Structural optimization and neurotrophic activity evaluation of neurotrophic gentiside derivatives.

C14 alkyl benzoate ABG001, derived from naturally occurring gentisides, was reported to exhibit neurotrophic activity which is similar to NGF (Nerve Growth Factor). In this research, ABG001 was modified by the strategy of isosteric replacement and conformational restriction with the purpose of improving the bioactivity. The cellular neurotrophic activity of those ABG001 derivatives were evaluated, among which 3-hydroxyquinolin-2-(1H)-one A3 and 4-decylphenol ester B7 displayed much better neurotrophic activity compared with ABG001, which highlights the potential of those novel scaffolds for future neurotrophic agent development.

HPTLC Autography Based Screening and Isolation of Mushroom Tyrosinase Inhibitors of European Plant Species.

In the course of this project, 133 plants were evaluated on their ability to inhibit tyrosinase, a key enzyme in melanogenesis. The screening was performed by means of a HPTLC autographic assay, resulting in the selection of three plants, Asplenium trichomanes, Pinus uncinata, and Scutellaria altissima, with promising tyrosinase inhibiting activities. With the aid of the HPTLC assay, it was not only possible to select the most interesting plant extracts, but also to monitor the activity-guided fractionation which, in a relatively short time period, led to the isolation of active principles. Benzoic acid, roseoside, and dihydrovomifoliol-O-ß-d-glucopyranoside could be identified as tyrosinase inhibitors present in P. uncinata. Globularin turned out to be the active principle of S. altissima, and 4-ethenylphenyl 6-O-(6-deoxy-α-l-mannopyranosyl)-ß-d-glucopyranoside was detected as tyrosinase inhibitor of A. trichomanes. The pure compounds were tested also in a 96 well-plate assay in order to determine their IC50 values. The lowest IC50 value (42 µm) could be obtained for globularin, whereas the other compounds, e. g., benzoic acid exhibited a rather high IC50 value (IC50 =552 µm). This stood in clear contrast to the autographic assay, but is has to be taken into account that the outcome of the autography assay is not only depending on the IC50 value of a compound, but also on the content of the respective constituent in the extract.

A new antifungal benzoic acid ester from Uvaria narum.

Uvaria narum has been used for gastrointestinal problems, jaundice, fever and skin diseases in traditional and ethnomedical practices. Our preliminary antifungal screening of various leaf extracts of U. narum revealed very good antifungal activity for its acetone extract. Active principle of U. narum leaf acetone extract was isolated by bioactivity-guided fractionation and characterised as a new molecule, 2-E-(2″-oxo-5″-acetoxy cyclopent-3″-en-1″-ylidene) ethyl benzoate, by NMR, IR and mass spectroscopic analyses. This active isolate showed very good activity against the fungal pathogen, Colletotrichum gloeosporioides.

Prenylated benzoic acid derivatives from the stem of Euodia lepta.

Two new prenylated benzoic acid derivatives, leptoic acid A and (+)-S-anodendroic acid (1-2), along with one known compound, 2,2-dimethyl-2H-1-benzopyran-6-carboxylic acid (3) were isolated from the stem of Euodia lepta (spreng.) Merr. Their structures were elucidated on the basis of the chemical and spectroscopic evidence.

HSCCC Separation of the Two Iridoid Glycosides and Three Phenolic Compounds from Veronica ciliata and Their in Vitro Antioxidant and Anti-Hepatocarcinoma Activities.

Five main compounds, including two iridoid glycosides (catalposide, verproside) and three phenolic compounds (luteolin, 4-hydroxy benzoic acid, 3,4-dihydroxy benzoic acid), were separated and prepared from the crude extract of Veronica ciliata by high-speed countercurrent chromatography. n-Hexane/n-butanol/water (1.5:5:5, v/v/v) was used for the separation of catalposide and verproside. n-Hexane/n-butanol/water (3:2:5, v/v/v) was used for the separation of luteolin, 4-hydroxy benzoic acid and 3,4-dihydroxy benzoic acid. The head-to-tail elution mode was used with a flow rate of 5.0 mL/min and a rotary speed of 800 rpm. Finally, a total of 1.28 mg luteolin, 6 mg 4-hydroxy benzoic acid, 2 mg 3,4-dihydroxy benzoic acid, 2 mg verproside and 10 mg catalposide with purities of 98%, 99.1%, 99.5%, 99.8% and 99%, respectively, were obtained from 200 mg of crude extract. In addition, their structure was identified using MS, ¹H-NMR and (13)C-NMR. To the best of our knowledge, this is the first report of the separation and purification of iridoid glycosides and phenolic compounds from V. ciliata by high-speed countercurrent chromatography (HSCCC). Among these compounds, luteolin, 4-hydroxy benzoic acid and 3,4-dihydroxy benzoic acid were separated from V. ciliata Fisch. for the first time. The results of the antioxidant activity show that protocatechuic acid and luteolin have strong antioxidant activity compared to 2,6-di-tert-butyl-4-methylphenol (BHT) and vitamin C (Vc). Five compounds also exhibited strong anti-hepatocarcinoma activities.

Antibacterial prenylbenzoic acid derivatives from Anodendron formicinum.

A phytochemical investigation on the stems of Anodendron formicinum led to the isolation of eight prenylbenzoic acid derivatives. Three of these were new compounds, designated as formicinuosides A (1), B (2), and C (3). Their structures were elucidated on the basis of extensive spectroscopic analysis, as well as by comparison with the reported spectroscopic data. This is the first report of chemical constituents from A. formicinum and their antimicrobial activities. Among the isolated compounds, compounds 4, 6 and 8 showed significant antibacterial activities against Providensia smartii with MIC values of 0.781 µg/mL. Moreover, compound 8 showed remarkable antibacterial activity against Escherichia coli with MIC value of 0.781 µg/mL.

Comparative analysis of the main bioactive components of San-ao decoction and its series of formulations.

A high performance liquid chromatographic (HPLC) method with diode array detection (DAD) was established for simultaneous determination of seven main bioactive components in San-ao decoction and its series of formulae (San-ao decoction, Wu-ao decoction, Qi-ao decoction and Jia-wei San-ao decoction). Seven compounds were analyzed simultaneously with a XTerra C(18) column (4.6 mm × 250 mm, 5 µm) using a linear gradient elution of a mobile phase containing acetonitrile (A) and a buffer solution (0.02 mol/L potassium dihydrogen phosphate and adjusted to pH 3 using phosphoric acid) (B); the flow rate was 1.0 mL/min. The sample was detected with DAD at 210, 254 and 360 nm and the column was maintained at 30 °C. All the compounds showed good linearity (r2 > 0.9984) in the tested concentration range. The precisions were evaluated by intra-day and inter-day tests, and relative standard deviation (R.S.D.) values within the range of 0.83%–2.53% and 0.64%–2.77% were reported, respectively. The recoveries of the quantified compounds were observed to cover a range from 95.34% and 104.82% with R.S.D. values less than 2.72%. The validated method was successfully applied for the simultaneous determination of seven main bioactive components including ephedrine (1), amygdalin (2), liquiritin (3), benzoic acid (4), isoliquiritin (5), formononetin (6) and glycyrrhizic acid (7) in San-ao decoction and its series of formulae. The results also showed a wide variation in the content of the identified active compounds in these samples, which could also be helpful to illustrate the drug interactions after some herbs combined in different formulations.

[Study on the bioactive constituents of Piper wallichii].

OBJECTIVE: To investigate the bioactive constituents in the stem of Piper wallichii. METHODS: Compounds were separated by column chromatography of silica gel, ODS-A and Sephadex LH-20. Their structures were elucidated based on spectral analysis. DPPH scavenging activity and AchE inhibitory activity were tested. RESULTS: 10 compounds were isolated and their structures were identified as 3,4-methylenedioxy-benzoic acid (1), vanillic acid (2), benzoic acid (3), N-p-coumaroyltyramine (4), futoenone (5), futoquinol (6), isofutoquinol A (7), 4-hydroxy-3,5-dimethoxy-benzoic acid (8), futoamide (9), dihydropiperlonguminine (10). CONCLUSION: Compounds 1-6 are isolated from P. wallichii for the first time. Vanillic acid (2) and 4-hydroxy-3,5-dimethoxy-benzoic acid (8) show scavenging activity against DPPH radical with ED50 at 224.33 microg/mL and 11.44 microg/mL, respectively. No compound shows inhibition activity against AchE.

New cucurbitane-type triterpenoids from Bryonia aspera.

Phytochemical investigation of the chloroform extract of BRYONIA ASPERA roots resulted in the isolation and structure elucidation of two new cucurbitacins (1, 2) together with eight known cucurbitane derivatives (6-13), the pentacyclic triterpene bryonolic acid (5) and two hydroxybenzoic acid amides (3, 4). Their structures were elucidated by spectroscopic analysis, including 2D NMR techniques.

Identification of bisprenylated benzoic acid derivatives from yerba santa (Eriodictyon ssp.) using sensory-guided fractionation.

Due to certain off-flavor problems and lacking bitter masking effects with Yerba Santa (Eriodictyon angustifolium and E. californicum) extracts, which are also described as bitter, herbal, medicinal, phenolic, or astringent, methanolic extracts were fractionated and evaluated for their taste properties using a high temperature liquid chromatography (HTLC)-based approach. The taste-guided fractionation led to the identification of a series of novel bisprenylated benzoic acids (erionic acids A (1), B (2), C (3), D (4), E (5), and F (6) and eriolic acids A (7), B (8), C (9), and D (10), respectively), along with the known flavonoids eriodictyol, homoeriodictyol, hesperetin, and chrysoeriol. The new compounds were isolated in larger amounts for characterization from Narrow Leaf Yerba Santa (E. angustifolium) and California Yerba Santa (E. californicum), respectively, using fast centrifugal partition chromatography (FCPC) and HTLC. The structures were elucidated using one and two-dimensional NMR spectroscopy and high resolution mass spectrometry (HR-MS). For E. californicum, data regarding seasonal and climatic variation of the eriolic acid contents and of the flavonoids were collected. The flavor properties of some of the isolated new compounds were evaluated; they showed strong off-flavor characteristics, such as bitter, astringent, phenolic, or woody, and may contribute to the sensory effects observed for crude Yerba Santa extracts. Erionic acid C (3) was not only able to increase the absolute bitterness but also to extinguish the bitter masking effect of homoeriodictyol in a caffeine solution.

Fractionation of antioxidants from autohydrolysis of barley husks.

The liquid phase from nonisothermal autohydrolysis of barley husks was extracted with ethyl acetate and redissolved in ethanol to yield a crude extract (denoted BHEAE), which was subjected to further processing to enhance the antioxidant activity. A fractionation method, carried out for characterization purposes, consisted of the extraction of BHEAE with organic solvents of increasing polarity and further fractionation in Sephadex LH-20. Among the tested solvents, ethyl acetate allowed the highest yield, phenolic content, and antioxidant activity. Upon elution with methanol, products with high DPPH radical scavenging capacity (IC50 = 0.22 g/L) were obtained. The major compounds in the isolate were benzoic and cinnamic acids. Adsorption-desorption in commercial polymeric resins was carried out as an alternative strategy for BHEAE refining. This method is more suited for possible scale-up and provided a concentrate with a Trolox equivalent antioxidant capacity of 9 mM, which was obtained at a yield of 18 g/kg of barley husks.

Microcalorimetric studies of the action on four organic acids in Radix isatidis on the growth of microorganisms.

The actions of four organic acids in Radix isatidis, a traditional Chinese medicinal (TCM) herb, on Escherichia coli, Staphylococcus aureus and Shigella dysenteriae growth were investigated by microcalorimetry. The four organic acids were syringic acid, 2-amino-benzoic acid, salicylic acid and benzoic acid. The power-time curves of Escherichia coli, Staphylococcus aureus and Shigella dysenteriae growth with and without organic acids were acquired, meanwhile the extent and duration of inhibitory effects on the metabolism were evaluated by growth rate constants (k1, k2), maximum heat-output[0] power (P(m)) and peak time (t(m)). The inhibitory activity varied with different drugs. The sequences of anti-microbial activity of the four organic acids on Escherichia coli, Staphylococcus aureus and Shigella dysenteriae were all: syringic acid > 2-amino-benzoic acid > salicylic acid > benzoic acid. And benzoic acid promoted the growth of Staphylococcus aureus and Shigella dysenteriae. This study provides a basis for the further study on Radix Isatidis.

Isolation of 5-hydroxypyrrolidin-2-one and other constituents from the young fronds of Pteridium aquilinum.

5-Hydroxypyrrolidin-2-one, along with (2R)-pterosin B, shikimic acid, kaempferol-3-O-beta-D-glucopyranoside, transtiliroside, beta-sitosterol, daucosterol, glycerol 1-stearate and benzoic acid, were isolated from the young fronds of the bracken fern Pteridium aquilinum. 5-Hydroxypyrrolidin-2-one, shikimic acid and glycerol 1-stearate were isolated from the plant for the first time.

An experimental implementation of chemical subtraction.

A preparative analytical method was developed to selectively remove ("chemically subtract") a single compound from a complex mixture, such as a natural extract or fraction, in a single step. The proof of concept is demonstrated by the removal of pure benzoic acid (BA) from cranberry (Vaccinium macrocarpon Ait.) juice fractions that exhibit anti-adhesive effects versus uropathogenic Escherichia coli. Chemical subtraction of BA, representing a major constituent of the fractions, eliminates the potential in vitro interference of the bacteriostatic effect of BA on the E. coli anti-adherence action measured in bioassays. Upon BA removal, the anti-adherent activity of the fraction was fully retained, 36% inhibition of adherence in the parent fraction at 100mug/mL increased to 58% in the BA-free active fraction. The method employs countercurrent chromatography (CCC) and operates loss-free for both the subtracted and the retained portions as only liquid-liquid partitioning is involved. While the high purity (97.47% by quantitative (1)H NMR) of the subtracted BA confirms the selectivity of the method, one minor impurity was determined to be scopoletin by HR-ESI-MS and (q)HNMR and represents the first coumarin reported from cranberries. A general concept for the selective removal of phytoconstituents by CCC is presented, which has potential broad applicability in the biological evaluation of medicinal plant extracts and complex pharmaceutical preparations.

[Studies on the chemical constituents of flowers of Prunus mume].

OBJECTIVE: To study the chemical constituents of flowers of Prunus mume. METHODS: Compounds were separated by silica gel. Their structures were identified and elucidated by spectral analysis and chemical methods. RESULTS: Eight compounds were obtained and identified as benzoic acid (I), isorhamnetin (II), quercetin (III), kaempferol-3-O-beta-D-galactopyranoside (IV), isorhamnetin-3-O-beta-D-glucopyranoside (V), isoquercitrin (VI), hypericin (VII) and rutin (VIII). CONCLUSION: Among them, II-VII are isolated from this plant for the first time.

[Studies on chemical constituents from root of Cynanchum atratum].

OBJECTIVE: To study the chemical constituents from the roots and rhizome of Cynanchum atratum. METHOD: The chemical constituents were isolated and repeatedly purified by silica gel chromatography and the structures were elucidated by the NMR spectra and physicochemical properties. RESULT: Twelve compounds were obtained and nine of them were identified as 2, 4-dihyroxyacetophe none (1), 2, 6-dihyroxyacetophenone (2), 4-hydroxybenzenemethanol (3), benzoic acid (4), beta-amyrin acetate (5), palmitic acid (6), beta-sitosterol (7), beta-daucosterol (8), glaucogenin C-3-O-alpha-D-oleandropyranosyl-(1 --> 4)-beta-D-digitoxopyranosyl-(1 -->4)-alpha-D-oleandropyranoside (9). CONCLUSION: Seven compounds were obtained from C. atratum for the first time.

Cytotoxic and anti-platelet aggregation constituents from the root wood of Melicope semecarpifolia.

A new acetophenone derivative, melicopone, along with twenty-nine known compounds has been isolated from the root wood of Melicope semecarpifolia. The structure of this new compound was determined using spectral analyses. The compound oxynitidine isolated in this study adds the Melicope genus to the benzo[c]phenanthridine-containing members chemotaxonomically. Three isolates were cytotoxic in P-388 and HT-29 cell lines, and anti-platelet aggregation activities were shown for 10 known compounds.

Antimicrobial screening and quantitative determination of benzoic acid derivative of Gomphrena celosioides by TLC-densitometry.

The antimicrobial activity of ethanolic extract and pure compounds of Gomphrena celosioides have been screened by Kirby-Bauer method. Quantitative determination of 4-hydroxy-3-methoxy-benzoic acid in stems, leaves, flowers and roots was established by TLC-densitometry. Results showed significant activity against Staphylococcus aureus and Salmonella typhi. There were no significant differences in the determined benzoic acid derivative.

[Phenolic compounds isolated from rhizoma of Aster tataricus].

OBJECTIVE: To study the chemical constituents in root and rhizome of Aster tataricus. METHODS: Compounds were isolated and purified by silica gel and sephadex LH-20 column chromatography. Their structures were identified by physicochemical properties and spectral analysis. RESULT: Nine compounds were isolated and identified as quercetin (I), kaemferol (II), emodin (III), chrysophanol (IV), physcion (V), benzoic acid (VI), p-hydroxy-bezoic acid (VII), E-caffeic acid (VIII), E-ferulic acid hexacosyl ester (IX). CONCLUSION: Compounds IV, V, VI, VII, VIII, IX were isolated from A. tataricus for the first time.

[Studies on chemical constituents in the root of Desmos grandifolius (I)].

OBJECTIVE: To investigate new compounds with anti-tumor activities from the root of Desmos grandifolius of Annonaceae. METHOD: The chemical constituents were isolated by silica gel column chromatography, and the structures were elucidated by UV, IR, MS, 1H NMR, 13C NMR, H-H COSY and NOESY analysis. RESULTS: Six compounds have been isolated from the CHCl3 extract of this plant and identified as lawinal(I), isolawinal(II), desmethoxymatteucinol(III), benzoic acid(IV), beta-sitosterol(V) and sitgmasterol (VI). CONCLUSION: All compounds were found from this plant for the first time. Three dihydroflavonoids isolated from this species are characterized by A-ring substitution and no B-ring substitution.