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Journal: Natural product research


These are the days when one would go online first seeking home remedies before seeing a doctor. Apple cider vinegar (ACV) is one such popular yet scientifically under-validated remedy. Our results prove the unequivocal antimicrobial activity of ACV to be true at full strength concentrations. However, the activity cannot be generalised because although strong antibacterial activity was observed at 25% concentrations, in terms of antifungal activity, yeasts, especially Candida were found to be less susceptible. The antimicrobial/antioxidant properties are ascertained to the total phenolic contents of ACV, as confirmed by our characterisation of the bioactive compounds and antioxidant activity. When checking for its cytotoxicity, ACV exhibited toxicity even at concentrations as low as 0.7%. These results indicate that there is no question of generalising the idea of ACV usage, instead more in vitro and in vivo validations are necessary in order to precisely weigh the pros and cons of ACV.

Concepts: Apple cider, Fermentation, Toxicity, In vivo, In vitro, Apple, Vinegar, Cider


A novel phenanthrenoid symmetrical dimer 8,8'-bidehydrojuncusol [1,1',6,6'-tetramethyl-5,5'-divinyl-8,8'-biphenanthrene-2,2',7,7'-tetraol], a related phenanthrenoid monomer, a phenolic chromone, and five flavonoids derivatives have been isolated from the halophyte Juncus acutus L., Juncaceae. The structure of the dimeric phenanthrenoid was determined on the basis of spectroscopic analyses, including 2D NMR spectroscopy, and by spectral correlations. The new dimer and the other isolated compounds bearing four phenolic hydroxy groups showed the significant in vitro antioxidant activity comparable with that of ascorbic acid using 2,2'-azino-bis[3-ethylbenzothiazoline-6-sulphonate] (ABTS) radical cation decolourisation assay. On the basis of the results from an in vitro anti-inflammatory assay using lipopolysaccharide-stimulated RAW264.7 macrophage cells linked with immunoblot analysis, it was found that dimerisation of dehydrojuncusol [1,6-dimethyl-5-vinyl-8-phenanthrene-2,7-diol] molecule nearly nullified its inhibitory effect on the expression of the pro-inflammatory inducible nitric oxide synthase (iNOS) protein.

Concepts: Vitamin C, Monomer, Juncus acutus, Nitric oxide synthase, Dimer, Radical, Antioxidant, Nitric oxide


Profound research has been done on the medicinal value of Brassica nigra (BN) seeds, and the leaves of the plant have been investigated in this study. The methanol extracts of the leaves were subjected to several in vitro studies. The antioxidant activity of methanol extract was demonstrated with a wide range of concentration, 10-500 µg mL(-1), and the antioxidant activity increased with the increase in concentration. Total phenol content was found to be 171.73 ± 5.043 gallic acid equivalents and the total flavonoid content 7.45 ± 0.0945 quercetin equivalents. Further quantification and identification of the compounds were done by HPTLC and GC-MS analyses. The predominant phenolic compounds determined by HPTLC were gallic acid, followed by quercetin, ferulic acid, caffeic acid and rutin. The free radical quenching property of BN leaf extract suggests the presence of bioactive natural compounds.

Concepts: Ferulic acid, Caffeic acid, Catechin, Phenols, Vanillin, Gallic acid, Quercetin, Resveratrol


The antioxidant properties of extracts of Sybaris liquorice roots have been assessed using 2,2'-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity assay. The extracts, obtained by Soxhlet extraction (Et(2)O, AcOEt, MeOH and BuOH) of the yellow (inner part) and brown (cortex) root powders ensuing from decortication of the raw dry roots, followed by separation and powderisation, were analysed for their scavenging activity by evaluating the colourimetric decrease in the absorbance of DPPH. The highest antioxidant activity (98.39 ± 0.56%) was observed in the case of the Et(2)O extract of the brown powder, at a concentration of 3.33 mg mL(-1). Moreover, the total phenolic content of the extracts was determined using the Folin-Ciocalteu reagent and expressed as milligram gallic acid equivalent per gram of dry extract. Our results show that the Et(2)O extract of the liquorice root cortex could be used as an attractive natural source of antioxidant additives for food, cosmetic or pharmaceutical applications.

Concepts: Propyl gallate, Polyphenol antioxidant, Tannin, Lowry protein assay, Analytical chemistry, Gallic acid, Antioxidant, Root


Investigation of the 95% EtOH extract of red yeast rice fermented with the pink mutant of the fungus Monascus purpureus BCRC 38108 led to the isolation of three new azaphilone derivatives, namely monascusazaphilones A-C (1-3), together with two known compounds. Compounds 1-3 were isolated from this species for the first time. Their structures were elucidated by 1-D and 2-D nuclear magnetic resonance spectroscopy together with HR-ESI-MS analysis and comparison of the spectroscopic data with those reported in the literatures. All isolates were evaluated for their inhibitory effects on nitric oxide (NO) production by macrophages. Among the isolates, compound 1 demonstrated stronger inhibition on NO production.

Concepts: Ethanol, Carbon dioxide, Spectroscopy, Magnetic resonance imaging, In vivo magnetic resonance spectroscopy, Nuclear magnetic resonance, Red yeast rice, Monascus purpureus


Cinnamomum tamala Nees and Eberm (tejpat) and Pimenta dioica (L.) Merr (pimento) leaves are commonly used for flavouring food and widely used in pharmaceutical preparations because of their hypoglycemic, carminative and stimulant properties. In this study, we compared the chemical composition and antioxidant activities of tejpat and pimento essential oils by employing various in vitro methods. GC and GC-MS analyses were done to find out the chemical composition, and the main constituent identified in tejpat and pimento leaf oils was eugenol. Both the oils showed significant radical scavenging activity against DPPH and superoxide radicals with a potent metal chelating activity and were compared with that of standard compound, eugenol. Among the two oils, tejpat oil showed better activity in terms of antioxidative potential.

Concepts: Cinnamomum, Malabathrum, Oils, Allspice, Oil, Bay leaf, Essential oil, Cinnamon


Phoradendron brachystachyum is a hemiparasitic plant widely distributed in México that belongs to the Viscaceae family. It has been commonly used in folk medicine as a substitute for the European mistletoe. In this chemical study, morolic acid was isolated as the major component (47.54% of the total composition of acetone extract) of this plant. In addition, 19 known compounds were identified: β-sitosteryl and stigmasteryl linoleates, β-sitosterol, stigmasterol, triacontanol, squalene, α- and β-amyrin, lupeol, lupenone, betulin aldehyde, betulon aldehyde, oleanolic aldehyde, betulinic acid, betulonic acid, moronic acid, morolic acid, oleanolic acid, flavonoids acacetin and acacetin 7-methyl ether. There have been no previous reports in the literature on the chemical composition of this potential natural source of hypoglycaemic and antihypertensive compounds.

Concepts: Viscaceae, Santalaceae, Phoradendron, Medicinal triterpenes, Oleanolic acid, Terpenes and terpenoids, Mistletoe, Betulinic acid


When cultures of Serratia marcescens, an enterobacteria isolated from the microflora associated with banana plantations incubated at 27°C in a yeast-calcium carbonate-dextrose solid medium (10 g of yeast extract, 20 g dextrose, 15 g bacteriological agar, 20 g calcium carbonate and 1000 mL distilled water) were extracted with chloroform and purified by column chromatography, we obtained a new colourless bacterial metabolite which according to spectroscopic data proved to be serratin.

Concepts: Microbiology, Enterobacteriaceae, Oxygen, Bacteriology, Gut flora, Ethanol, Serratia, Serratia marcescens


This work deals with optimisation of adventitious root suspension culture of Withania somnifera (L.) Dunal (Solanaceae) for the production of biomass and withanolide A and we investigated the effect of carbon source and the initial medium pH on growth and production of withanolide A in adventitious root cultures of Withania somnifera. A 2% sucrose concentration was found to be best for both biomass (113.58 g L(-1) fresh weight (FW) and 11.33 g L(-1) dry weight (DW)) and secondary metabolite accumulation (8.93 mg g(-1) DW) in the tested range of concentration (1-8%). The biomass of adventitious roots was optimal when the initial medium pH was 5.8 (113.26 g L(-1) FW and 11.33 g L(-1) DW) but the withanolide A production was highest at the medium pH level of 5.5 (9.09 mg g(-1) DW).

Concepts: Culture, Optimization, The Medium, Carbon dioxide, Withania, Withania somnifera, Carbon


Salvia officinalis (Common sage, Culinary sage) is an aromatic plant that is frequently used as a spice in Mediterranean cookery and in the food industry and as a traditional medicine for the treatment of several infectious diseases. The essential oils were obtained by two different methods [hydrodistillation (HD) and microwave (Mw)] from the aerial part of S. officinalis L. growing wild in Ourika - Marrakech in Morocco. Ourika is a large zone of the Atlas Mountains which is considered as a large reserve of Flora, especially medicinal and aromatic plants. The obtained oils were analysed by gas chromatography and gas chromatography-mass spectrometry and compared with that of Tunisia. Thirty-six compounds were identified from the Mw-extracted oil which accounted for 97.32% of the total oil composition. However, 33 compounds obtained by HD representing 98.67%. The major components were trans-thujone (14.10% and 29.84%), 1,8-cineole (5.10% and 16.82%), camphor (4.99% and 9.14%), viridiflorol (16.42% and 9.92%), β-caryophyllene (19.83% and 5.20%) and α-humulene (13.54% and 4.02%). Antibacterial, allelopathic (% germination in lettuce seeds and inhibited root growth obtained after treatment with S. officinalis oils) and antioxidant (IC(50) values 22 mg/mL) activities were studied.

Concepts: Morocco, Oils, Salvia fruticosa, Salvia, Plant, Oil, Salvia officinalis, Essential oil