Two new phenolic amides from the seeds of Pharbitis nil

Two new phenolic amides, pharnilatins A (1) and B (2), were isolated from the seeds of Pharbitis nil. These new compounds possess a p-coumaroyl unit with a structurally unique side chain, (2S,3S)-2,3-dihydroxyputrescine. The chemical structures and absolute stereochemistries of the new compounds were determined on the basis of spectroscopic analyses including 1D- and 2D-NMR experiments and chemical reactions. Compounds 1 and 2 exhibited cytotoxicity against A549, SK-OV-3, SK-MEL-2, and HCT-15 human tumor cells. However, none of the compounds inhibited nitric oxide (NO) production in lipopolysaccharide (LPS)-activated microglia cells.     

Triterpenoid saponins from the seeds of Pharbitis nil

From the seeds of Pharbitis nil (Convolvulaceae), two new oleanene-type triterpene glycosides, pharbitosides A (1) and B (2), together with beta-sitosterol, beta-sitosterol glucoside (daucosterol), caffeic acid, and methyl caffeate were isolated. The structure of pharbitoside A (1) was elucidated to be queretaroic acid 3-O-alpha-L-rhamnopyranosyl-(1-->2)-O-beta-D-glucopyranosyl-(1-->2)-beta-D-glucopyranoside (1). Pharbitoside B (2) is a 21alpha-hydroxyoleanolic acid saponin carrying the same sugar moiety as that of pharbitoside A (1).     

Bioactive constituents from Michelia champaca

(-)-Anonaine (1), (-)-asimilobine (2), (-)-nuciferine (3), (-)-anolobine (4), (-)-romerine (5), (-)-N-acetylanonaine (6), liriodenine (7), (+)-syringaresinol (8), N-trans-feruloyltyramine (9), N-cis-feruloyltyramine (10), scopoletin (11), 4-acetonyl-3,5-dimethoxy-p-quinol (12), vanillin (13), vanillic acid (14), syringic acid (15), beta-sitosterol (16) and stigmasterol (17) were isolated from branches of Michelia champaca L. In addition, a cell proliferation assay of five of the isolated compounds on human breast and lung cancer cells showed that liriodenine (7) was the strongest inhibitor.     

Bioactive phenolic amides from Celtis africana

Nine compounds have been isolated for the first time from Celtis africana, namely trans-N-coumaroyltyramine (1), trans-N-feruloyltyramine (2), trans-N-caffeoyltyramine (3), lauric acid (4), oleic acid (5), palmitic acid (6), lupeol (7), β-sitosterol (8) and oleanolic acid (9), respectively. Their structures have been elucidated by different spectroscopic techniques. The isolated compounds were screened for their antioxidant, anti-inflammatory and acetylcholinestrease enzyme inhibitory activities. Compounds 1-3 showed significant antioxidant and anti-inflammatory activities and weak to moderate acetylcholinestrease enzyme inhibition activity.     

Bioactive constituents from Croton sparsiflorus Morong

Whole plant extracts of Croton sparsiflorus in methanol have shown significant enzyme inhibition and antioxidant activities. Bioassay-guided isolation of chloroform fraction at pH 3 resulted in the identification of crotsparinine (1) and crotsparine (2), while sparsiflorine (3) was purified from the chloroform fraction at pH 9. The structures of the compounds were confirmed through spectral analyses (EI-MS, ¹H and ¹³C NMR). The isolated compounds 1–3 exhibited remarkable enzyme inhibition activity with IC₅₀ values 27.01 ± 1.1, 22.26 ± 1.0 and 18.02 ± 1.3 μM in xanthine oxidase and 48.42 ± 1.5, 48.05 ± 1.4 and 7.42 ± 1.0 μM in acetylcholine esterase assays, respectively. These compounds also showed potent radical scavenging and reducing properties in DPPH and FRAP assays, respectively. The present results suggest the validity of the traditional uses of C. sparsiflorus in rheumatism and gout. Furthermore, the isolated noraporphine alkaloids can be useful in the treatment of neurodegenerative diseases.     

Effect of light on soluble guanylyl cyclase activity in Pharbitis nil seedlings

Cyclic GMP acts as a chemical switch in plant cells to modulate cellular reactions. However, its metabolism has not been extensively explored and is still poorly understood. Previous experiments suggest that an endogenous cGMP system could participate in the mechanism of phytochrome controlled photoperiodic flower induction in Pharbitis nil. In order to gain further information on the role of cGMP, we have begun to study the enzyme of cGMP synthesis. In this article, the presence of the enzyme with guanylyl cyclase (GC) activity in soluble protein fractions of P. nil is reported. A large portion of the enzymatic activity is present in the cotyledons, where enzyme activity amounted to 0.45 pmol cGMP/min/mg protein. The enzyme exhibited a K(m) 0.5mM for GTP. A plot of 1/v versus 1/[GTP] was linear and V(max) was 0.74 pmol cGMP/min/mg protein. It was shown that the anti-sGC antibody recognise a 40 kDa protein. Moreover, the NO-donor, sodium nitroprusside (SNP) and YC-1, as a NO-independent stimulator, enhanced enzyme activity. The NS 2028 (a potent GC inhibitor) treatments provoked a 3-fold reduction of the enzyme activity in comparison to the untreated fractions. Furthermore, the influence of light on GC activity was analysed. It was noted that cGMP level increased in cool white light, and darkness inhibited enzyme activity. Exposure to blue light acts to stimulate cGMP formation, whereas in red light a rapid decrease in GC activity was observed that returned to the high level when far-red light was applied after the red light treatment. The results presented in this work strongly argue that an enzyme with guanylyl cyclase activity is present in P. nil organs and its activity is controlled by light via the photoreceptors-dependent pathways.     

Biotransformation of benzaldehyde-type and acetophenone-type derivatives by Pharbitis nil hairy roots

The glucosylation of some coumarin and flavone derivatives on incubation with the hairy roots of morning glory (Pharbitis nil) was previously reported. We further studied the biotransformation of benzaldehyde- and acetophenone-type derivatives. Vanillin and isovanillin were reduced to alcoholic derivatives and glucosylated at the phenolic and the alcoholic hydroxyl groups. In the case of 3,4-dihydroxybenzaldehyde, the formyl group was reduced and the 3-hydroxyl or 4-hydroxyl groups were glucosylated to give monoglucosides. The 3-hydroxyl group was predominantly glucosylated to the 4-hydroxyl group. 4-beta-D-Glucopyranosyloxy-3-methoxybenzylalcohol was obtained in low yield. In time-course experiments with vanillin, it was found that the high-level reduction of the formyl group and glucosylation of the phenolic hydroxyl group occurred, and finally 4-O-beta-D-glucopyranosylvanillylalcohol was obtained as the main product. In the case of 3,4-dimethoxybenzaldehyde, 3,4,5-trimethoxybenzaldehyde, and salicylaldehyde, the formyl groups were reduced, and then the hydroxyl groups at the benyl position were glucosylated to give alcoholic glucosides in relatively high yields. In 4-hydroxy-3-methoxyacetophenone, the 4-hydroxyl group was glucosylated and two dimerized glucosides, biphenyl and biphenylether types, were obtained in low yields. In acetophenone, 1-beta-D-glucopyranosyloxy-1-phenylethane and 2-beta-D-glucopyranosyloxyacetophenone were obtained. As mentioned above P. nil hairy roots showed various biotransformative activities including glucosylation of phenolic and benzylic hydroxyl groups, reduction of the formyl group near the benzene ring, and phenol oxidation dimerization. The glucosylation reaction was especially interesting for the production of valuable glucosides.     

Bioactive chemical constituents from Hyptis suaveolens stem

Our previous studies have found that the aerial part of Hyptis rhomboides and the seed of Hyptis suaveolens contain xanthine oxidase (XO) inhibitors, inspiring us to investigate the chemical constituents of H. suaveolens stem. The EtOH extract of H. suaveolens stem was fractionated by liquid-liquid partitioning, followed by separation over Sephadex LH-20, silica gel, and reverse-phase column chromatography, centrifugal partition chromatography, and semi-preparative RP-HPLC, to give 17 bioactive isolates. Of these, dimethyl melitrate A ( 9 ) is a new natural product, 10 is likely (7″ E)-9′-methyl melitrate A, only caffeic acid ( 2 ) is the same as those isolated from the seed of the same plant, and only nepetoidins A ( 14 ) and B ( 11 ) are the same as those from H. rhomboides stem. Nepetoidin B ( 11 ) showed the best anti-XO activity. Rosmarinic acid ( 3 ) is the most abundant (>661 ppm; w/w, dried stem), while melitric acid ( 12 ) (>277 ppm), caffeic acid ( 2 ; >125 ppm), and methyl rosmarinate ( 4 ; >81 ppm) are the major ones. This outcome could serve as a good basis for chemotaxonomy of the Hyptis plants and is beneficial for developing H. suaveolens stem as anti-hyperuricemic nutraceutical.     

New phenolic glycosides from the seeds of Cucurbita moschata

Five new phenolic glycosides, cucurbitosides A-E (1-5), were isolated from the seeds of Cucurbita moschata. Their structures were elucidated as 2-(4-hydroxy)phenylethanol 4-O-(5-O-benzoyl)-beta-D-apiofuranosyl(1-->2)-beta-D-glucopyranoside (1), 2-(4-hydroxyphenyl)ethanol 4-O-[5-O-(4-hydroxy)benzoyl]-beta-D-apiofuranosyl(1-->2)-beta-D-glucopyranoside (2), 4-hydroxybenzyl alcohol 4-O-(5-O-benzoyl)-beta-D-apiofuranosyl(1-->2)-beta-D-glucopyranoside (3), 4-hydroxybenzyl alcohol 4-O-[5-O-(4-hydroxy)benzoyl]-beta-D-apiofuranosyl(1-->2)-beta-D-glucopyranoside (4) and 4-hydroxyphenyl 5-O-benzoyl-beta-D-apiofuranosyl(1-->2)-beta-D-glucopyranoside (5) on the basis of spectroscopic analysis and chemical evidence.     

Bioactive constituents from Rollinia emarginata (Annonaceae)

From an Argentine collection of the tropical tree Rollinia emarginata (Annonaceae), vomifoliol, dehydrovomifoliol, blumenol C, loliolide, 7-epiloliolide, vanillin, dihydroactinolide, as well as other common plant constituents were obtained, and identified by their NMR and MS features compared with authentic samples. Antifeedant and toxic actions were exerted to the polyphagous moth Spodoptera frugiperda by the ethanol extract of the plant, at 250 ppm in the larval diet. Additionally, in greenhouse studies, a 200 ppm aqueous solution of the extract produced a post-emergency herbicidal effect on the annual weed common lambsquarter (Chenopodium album).     

New phenolic constituents from the fruit juice of Phyllanthus emblica

Six new phenolic constituents, L-malic acid 2-O- (1), mucic acid 2-O- (5), mucic acid 1,4-lactone 2-O- (6), 5-O- (8), 3-O- (10), and 3,5-di-O- (11) gallates, were isolated from the fruit juice of Phyllanthus emblica together with their methyl esters (2-4, 7, 9), and their structures were determined by spectral and chemical methods. Compounds 5, 6, and 8, the major phenolic constituents of the juice, were present as an equilibrium mixture in aqueous solution.     

Bioactive constituents from Chinese natural medicines. XX. Inhibitors of antigen-induced degranulation in RBL-2H3 cells from the seeds of Psoralea corylifolia

The ethyl acetate-soluble fraction of the methanolic extract from the seeds of Psoralea corylifolia was found to inhibit the release of beta-hexosaminidase, as a marker of antigen-IgE-induced degranulation in RBL-2H3 cells. Sixteen constituents were isolated from the ethyl acetate-soluble fraction and several constituents, Delta(1),3-hydroxybakuchiol (IC(50) = 49 microM), Delta(3),2-hydroxybakuchiol (69 microM, bavachin (58 microM), and psoralidin (ca. 100 microM), showed inhibitory activities against the antigen-induced degranulation.     

Enantio-selective reduction of the flowering related compound KODA and its analogues in Pharbitis nil cv. Violet

Plant oxylipins are an important class of signaling molecules in plants. The cyclic adducts of epinephrine or norepinephrine with the naturally occurring oxylipin (12Z,15Z)-9-hydroxy-10-oxo-octadeca-12,15-dienoic acid (KODA, 1) or its synthetic analogues (2–6) have been reported to possess flower-inducing activity toward Lemna paucicostata. By in vivo and in vitro experiments with seedlings of Pharbitis nil cv. Violet carbonyl groups of the α-ketols (1 and 3) and the ketones (7 and 9) were enantio-selectively reduced to give their corresponding vicinal diols (2 and 4) and alcohols (8 and 10). The stereo-chemistry at the oxymethine carbon was determined based on the long range C–H coupling constants and the modified Mosher's method. Orientation of the adjacent hydroxyl group in (1 and 3) did not affect the enantio-selectivity, whereas the conversion was slightly affected and higher yields were obtained with the R-enantiomers of the α-ketols.     

Four new phenolic constituents from the rhizomes of Gastrodia elata Blume

Four new gastrodin derivatives containing a trans-cinnamoyl unit (1–4) and nine known compounds (5–13) were isolated from the rhizomes of Gastrodia elata Blume. All these compounds were evaluated for their neuroprotective effects against 6-hydroxydopamine-induced cell death, and compounds 7 and 12 showed potent activities with EC₅₀ values of 10.5 and 10.2 μM, respectively.     

Anticyanobacterial phenolic constituents from the aerial parts of Eupatorium fortunei Turcz

Four thymol derivatives and two phenolic compounds were isolated from the aerial parts of Eupatorium fortunei. The new structures were elucidated to be 7,8,9-trihydroxythymol (1), and 8,10-didehydro-7,9-dihydroxythymol (2) by means of MS and NMR analysis. The known compounds were identified as 8,9,10-trihydroxythymol (3), 10-acetoxy-8,9-dihydroxythymol (4), o-coumaric acid (5) and 4-(2-hydroxyethyl)benzaldehyde (6). Compound 3 showed strongest inhibitory effect on the growth of Microcystis aeruginosa in comparison with CuSO₄.     

SPECTRAL PROPERTIES,PHOTOTRANSFORMATION KINETICS AND PELLETABILITY OF PHYTOCHROME IN Pharbitis nil Chois*

Abstract— An examination has been made of the involvement of phytochrome in the circadian rhythm of flowering in Pharbitis nil Chois. The peak position of P_fr absorption changes with time after a red light pulse. The shortest absorption wavelength of P_fr occurs at the same time as flowering is inhibited by red light in dark grown, red light pretreated plants. Pelletable and supernatant phytochrome show a similar trend with lowest values found at the time of flower inhibition. Neither phototransformation kinetics nor intermediates of phytochrome which accumulate in white light show such a relationship to the circadian rhythm found in flowering of dark grown P. nil.     

Prenylated anthraquinones and other constituents from the seeds of Vismia laurentii

Two new prenylated anthraquinones, laurenquinone A (1) and B (2) were isolated from the seeds of Vismia laurentii together with four known compounds; xanthone V(1) (3), physcion (4), 3-geranyloxyemodin anthrone (5) and friedelin (6). The structures of the new metabolites were determined with the help of spectroscopic data including extensive 2D-NMR spectroscopy. The known compounds were identified by comparison of their physical and spectroscopic data with those reported in the literature. Compounds 1, 4 and 5 exhibited moderate algicidal activity against Chlorella fusca and 3 showed moderate activity against the gram-positive bacterium Bacillus megaterium.     

Cytotoxic constituents from Vicia monantha subsp. monantha seeds

Chemical investigation of Vicia monantha subsp. monantha Retz. revealed isolation of one new hydroxy- fatty acid (6) identified as (6-Z, 10-E)-9-hydroxy henicosa-6,10-dienoic acid in addition to six known metabolites; hexadecanoic acid (1), β-sitosterol (2), β-amyrin (3), β-sitosterol-glucoside (4), 2,3-dihydroxypropyl tetradecanoate (5) and (Z)-9-hydroxypentadec-6-enoic acid (7). The cytotoxic effect of the isolated compounds was assessed by MTT assay using lung cancer A-549, prostate cancer PC3, breast cancer MCF-7, colon cancer HCT-116 and liver cancer HepG2 cell lines. Only compounds 1, 2, and 4 showed cytotoxic effect on HCT-116 cells where compound 2 was the most active with IC₅₀ value of 22.61 μg/mL. In addition, compounds 1, 2, 3, and 4 showed promising cytotoxic effect on MCF-7 cells with IC₅₀ values of 21.03, 15.42, 10.089, and 11.34 μg/mL, respectively.