Records of Natural Products Articles

Plants are rich sources of biologically and/or pharmacologically active phytochemicals. This study aimed to determine the chemical composition, antioxidant, tyrosinase, anti-cholinesterase, and anti-diabetic activities of ethyl acetate (EtOAc), methanol (MeOH), and water extracts obtained from the aerial parts of Onopordum caricum (Hub.-Mor.), which is an endemic plant species to Turkish flora. As a result of spectrophotometric analysis, the MeOH extract was the richest in total phenolics and flavonoids (46.26 mg GAEs/g and 20.97 mg QEs/g, respectively). In quantitative chromatographic analysis, the MeOH extracts contained considerable amounts of chlorogenic acid, eriodictyol, luteolin 7-O-glucoside, vanillic acid, syringic acid, 4-hydroxybenzoic acid, and pinoresinol. Except for the ferrous ion chelating activity assay, MeOH extract showed higher activity than others in all test systems. The activity data exhibited by the MeOH extract in phosphomolybdenum, DPPH and ABTS radical scavenging, CUPRAC, and FRAP tests were 1.46, 1.10, 1.30, 0.87, and 0.76 mg/mL, respectively. The EtOAc extract showed higher activity in all enzyme inhibition assays. The AChE, BChE, α-amylase, α-glucosidase and tyrosinase inhibitory activities of this extract were 0.95, 1.20, 2.37, 1.18 and 1.77 mg/mL, respectively. There was a very high correlation between the extracts' total phenolic and flavonoid contents and their antioxidant activities (phosphomolybdenum, radical scavenging, and reducing power). Since the antioxidant and enzyme inhibitory activity data presented in the current study were found to be higher than the activities of some other Onopordum species in the literature, it was concluded that the plant species in question could be used in the treatment of Alzheimer's, diabetes, hyperpigmentation, and disorders occurred as a result of oxidative stress pressure.

A new alkaloid, named scopariaine A (1), was obtained from the whole plant of Scoparia dulcis L. The new structure was established by various spectroscopic tmethods including 1D (1H-, 13C-NMR), 2D-NMR (HMBC, HSQC) and high resolution electrospray ionization mass spectrometry (HR-ESI-MS). Scopariaine A (1) was tested for its protective effect on attenuating palmitate-induced viability at 5, 10 and 25 μM. The results showed that the cell viability was increased in palmitic acid combined with scopariaine A (1) treated H9C2 cells.

Abstract

In the present work, the flower volatiles and seed fatty acids compositions of three populations (P-I, P-II, P-III) of Rosa iliensis were investigated for the first time. R. iliensis is a rare, endangered, narrow-endemic species growing in floodplains of the Ili and Sharyn rivers of Almaty region. The flower volatiles have been investigated with the tandem of MSD-SPME and GC-MS/FID techniques. The seed lipids were extracted from the ripe fruits with the microextraction technique. The flower volatiles of R. iliensis three populations were characterized by the abundance of oxygenated monoterpenes with benzaldehyde (13.3-38.7 %) and citronellol (2.6-8.8 %) as the major constituents. There were detected significant differences in floral scents between the populations. The flowers of P-I (from Sharyn River) contain sesquiterpene g-elemene (8.8%), the flowers of P-II (upper reaches of the Ili River) were rich in a-gurjunene (12.8%), while flowers of P-III (lower reaches of the Ili River) contained any sesquiterpenes. Seven fatty acids were determined in the seeds and unsaturated acids were found to be dominant for studied populations. Linoleic (43.0-51.0%), a-linolenic (26.5-28.1%) and oleic (12.0-16.1%) acids were detected as the major constituents. The present study shows that R. iliensis species is rich source of valuable volatiles and fatty acids.

Two new 13-oxomilbemycins, 13-oxomilbemycin β3 (1) and 25-ethyl-13-oxomilbemycin β3 (2), were isolated from the broth of a NTG-induced mutation strain of Streptomyces avermitilis AVE-H39. The structures of 1 and 2 were determined based on MS and extensive NMR analysis. Compounds 1 and 2 possessed moderate nematocidal activity.

In the course of searching for bioactive components from a Vietnamese spice, the fruits of Amomum aromaticum, a new bicyclic nonane (1) and seven known compounds including 4 monoterpenes (2, 3, 5, 6), one fatty acid (4), and two steroids (7-8) were isolated. Their structures were determined on the basis of spectroscopic analysis. This is the first report of compounds tsaokoin (2), 1β,2α-dihydroxy-p-menth-5-ene (3), oleic acid (4), β-sitosterol (7), and daucosterol (8) in A. aromaticum. To evaluate the anti-inflammatory activities of the isolates, we measured their inhibitory activity against lipopolysaccharide-induced nitric oxide production in a RAW264.7 murine macrophage model. The new compound rel-(1S,5R,6S)-5-methoxybicyclo[4.3.0]non-2-ene-2-carbaldehyde (1) and tsaokoin (2) showed substantial anti-inflammatory effects, with IC50 values of 17.78 and 6.31 µM, respectively. Thus, A. aromaticum fruits could be a rich source for the discovery of anti-inflammatory agents.

A new neoflavonoid, (1R,8R,9R)-pterolinuse K (1) and six known neoflavonoids (2-7) were obtained from the heartwood of Dalbergia melanoxylon. The structure of the new neoflavonoid was elucidated by extensive NMR investigation, and X-ray crystallographic analysis. Compounds 3 and 6 showed anti-inflammatory activity with IC50 values 23.14 ± 0.30 and 19.46 ± 1.02 μΜ, respectively. Compounds 2, 3, 4, 6, 7 were showed cytotoxicity on Caco-2, MDA-MB-468, MDA-MB-231, CT26 cell lines. Moreover, compounds 2, 4 exhibited the significant activity in MDA-MB-231 cell lines with IC50 values 7.54 ± 1.50 and 7.23 ± 0.40 μΜ, respectively.

Essential oils from renewable plant sources are important considerations for environmentally benign botanical pesticides. In this work, the leaf essential oils of four species of Vitex (Lamiaceae) have been collected from north-central Vietnam, analyzed by gas chromatographic techniques, and screened for mosquito larvicidal activity and molluscicidal activity. Vitex ajugifolia and V. pinnata essential oils were dominated by sesquiterpenoids (97.8% and 95.8%, respectively). In contrast, however, the essential oils of V. trifolia subsp. litoralis showed monoterpenoids to be dominant. The essential oils of V. trifolia subsp. trifolia also showed abundant monoterpenoids (38.4% and 68.0%), but also included (E)-β-caryophyllene (15.8 and 14.5%). Vitex pinnata essential oil showed excellent larvicidal activity against Aedes aegypti and Culex quinquefasciatus. Both V. trifolia litoralis and V. trifolia trifolia demonstrated notable molluscicidal activities against Gyraulus convexiusculus and Pomacea canaliculata. The research results suggest that essential oils of Vitex species might have potential to be used as natural pesticides.

Two humulene derivatives (asteriscunolides A (1) and C (2)) were isolated from the methanolic extract of the whole plant of Asteriscus hierochunticus. Their structures were characterized by IR, 1D, and 2D NMR and HRESIMS data analysis, in addition to comparison with literature. Compounds 1 and 2 exhibited excellent in vitro antileishmanial activities against Leishmania donovani promastigotes with IC50 values of 8.38 and 3.26 µg/mL and against Leishmania donovani axenic amastigotes with IC50 values of 9.41 and 4.69 µg/mL, respectively while Pentamidine (the standard drug) exhibited IC50 values of 4.40 and 29.36, respectively. The isolated compounds possessed good activities against Plasmodium falciparum (D6) and (W2) strains with IC50 values ranging from 3.134 - 4.153 µg/mL. Furthermore, 1 and 2 showed no cytotoxic activity against the transformed human monocytic (THP1) cells. The chemical structures of 1 and 2 showed the essential pharmacophoric features of tubulin inhibitors that act through the colchicine binding site. Accordingly, molecular docking studies against the colchicine binding site of Leishmania tubulin have been preceded. Compounds 1 and 2 showed excellent binding mode with free energies of -5.62 and -5.54 kcal/mol, respectively. Further in silico studies were carried out and expected that 1 and 2 have the likeness to be drugs through exhibiting good ADMET results, no significant affinity against CYP3A4, and general low toxicity.

In this present study, Rosmarinus officinalis L. essential oil, and its major component 1,8-cineole was evaluated in vitro for angiotensin converting enzyme 2 (ACE2), as well as for 5-lipoxygenase (5-LOX) enzyme inhibitory activity. The essential oil composition was confirmed both by GC-FID and GC/MS, where 1,8-cineole (62.7%), α-pinene (12.6 %), and camphor (8.3 %) were identified as the main constituents. Activity studies were performed at concentrations of 20 µg/mL for essential oil, and 5 µg/mL for the major compound 1,8-cineole, which were compared experimentally with standards. The essential oil was evaluated using a fluorometric multiplate based enzyme inhibition kit, where the ACE2 inhibition of Rosmarinus aetheroleum was 20%, while the 5-LOX inhibition was observed as 81.1%, respectively. In addition, the major constituent 1,8-cineole also showed remarkable ACE2 inhibition with 89.2%, and 5-LOX inhibition with 37.2%, respectively. As a result, the cineole chemotype rosemary essential oil, and its major constituent 1,8-cineol may have antiviral potential applications against coronaviruses due to ACE2 enzyme inhibition with anti-inflammatory effects. Further in vivo studies are needed to confirm the efficacy of essential oils and their constituents.

Bioassay-guided led to the isolation of five compounds, including a new picrotoxane-type sesquiterpene lactone, aduncin C (1), together with four known ones (2-5) from Dendrobium huoshanense. Their structures were elucidated by means of extensive spectroscopic analysis. Biological evaluation of the isolates against four human cancer cell lines indicated broad-spectrum and cytotoxic activities with IC50 values ranging from 4.08 to 26.75 μM. Among them, α-dihydropicrotoxinin (3) exhibited significant cell proliferation inhibitory activity, especially for HL-60 (IC50 5.81 μM), MCF- 7 (IC50 6.49 μM), SW-480 (IC50 6.80 μM), respectively.

This study investigates the activation of human immune cells (T, B, and NK cells, and granulocytes) by the ethanolic and aqueous extracts of Scutellaria baicalensis root (SBR) and to identify the compounds responsible for such an effect. The cell activation was determined by expression of the cell surface glycoprotein CD69 (cluster of differentiation 69), as measured by flow cytometry. The content of the main flavonoids in SBR extracts was estimated by high performance liquid chromatography with a diode array detector. NK cells were substantially activated by the SBR ethanolic extract (25–200 µg/mL), whereas B cells were activated on a lower scale. NK cells were slightly activated by the SBR aqueous extract (100–200 µg/mL). Wogonoside and baicalin, two major flavonoids present in the SBR extracts, exhibited the highest activation effect on NK cells. The content of baicalin, wogonoside, and baicalein accounted for 201.2, 47.7, and 3.4 mg/g in the ethanolic extract; and for 150.4, 33.6, and 4.6 mg/g in the aqueous extract, respectively. This study shows the immune-stimulating properties of SBR extracts and identifies their active compounds. This data may support the potential utilization of SBR for strengthening the human immune system against bacterial and viral infections.

The aim of the present study was to evaluate the variations in the phytochemical compositions and the antimicrobial activities of Syzygium grande and Oenanthe javanica leaf extracts against Bacillus sp. The antibacterial activity of the methanol, 70% methanol, ethyl acetate, and hexane extracts of both plant species were examined in vitro, against various Bacillus species. In addition, the 1H Nuclear Magnetic Resonance (1H NMR) spectroscopy-based metabolomics was employed to gain insights into the correlations between the chemical constituents of the bioactive extract to the biological activity. The hexane extract of S. grande leaves and methanolic extract of O. javanica leaves showed more potent anti-Bacillus activity, among the test extracts. Principal component analysis (PCA) successfully differentiated the extracts on the basis of their metabolite profiles.  The results of the Partial Least Square (PLS) analysis showed that the non-polar compounds of the hexane extract of S. grande (alanine, betulin, β-sitosterol, β-caryophyllene, acetic acid and 3-hydroxybutyric acid) were strongly correlated to its anti-Bacillus activity. On the other hand, choline, ellagic acid, and gallic acid, the metabolites present in the methanolic extract of O. javanica, were strongly correlated to its anti-Bacillus activity.  On this basis, it was therefore concluded that these conmpounds could be the potential bioactive constituents, contributing to the anti-Bacillus activity of the individual plant species.  Further in-depth investigations into the potential utilization of the two plants for useful applications in managing and control of Bacillus sp., will help pave the way towards their valorization.

Mosquitoes are vectors of numerous pathogenic viruses and freshwater snails are intermediate hosts for several parasitic worms. There is a need for environmentally-benign botanical pesticides to augment or replace synthetic pesticides. In this research, essential oils from the leaves, stems, rhizomes, and roots of Alpinia galanga, an important Vietnamese medicinal plant, have been obtained by hydrodistillation and analyzed by gas chromatographic techniques. The essential oils were screened for mosquito larvicidal activity against Aedes aegypti and Culex quinquefasciatus, for molluscicidal activity against Gyraulus convexiusculus and Pomacea canaliculata, and for inhibition of acetylcholinesterase (AChE). The essential oils showed moderate to good pesticidal activities against these organisms. However, the oils also showed pronounced lethality to a non-target water bug, Diplonychus rusticus.

This study we aimed to characterize the chemical and biological properties of the edible plant, Clausena harmandiana (Pierre) Guillaumin. Fresh leaves of this plant were hydrodistilled to obtain the essential oil, which was characterized by GC-MS. Total phenolic content was evaluated by Folin-Ciocalteau assay. Biological activity was assessed by measuring antioxidants, antimicrobial activities, and the inhibitory effects on tyrosinase, collagenase, and a-glucosidase. The primary components were trans-anethole (91.44%), followed by estragole (2.98%) and cis-anethole (2.55%). The essential oil contained the amount of phenolic 20.63 mg GAE/g extract and showed the activity to scavenge DPPH (IC50 18.48 mg/mL), ABTS (IC50 3.97 mg/mL) radicals and also presented the ability to reduce Fe3+-TPTZ complex on FRAP assay (3.74 mg TEAC/g extract). Additionally, the C. harmandiana essential oil exhibited antimicrobial activity against Candida albicans (MIC 6.63 mg/ml, MFC 13.25 mg/mL) and interestingly presented enzymatic inhibitory effects on collagenase (IC50 0.059 mg/mL) and a-glucosidase (IC50 0.677 mg/mL). The remarkable activity of inhibition on a-glucosidase was two times more to acarbose (IC50 1.26 mg/mL).

A new isoflavonoid glycoside, achyranthoside C (1), along with two known compounds (2 and 3) were isolated from the rhizomes of Achyranthes bidentata. Compounds 1-2 were two rare natural isoflavonoid glycosides with C8 hydroxymethylene derivatization. Their structures were elucidated through comprehensive 1D and 2D NMR, UV, IR, and HRMS analyses. Bioassay results showed all the three compounds had obviously cell-protective effects against H2O2-induced H9c2 cardiomyocytes injury in a concentration -dependent manner.