery and development against COVID-19, and these computational methods and tools will be helpful for the discovery of lead compounds from phytochemicals and understanding the molecular mechanism of action of TCM in the prevention and control of the other diseases. METHODS: A search conducting in scientific databases (PubMed, Science Direct, ResearchGate, Google Scholar, and Web of Science) found a total of 2172 articles, which were retrieved via web interface of the following websites. After applying some inclusion and exclusion criteria and full-text screening, only 292 articles were collected as eligible articles. RESULTS: In this review, we highlight three main categories of computational approaches including structure-based, knowledge-mining (artificial intelligence) and network-based approaches. The most commonly used database, molecular docking tool, and MD simulation software include TCMSP, AutoDock Vina, and GROMACS, respectively. Network-based approaches were mainly provided to help readers understanding the complex mechanisms of multiple TCM ingredients, targets, diseases, and networks. CONCLUSION: Computational approaches have been broadly applied to the research of phytochemicals and TCM against COVID-19, and played a significant role in drug discovery and development in terms of the financial and time saving.

New monoterpenoids from the stigmas of Crocus sativus.

One new compound, crocusatin M (1), and three new glycosidic compounds, crocusatins N-P (2-4), along with nine known compounds were isolated from the dried stigmas of Crocus sativus. The structures of new compounds were elucidated on the basis of spectroscopic analysis, and the absolute configurations of 1, 2, and 3 were unambiguously assigned by the comparison of experimental and calculated ECD data. This is the first report of the isolation of 4 with the HMG moiety from the genus Crocus. Compounds 1 and 4 exhibited weak anti-inflammatory activities on inhibiting lipopolysaccharide (LPS)-induced NO production.

Platycoside O, a new triterpenoid saponin from the roots of Platycodon grandiflorum.

A new unusual minor triterpenoid saponin, platycoside O (1), was isolated from the 75% EtOH extract obtained from the roots of Platycodon grandiflorum, together with four known saponins: platycoside M-3 (2), platycoside J (3), platycoside F (4) and platycoside B (5). The structure of 1 was determined as 3-O-ß-D-glucopyranosyl-(1→6)-ß-D-glucopyranosyl-2ß,3ß,16α,23-tetrahydroxyolean-12-en-24-methoxyl, 24-oxo-28-oic acid 28-O-ß-D-xylopyranosyl-(1→4)-α-L-rhamnopyranosyl-(1→2)-α-L-arabinopyranoside on the basis of spectral analysis and chemical evidence.

Simultaneous determination of five nucleosides and nucleobases of Rehmannia glutinosa Libosch. by high performance liquid chromatography.

This study is to establish a method for simultaneously determination of five nucleosides and nucleobases, including hypoxanthine, uridine, adenine, guanosine and adenosine in Rehmannia glutinosa Libosch. which was collected from different regions in China. A Diamonsil C18 column (250 mm x 4.6 mm, 5 microm) was used. Acetonitrile and 0.04 mol L(-1) potassium dihydrogen phosphate solution were adopted as mobile phase with gradient elution. The flow rate was 1 mL min(-1) and column temperature was 30 degrees C. The detection wavelength was at 254 nm. The method had good linearity over the range of 1.0 - 16.0 microg mL(-1) (r2 = 0.999 8), 5.0 - 80.0 microg mL(-1) (r2 = 0.999 8), 1.0 - 16.0 microg mL(-1) (r2 = 0.999 5), 1.25 - 20.0 microg mL(-1) (r2 = 0.999 8) and 1.0 - 16.0 microg mL(-1) (r2 = 0.999 8) for hypoxanthine, uridine, adenine, guanosine and adenosine, respectively. The average recoveries were between 98.8% and 100.7%. The content of hypoxanthine, uridine, adenine, guanosine and adenosine in Rehmannia glutinosa Libosch. from different regions was significantly different. This established method was sensitive and reliable for the quantification of five chemical constituents in Rehmannia glutinosa Libosch.

Novel Meroterpenoids from Hypericum patulum: Highly Potent Late Nav1.5 Sodium Current Inhibitors.

Hypulatones A and B (1 and 2), two racemic meroterpenoids possessing an unprecedented spiro[benzofuran-2,1'-cycloundecan]-4'-ene-4,6(5H)-dione core, were characterized from Hypericum patulum. Compound 2 was found to significantly inhibit the late current of Nav1.5 (late INa, IC50 = 0.2 µM). Importantly, 2 exhibited remarkable separation (>100-fold) of late INa relative to peak INa and notable selectivity over Cav3.1, Kv1.5, and hERG. 1 showed comparable inhibition on late INa compared to that of 2 with poorer selectivity.

Dearomatized Isoprenylated Acylphloroglucinol Derivatives with Potential Antitumor Activities from Hypericum henryi.

A series of dearomatized isoprenylated acylphloroglucinols derivatives, hyperhenols A-E (1-5), as well as seven known analogues (6-12), were characterized from Hypericum henryi. Their structures were determined by combination of NMR, ECD spectroscopy, and X-ray diffraction analysis. Compounds 1 and 6-8 were tested to exhibit potential antitumor properties, of which 6 and 7 inhibited cell growth through inducing apoptosis and cell cycle arrest. In addition, these compounds could induce autophagy and PINK1/Parkin-mediated mitophagy in cancer cell lines, as well as suppress lung cancer A549 cells metastasis in vitro.

Xanthone derivatives from the leaves of Garcinia oligantha.

Nine new and unique xanthone derivatives, including one novel hybrid monoterpene-tetrahydroxanthone (1), three dihydro-xanthone derivatives (2-4), and five skeleton-rearranged xanthone derivatives (5-9), were obtained from a 95% EtOH extract of Garcinia oligantha leaves by a LC-MS-guided fractionation procedure. The structures of the new compounds were elucidated by analysis of their 1D and 2D NMR and MS data. The relative configurations of 2 and 8 were determined via X-ray crystallographic data analysis, while the absolute configurations of 1-2, 5-9 were assigned based on a comparison of calculated and experimental ECD and/or OR data. In SRB, PI-exclusion and Hoechst staining assays, 6 showed strong cytotoxic activities which could dose-dependently induce Taxol-insensitive quiescent LNCaP cell death. Additionally, a preliminary mechanism investigation using immunoblotting and Caspase-3 activity assay, indicated that 6 induced quiescent LNCaP cell death potentially through caspase-dependent mitochondrial apoptosis pathway.

Garsubelone A, the First Dimeric Polycyclic Polyprenylated Acylphloroglucinols with Complicated Heptacyclic Architecture from Garcinia subelliptica.

Garsubelone A (1), the first dimeric polycyclic polyprenylated acylphloroglucinols type metabolite featuring a complicated 6/6/6/6/6/6/6 heptacyclic architecture containing 10 stereogenic centers, was isolated from Garcinia subelliptica. Biogenetically, this compound was constructed by the plausible monomeric precursor, garsubelone B (2) and secohyperforin, via a key Diels-Alder cycloaddition to form an unique 2-oxabicyclo[3.3.1]nonane core. Their structures and absolute configurations were determined by comprehensive spectroscopic and X-ray diffraction techniques. The cytotoxic activities of these isolates were also evaluated.